American Botanical Council Publishes Online Version of The Identification of Medicinal Plants Book

Online access to identification book provides new quality control resource for herb industry

AUSTIN, Texas (October 19, 2017) — The American Botanical Council (ABC) announces a new benefit for its members around the world: the online publication of The Identification of Medicinal Plants: A Handbook of the Morphology of Botanicals in Commerce, a manual that addresses the macroscopic assessment of 124 medicinal plants used in North America and Europe.

The book was originally co-published in 2006 by ABC with the Missouri Botanical Garden in St. Louis. It was written by Wendy Applequist, PhD, associate curator at the Missouri Botanical Garden’s William L. Brown Center, and illustrated with botanically accurate black-and-white line drawings by artist Barbara Alongi.

Accurate identification of the correct genus and species of botanical raw materials is the first step in quality control of botanical preparations. While several methods of identification are addressed in the introduction — including macroscopic taxonomic identification, microscopy of plant cells, chemical analysis of plant constituents, and molecular analysis of the plant’s DNA — it is Applequist’s opinion that macroscopic analysis of whole plants and plant parts (when possible) is often a preferred method of species identification because it is quick and relatively inexpensive.

The drawings by Alongi emphasize various morphological features of plant parts to aid in the identification process. In some cases (e.g., to estimate the actual size of a plant part, or to illustrate small details), such drawings can be more useful than actual photographs.

“ABC is pleased to be able to make this important book available to its members, particularly those in academic analytical research and in the herb industry,” noted ABC Founder and Executive Director Mark Blumenthal. “Because many botanical raw materials used in the current herb industry are either cut plant parts (e.g., for use as teas) or powders (to be made into capsules or tablets), many companies never receive and process whole plants or whole plant parts. In such cases, microscopy, chemical analysis, and/or genetic (DNA) testing are required analytical methods. But for growers, wildcrafters, collectors, processors, and others who deal with whole plants and their whole parts, this manual is a highly valuable quality control resource.”

Part 1 of the text provides a succinct discussion of the main morphological features of medicinal plants; practical plant identification, including necessary tools and how to deal with dried plant materials; botanical nomenclature and its importance in the identification process; and a description of the format of the botanical entries included in the book.

Part 2 provides a detailed macroscopic description of each of the 124 plants included. Ordered alphabetically by Latin binomial, each entry includes the standardized common name per the American Herbal Products Association’s Herbs of Commerce, 2nd edition, other common names, family, a brief taxonomic representation, plant parts in commerce, a description of the plant and key morphological characteristics, organoleptic characteristics such as taste and odor, information on potential adulteration, references, and botanical illustrations. Each plant entry a downloadable PDF for ease of use.

“Morphological identification of unprocessed botanicals, when it is feasible, is the most rigorous possible form of authentication and the lowest-cost and quickest,” said Applequist. “I hope that ABC’s making this work available online will help to encourage people who work with herbs to develop the skill of old-fashioned botanical identification.”

Stefan Gafner, PhD, ABC’s chief science officer, added: “Macroscopic identification is an essential step in the identification of whole or cut crude herbal materials. Visual inspection not only helps to authenticate the material, but it also enables the detection of excess amounts of foreign matter such as dirt or sand, and improperly handled material that is rotten or filthy. Resources that help with the training and education of analysts in macroscopic analysis are scarce, and, as such, this is a very valuable book and one of the few texts in which information on macroscopic identification of many commercial botanical ingredients is gathered in one place.”

An appendix contains general references, a glossary that defines botanical terms, and illustrations of common leaf and flower characteristics. Finally, an index is included to facilitate easy access to the materials.

The Identification of Medicinal Plants will be available online to ABC members at the Professional level and above effective October 20, 2017. To become an ABC Member or upgrade membership levels, visit ABC’s membership page or call 512-926-4900.


Adulteration of Rhodiola (Rhodiola rosea) Rhizome, Root, and Extracts

By Ezra Bejar, PhD,Roy Upton,b and John H. Cardellina II, PhDc

American Botanical Council, PO Box 144345, Austin, TX 78714
American Herbal Pharmacopoeia, PO Box 66809, Scotts Valley, CA 95067,
cReevesGroup, 1137 Treefern Drive, Virginia Beach, VA 23451*Corresponding author

Keywords: Rhodiola rosea, rhodiola, rhodiola root, rhodiola root extract, arctic root, arctic rose, golden root, adulterant, adulteration, substitution, Rhodiola crenulata, Crassulaceae


Goal: The goal of this bulletin is to provide timely information and/or updates on issues of adulteration, substitution, potential interchangeable use, and mislabeling of Rhodiola rosea rhizome/root, in particular with other species from the genus Rhodiola, e.g., R. crenulata. The bulletin may serve as guidance for quality control personnel, the international herbal products industry, regulators, and extended natural products community in general. It is also intended to summarize the scientific data and analytical methods on the occurrence of species substitution and/or adulteration, the market situation, and economic and safety consequences for the consumer and the industry.

1          General Information 

1.1 Common name for Rhodiola rosea: Rhodiola1

The American Herbal Products Association’s Herbs of Commerce, 2nd edition1 also applies the Standardized Common Name “rhodiola” to R. algida and R. kirilowii. (see section 1.10)


1.2 Other common names:

English: Arctic rose, king’s crown, roseroot, Arctic root, rosewort, snowdown rose, Tibeten rhodiola root1-4

Chinese: Hong jing tian (红景天)1,3,5-8

Danish: Rosenrod

Dutch: Rozewortel

French: Orpin rose, rhodiole, racine arctique, racine d’or

German: Rosenwurz

Italian: Rhodiola, rodiola, radice d’oro, radice ártica

Japanese: Iwa-benkei (イワベンケ)

Mongolian: Yagaan mugez, altan gagnuur9

Norwegian: Rosenrot

RussianRodióla rózovaya (Родиола розовая), zolotoy koren (золотой корень – golden root)

Spanish: Raíz dorada Siberiana, raíz del Ártico, rizoma de Rhodiola

Swedish: Rosenrot

1.3 Accepted Latin binomial: Rhodiola rosea L. 10


1.4 Synonyms: Sedum rhodiola DC., Sedum rosea (L.) Scop., Sedum roseum (L.) Scop. 10

1.5 Common names for Rhodiola crenulata:


English: Bigflower rhodiola root,11 Rhodiola crenulata1


Chinese: Da hua hong jing tian (大花红景天)5-7

1.6 Botanical family: Crassulaceae

1.7 Distribution: Rhodiola rosea is native to boreal areas of Eastern Europe, China, and North America; its range extends from China to Russia, US Northern states, northern Canada, and Alaska. In New England it occurs along the Maine Coast and in southern Vermont. Disjunctive populations extend from the southern Appalachians to North Carolina. Taxonomic lumpers include the genus Rhodiola in a broader concept ofSedum, though most modern floras follow Linnaeus in segregating Rhodiola from Sedum. It is important to be aware that some references to Rhodiola rosea may treat the species as Sedum rosea or Sedum roseum.In the Arctic, plants typically occur in crevices or among patches of moss and other vegetation, often near shores. 9,10 The highest plant densities are found on grassy or rocky slopes on the weather side of coasts (in the north) or mountains (in the south). Depending on the latitude, the plants grow at altitudes from 800–3000 m (2625–9843 ft). In China, Rhodiola rosea grows in the northern to central provinces of Xinjiang, Gansu, Shanxi, Hebei, and Jilin.

Rhodiola crenulata (J.D. Hooker & Thomson) H Ohba is native to the high mountains and plateaus close to the Himalayas of China, Bhutan, Nepal, and the Indian province of Sikkim. In China, R. crenulata is found in the southwestern provinces of Xizang (Tibet), Qinghai, Sichuan, and Yunnan.12,13

1.8 Plant part and form: Rhodiola rosea raw material is sold in the United States in bulk, either in the form of dried rhizome, dried rhizome/root, or standardized extracts of dried rhizome or dried rhizome/root. According to the United States Pharmacopeia (USP), the raw plant material consists of the dried roots and rhizomes of R. rosea L. containing not less than (NLT) 0.3% of the phenylpropanoid glycosides rosarin, rosavin and rosin (these three compounds are also collectively referred to as ‘rosavins’) calculated as rosavin, and NLT 0.08% of salidroside, calculated on a dry weight basis.8 Hydro-alcoholic extracts of R. rosea roots and rhizomes should contain NLT 90.0% and not more than (NMT) 110.0% of the labeled amount of the above-mentioned phenylpropanoid glycosides (rosavins), and NLT 90.0% and NMT 110.0% of the labeled amount of salidroside.7 In Canada, R. rosea is sold as the dried root/rhizome, as an extract (standardized to contain 1-6% rosavins, or 0.8-3% salidroside), or as a tincture.14 Rhodiola rosea is sold in the EU as dried root/rhizome, an herbal tincture or dry extract, (drug:extract ratio 1.5-5:1, extraction solvent 67-70% ethanol, v/v).10

1.9 General use(s): Rhodiola rosea has a long history of use as a medicinal plant, appearing in the body of collected knowledge (materia medica) of many European countries15 and included in several traditional herbal systems in Asia and North America.5,6,14 Between 1748 and 1961, diverse medicinal applications for R. rosea have been reported in the scientific literature of Sweden, Norway, France, Germany, Iceland, and the Soviet Union, principally considered as an adaptogen, or an agent stabilizing physiological processes and promoting homeostasis, with various health-promoting effects.2,15 In Europe it is considered a traditional herbal medicinal product used for temporary relief of stress symptoms, such as fatigue and sensation of weakness.5,16 Uses in the European Union (EU), Australia, and New Zealand include support of cognitive function, such as mental focus and mental stamina, a source of antioxidants, and a source of immune function-enhancing constituents. In North America and Brazil, it is primarily used as an adaptogen, and to improve athletic performance by reducing recovery time after prolonged exercise. 2,14,17-19 In Central Asia, R. rosea was used traditionally as a remedy for the prevention and treatment of cold and flu.2 In Mongolia, R. rosea is traditionally used for fever, lung inflammation, and strengthening of the body, as well as a mouthwash for bad breath. 62

The genus Rhodiola has about 90 species possibly having originated in the mountainous regions of southwest China and the Himalayas. Altogether, over 20 species are used throughout Asia, in some cases interchangeably. Specific uses are given today in traditional Chinese medicine (TCM) to R. crenulata, R. kirilowii, R. quadrifida, R. sacra, and R. yunnanensis; the last four species have been often used as a substitute and even sold as R. crenulata in the Chinese markets.9 Rhodiola crenulata uses include tonification of qi, activation of blood circulation, and unblocking the meridians.11 Other species also mentioned as being used in TCM include R. atuntsuensis, R. algida, R. coccinea, R. himalensis, and R. subopposita. In Tibetan medicine, species such as R. alsia and R. chrysanthemifolia have also been used as a substitute to the more popular R. crenulata.9

According to traditional Chinese medicine expert Subhuti Dharmananda, PhD, of the Institute for Traditional Medicine in Portland, Oregon, the herb entered into some folk applications (local uses, not tied to the theoretical framework of TCM), but it was not an herb commonly recorded in standard Chinese materia medica. Hong jing tian is the Chinese denomination given to the root and rhizome of several Rhodiolaspecies. It is described as an adaptogenic herb that regulates physiological functions, and is believed to have a central stimulant action. Its general tonic actions are similar to those of ginseng (Panax ginseng, Araliaceae) and root and rhizome of Eleutherococcus senticosus (Araliaceae). [email to S. Gafner, May 5, 2017]

1.10 Nomenclature considerations: In the United States, many rhodiola products in the marketplace bear the R. rosea binomial in the nutritional/supplement facts panel listing ingredients on the label. Due to this species-specific statement, any mixing, dilution, substitution, or replacement with other Rhodiolaspecies will lead to a product’s being considered misbranded. Regardless of the law, the interchangeable use of different species within the same genus may create some variations in chemical composition, which could affect quality, safety and efficacy.

The first edition of Herbs of Commerce (1992),20 formerly the basis for standard nomenclature for herbal dietary supplements in the United States and the official document for commercial nomenclature cited in the Code of Federal Regulations (CFR), does not include any Rhodiola species. The second edition of Herbs of Commerce (2000)1 includes R. algida, R. kirilowii, and R. rosea under the standardized common name “rhodiola”, which means these species should be labeled as “rhodiola” or with the correct scientific name. The roots and rhizomes of these species are also assigned the Chinese pinyin name hong jing tian. Rhodiola crenulata is listed separately with the standardized common name of “Rhodiola crenulata” and the Chinese pinyin name da hua hong jing tian. However, the CFR codification was not updated to include this second edition of Herbs of Commerce. In the Pharmacopoeia of the Peoples’ Republic of China (2010 Edition – Part I), the officially accepted species is Rhodiola crenulata and the medicinally used part is the dried root and rhizome. However, the Chinese pharmacopoeia lists hong jing tian rather than da hua hong jing tian as the common name of R. crenulata.

2          Market

2.1 Importance in the trade and market dynamics: The use of R. rosea as an ingredient in dietary supplements is quite extensive. According to the market research company SPINS, sales of R. rosea in the natural channel in the United States have been stable for four consecutive years from 2013-2016 (Table 1). Rhodiola rosea ranked #35 in 2013, and #36 in 2016, with sales in the range of US $2.2-2.5 million in the years 2013-2016. However, in the Mainstream Multi-outlet channel, R. rosea ranked #11 in 2013 with $17.7 million in sales, sliding to #28 in 2016 with $10.1 million in sales. The decrease in the Mainstream Multi-outlet channel is thought to be multifactorial.21

As noted above, the sales data for 2013-2016 (Table 1) indicate a gradual decrease in sales of R. rosea-based products in the United States. Retail pricing for the rhizome is in the range of US $30-100/kg dried rhizome, according to an informal Internet search conducted in September 2016. However, standardized R. rosea extract (3% rosavins/1% salidroside) is sold by suppliers to dietary supplement manufacturers in a price ranging from 80-110 €/kg in the EU and US $70-100/kg, depending on the extract quality. (A. Bily [Naturex] oral communication to E. Bejar, October 5, 2016)

Table 1. Rhodiola Dietary Supplement Sales in the US from 2013-2016

Channel 2013 2014 2015 2016
Rank Sales [US$] Rank Sales [US$] Rank Sales [US$] Rank Sales [US$]
Naturala 35 2,214,255 32 2,561,873 35 2,461,235 36 2,588,730
Mainstream Multi-Outletb 11 17,716,775 17 14,188,978 27 10,624,592 28 10,080,448

aAccording to SPINS (SPINS does not track sales from Whole Foods Market.)
bAccording to SPINS/IRI (The Mainstream Multi-Outlet channel was formerly known as the Food, Drug, and Mass Market channel [FDM], exclusive of possible sales at Walmart, a major retailer in the US and beyond.)
Sources: Smith T, et al.22; T. Smith (American Botanical Council) e-mail to S. Gafner, September 2, 2015 and September 3, 2015. K. Kawa (SPINS) e-mail to S. Gafner, July 11, 2016.

2.2 Supply sources: The largest natural resources for R. rosea are in Russia. The major part of the growing range cannot be exploited due to difficulties in access or sparse populations. Most R. rosea raw material is collected in China by wildcrafters, whose subsistence depends on selling their fresh produce at regional collection sites. Most of the root plant material is gathered in the summertime from a minimum of four-year old plants by digging under the plant, removing most of the rhizome/root and (hopefully) leaving a part of the rhizome/root for the plant to regenerate over the next years. Rhodiola crenulata is often collected for the Chinese market in some regions in China and Mongolia where both species may share ecological niches. Wildcrafters should be able to distinguish R. rosea from R. crenulata easily during the collection season, since R. rosea has yellow flowers with yellow to reddish buds, while R. crenulata flowers are purple.12

The Xinjiang region is one of the most prolific producers of R. rosea with 4-5 collection sites selling about 500 tons of dry rhizomes annually. The dried roots/rhizomes are cleaned, dried, and sold to one of several East China extract manufacturers; most such extracts are sold abroad. Other regions of China, Mongolia, Kazakhstan, Russia, and North America have a more limited supply of R. rosea, and their contribution to the US market is small, except for a few select products. Most Mongolian and Kazakhstani R. rosea end up in the Russian market at a higher price. (A. Bily and C. Pierron [Naturex] oral communication to E. Bejar. September 29, 2016).

Projects for cultivation of R. rosea exist in Denmark, Germany, Canada, Alaska, Bulgaria, Switzerland, and Norway. Production in the latter two countries is small and limited to supply local and regional markets.

2.3 Raw material forms: Dried rhizome/root is sold in whole or powdered form, or after extraction with alcohol-water mixtures and subsequent spray-drying. The extract may contain suitable added substances as carriers. Various lots of extracts are often mixed to meet standardization requirements of the USP monographs.7,8

Because wildcrafters collect the rhizome (with root material) exclusively, and leave parts of the root with the aerial parts of the plant behind to regenerate, it is rare to find adulteration of R. rosea rhizome with aboveground plant parts. However, suppliers from China sell R. rosea aerial plant (herb), flowers, and stems according to their certificates of analysis. The sale of R. rosea herb and flower extracts, correctly labeled as such, is not within the scope of this bulletin.

3          Substitution

3.1 Known substitutes and adulterants: The main concern regarding the authenticity and quality of R. rosea is the admixture of, or substitution with, rhizome/root material from other Rhodiola species. Over 90 Rhodiola species have been documented in the world and in China 73 different Rhodiola species have been reported, mainly in the northwest and southwest regions, such as Tibet and the Sichuan province.19 ManyRhodiola species have similar pinyin names (hong jing tian)23 and are used interchangeably in China and other parts of Asia, including R. crenulata R. heterodontaR. kirilowiiR. quadrifida, and R. semenovii.1,15,19However, R. crenulata is the only species formally accepted in the PPRC.11 Because of the number of imports from Asia, mainly from China, to the United States and to the European herbal supplement industry, R. rosea raw materials are often mixed or interchanged with other Asian species, including R. crenulata, but also other Rhodiola species.19,23 Adulteration with materials other than those from the Rhodiola genus, e.g., with 5-hydroxytryptophan, has been described by Booker et al.,19 but seems to be infrequent.

Herbal medicine experts have expressed contrasting views about the interchangeable use of R. rosea and other Rhodiola species in standard-setting documents and reference textbooks. The European Medicines Agency’s community herbal monograph specifies the use of R. rosea for rhodiola-containing products that are marketed as an herbal drug for temporary relief of symptoms of stress.4,5  Similarly, the highly regarded German textbook Wichtl – Teedrogen und Phytopharmaka24 indicates that rhizomes from other Rhodiola species may appear as adulterants of R. rosea. However, the USP Herbal Medicines Compendiumlists R. crenulata, R. kirilowii, R. sacra, R. sachalinensis, and R. yunnanensis, as confounding materials for R. rosea rhizome.8 This is a more accurate way to characterize the substitution or admixing of related species within a genus. In the United States, by regulatory definition, replacement by, or admixing with a species that is listed under the same common name in the American Herbal Products Association’s Herbs of Commerce, 1st edition,20 is considered substitution, unless the product label notes a particular species in the ”active ingredients” section. Hence, products labeled to contain “rhodiola”, but not specifying a particular species of Rhodiola, may be derived from a number of Rhodiola species (see section 1.1).

3.2 Sources of information supporting substitution of rhodiola and frequency of occurrence: With the use of a rapid resolution liquid chromatography (RRLC, a variation of high-performance liquid chromatography [HPLC]) method, Ma et al. found that approximately one-third of the commercial rhodiola rhizome powder extract samples they tested did not show a consistent RRLC profile and lacked the characteristic peaks of rosarin, rosavin, and rosin present in authentic R. rosea rhizome.25 However, absence of rosavins may not always be indicative of adulteration. If not handled properly, rosavins may be subject to enzymatic degradation and thus not be present in a finished product (Y-C Ma email to S. Gafner, May 26, 2017).

Booker et al. analyzed 39 raw materials of products from different vendors in the United Kingdom (UK) labeled as R. rosea. Most products were sold without any registration (i.e., generally unlicensed food supplements available on the internet or from retail outlets), although the researchers included two Traditional Herbal Medicine products registered under the traditional herbal medicine products directive (THMPD).19 Registration of a product under the THMPD requires the submission of appropriate data supporting the safety of the product (qualitative and quantitative composition, manufacturing process and controls, potential risks to the environment, therapeutic benefits and dosage, contraindications and known adverse reactions, pharmacovigilance data, and packaging information), but does not include the need for preclinical or clinical data. Products were compared to R. rosea crude drug reference material and two bulk powders. The samples were analyzed by 1H-NMR (nuclear magnetic resonance) spectroscopy and high-performance thin-layer chromatography (HPTLC). Results from 1H-NMR were evaluated statistically using principal component analysis (PCA). Rhodiola rosea products registered under the THMPD were confirmed to contain authentic R. rosea, but seven (about 25%) unregistered food supplements labeled as R. roseaproducts were determined to be substituted with various other Rhodiola species, and in one instance adulterated with synthetic 5-hydroxytryptophan (5-HTP). The PCA model used to analyze 1H NMR spectroscopy data appeared to discriminate poorly between dietary supplement products containing R. rosea extracts and those extracts containing R. crenulata or other Rhodiola species when using the entire NMR spectrum, likely due to the presence of excipients. Restricting the 1H NMR spectrum to the aromatic region allowed the distinction among R. rosea and various other Rhodiola species. The HPTLC method detected both admixed/substituted and adulterated samples effectively.19

Several analyses of crude samples of R. crenulata rhizome confirmed that the rhizome does not contain rosavin, but does contain salidroside and other p-tyrosol derivatives, a class of compounds also found in R. rosea.15,26 Salidroside is associated with increase of exercise tolerance.27 Another Rhodiola species, R sachalinensis, was found to contain both rosavin and salidroside, but at lower concentrations than R. rosea;23,29 contrarily, a TLC analysis by Kurkin et al.28 did not find any rosavins in R. sachalinensis.23,29Booker et al. verified the identity of 45 commercial samples (labeled to contain R. rosea [N = 11], R. crenulata [N = 7], R. sachalinensis [N = 4], R. quadrifida [N = 3] or Rhodiola spp. [N = 20]), collected from retailers, local markets, and the internet in China and the United Kingdom, by HPTLC and 1H NMR with subsequent statistical analysis. An analysis of the 11 samples labeled to contain R. rosea indicated that eight (72.7%) contained other Rhodiola species, with four samples containing R. crenulata and one R. serrata23,29 Three of the seven purported R. crenulata samples were also composed of the incorrect species, containing either R. serrata (N = 2) or an unknown material (N = 1).

An unpublished investigation from 2008 by researchers of the University of Ottawa and the Montreal Botanical Garden of the quality of 20 commercial products sold as tablets, capsules, or liquid extracts on the North American market found salidroside (14.4-45.7 mg/g of product) and rosavins (6.1-68.5 mg/g of product) to be present in every sample. The data, obtained using HPLC-UV, suggest that these products contained authentic R. rosea rhizome and root (A. Cuerrier [Montreal Botanical Garden] email to S. Gafner, November 8, 2016).

3.3 Accidental vs intentional substitution: Both intentional and accidental Rhodiola substitution seems to occur during collection based on anecdotal (A. Bily and C.Pierron [Naturex], oral communication to E. Bejar, September 29, 2016) and scientific evidence. 23,29,30 This has been confirmed in a systematic field collection study, which identified several factors contributing to a substitution of Rhodiola species: (1) the lack of genuine raw material, (2) confusion over the (vernacular) Chinese pinyin name of the plant when sourcing from China, and, (3) deliberate substitution during the (collection and) manufacturing of a dietary supplement. 23 In the Altai region, an area in southern Siberia in Russia, there are 24 different species of the genus Rhodiola that could be misclassified as R. rosea by collectors.15

Resource depletion and habitat destruction have led to the disappearance of Rhodiola species in many locations, as most raw materials are wildcrafted and the plant needs several years to regenerate. In some geographical areas, the two most frequently used species, R. crenulata and R. rosea, are becoming vulnerable or at-risk (one source uses the terms “threatened” and “critically endangered” when referring to specific areas),31 making them more expensive to obtain. 23,30,31

Lack of proper collection procedures and the possible interchangeability of Rhodiola species may also contribute to R. rosea and/or R. crenulata being frequently substituted by or accidentally substituted with other Rhodiola species. The fact that most Rhodiola species (in particular, R. rosea and R. crenulata) are morphologically distinct suggests that the lack of raw material definitions and collection guidelines leads collectors to pick or substitute with whatever Rhodiola is locally available. After removal of the aboveground parts, the similarity in the root/rhizome morphology makes it practically impossible to distinguish one species macroscopically from the other and separate them before processing, although they can be distinguished chemically.

Different Rhodiola species, including R. rosea and R. crenulata, can be found on the Chinese market. Often, these are neither sold separately nor well-identified; therefore, there is a high potential of substitution and admixing among these species. While R. crenulata root/rhizome is preferred over R. rosea in TCM, this species is sometimes substituted with R. rosea, R. serrata, or other Rhodiola species. 23,30

The prevalence of R. crenulata on the Chinese market is most likely due to its greater abundance; it is not considered to be a substitute or an adulterant for R. rosea. Overall, the Chinese market is driven by Chinese names, not Latin names, and the Chinese name hong jing tian as an umbrella term generally refers to multiple species of Rhodiola, of which R. crenulata is the most abundant in trade. In China, it is rare for vendors to differentiate the various species, and most vendors have little knowledge about rhodiola because it has a short history of use in TCM and trade. They sell it because it is popular as a general health food item but most vendors know little about it beyond its province of origin, which does not always correlate to the species or morphological form.

As certain Rhodiola species, e.g., R. rosea and R. crenulata, are becoming scarce in the field, other Rhodiola species such as R. fastigiata, R. quadrifida, R. sacra, and R. serrata appear to be replacing them in the market. 32 For example, in a recent analysis of raw material samples purchased from drug stores and hospitals in China, only 40% of the samples labeled to contain R. crenulata were conclusively identified as such, while 40% were replaced with R. serrata, and the remaining samples with other Rhodiola species. 32As demand for the rhizome of R. rosea and R. crenulata increases, so does the cost, creating a greater risk that species substitution will occur.

Although substitution of R. rosea products with R. crenulata is considered the main problem with respect to authenticity of R. rosea species, 19,29 field work data suggest that other species are being implicated. A particular case is R. sachalinensis, a species that has a similar composition to R. rosea, containing rosavins (the marker compounds used to identify R. rosea), as well as salidroside, and is considered by some botanists to be the same species as R. rosea.23,32,33 To complicate matters, different populations of R. sachalinensis may display differences in their high-performance liquid chromatography-ultraviolet detection (HPLC-UV) fingerprints, making accurate species identification based on chemical analysis difficult.32However, substitution with R. sachalinensis may become less of a concern, since its growing range has decreased significantly and it is now considered to be critically endangered in China.Conversely, as the various species of Rhodiola are used interchangeably within traditional systems, differentiation may be necessary only when claiming to sell a specific species.

3.4 Possible safety issues: According to an assessment report by the European Medicines Agency and a more recent safety review, ingestion of R. rosea is considered safe.4,34 Although no assessments of R. crenulata or other Rhodiola species that might be used as substitutes have been published, there are no apparent health concerns when R. rosea is substituted with other materials from the same genus. There is a report about herb-drug interactions based on the fact that Rhodiola species rhizomes contain various amounts of salidroside. Salidroside has been found to significantly inhibit CYP3A4, which is an important drug-metabolizing enzyme. Although the potential for this interaction is based mostly on in vitro data, one clinical case report suggests this could be of clinical relevance leading to amplification of the effects of drugs with CYP3A4 mediated metabolism.34

3.5 Analytical methods to detect substitution: Roots and rhizomes of R. rosea can be distinguished from roots/rhizomes of R. crenulata and other Rhodiola species by trained experts using botanical, TLC, HPLC, NMR, and genetic methods. The color of the flower allows distinguishing R. rosea from R. crenulataand other purple-flowering species botanically.8,9,12,35 Dried rhizomes of various Rhodiola species, however, cannot be differentiated macroscopically from one another, but can be distinguished by chemical comparisons to authentic reference materials.

One of the approaches to distinguish R. rosea rhizome from other Rhodiola species is the presence/absence of rosavins by TLC. The first TLC method to detect rosavins was reported by Kurkin et al.28 Several other methods have been developed since then, including an HPTLC method with very clear criteria to distinguish R. rosea from other Rhodiola species.23,36,37

Kurkin et al. noted that salidroside was common in the genus Rhodiola, but among 11 Rhodiola species that were tested, only R. rosea contained the rosavins, allowing one to use the presence or absence of these compounds to possibly differentiate among species.28 The lack of rosavins in R. sachalinensis was later refuted by other researchers.23,29 Various HPLC methods have been reported in the literature to distinguish R. rosea chemically from other species. 38-40 The use of rosarin, rosavin, and rosin as marker compounds is critical to ensure identity of R. rosea products. Identification of R. rosea products containing other Rhodiola species may require not only identification of the presence of the rosavins, but also quantification of the amount of each and their ratios. Other methods have been suggested, including NMR-based metabolomics, 23,41 and HPTLC. The suite of methods appears to be helpful in detecting irregularities in commercial R. rosea products.

A DNA barcoding approach to identify Rhodiola species, based on 189 accessions representing 48 of the 55 species of Rhodiola described in the Flora of China,7 has been reported.42 The results suggested that the internal transcribed spacer (ITS) genomic region was best suited for use as a single-locus barcode, resolving 66% of the Rhodiola species. Combining five loci (rbcLmatKtrnH-psbAtrnLF, and ITS) increased the resolution to 81% of the species. However, the DNA method may not be considered adequate when used alone in quality control procedures, since close to 20% of species cannot be distinguished, and also due to the inability to discern the plant part. Various DNA-based approaches have also shown little success in species identification of highly processed botanical ingredients, e.g., extracts.

4          Conclusions

Substitution or mixing of R. rosea root/rhizome raw material and extracts with other species, especially R. crenulata, remains an issue of regulatory concern for manufacturers and marketers of products labeled as R. rosea. Substitution of R. rosea with other Rhodiola species can be detected botanically and through chemical analysis (e.g., HPTLC, HPLC and NMR). The increasing scarcity of wildcrafted R. rosea and R. crenulata, as well as reliance on complex supply chains involving many stakeholders (especially many collectors in diverse regions, particularly in China), is increasing the likelihood for substitution and admixing with other Rhodiola species, particularly R. fastigiata, R. quadrifida, R. sacra, and R. serrata.

5                 References

  1. McGuffin M, Kartesz JT, Leung AY, Tucker AO. American Herbal Products Association’s Herbs of Commerce. 2nd ed. Silver Spring, MD: American Herbal Products Association; 2000.
  2. Brown R, Gerbarg P, Ramazanov Z. Rhodiola rosea – a phytomedicinal overview. HerbalGram. 2002;56:40-52.
  3. Moran RV. Rhodiola rosea. Flora of North America. Vol 8. New York, NY and Oxford, United Kingdom: Flora of North America North of Mexico. 20+ vols.; 1993-2017:167.
  4. Assessment report on Rhodiola rosea L., rhizoma et radix London, United Kingdom: European Medicines Agency Committee on Herbal Medicinal Products (HMPC); 2011:1-32.
  5. Community herbal monograph on Rhodiola rosea L., rhizoma et radix. London, United Kingdom: European Medicines Agency Committee on Herbal Medicinal Products (HMPC); 2012:1-5.
  6. Rhodiola quadrifida Fisch & Mey and Rhodiola rosea L. Medicinal Plants in Mongolia. Geneva, Switzerland: World Health Organization (WHO); 2013:163-172.
  7. Powdered Rhodiola rosea extract. USP 40 – NF 35. Rockville, MD: United States Pharmacopeial Convention; 2017:6809-6810.
  8. Rhodiola roseaUSP 40 – NF 35. Rockville, MD: United States Pharmacopeial Convention; 2017:6805-6807.
  9. Cuerrier A, Tendland Y, Rapinski M. Ethnobotany and conservation of Rhodiola species. In: Cuerrier A, Ampong-Nyarko K, eds. Rhodiola rosea. Boca Raton, FL: CRC Press; 2014.
  10. Rhodiola rosea. Germplasm Resources Information Network [Internet]. United States Department of Agriculture, Agricultural Research Service; 1998. Available at: Accessed May 24, 2017.
  11. Rhodiola crenulataPharmacopoeia of the Peoples Republic of China. Vol 1. Beijing, China: China Medical Science; 2010:376-377.
  12. Rhodiola. In: Wu Y-Z, Raven PH, eds. Flora of China. Vol 8. Beijing, China and St. Louis, MO: Missouri Botanical Garden Press; 2001:251-268.
  13. Bohm BA. The Geography of Phytochemical Races. Dordrecht, Netherlands: Springer Netherlands; 2009.
  14. Rhodiola – Rhodiola rosea. Ottawa, ON, Canada: Natural Health Products Directorate, Health Canada; 2013.
  15. Panossian A, Wikman G, Sarris J. Rosenroot (Rhodiola rosea): traditional use, chemical composition, pharmacology and clinical efficacy. Phytomedicine. 2010;17(7):481-493.
  16. Hartwich M. The importance of immunological studies on Rhodiola rosea in the new effective and safe herbal drug discovery. Centr Eur J Immunol. 2011;35(4).
  17. Rhodiola rosea. Therapeutic Research Faculty; 2007.
  18. Anonymous. Rhodiola rosea. Monograph. Altern Med Rev. 2002;7(5):421-423.
  19. Booker A, Jalil B, Frommenwiler D, et al. The authenticity and quality of Rhodiola rosea products. Phytomedicine. 2016;23(7):754-762.
  20. Moley T, Foster S, Awang D, Hu SY, Kartesz JT, Tucker AO. Herbs of Commerce. 1st ed. Austin, TX: American Herbal Products Association; 1992.
  21. Smith T, Kawa K, Eckl V, Johnson J. Sales of herbal dietary supplement sales in US increased 7.5% in 2015. HerbalGram. 2016;111:67-73.
  22. Smith T, Kawa K, Eckl V. Herbal supplement sales in US increase 7.7% in 2016. HerbalGram. 2017;115:56-65.
  23. Booker A, Zhai L, Gkouva C, Li S, Heinrich M. From traditional resource to global commodities: a comparison of Rhodiola species using NMR spectroscopy-metabolomics and HPTLC. Front Pharmacol. 2016;7:254.
  24. Lichius JJ, Loew D. Rhodiola rhizoma et radix. In: Blaschek W, ed. Wichtl – Teedrogen und Phytopharmaka. 6th ed. Stuttgart, Germany: Wissenschaftliche Verlagsgesellschaft mbH; 2016:554-555.
  25. Ma Y-C, Wang X-Q, Hou F, et al. Rapid resolution liquid chromatography (RRLC) analysis for quality control of Rhodiola rosea roots and commercial standardized products. Nat Prod Commun. 2011;6(5):645-650.
  26. Ma C-Y, Tang J, Wang H-X, Gu X-H, Tao G-J. Simultaneous determination of six active compounds in Rhodiola L. by RP-LC. Chromatographia. 2008;67(5):383-388.
  27. Xu J, Li Y. Effects of salidroside on exhaustive exercise-induced oxidative stress in rats. Mol Med Rep.6(5):1195-1198.
  28. Kurkin VA, Zapesochnaya GG, Shchavlinskii AN, Nukhimovskii EL, Vandyshev VV. Method of analysis of identity and quality of Rhodiola rosea rhizome. Khim Farm Zh. 1985;19(3):185-190.
  29. Booker AJ, Zhai L, Heinrich M. A metabolomic and phytochemical based study of Rhodiola species sourced from Asia and Europe. Planta Med. 2015;81(16):SL3A_03.
  30. Xin T, Li X, Yao H, et al. Survey of commercial Rhodiola products revealed species diversity and potential safety issues. Sci Rep. 2015;5:8337.
  31. Allen D, Bilz M, Leaman DJ, Miller RM, Timoshyna A, Window J. European Red List of Medicinal Plants.Luxembourg, Luxemburg: Publications Office of the European Union; 2014.
  32. Zhao W, Shi X, Li J, Guo W, Liu C, Chen X. Genetic, epigenetic, and HPLC fingerprint differentiation between natural and ex situ populations of Rhodiola sachalinensis from Changbai Mountain, China. PLoS One. 2014;9(11):e112869.
  33. The Plant List. Version 1.1 Available at: Accessed May 19, 2017.
  34. Semple H, Bugiak B. Toxicology and safety of Rhodiola rosea. In: Cuerrier A, Ampong-Nyarko K, eds. Rhodiola rosea. Boca Raton, FL: CRC Press; 2014.
  35. Compositional guideline: Rhodiola rosea dried root (powdered) extract. In: Aging DoHa, ed. Symonston, ACT, Australia: Therapeutic Goods Administration; 2012:1-3.
  36. Rumalla C, Avula B, Ali Z, et al. Quantitative HPTLC analysis of phenylpropanoids in Rhodiola species. J Plan Chromatogr – Modern TLC. 2011;24(2):116-120.
  37. Rhodiola rosea root (Rhodiola rosea). HPTLC Association. Available at: Accessed May 24, 2017.
  38. Ganzera M, Yayla Y, Khan IA. Analysis of the marker compounds of Rhodiola rosea L. (golden root) by reversed phase high performance liquid chromatography. Chem Pharm Bull 2001;49(4):465-467.
  39. Wang Q, Ruan X, Jin Z-h, Yan Q-c, Tu S-j. Identification of Rhodiola species by using RP-HPLC. J Zhejiang Univ Sci B. 2005;6(6):477-482.
  40. Avula B, Wang Y-H, Ali Z, et al. RP-HPLC determination of phenylalkanoids and monoterpenoids in Rhodiola rosea and identification by LC-ESI-TOF. Biomed Chromatogr 2009;23(8):865-872.
  41. Ndjoko Ioset K, Nyberg NT, Van Diermen D, et al. Metabolic profiling of Rhodiola rosea rhizomes by (1)H NMR spectroscopy. Phytochem Anal. 2011;22(2):158-165.
  42. Zhang JQ, Meng SY, Wen J, Rao GY. DNA barcoding of Rhodiola (Crassulaceae): a case study on a group of recently diversified medicinal plants from the Qinghai-Tibetan Plateau. PLoS One. 2015;10(3):e0119921.

Revision Summary

Version # , Author Date Revised Section Revised List of Changes
Version 1, E. Bejar, R. Upton, J.H. Cardellina II n/a n/a none

Rooibos Tea: Research into Antioxidant and Antimutagenic Properties

Antioxidants are hot topics in the health news these days, and a herbal tea called rooibos (pronounced ROY-boss) is becoming popular partly because it is being marketed as a healthy beverage with high levels of antioxidants. The rooibos plant (Aspalathus linearis (Burm. f.) Dahlgren, Fabaceae) is a South African flowering shrub used to make a mild-tasting tea that has no caffeine, very little tannin, and significant amounts of polyphenol antioxidants. Although the tea is new to many Americans, it has been made in the Cedarberg mountain region of South Africa for generations. Distributors are promoting the tea for numerous health benefits, citing recent studies that show some antioxidants found in rooibos tea may protect against cancer, heart disease, and stroke. What’s the evidence for these claims?

A Note on Tea Terminology

In the strict sense, the word tea has been reserved for infusions made from leaves of the evergreen shrub Camellia sinensis (L.) Kuntze, Theaceae, while infusions made from herbs such as rooibos have been called tisanes. Over time, however, the common use of the word tea has been extended to include herbal infusions, and this relaxed usage is followed here. Rooibos is often referred to as red tea because it makes a vibrant red-colored tea, which can be confusing because black tea and hibiscus herbal tea are also sometimes called red tea.

Botanical Description

Rooibos is a shrubby legume that is indigenous to the mountains of South Africa’s Western Cape.1-3 The genus Aspalathus includes more than 200 species native to South Africa.2-5 Alinearis is a polymorphic species; various wild forms have been described, each with characteristic morphology and geographical distribution.1-3 Some forms are prostrate and remain less than 30 cm (1 foot) tall, while other forms grow erect and may reach up to 2 m (about 6 feet) in height.1-3,6 The types of wild rooibos that have been used to make tea are sometimes referred to as the Red, Black, Grey, and Red-Brown types.1,2

The type of A. linearis that is cultivated commercially for tea is the Red type, also known as the Rocklands type;1,6 it is native to the Pakhuis Pass area in the northern Cedarberg region.6 The Rocklands type grows erect, up to 1.5 m (about 5 feet) in height. It has a single basal stem that divides just above the ground surface into multiple thin branches that carry bright green, needle-like leaves of about 10—40 mm (0.4—1.6 inches) in length.7 The plant produces small yellow flowers in spring through early summer,6 and each flower generates a one-seeded leguminous fruit.4,5

Rooibos has adapted to coarse, nutrient-poor, acidic soil and hot, dry summers.4,5,8 In addition to a network of roots just below the soil surface, the plant has a long tap root that reaches as deep as 2 m (about 6 feet) and helps the plant find moisture during summer drought.5 As a legume, rooibos contains nodules of nitrogen-fixing bacteria on its roots; this characteristic helps the plant survive in the poor Cedarberg soils and minimizes the need for fertilizing commercial crops with nitrogen.8 The bacteria convert nitrogen dioxide to biologically useful ammonia in a process known as nitrogen fixation. The plant absorbs the nitrogen and benefits from it in exchange for providing the bacteria with food sources created from photosynthesis.

One study found genetic variations between four morphologically different populations of A. linearis.1 The authors suggest that the wild forms of A. linearis might be used to improve characteristics, such as yield and disease resistance, of the cultivated form. They also observe that because the cultivated Rocklands form is being grown outside of its original Pakhuis Pass location, this introduction of the cultivated form into new areas could threaten the genetic integrity of the wild forms in these areas.

A later study7 showed genetic differences between populations of A. linearis that are sprouters (plants that can resprout from a deep rootstock to regenerate after a fire) and populations that are seeders (plants that rely on producing plentiful seeds to reproduce). The authors suggest that reseeding is the primitive character state in A. linearis and resprouting is a derived state that evolved to help the plant survive in a region prone to wildfires. The rooibos plant that is commercially grown for tea is the seeder type.7

In addition to differences in morphology and genetics, researchers have found differences in chemistry between various populations of A. linearis.6,9 Van Wyk, of the Department of Botany at Rand Afrikaans University, presented results of his tests on the different wild populations of rooibos, showing significant variations in the polyphenol profile by population.9

Historical Background

More than 300 years ago, indigenous inhabitants of the mountainous regions of South Africa’s Western Cape were the first to collect wild rooibos and use it to make tea.10 These people discovered that they could brew a sweet, tasty tea from rooibos leaves and stems that they cut, bruised with wooden hammers, fermented in heaps, and then sun-dried. Botanists first recorded rooibos plants in 1772 when they were introduced to the tea by the Khoi people.10

Rooibos became a cultivated crop by the early 1930s, has been grown commercially since World War II, and now is exported to countries worldwide, including Germany, Japan, the Netherlands, England, Malaysia, South Korea, Poland, China, and the United States.10 In 1999, about 29 percent of South Africa’s total rooibos sales were exported to 31 countries.10 The quantity of rooibos exported in 2000 was two and a half times greater than the quantity exported in 1999, and exports continue to grow.10 The small towns of Clanwilliam and Wupperthal, north of Cape Town in the Cedarberg region, have a long history of rooibos cultivation; these towns are popular tourist stops because of their beautiful rural scenery and their role in the rooibos industry.

Roughly 70 percent of the bulk rooibos that is exported goes through Clanwilliam-based Rooibos Ltd. <>, a partnership of private growers/processors and a cooperative of large and small farmers in the area. The rooibos is sold in a variety of products in Europe, Asia, and, increasingly, America. Other South African companies that market rooibos tea products include Khoisan, Cape Natural Tea Products, and Coetzee & Coetzee. International demand for rooibos has been increasing since trade sanctions against South Africa were lifted following the demise of apartheid in the 1990s. Since 1999, the nonprofit organization Agribusiness in Sustainable Natural African Plant Products (ASNAPP, <>) has helped small farmers in and around Wupperthal to introduce sustainable methods of rooibos cultivation that allow them to compete in the world market. ASNAPP is sponsored by the U.S. Agency for International Development, Rutgers University, and Stellenbosch University. Through Stellenbosch University, ASNAPP also helped the farmers at Wupperthal fund construction of a tea court to process rooibos.

Rutgers University provides a quality control program for ASNAPP’s Wupperthal tea program, evaluating parameters such as color, taste, aroma, pH, moisture content, cleanliness, total phenol content, and antioxidant capability for tea samples collected from the industry in general and from all the growers in the Wupperthal tea program.11 Data from their analyses are made available to the farmers and also to prospective buyers via product specification sheets.

The Perishable Products Export Control Board (PPECB) of South Africa ensures that all exported rooibos products pass a phytosanitary inspection and are certified to be free of bacteria and impurities.4,10 In order to pass these health and safety tests, rooibos producers steam pasteurize the tea as the final step before packing. Organic rooibos is also monitored by various international organizations that provide organic certification, such as the German firms Ecocert and Lacon.

Harvesting and Processing: Fermented and Unfermented Rooibos

When rooibos is cultivated commercially, the needle-like leaves and stems are usually harvested in the summer, which corresponds to January through March in South Africa.4 The plants are cut to about 30 cm (1 foot) from the ground at harvest time and begin another major growth cycle the following spring. The harvested rooibos is processed two different ways, producing two types of tea. The green leaves and stems are either bruised and fermented or immediately dried to prevent oxidation. The traditional fermented tea is processed today in much the same way as the indigenous people processed it hundreds of years ago, including the sun-drying step, but the tools are more sophisticated now.

The fermented type is called red tea because fermentation turns the leaves and the resulting tea a rich orange/red color; this distinctive color led to the Afrikaans name rooibos, which means “red bush.” The unfermented type, often called green rooibos, contains higher levels of polyphenol antioxidants because fermented rooibos loses some antioxidants during the fermentation process. The unfermented type was developed to maximize antioxidant levels in response to recent interest in the health benefits associated with the antioxidants found in C. sinensis teas. Unfermented rooibos tea is a tan/yellow color rather than the rich reddish color of fermented rooibos.

Both types of rooibos tea are available plain or flavored, loose or in tea bags, organic or conventionally grown. Rooibos is graded according to color, flavor, and cut length, with the highest grade labeled “supergrade.” The tea has a smooth, non-bitter flavor that is pleasant hot or chilled. The unfermented variety has a very mild “green” taste reminiscent of green tea but without the astringency; the fermented type is quite different, with a stronger sweet and fruity taste. The mild flavor of rooibos has made it popular in multi-ingredient herbal tea blends.

Antioxidants in Rooibos

Free radicals (unstable molecules that have lost an electron) can damage the DNA in cells, leading to cancer, and they can oxidize cholesterol, leading to clogged blood vessels, heart attack, and stroke. Antioxidants can bind to free radicals before the free radicals cause harm. Some antioxidants are called polyphenols because these substances contain a phenolic ring in their chemical structure. Polyphenols are common in plants; they act as pigments and sunscreens, as insect attractants and repellants, and as antimicrobials and antioxidants.12,13 The polyphenol group is further divided into subgroups such as flavonoids and phenolic acids. Polyphenols can also be classified as monomeric (molecules containing a single unit) or polymeric (larger molecules containing more than one unit). As described in this section, laboratory studies have found that rooibos tea contains polyphenol antioxidants, including flavonoids and phenolic acids, that are potent free radical scavengers.

Flavonoids: The polyphenol antioxidants identified in rooibos tea include the monomeric flavonoids aspalathin, nothofagin, quercetin, rutin, isoquercitrin, orientin, isoorientin, luteolin, vitexin, isovitexin, and chrysoeriol.14-19 Currently, rooibos is the only known natural source of aspalathin.15 Nothofagin is similar in structure to aspalathin and has only been identified in one other natural source besides rooibos: the heartwood of the red beech tree (Nothofagus fusca (Hook F.) Oerst, Nothofagaceae), which is native to New Zealand.20

A recent analysis of fermented rooibos measured the levels of all the flavonoids listed above except nothofagin (see Table 1).19 Of the 10 flavonoids measured, the three that occurred in largest amounts were aspalathin, rutin, and orientin, followed by isoorientin and isoquercitrin. Nothofagin was identified by mass spectrometry but was not quantified because a standard was not available. The amount of nothofagin in fermented and unfermented rooibos was estimated to be about three times less than aspalathin in one study.20 Aspalathin and nothofagin arepresent in relatively large amounts in unfermented rooibos tea,19,20but some of the aspalathin and nothofagin oxidizes to other substancesduring fermentation; thus, fermented rooibos contains less aspalathin and nothofagin than unfermented rooibos.20 The change in polyphenol composition is the reason the tea changes color with fermentation.20

Phenolic Acids: In addition to flavonoid antioxidants, rooibos also contains phenolic acids that have been shown to have antioxidant activity.14,18,21 Like flavonoids, phenolic acids are polyphenol substances that are found in fruits, vegetables, and whole grains. The phenolic acids identified in rooibos tea, in decreasing order of antioxidant activity as measured in one study21 with the commonly used 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, include caffeic acid, protocatechuic acid, syringic acid, ferulic acid, vanillic acid, p-hydroxybenzoic acid, and p-coumaric acid.14,18 Using the DPPH assay, caffeic acid was just as active an antioxidant as the most potent flavonoids tested (quercetin, isoquercitrin, and aspalathin).21

Total Polyphenol Content: Despite some promotional claims, a serving of rooibos tea has less total polyphenols than the same size serving of green or black tea. Serving size varies, but for comparison purposes a 150 to 200 ml serving is often used (about 3/4 of a standard baking measuring cup). Elizabeth Joubert, Ph.D., specialist researcher at South Africa’s ARC Infruitec-Nietvoorbij and a rooibos expert, says that the total polyphenol content of an average 150 to 200 ml serving of rooibos tea can be as much as 60 to 80 mg, depending on factors such as the brewing time and amount of leaves used.22 For comparison, one study found that brewing black tea leaves for 1 to 3 minutes at a concentration of 1 g leaves per 100 ml water resulted in black tea that contains 128 to 199 mg of polyphenols per 200 ml serving of tea.23 The types of polyphenols in rooibos tea are different than those in green and black teas, so the potential health benefits of the teas cannot be compared solely on their total polyphenol content. Rooibos tea does not contain epigallocatechin gallate (EGCG), which is a polyphenol in green tea that has shown anticarcinogenic and antioxidant capabilities, but many of the polyphenols in rooibos tea are also strong antioxidants.

Quercetin and Luteolin: Two of the flavonoids in rooibos tea, quercetin and luteolin, are potent antioxidants found in many fruits and vegetables. Studies in vitro (in the test tube) have shown that these antioxidants can cause cancer cells to “commit suicide,” referred to as apoptosis.24-27 Quercetin decreased primary tumor growth and prevented metastasis in a model of pancreatic cancer.25 Luteolin and quercetin inhibited proliferation of thyroid28 and colon29 cancer cells, respectively, in vitro. Quercetin inhibited cyclooxygenase-2 (COX-2) expression in colon cancer cells, which may help prevent colon cancer.30,31 Both luteolin and quercetin can block the formation of lipid peroxides.32-34

Although studies like these show quercetin and luteolin are strong antioxidants, researchers haven’t yet determined whether enough of either of these two flavonoids are present in rooibos tea and absorbed by the body to have beneficial effects. As shown in Table 1, recent analysis of fermented rooibos found considerably more quercetin than luteolin,19 but even quercetin was present in much lower amounts than aspalathin, orientin, and rutin.

Based on the data in Table 1, a 150 ml serving of fermented rooibos tea made with 2.5 g of tea leaves has about 0.27 mg of quercetin; for comparison, one study found that C. sinensis contains 1.5 to 3.75 mg of quercetin per 150 ml serving of tea.35 A previous study36 found 1.5 mg of quercetin per 150 ml serving of fermented rooibos, but that may be an upper limit. Joubert says that the 1.5 mg estimate is probably high,22 but emphasizes that these estimates will vary with parameters such as the brewing time and the amount of water and tea leaves used. At any rate, the amount of quercetin per serving of rooibos is a small percentage of the total polyphenol content per serving of rooibos.

Aspalathin and Nothofagin: A unique polyphenol that is one of the most abundant monomeric flavonoids in rooibos tea,19,20 aspalathin seems to contribute to the antioxidant capabilities of rooibos,21 but aspalathin is not as well studied as quercetin and luteolin. Nothofagin is similar in structure to aspalathin and may have similar antioxidant capabilities.

Joubert says that chief research technologist Petra Snijman of the Program on Mycotoxins and Experimental Carcinogenesis (PROMEC) at the Medical Research Council of South Africa recently developed a way to isolate pure aspalathin and nothofagin from rooibos. Joubert says, “According to unpublished in vitro studies done at ARC Infruitec-Nietvoorbij, aspalathin compared well with quercetin in terms of antioxidant activity, except in a fat medium where quercetin demonstrated much higher potency than aspalathin. What is important in these comparative studies is the test environment. Relative efficacy will depend on the test system used (the polarity of the medium, the type of free radical that needs to be scavenged, etc.).”22

Joubert co-authored a study21 that found aspalathin compared well to other antioxidants with the DPPH radical scavenging assay. The study measured the antioxidant capability of many of the flavonoids and phenolic acids found in rooibos tea and compared them to several reference standards such as alpha-tocopherol (vitamin E). The percent inhibition of the DPPH radical by quercetin, isoquercitrin, aspalathin, rutin, luteolin, and alpha-tocopherol was 98.27, 91.99, 91.74, 91.18, 90.85, and 75.10, respectively (using a 0.25 mole ratio of antioxidant to DPPH). All of the flavonoids tested showed potent hydrogen donating abilities with DPPH except for vitexin, which only had a 7.26 percent inhibition even at a 0.5 mole ratio to DPPH.

According to the data in Table 1, a 150 ml serving of fermented rooibos made with 2.5 g of tea leaves has about 3 mg of aspalathin; since the amount of nothofagin was measured to be three times less than aspalathin in one study,20 a 150 ml serving of fermented rooibos has on the order of 1 mg of nothofagin. A serving of unfermented rooibos has considerably more aspalathin and nothofagin than an equal serving of fermented rooibos because a portion of these flavonoids oxidizes to other substances during fermentation.20

Orientin and Rutin: Orientin and rutin are two of the other most abundant monomeric flavonoids in rooibos,19 and both have been associated with health benefits. Orientin is a potent free radical scavenger. It reduced by half the number of cancer-associated changes in cells of human blood exposed to radiation.38When mice were exposed to radiation, orientin protected against lipid peroxidation in the liver and also reduced damage to the bone marrow and gastrointestinal tract.39,40 Rutin, a flavonoid found in buckwheat (Fagopyrum esculentum Moench, Polygonaceae) and some fruits and vegetables, seems to help maintain the strength of capillary walls; oral rutin as well as oral and topical o-(beta-Hydroxylethyl)-rutoside (HR) have been used to treat hemorrhoids, varicose veins, and the lower leg edema associated with venous insufficiency and venous hypertension.41-46 According to the data in Table 1, a 150 ml serving of fermented rooibos tea made with 2.5 g of tea leaves has about 2.5 mg of orientin and 3.2 mg of rutin.

Total Antioxidant Capability: Although the 10 flavonoids in Table 1 are important because they are known to have antioxidant properties, they only represent a small percentage of the total polyphenol content of a serving of fermented rooibos tea. A 150 to 200 ml serving of rooibos can have up to 60 to 80 mg of total polyphenols,22 and Table 1 shows that a 150 ml serving of fermented rooibos made with 2.5 g of leaves has about 14 mg of the 10 flavonoids in the table. Many other polyphenols are present, but they have not all been identified or quantified.

To assess the antioxidant capability of rooibos tea as a whole, researchers compared the antioxidant activity of rooibos tea extracts to that of green and black tea extracts with the DPPH radical scavenging assay as well as the beta-carotene bleaching method.47 All the teas showed strong antioxidant activity with both methods. Using the DPPH method, the ranking from highest to lowest antioxidant activity was green tea (90.8 percent inhibition), unfermented rooibos (86.6 percent), fermented rooibos (83.4 percent), and black tea (81.7 percent). Green tea was significantly higher than the others (< 0.05), but the other three teas did not differ from each other significantly with respect to DPPH inhibition. Using the beta-carotene bleaching method, the ranking was green tea, black tea, fermented rooibos, and unfermented rooibos. The relative ranking varies with the type of test because the substance to be tested will have different reactivity to the different oxidizing agents used. These tests only measure the antioxidant capability of substances outside of the body and don’t provide data on whether the antioxidants are absorbed by the body and effective after the food is consumed.

In this study, all the tea extracts were diluted to the same amount of soluble solids rather than to the amounts of solids found in the teas.47 This method allows a comparison of antioxidant capability on a mass equivalent basis, but does not reflect a comparison of the antioxidant strength of equal volume servings of the teas. Although the soluble solid content varies with the method of tea preparation, it usually decreases in the order green tea, black tea, unfermented rooibos, fermented rooibos.47 The percent of soluble solids represented by polyphenols is similar for the four teas and the DPPH antioxidant activity is similar on a mass equivalent basis, so the DPPH antioxidant capability of equal-sized servings will decrease in the order of the soluble solid content.47 Black and green teas have over twice as much soluble solids as rooibos tea when prepared conventionally, so over two 200 ml servings of rooibos tea would need to be consumed to receive the same antioxidant benefit (as measured by DPPH) as one 200 ml serving of black or green tea (or the rooibos would need to be brewed to twice the standard concentration).47 This result agrees with the data given previously for 60 to 80 mg polyphenols for a 150 to 200 ml serving of rooibos tea22 as compared to 128 to 199 mg polyphenols for a 200 ml serving of black tea.23

The studies referenced above show that rooibos tea contains antioxidants that have positive effects when tested as isolated substances and that the tea as a whole has good antioxidant activity in vitro. So, do all these antioxidants in rooibos tea lead to health benefits for tea drinkers?

Rooibos Research in Live Animals and Animal Cells

Laboratory studies have demonstrated potential health benefits of rooibos in vitro (in test tubes) and in vivo (in live animals), but human studies have not been conducted. Much more research is needed, but the studies so far look intriguing.

Fermented Rooibos against Mutagens: Researchers found that fermented rooibos tea reduced cancer-associated changes in animal cells induced by the mutagens benzo[a]pyrene (B(a)P) and mitomycin C (MMC) both in vitro and in vivo.48 The in vitro part of the study measured chromosomal aberrations in animal cells caused by exposure to the mutagens. The cells were treated with tea extract either at the same time as the mutagen or after the mutagen. Some of the tests used rat liver microsomal enzyme, called S9, to provide metabolic activation of the mutagen; B(a)P requires metabolic activation, but MMC can act with or without it.

Both green tea and rooibos tea suppressed aberrant cells caused by B(a)P and MMC in the presence of S9, but rooibos showed a greater suppression of aberrant cells than did green tea (see Table 2). In fact, when the cells were exposed to B(a)P and S9 simultaneously with rooibos tea, the highest concentration of rooibos tea (1000 microgram/ml) completely inhibited the aberrant cells, bringing their percentage down to the level of the controls that were not exposed to any mutagen. Also, rooibos tea suppressed aberrant cells caused by MMC both with and without the presence of S9, but green tea showed no suppression without S9. Treating the cells simultaneously with the mutagen and tea extract caused a greater protective effect than treating the cells with tea extract following exposure to the mutagen (compare Tables 2 and 3).

In the in vivo part of this study, mice were given oral doses of tea and an injection of B(a)P or MMC.48 The researchers measured the frequency of micronucleated reticulocytes (MNRETs), which are cells with damaged DNA that may lead to cancer. In one experiment, a single oral dose of tea (1 ml of 0.2 percent green tea or 0.1 percent rooibos tea) was given 6 hours prior to an injection of MMC and the number of MNRETs was counted at 24, 48, and 72 hours after the MMC. Rooibos tea and green tea provided similar inhibition of the frequency of MNRETs. After 48 hours, rooibos tea reduced the level of MNRETs by about 34 percent, and green tea reduced the level by about 38 percent. When the mice received the single dose of tea either after the mutagen or 24 hours prior to the mutagen, neither green tea nor rooibos tea reduced the frequency of MNRETs.

When the teas were given as one oral dose daily for 28 days and then the mutagen was injected on day 29, both rooibos tea and green tea reduced the frequency of MNRETs caused by B(a)P. Daily doses of 0.2 percent green tea reduced MNRETs by about 62 percent 48 hours after B(a)P exposure, and daily doses of 0.1 percent rooibos tea reduced MNRETs by about 49 percent. Daily doses of 0.1 percent rooibos tea reduced MNRETs by about 34 percent 48 hours after MMC exposure, but daily doses of green tea did not provide a significant reduction with MMC.

Fermented Rooibos against Irradiation: Another research group found that extract of fermented rooibos tea reduced cancerous transformation of mouse cells exposed to x-rays in vitro.49 The amount of protection correlated with the dose of rooibos, and an extract concentration of 10 percent reduced the cell transformations to a level similar to the spontaneous level of the controls. Interestingly, green tea in equivalent concentrations did not show any detectable protective effect. In another study, fermented rooibos tea reduced cell damage in live mice that were exposed to irradiation two hours following a single dose of rooibos administered by gastric intubation.34

Fermented Rooibos against Brain Lipid Peroxidation: Rats given fermented rooibos tea daily ad libitum (free access) from the age of 3 months to 24 months had greatly reduced age-related lipid peroxide accumulation in four areas of their brains compared to rats that drank plain water.50 Increases in lipid peroxides in the brain may damage neuronal cells and contribute to age-related diseases.50 The lipid peroxide levels were evaluated by measuring the amounts of thiobarbituric acid reactive substances (TBARS) in eight regions of the brain. The 24-month-old rats that had been drinking plain water had significantly higher TBARS in the frontal cortex, occipital cortex, hippocampus, and cerebellum compared to 5-week-old rats, but the 24-month-old rats that had been drinking rooibos tea had no increase in TBARS in those four areas of the brain. The TBARS of the 24-month-old rooibos group were similar to the TBARS of the young 5-week-old group (see Table 4).

The authors give a bar chart that summarizes the TBARS data for each area of the brain.50 The TBARS values in nmol/g for 24-month-old rats without rooibos tea, 24-month-old rats given rooibos tea, and 5-week-old rats, respectively, were approximately 120, 80, 80 in the frontal cortex; 115, 70, 80 in the occipital cortex; 80, 40, 50 in the hippocampus; and 115, 80, 85 in the cerebellum. The authors say these results suggest that the administration of rooibos tea protected several regions of the rat brain against lipid peroxidation accompanying aging. Magnetic resonance images taken of the brain were consistent with the TBARS data.

Fermented vs. Unfermented Rooibos:Another study found that both fermented and unfermented rooibos tea exhibits antimutagenic properties in vitro as measured by the Salmonella typhimurium mutagenicity assay with several different mutagens; the antimutagenic activity was stronger against the metabolically activated mutagens 2-acetylaminofluorene (2-AAF) and aflatoxin B1 (AFB1) than it was against three direct-acting mutagens.51 Further research showed that the fermentation process causes a decrease in the antimutagenic and antioxidant activity of rooibos tea as measured by the Salmonella typhimurium mutagenicity assay (with 2-AAF), the hydrogen donating ability (assessed with DPPH), and the superoxide anion radical scavenging assay.52 The researchers suggest that fermented rooibos may show less antioxidant and antimutagenic activity because it has less polyphenols than unfermented rooibos. One analysis showed that polyphenols represent about 41 percent of the total solid matter in unfermented rooibos tea extract, but only about 30 percent of the total solid matter in fermented rooibos tea extract.51

One of the authors of both these studies is senior research scientist Jeanine Marnewick of the Program on Mycotoxins and Experimental Carcinogenesis (PROMEC) at the Medical Research Council of South Africa. She says, “Rooibos showed protective effects against DNA damage when tested in an in vitro assay as well as in an in vivo animal system.” 53 The in vitro studies found unfermented rooibos was generally more protective against DNA damage than fermented rooibos. But Marnewick says her group’s research shows that fermented rooibos has a stronger effect against some mutagens. She says, “Both the fermented and unfermented rooibos showed a significant protection, and we’re busy elucidating the mechanisms.”53 She is currently evaluating the protective effect of rooibos on liver, esophageal, colon, and skin cancer induced in live animal models. The studies are in the early phases and she cautions, “Very little is known about the effect of rooibos on cancer development.” 53

Joubert also adds a cautionary note, saying that many questions about rooibos still need to be answered.22She says that researchers need to determine which of the antioxidant substances in rooibos tea are absorbed by the body and how much tea is needed to produce a measurable benefit. She also emphasizes that no human studies have been conducted yet.

Whole Foods vs. Isolated Antioxidants: The full benefits of teas are likely to come from a combination of all the antioxidants in them rather than from just one substance. Quite a few studies have found that isolated antioxidants don’t have as positive an anticancer effect as the mixture of antioxidants found in natural food sources; whole apple extracts were better than pure quercetin at inhibiting the growth of cancer cells in vitro,13,54 tomato powder was better than pure lycopene at extending the life of rats with prostrate tumors,13,55 and freeze-dried strawberries exhibited better anticancer properties in animals than did pure ellagic acid.13,56 Also, white and green tea extracts demonstrated better antimutagenic propertiesin vitro than mixtures of nine polyphenols found in the teas (mixed according to their relative proportions in the teas).57 Researchers believe these results indicate that other substances in the whole food products besides the identified antioxidants probably contribute to the total anticancer effect of the food, and that the relative amounts of all these substances could be important. Different teas have different mixtures of antioxidants, and they will protect against different mutagens. Sorting out all of these interactions will take time.

Rooibos Folklore: What’s Proven?

Although rooibos does contain active antioxidants, many of the other health claims made for rooibos tea are not well documented (based only on anecdotal evidence) or are not supported by science. Researchers are still investigating many of these claims to evaluate all the potential benefits of rooibos.

Vitamins And Minerals: Despite some promotional claims that rooibos is a source of vitamin C, Joubert says it is not. “We have tested both the traditional rooibos and green rooibos, and vitamin C was not present,” she says.22

With the exceptions of fluoride and copper, the trace amounts of minerals in rooibos are not enough to make the tea a meaningful dietary source of minerals for the average consumer. As shown in Table 5, the nutritional labeling that is given on some packages of rooibos tea and on some websites of distributors4,5indicates that the amounts of iron, potassium, zinc, calcium, and magnesium in a 200 ml serving of rooibos tea are all less than 1 percent of the U.S. reference daily intake (RDI). A 200 ml serving of rooibos provides over 5 percent of the RDI of fluoride for adults and over 7 percent of the RDI for copper (see Table 5). Marc S. Micozzi, M.D., Ph.D., director of the Policy Institute for Integrative Medicine in Bethesda, Maryland, notes that when rooibos is used as a fluid replacement throughout the day, as is done with some athletes in South Africa, it does provide measurable amounts of several minerals and electrolytes.58

Colic, Allergies, And Other Ailments:Distributors of rooibos tea often suggest it can help allergies, sleep problems, digestive problems, headache, and other ailments,4,5but these claims have not been verified by scientific research. If the indigenous people of the Cedarberg region used rooibos tea medicinally, that tradition was lost and rooibos was just enjoyed as a good-tasting beverage until the recent interest in its health benefits.10 Many of the health claims for rooibos tea began in 1968 when a South African woman, Annekie Theron, found that rooibos tea eased her infant’s colic.10 As the story goes, she found no documentation on the benefits of rooibos and began her own experiments with local babies who had colic and allergies.10 She concluded that rooibos helped these babies, and she published a book in 1970 titled Allergies: An Amazing Discovery. Since then, she patented a rooibos extract that is now used in cosmetic products, and she started her own line of health and cosmetic products.10

Today, South African physicians recommend rooibos for infant colic.59 South Africans also use it to calm digestive upset in adults, to help induce sound sleep, and topically to sooth eczema, skin allergies, and diaper rash.59 Not enough research has been done to know if these folk remedies really are effective or to identify the substances in the tea that might be responsible for any observable benefits. Joubert says the tea does seem to help infant colic, but no formal studies have been done.22

Immune Function: An in vitro and in vivo study showed that rooibos might enhance immune function, but very little research has been done on this topic.60 One study found that a polysaccharide in rooibos leaves may have antiviral activity against the HIV virus, but the polysaccharide had to be chemically extracted from the leaves and is not found in tea made by steeping the leaves in water.61 There’s no evidence that rooibos tea fights the HIV virus.

Zero Caffeine And Low Tannin: Several other health advantages of rooibos tea that are often mentioned are its zero caffeine content and its low tannin content. Because rooibos is naturally caffeine-free, it does not have to be subjected to a decaffeination process and, therefore, does not lose any of its polyphenol content (as occurs when green and black teas are decaffeinated). The zero caffeine content also means rooibos can be enjoyed by those who want to avoid the stimulating effects of caffeine and can be consumed in quantity by those who want to use it as a fluid replacement.

Rooibos only has about 4.4 percent tannin content,51 which means that it does not have the astringent taste associated with C. sinensis and will not become bitter even after long steeping times. Rooibos tea can be a good alternative to C. sinensis for people who prefer the milder taste of a less astringent herbal tea or for those who have digestive problems with tannin-rich beverages. And as Micozzi observes, some people can receive a higher total antioxidant intake from rooibos than from green or black tea because the low tannin content and caffeine-free nature of rooibos allow it to be consumed in larger quantities.58

Iron Absorption: Other disadvantages have been attributed to tannins; they can bind to non-heme iron (iron from non-meat sources), reducing iron absorption, and they can decrease the metabolism and utilization of proteins.62-69 Black and green teas reduce the amount of non-heme iron absorbed by the body when the tea is consumed at the same time as the iron source.62-66 These effects do not cause problems for most people, but they can cause problems for people who have nutritionally marginal diets or low intake of heme iron sources (meats).69

Other polyphenol-rich beverages besides C. sinensis teas can also inhibit iron absorption. One study found that the inhibition of iron was 79 to 94 percent for black tea, 84 percent for peppermint tea, 73 percent for hot cocoa, and 47 percent for tea of chamomile (Matricaria recutita L., Asteraceae).62 The teas still inhibited iron absorption to the same degree even if milk was added to them. Some of these beverages contain only low levels of tannins, but other polyphenols in foods and beverages can also reduce iron absorption.62,64The ability of polyphenols to chelate prooxidant metal ions might provide some antioxidant protection, but it can also be a disadvantage by decreasing absorption of necessary dietary minerals such as iron.64

The low tannin content of rooibos is sometimes used to infer that rooibos tea won’t inhibit iron absorption, but that conclusion is not automatic since rooibos is rich in other polyphenols that might decrease iron absorption. In one small study, three groups of 10 young healthy men were given an oral dose of iron, followed by rooibos tea, C. sinensis tea, or plain water.71 Iron absorption was measured to be 7.25 percent for rooibos tea, 1.70 percent for C. sinensis tea, and 9.34 percent for plain water. The result for C. sinensis was significant (P < .0001), but the data for rooibos did not reach statistical significance (that is, the data for rooibos were not good enough to determine whether this result can be generalized to the whole population or whether the result was just chance). More studies are needed to better document the effect of rooibos on iron absorption, but this study implies that rooibos might not inhibit iron absorption nearly as much as C. sinensis tea.

The Bottom Line

Rooibos tea has become popular because of its fruity, sweet taste and its caffeine-free, low tannin, antioxidant-rich status. Although more research is needed, rooibos appears to be safe and free of side effects. The antioxidants present in rooibos may help protect against free radical damage that can lead to cancer, heart attack, and stroke. Unfermented (green) rooibos has a higher amount of polyphenols than traditional fermented rooibos and generally demonstrates higher antioxidant and antimutagenic capabilities in vitro. Future research should reveal whether the antioxidant benefits of rooibos observed in vitro and in animals translates into health benefits for humans.


The author thanks Elizabeth Joubert, Ph.D., specialist researcher at South Africa’s ARC Infruitec-Nietvoorbij, and Jeanine L. Marnewick, senior research scientist at the Program on Mycotoxins and Experimental Carcinogenesis (PROMEC) at the Medical Research Council of South Africa, for their quotes and technical input, as well as for providing copies of several research papers. Their expertise on rooibos has contributed much valuable information to this article. Lorenzo Bramati, Ph.D., research scientist at the Instituto Tecnologie Biomediche CNR in Italy, provided helpful input and copies of several research papers. Erica Renaud, a member of the quality control program for ASNAPP (Agribusiness in Sustainable Natural African Plant Products) at the Center for New Use Agriculture and Natural Plant Products at Rutgers University provided valuable input and photos. Marc S. Micozzi, M.D., Ph.D., director of the Policy Institute for Integrative Medicine, offered helpful review and comments. Rooibos Ltd./SunnRooibos also provided valuable insight and photos.

Laurie Erickson, a freelance writer in Mountain View, California, is interested in the medicinal and horticultural aspects of herbs. She began investigating rooibos out of personal curiosity and has no financial connections with the rooibos industry. Her educational background includes a B.S. in Environmental Earth Science and an M.S. in Geomechanics from Stanford University. She has also written the medical website <> and has been published in the garden section of several newspapers.


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41. Cesarone MR, Belcaro G, Incandela L, Geroulakos G, Griffin M, Lennox A, DeSanctis MT, Acerbi G. Flight microangiopathy in medium-to-long distance flights: prevention of edema and microcirculation alterations with HR (Paroven, Venoruton; 0-(beta-hydroxyethyl)-rutosides): a prospective, randomized, controlled trial. J Cardiovasc Pharmacol Ther 2002; 7 Suppl 1:S17-20.

42. MacLennan WJ, Wilson J, Rattenhuber V, Dikland WJ, Vanderdonckt, Moriau M. Hydroxyethylrutosides in elderly patients with chronic venous insufficiency: its efficacy and tolerability. Gerontology 1994;40(1):45-52.

43. Gouny AM, Horovitz D, Gouny P, Sauvage E, Nussaume O. Effectiveness and safety of hydroxyethyl-rutosides in the local treatment of symptoms of venous insufficiency during air travel. J Mal Vasc1999;24(3):214-20.

44. Titapant V, Indrasukhsri B, Lekprasert V, Boonnuch W. Trihydroxyethylrutosides in the treatment of hemorrhoids of pregnancy: a double-blind placebo-controlled trial. J Med Assoc Thai 2001;84(10):1395-400.

45. Nocker W, Diebschlag W, Lehmacher W. A 3-month, randomized double-blind dose-response study with 0-(beta-hydroxyethyl)-rutoside oral solutions. Vasa 1989;18(3):235-8.

46. Cataldo A, Gasbarro V, Viaggi R, Soverini R, Gresta E, Mascoli F. Effectiveness of the combination of alpha tocopherol, rutin, melilotus, and centella asiatica in the treatment of patients with chronic venous insufficiency. Minerva Cardioangiol 2001;49(2):159-63.

47. Von Gadow A, Joubert E, Hansmann CF. Comparison of the antioxidant activity of rooibos tea (Aspalathus linearis) with green, oolong and black tea. Food Chem 1997;60(1):73-7.

48. Sasaki YF, Yamada H, Shimoi K, Kator K, Kinae N. The clastogen-suppressing effects of green tea, Po-lei tea and Rooibos tea in CHO cells and mice. Mutat Res 1993;286(2):221-32.

49. Komatsu K, Kator K, Mitsuda Y, Mine M, Okumura Y. Inhibitory effects of Rooibos tea, Aspalathus linearis, on X-ray-induced C3H10T1/2 cell transformation. Cancer Lett 1994;77(1):33-8.

50. Inanami O, Asanuma T, Inukai N, Jin T, Shimokawa S, Kasai N, Nakano M, Sato F, Kuwabara M. The suppression of age-related accumulation of lipid peroxides in rat brain by administration of rooibos tea (Aspalathus linearis). Neurosci Lett 1995;196(1-2):85-8.

51. Marnewick JL, Gelderblom WC, Joubert E. An investigation on the antimutagenic properties of South African herbal teas. Mutat Res 2000;471(1-2):157-66.

52. Standley L, Winterton P, Marnewick JL, Gelderblom WC, Joubert E, Britz TJ. Influence of processing stages on antimutagenic and antioxidant potentials of rooibos tea. J Agric Food Chem 2001; 49(1):114-7.

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Health Benefits of Fennel Tea

In the Middle Ages, on Midsummer’s night, people hung fennel over doorways to protect the household from evil spirits.

Although it is no longer used as a protective decoration, fennel is still one of the more widely used medicinal plants, being suggested for everything from colic to conjunctivitis.

The benefits of fennel tea are both culinary and curative. Fennel is used in many different cuisines, from Indian to Italian, to contemporary fusion, and all parts of the plant are used, including the leaves, seeds, and bulb.

Fast facts on fennel:

  • The Latin name for fennel is foeniculum vulgare.
  • The ancient Greeks and Romans thought fennel could bring strength and fortitude and lead to longer life.
  • The benefits of fennel tea are very similar to those derived from fennel seeds.

What is fennel?

Fennel tea in clear mug, with fennel seed in a bowl and wooden spoon, and a caraway flower,
Fennel tea has long been enjoyed for its flavor, though many choose to drink it for its purported health benefits.

Native to the Mediterranean region, fennel is now found all over the world, and its uses are as numerous as the places in which it grows.

Flavorful and fragrant, fennel is used in the following ways:

  • as a spice
  • eaten raw
  • dried
  • braised
  • grilled
  • shaved
  • stewed

It has a distinctive licorice-like flavor and is used in salads, sausages, ice cream, cookies, alcoholic beverages, pasta dishes, and more.

The history of fennel

Emperor Charlemagne was so taken with fennel that he brought the flowering plant to Europe and grew it on his estates.

Through the ages, many health claims have been made for fennel, and drinking fennel tea is an established practice in traditional medicine throughout the world.

Although Western science has not verified all these benefits, humans have used fennel to:

  • relieve flatulence
  • encourage urination
  • boost metabolism
  • treat hypertension
  • improve eyesight
  • prevent glaucoma
  • regulate appetite
  • clear mucus from the airways
  • stimulate milk production in nursing women
  • speed digestion
  • reduce gas
  • reduce stress
  • detoxify the body

Health benefits

Fennel seeds in a tea strainer over a mug of herbal tea.
Fennel tea may aid healthy digestion, and treat bloating, gas, or cramps, and may also act as a diuretic.

According to herbalists, fennel seed is an effective aid to digestion. It can help the smooth muscles of the gastrointestinal system relax and reduce gas, bloating, and stomach cramps.

In fact, tinctures or teas made from fennel seeds can be used to treat stomach muscle spasms caused by irritable bowel syndrome, ulcerative colitis, Crohn’s disease, and other conditions affecting the gastrointestinal system.

Fennel may also be used in combination with other herbal remedies to modify the side effects of herbal formulas used as laxatives, or other treatments for digestive problems.

1. Painful periods

Painful periods or dysmenorrhoea are a common problem for many women, who often use over-the-counter medications, such as non-steroidal anti-inflammatory drugs (NSAIDs) to treat the pain.

However, roughly 10-20 percent of women who suffer from severe cramping and discomfort during their period do not find relief through this approach.

Many turn to alternative or complementary treatments instead, and a 2012 study suggested that fennel can be helpful in this regard.

Researchers speculate that fennel helps keep the uterus from contracting, which is what prompts the pain reported by women with dysmenorrhea.

2. Colic

One of the significant benefits of fennel is its anti-spasmodic qualities. Because of this, some people believe that fennel tea may also play a role in reducing the symptoms of colic in infants.

3. Regulating blood sugar

Many herbalists and complementary healthcare practitioners recommend fennel tea as a way to regulate blood sugar.

study in Bangladesh, in which mice were treated with an extract made from mentholated fennel seeds, found that, at some dosage levels, this extract reduced blood glucose levels at a rate comparable to that of standard antihyperglycemic medications.

4. Pain relief

Fennel is also considered helpful for pain relief. The same study from Bangladesh found that fennel extract reduced indications of pain at a level close to that provided by aspirin.

5. Hydration

Staying well hydrated is important for overall health, so one of the more direct benefits of fennel tea is that it provides individuals with a tasty, caffeine-free beverage.

Fennel tea or fennel extract?

Extract of fennel seeds is not the same thing as fennel tea. Fennel tea is less processed and more likely to be pure; and the measurable, beneficial impacts of fennel tea suggest multiple reasons for drinking it. The U.S. Food and Drugs Administration (FDA) do not monitor supplements and extracts of herbs.

Also, some people simply find fennel tea delicious.

Studies on fennel benefits

Fennel on a wooden table, with a small bottle of fennel oil and some seed in a larger jar.
The essential oils derived from fennel seeds have a range of potentially beneficial properties.

Although most of the health claims made for fennel and fennel tea are based on traditional medicine, some scientific, medical studies have identified specific drug-like qualities of the plant, particularly its essential oils, which may promote health.

Studies have found that fennel tea benefits linked to fennel’s essential oils include:

  • reducing the formation of blood clots
  • increasing milk secretion and supporting the female reproductive system
  • acting as an antioxidant
  • antibacterial effects
  • antifungal activity
  • anti-inflammatory properties
  • anti-diabetic
  • controlling dust mites

Researchers found that ground fennel seeds in solution were effective against bacteria that cause indigestion, diarrhea, and dysentery, as well as some hospital-acquired infections.

According to one study, fennel was effective at collecting free radicals, which cause disease. This suggested fennel extracts could be used to help individuals ward off the effects of many chronic diseases and dangerous health conditions, including cancer, hardening of the arteries or atherosclerosis, and inflammation.

While even the most committed natural care providers are not claiming that drinking a cup of fennel tea could be like taking a dip in the Fountain of Youth, this research suggests that the compounds found in fennel could help buffer the effects of ageing.

Who should avoid fennel tea?

Fennel is considered fairly mild, although some people may be allergic to it. It is also possible to overdose on the extracted oils found in fennel.

Some studies have found that fennel has an estrogenic effect, which means that it mimics the effects of estrogen. Pregnant and breastfeeding women should not drink fennel tea. People with cancers that are sensitive to estrogen should also avoid the use of fennel.

Estragole, a key element in fennel, has been identified as a potential carcinogen, so individuals with cancer, or at a high-risk for the disease, are urged to limit their use of fennel tea, or avoid it altogether.


Health Benefits of Turmeric Tea

Turmeric is a popular spice made from the rhizome or root of the Curcuma longa plant.

Turmeric is native to Southeast Asia and is a member of the Zingiberaceae or ginger family. It has been used as a herbal remedy for thousands of years in Indian Ayurvedic and Chinese medicine.

India grows 78 percent of the global supply of turmeric. In this article, we look at a range of potential health benefits.

Fast facts on turmeric tea:

  • The active ingredient in turmeric is curcumin.
  • Curcumin gives turmeric its characteristic yellow color.
  • Curcumin is proven to have anti-inflammatory and immune-boosting properties.

What is turmeric tea?

turmeric tea
The most effective way to consume turmeric may be as a tea.

Curcumin has low bioavailability, which means the body has a hard time accessing and absorbing the compound. For this reason, turmeric supplements, with their guaranteed high concentrations of curcumin, are popular.

Turmeric tea, brewed using grated turmeric root or pure powder, is considered one of the most effective ways to consume the spice.

There is no specific recommended daily intake of turmeric. Based on available research, the suggested daily intake depends largely on the condition it is being used to treat.

Most research in adults supports the safe use of 400 to 600 milligrams (mg) of pure turmeric powder three times daily, or 1 to 3 grams (g) daily of grated or dried turmeric root. Grating the turmeric yourself is the best way to ensure a pure product.

Nine potential benefits of turmeric tea

Drinking turmeric tea is believed to bring about several benefits, nine of which are described in more detail here.

1. Reduces arthritis symptoms

As an anti-inflammatory, curcumin may help reduce the most prominent symptoms of arthritis.

2017 study found that out of 206 American adults with self-reported rheumatoid arthritis, 63 percent used non-vitamin supplements to manage their symptoms, with turmeric being the most popular product that was taken.

2. Boosts immune function

Curcumin is proven to improve immune function with antioxidant, anti-inflammatory, antiviral, and antibacterial properties.

Curcumin has also been shown to act as an immune modulator, helping regulate immune cell function against cancer.

3. Help reduce cardiovascular complications

Several studies have shown curcumin to have beneficial heart health properties by acting as an antioxidant and anti-inflammatory.

A 2012 study found that taking 4 g per day of curcumin 3 days before and 5 days after coronary artery bypass grafting surgery, reduced the risk of acute myocardial infarction or heart attack by 17 percent.

4. Helps prevent and treat cancer

One of the most clinically established therapeutic properties of curcumin is its anti-cancer action.

As an antioxidant and anti-inflammatory, curcumin is thought to lower the risk of cells in the body becoming damaged, reducing the risk of cell mutations and cancer.

Furthermore, numerous studies have shown that curcumin has anti-tumor properties, limiting the growth of tumors and spread of cancerous cells.

According to a 2014 medical review, more than 2,000 articles have been published using the keywords “curcumin” and “cancer.” The use of curcumin as a cancer treatment alongside chemotherapy and radiation therapy is currently being investigated.

5. Helps manage irritable bowel syndrome or IBS

Curcumin has long been used in traditional medicines as a treatment for many digestive conditions.

Several studies have found that curcumin may help reduce the pain associated with IBS and improve the quality of life of those people with the condition.

2012 study in rats found that curcumin helped decrease the time it took for food to empty from the stomach to the small intestine, otherwise known as gastric emptying.

6. Prevents and treats Alzheimer’s

Studies have shown that curcumin may help reduce the chances of several neurodegenerative conditions. Its antioxidant and anti-inflammatory powers are thought to reduce cellular damage, inflammation, and amyloid deposits or plaques that occur with these conditions.

Curcumin may also be able to slow down or prevent some of the age-associated protein changes linked to neurodegeneration.

7. Protects against liver damage, gallstones, and manages liver conditions

Several studies have shown that curcumin can protect against liver damage. Potential liver and gallbladder benefits of curcumin include increasing production of the digestive fluid bile while also protecting liver cells from damage from bile-associated chemicals.

8. Helps prevent and manage diabetes

Traditional medicines have used turmeric for diabetes for thousands of years. Several studies using animal and human models have shown that curcumin supplementation may have anti-diabetes properties.

9. Helps treat and manage lung conditions

Researchers suspect that the anti-inflammatory and antioxidant properties of curcumin may help reduce the symptoms of chronic or long-lasting lung conditions.

2017 medical review concluded that although the clinical evidence is limited, curcumin might help treat asthma, pulmonary and cystic fibrosis, lung cancer or injury, and chronic obstructive pulmonary disease (COPD).

How to prepare turmeric tea

turmeric powder on a plate
To make a turmeric tea, a person can add ground, grated, or powdered turmeric to boiling water.

Turmeric tea can be prepared from either pure turmeric powder or grated or ground, dried turmeric. Fermented turmeric preparations, commonly sold as tea products, claim to have higher concentrations of biologically available or absorbable curcumin.

The steps to follow for making turmeric tea are:

  • boil 4 cups of water
  • add 1 to 2 teaspoons of ground, grated, or powdered turmeric
  • allow the mixture to simmer for approximately 10 minutes
  • strain the tea into a container and allow it to cool for 5 minutes

Many people put additional ingredients into their turmeric tea to improve the taste or help with its absorption. Common additives include:

  • Honey, to sweeten the tea and give the mixture more anti-microbial properties.
  • Whole milk, cream, almond milk, coconut milk, or 1 tablespoon of coconut oil or ghee (unclarified butter) to help with absorption, as curcumin requires healthy fats to dissolve properly.
  • Black pepper, which contains piperine, a chemical known to help promote curcumin absorption, and that can add a spicy flavor to the tea.
  • Lemon, lime, or ginger, to enhance antioxidant and antimicrobial properties in the mixture and improve taste.

Rhodiola Rosea

Benefits, Side Effects

Rhodiola Rosea is a flowering herb that grows in cold, high-altitude regions of Europe and Asia. Other names for it include arctic root, golden root, king’s crown, and roseroot.

Rhodiola Rosea has been used in traditional medicine for many years, particularly in Russia, Scandinavia, and other cold, mountainous areas. Some people believe the herb can treat anxiety, depression, fatigue, anemia, and headaches.

Numerous studies have been conducted on the plant. While some results appear promising, many of the studies have been small, biased, or flawed. As such, experts say more research needs to be done to determine how Rhodiola Rosea is effective, and whether it should be included in treatment plans.

Meanwhile, Rhodiola Rosea has a low risk of side effects and appears to offer some benefits for many of these conditions. Therefore, it may be a natural option that is worth trying for its supposed uses.

Possible health benefits and evidence

The evidence for Rhodiola Rosea’s health claims varies. The following are some of its popular uses and what research says about each one. The health benefits of this herbal root are probably linked to anti-inflammatory properties it may have.


Rhodiola rosea flowering herb on a board
Rhodiola Rosea is a flowering herb that has been used in traditional medicine for many years.

One of the best-known claims about Rhodiola Rosea is its power as a substance that helps the body adapt to stress, otherwise known as an adaptogen.

Its specific abilities and qualities, however, have not yet been scientifically proven with enough well-designed studies.

A report published in Alternative Medicine Review found that Rhodiola Rosea shows promise as an adaptogen. Based on evidence from several small studies, the author states that the plant’s extracts provide benefits for mental health and heart function.

Another 2005 article describes Rhodiola Rosea as “a versatile adaptogen,” stating that the herb can increase resistance to stress. In particular, the authors state that it holds promise as a possible treatment for reducing stress hormone levels and stress-induced heart problems.

Physical and mental performance

Some people take Rhodiola Rosea to enhance physical performance before exercise or as a way to improve concentration and thinking. There are also claims that it helps reduce physical and mental fatigue.

A number of studies touch on these claims. They include the following:

  • A review that states Rhodiola Rosea may hold promise as an aid for enhanced physical and mental performance. The authors conclude that more research on the plant is needed to further examine and prove its effects.
  • A study in 2009 found that women who took a high dose of Rhodiola Rosea were able to run faster than those who got a placebo. The study examined 15 college-age women.
  • Another study suggests that taking a standardized extract of Rhodiola Rosea may improve concentration and reduce fatigue. The research looked at 60 men and women, who took an extract called SHR-5. The dosage given for these effects was 576 milligrams (mg) per day.

Despite these results, a large 2012 review published in BMC Complementary and Alternative Medicine looked at 206 studies on Rhodiola Rosea and fatigue but found only 11 were suitable to include.

Five of these trials determined that Rhodiola Rosea helped with symptoms of physical and mental fatigue. But, the reviewers state, all of the studies had a high risk of bias or had reporting flaws with an unknown bias.

The reviewers conclude that research on Rhodiola Rosea is “contradictory and inconclusive.” They recommend a non-biased, valid trial of the herb before it is put forward as a treatment for fatigue.

Depression and anxiety

One study found evidence to suggest that Rhodiola Rosea may reduce symptoms of generalized anxiety disorder. Ten people were included in this study, and they took 340 mg of Rhodiola Rosea extract for 10 weeks.

Another study in Phytomedicine found that Rhodiola Rosea reduced symptoms of depression, but its effects were mild. The herb did not reduce symptoms as effectively as sertraline, a prescription antidepressant, although it had fewer and milder side effects.

The authors of this 2015 study concluded that, as it may be better tolerated by some people and did provide benefit, Rhodiola Rosea may be suitable as a treatment for mild to moderate depression. The study included 57 people who took the herb for 12 weeks.

Stress-induced eating disorders

An active ingredient in Rhodiola Rosea known as salidroside was studied for its effects on binge eating. This study, published in Physiology & Behavior, was done using rats. It found that a dry extract of Rhodiola Rosea that included 3.12 percent salidroside did help reduce or eliminate binge eating in the animals.

The rats that took Rhodiola Rosea also had lower blood levels of a stress hormone that may play a role in binge eating.

Another study in the Journal of Psychopharmacology, similarly conducted on rats, determined that Rhodiola Rosea may reduce stress-induced anorexia. The authors say their findings provide evidence to support claims that the herb has anti-stress properties.

How is it taken?

Rhodiola rosea tea
Rhodiola Rosea is available in many forms. Any side effects experienced will likely be mild.

Like many herbs, Rhodiola Rosea is available in the form of capsules, tablets, dried powder, and liquid extract.

The dosage and amount of extract vary between brands and product types.

Herbs and supplements are regulated as food, not drugs, by the United States Food and Drug Administration (FDA).

As a result, knowing what dose to take and how much is included in the product is not always clear. There may also be issues with quality or purity.

Although some studies have listed dosages used for specific purposes, it appears that the herb may be taken at different strengths to treat different problems. In the Alternative Medicine Review article, the author says the dosage may vary, depending on how much-standardized extract it contains.

Rosavin, in particular, is one of the compounds named as having an effect on reducing stress. The author of the review suggests approximately:

  • 360-600 mg daily of an extract standardized for 1 percent rosavin
  • 180-300 mg of an extract standardized for 2 percent rosavin
  • 100-170 mg for an extract standardized for 3.6 percent rosavin

Risks and side effects

Though its therapeutic effects have yet to be proven, the studies on Rhodiola Rosea all seem to agree that any side effects are mild.

Side effects have included:

  • dizziness
  • dry mouth
  • sleep problems
  • jitteriness

Jitteriness is a particular problem among those prone to anxiety who take higher doses of the supplement.

As it has a mild stimulant-type effect, Rhodiola Rosea is not recommended for people who have bipolar disorder or who are taking other stimulants.

One article suggests that people can take the herb on an empty stomach 30 minutes before breakfast and lunch. Avoiding it in the evening may help reduce sleep problems at night.

Rhodiola Rosea has a long tradition of being used to help increase stamina, concentration, and mental well-being.

Large, valid studies on these effects are lacking. However, the herb’s low risk of side effects makes it an attractive option for people looking to improve their health in these specific areas.

As with any supplement, it is best for people to speak with a doctor before taking it.

Problems such as fatigue and trouble concentrating can sometimes be symptoms of an underlying health condition that needs treatment. Likewise, depression and anxiety can be serious mental health conditions that require the care of a doctor.

Black Cumin Oil Is More Effective than Acetaminophen in Reducing Pain in Elderly Patients with Knee Osteoarthritis

Knee osteoarthritis (KO) is a common disabling condition in the elderly. Its treatment includes medications, surgery, and complementary therapies. Nonsteroidal anti-inflammatory drugs, which are often used, are not completely effective and are associated with adverse effects. Black cumin (Nigella sativa, Ranunculaceae) oil and its active components, especially thymoquinone, have antioxidant, anti-inflammatory, and analgesic properties. These authors conducted a crossover, clinical trial to evaluate the topical application of black cumin oil (Barij-e-Kashan; Kashan, Iran) and oral acetaminophen on KO in elderly patients living in a nursing home in Sabzevar City, Iran. The study was conducted from November 21, 2014, to January 20, 2015.

Patients were eligible for the study if they were older than 65 years and had been diagnosed with KO using the American College of Rheumatology criteria, which included knee pain on most days of the preceding month, crepitus on active motion, morning stiffness for less than 30 minutes, and bony enlargement found on physical examination of the knee. Forty-two patients with a mean age of 75.66 ± 8.9 years were enrolled in the study. Two patients did not comply with the study protocol and were excluded from the final analysis.

During phase 1 of the study, the patients in group 1 applied 1 mL black cumin oil to the knee 3 times daily every 8 hours for 3 weeks, massaging the knee for 5 minutes with the palm of the hand in a clockwise direction at the front and sides of the joint. [Note: The Intervention section of the article says 1 week; however, the Discussion section and abstract say 3 weeks.] The patients in group 2 were instructed to take 1 tablet of 325 mg acetaminophen 3 times daily every 8 hours for 3 weeks. Following a 1-month washout period, each group then followed the alternate treatment protocol.

Pain intensity was measured using a visual analogue scale before and after the 2 phases of the study, with 0-3 indicating mild pain; 4-5, moderate pain; and 8-10, severe pain. The authors report that significant improvements in knee pain were seen after both treatments (P = 0.0001). The improvement in pain intensity was significantly greater in the black cumin oil group compared with the acetaminophen group (P = 0.01).

Thymoquinone in black cumin is reported to inhibit oxidative stress and exhibit an analgesic effect on the central nervous system of study rats with experimental allergic encephalomyelitis.1 In another cited animal study, the analgesic and anti-inflammatory effects of black cumin were attributed to its polyphenols.2

“This study showed that topical use of Nigella sativa oil can be more effective in reducing knee pain in elderly patients than acetaminophen, which is typically used as a safe supplement for the elderly,” conclude the authors. The mechanisms involved should be explored further in studies of longer duration.

This study was funded by Sabzevar University of Medical Sciences (Sabzevar, Iran).


1Mohamed A, Shoker A, Bendjelloul F, et al. Improvement of experimental allergic encephalomyelitis (EAE) by thymoquinone; an oxidative stress inhibitor. Biomed Sci Instrum. 2003;39:440-445.

2Ghannadi A, Hajhashemi V, Jafarabadi H. An investigation of the analgesic and anti-inflammatory effects of Nigella sativa seed polyphenols. J Med Food. 2005;8(4):488-493.

Kooshki A, Forouzan R, Rakhshani MH, Mohammadi M. Effect of topical application of Nigella sativa oil and oral acetaminophen on pain in elderly with knee osteoarthritis: a crossover clinical trial. Electron Physician. 2016;8(11):3193-3197.

Systematic Review of Ginkgo Finds Potential Treatment for Dementia

Dementia encompasses a wide range of symptoms associated with a decline in memory and loss of the ability to perform everyday activities in elderly populations. Alzheimer’s disease (AD) and vascular dementia (VD) make up the vast majority of dementia cases. Ginkgo (Ginkgo biloba, Ginkgoaceae) leaf extract (GbE) has become one of the most widely used herbal remedies for dementia. Thus, many clinical trials have already examined the effects of GbE on dementia, and many systematic reviews (SRs) have analyzed these trials. This study sought to provide a comprehensive assessment of the effectiveness of GbE in the treatment of dementia based on the evidence provided in the SRs.

All SRs which evaluated the efficacy and effectiveness of GbE as treatment (not prevention) of patients with diagnosed dementia, AD and/or VD, or mild cognitive impairment (MCI) were included. SRs were eligible only if they included the use of statistical methods (i.e., meta-analysis) to analyze randomized controlled trial (RCT) data. SRs were included whether GbE was administered alone or in combination with drugs. There were no limitations on dosage, and GbE could be administered orally or intravenously. PubMed/MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effects (DARE), and Google Scholar were searched from inception to June 2016.

In total, 59 RCTs were reviewed, with patients ranging from those with any form of dementia, dementia with behavioral and psychological symptoms, cognitive impairment, or AD. Twelve SRs met the inclusion criteria; all included only RCTs (of which most were placebo-controlled trials). The included SRs were published between 2009 and 2016, and they were performed in China, Germany, Japan, and the United Kingdom. The standardized extract EGb 761® (Dr Willmar Schwabe GmbH & Co. KG; Karlsruhe, Germany) was used in many RCTs, with six SRs including only RCTs that used EGb 761. Intervention duration varied from two to 52 weeks, and dosing varied from 60 mg/day to 600 mg/day.

Outcomes of interest varied but included one or more of the following: cognitive performance, activities of daily living (ADLs), clinical global impression, quality of life (QOL), and safety. With the exception of three SRs1-3 all remaining SRs showed the statistically significant effectiveness of GbE on cognitive performance in people with dementia. Eight SRs evaluated the effect of GbE on ADLs, and, apart from one SR,3 seven SRs showed a statistically significant effect of GbE on ADLs in people with dementia. Five SRs evaluated the effect of GbE on clinical global impression of dementia, of which three showed a statistically significant effect of GbE. Of the five SRs that evaluated QOL, two concluded there was no significant difference in QOL, two did not pool the QOL data, and only one SR pooling data from two RCTs suggested a beneficial effect of GbE on QOL. Eight SRs evaluated the safety of GbE, and none found any significant difference in adverse events or side effects compared to placebo.

Seven SRs included RCTs in which GbE was administered for at least 22 weeks, and the data reported in these SRs consistently favored the beneficial effects of GbE. The five SRs in which GbE was administered for less than 22 weeks reported data that were “quite inconsistent.” This study found no particular evidence suggesting a beneficial effect of GbE on cognitive performance, ADLs, or clinical global impression when GbE was administered for less than 22 weeks. In addition, few SRs showed a beneficial effect of GbE at a dose less than 200 mg/day. In fact, four SRs consistently showed a beneficial effect of GbE on cognitive performance at a dose greater than 200 mg/day (usually 240 mg/day). Few SRs indicated a beneficial effect of GbE on ADLs and clinical global impression at a dose less than 200 mg/day.

The quality of SRs was evaluated using the AMSTAR (Assessment of Multiple Systematic Reviews) tool, and overall, the majority of reviews were found to be of good or acceptable quality. However, many of the reviewed RCTs in these SRs were of poor quality and had a high risk of bias, meaning the overall quality of evidence reviewed was low to moderate. That being said, based on the evidence gathered that met inclusion criteria, this overview found GbE to have beneficial effects over placebo on cognitive performance, ADLs, and clinical global impression when administered at a dose greater than 200 mg/day for 22 weeks or more. Globally, over 46 million people were living with dementia in 2015, and this number is expected to reach 131.5 million by 2050.4 With no cure or prevention yet found, future research is warranted. In order to better assess GbE efficacy as a treatment for dementia, future studies should take the beneficial dosing and intervention length found by this overview into account.


1Yang Z, Li W, Huang T, Chen J, Zhang X. Meta-analysis of Ginkgo biloba extract for the treatment of Alzheimer’s disease. Neural Regen Res. 2011;6(15):1125-1129.

2Wang BS, Wang H, Song YY, et al. Effectiveness of standardized Ginkgo biloba extract on cognitive symptoms of dementia with a six-month treatment: a bivariate random effects meta-analysis. Pharmacopsychiatry. 2010;43(3):86-91. doi: 10.1055/s-0029-1242817.

3Birks J, Grimley Evans J. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database Syst Rev. January 21, 2009;(1):CD003120. doi: 10.1002/14651858.CD003120.pub3.

4Dementia statistics. Alzheimer’s Disease International website. Available at: Accessed September 11, 2017.

Yuan Q, Wang CW, Shi J, Lin ZX. Effects of Ginkgo biloba on dementia: An overview of systematic reviews. J Ethnopharmacol. January 2017;195:1-9.

Analysis of Helichrysum (Immortelle) Chemistry, Antioxidant Activity, and Chemotaxonomy

Traditionally, helichrysum (immortelle; Helichrysum italicum, Asteraceae) has been used for the treatment of scars and cuts, as well as used as a liver stimulant and diuretic. The essential oil of helichrysum has been found to have anti-inflammatory, antioxidant, fungicidal, and astringent effects. As an emollient and fragrance in the cosmetic and perfume industry, the chemical composition of helichrysum essential oil has been somewhat characterized. The aim of this study was to further characterize the chemical content and antioxidant activity of helichrysum aerial parts and to assess the chemotaxonomy of the H. italicum taxa.

The flowering aerial parts of helichrysum (H. italicum ssp. italicum) were collected in May 2011, near Valdanos, Montenegro. The air-dried aerial parts of the plant were extracted with 45% ethanol and dried. The air-dried flowering upper parts of helichrysum were submitted to hydrodistillation to produce the essential oil.

The essential oil was characterized by using chromatography and mass spectrometry techniques. Principal component analysis (PCA) and cluster analysis (CA) was used to compare the main chemical constituents identified in this study with 16 different H. italicum taxa. The dried ethanol extract was dissolved in an aqueous solution for analysis of total phenolics and flavonoids. Both the essential oil and the ethanol extract were assessed for antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The ethanol extract was also evaluated for inhibition of hydroxyl radical (OH) generation.

The essential oil yield was found to be 0.15 ± 0.02%. A total of 27 compounds were identified, which represented 96.1% of the total oil composition. Most of the compounds were oxygenated monoterpenes (43.9%) and sesquiterpene hydrocarbons (41.2%). [Note: There are discrepancies between the article text and the data in Table 1, which lists these as 43.1% and 42.2%, respectively.] The major compounds found in the oil were neryl acetate (28.2%), neryl propionate (9.1%), γ-curcumene (17.8%), and ar-curcumene (8.3%). [Note: There are discrepancies for three of these compounds among the abstract, article text, and data in Table 1, which lists these as neryl acetate (29.2%), neryl propionate (10.1%), and γ-curcumene (18.8%).] Other compounds found included α-selinene (3.9%), isoitalicene (3.2%), thymol (2.8%), and α-cedrene (2.4%). These concentrations are consistent with previous reports for this plant subspecies.

PCA indicated that H. italicum ssp. italicum from Greece, H. italicum ssp. serotinum from the Iberian Peninsula, and plant material collected from the region of former Yugoslavia could all be clearly differentiated from one another based on different dominant chemical components. Helichrysum italicum ssp. italicum and H. italicumssp. microphyllum were phylogenetically similar and had similar dominant chemical components. These and other taxa consisting of the main chemical components (e.g., neryl acetate) were found to represent four chemotypes. Two of these chemotypes had subchemotypes. CA indicated similar results in terms of the differentiation of H. italicum ssp. italicum from Greece and H. italicum ssp. serotinum from the Iberian Peninsula. The other taxa were classified in a similar way as that found by PCA, but with some differences, especially for the italicum subspecies.

The yield of the aqueous ethanol extract was 19.77%. The total phenolics and total flavonoids of this extract were found to be 31.97 ± 1.42 mg gallic acid equivalents (GAE)/g of dry extract and 20.68 ± 0.66 mg quercetin equivalents (QE)/g of dry extract, respectively. The radical scavenging capacity (RSC) of the ethanol extract and the essential oil was dose-dependent. In terms of DPPH RSC, the half maximal inhibitory concentration (IC50) was significantly lower (more effective) for the ethanol extract (0.99 µg/ml) compared to the essential oil (1.76 mg/ml) (P value not given). [Note: Table 3 lists the essential oil IC50 as 1.37 mg/ml.] The extract had results that were similar to propyl gallate and quercetin dihydrate. Only the ethanol extract was evaluated for OH scavenging capacity (IC50 = 26.47 µg/ml), but the RSC was significantly less effective compared to its DPPH RSC (P value not given).

The chemical constituents identified from the essential oil of helichrysum aerial parts in this study are consistent with reports assessing the main chemical components of this plant subspecies. A chemotaxonomic analysis suggests that different regions of the world can affect the chemistry of the essential oil. The authors recommend classifying the species further based on these chemical differences. The authors also indicate that helichrysum extracts and essential oils may be effective natural antioxidants for foodstuff and pharmaceuticals. Further studies should be conducted on how differences in chemical composition may affect biological activity, fragrance, and other qualities of the helichrysum extracts and essential oils.


Kladar NV, Anačkov GT, Rat MM, et al. Biochemical characterization of Helichrysum italicum (Roth) G.Don subsp. italicum (Asteraceae) from Montenegro: phytochemical screening, chemotaxonomy, and antioxidant properties. Chem Biodivers. 2015;12(3):419-431.

Herbs For A Healthy Heart

Cholesterol, poor circulation, and high blood pressure can prevent the heart from running smoothly. Thankfully, nature provides herbal remedies to support this vital life source and keep it running optimally.

When we talk about vitality in body, mind, and spirit, no organ takes center stage with more panache than the heart. Its rhythmic beating helps push blood through approximately 100,000 miles of blood vessels that weave through the body, delivering essential oxygen, nutrients, and compounds to cells, while picking up waste for the kidneys, liver, and lungs to filter and eliminate. It also functions as a center of emotion. When we snuggle up to a loved one, good vibes emanate from the chest, and when we suffer from extreme stress or loss, we often feel it in the heart. Simply put, the heart symbolizes the essence of life.

While life-or-death cardiovascular events require immediate medical attention, we can do a lot with herbs to improve the heart’s performance, manage chronic conditions, help heal from heart trauma {both physical and emotional}, and reduce the risk of cardiovascular disease.

Heart Tonics

A few key categories of plant compounds benefit the heart, including anthocyanin and anthocyanidin – pigments that give berries, pomegranates, purple grapes, and red wine, hibiscus, and other foods and herbs their famous deep blue/purple/ red color and healing properties. These compounds have profound antioxidant and anti-inflammatory properties that protect the cardiovascular system from oxidative damage while also limiting the ability of fats in the blood to oxidize. They also improve the integrity of blood vessel {endothelial} lining. Oligomeric proanthocyanidins {OPC’s or PCO’s}, precursors to these pigments, are found in Hawthorn, grape seeds, and skin, pine bark, and Pycnogenol {a supplement derived from pine bark {Pinus pinaster} and other plants, including peanuts, grape seed, and witch hazel}.

Flavanols, another related class of antioxidant compounds, help keep the endothelial lining smooth and flexible. One of the reasons why cacao and dark chocolate are associated with cardiovascular health is the abundance of these flavanols. {Alas, chocolate candy companies funded the more “promising” cacao research, while less vested researchers have not had quite as impressive results.}

Meanwhile, sulfur-based compounds in pungent vegetables like garlic and onions help lower cholesterol and blood pressure while also providing an antioxidant effect. Heart tonics may not dramatically lower cholesterol or blood pressure, but they offer benefit modestly over time while also providing a multitude of other beneficial effects throughout the cardiovascular system. These tonics are best taken regularly and long-term, including as functional foods in the diet.

Hawthorn {Crataegus spp.} shines as the most heart-focused herb for a reason. It seems as if it benefits every single aspect of cardiovascular well-being. The berries, flowers, and leaves {some herbalists also include the thorny spring twigs} are rich in antioxidant compounds, including OPC’s.

hawthorn btanical artHawthorn improves circulation and blood vessel lining and helps to normalize blood pressure by dilating vessels and acting as a natural angiotensin-converting-enzyme {ACE} inhibitor. {ACE inhibitors help relax blood vessels.} The herb strengthens the heart muscle, improving its ability to pump blood efficiently, with strong research supporting its use in congestive heart failure. It may promote healing after a heart attack and relieve angina and mild arrhythmias.

It’s also a classic herb for the emotional aspects of the heart: healing heartbreak, quelling anxiety felt in the heart and opening the heart to love.

Hawthorn is not drug-like in its actions, though, and can take several months of regular use for its benefits to show, which may not prove fast enough in acute conditions. I prefer to take hawthorn as a concentrated, tasty solid extract, but standard methods also work; teas, capsules, and tinctures. It’s extremely safe and food-like, but it may interact with some medications by acting in synergy to increase their effects, including some blood pressure medications and possibly digoxin. If you’re working with a skilled doctor, they may be able to monitor and reduce your drug dose accordingly, but don’t change your medications without your doctor’s approval.

garlic botanical artGarlic {Allium sativum} contains potent sulfur compounds, including allicin, that help improve circulation by thinning the blood and breaking down clots and inflammation-related fibrin, thereby reducing cholesterol and lipid peroxidation {undesirable oxidation of blood fats that leads to atherosclerosis and increased risk for heart attack}. It also modestly reduces blood pressure. I think of garlic as a remedy that cleans the blood and blood vessel linings so that everything flows more smoothly.

You can eat one or more raw cloves of garlic per day, best crushed and allowed to sit for 10 to 15 minutes before consumption. This allows allicin to transform into its more potent form. You may still get some benefits from cooked garlic. Garlic tinctures, capsules, and other remedies provide another option. Some companies even make low-odor or odor-free pills if you’d rather not ward off vampires and coworkers with the metallic scent of garlic pouring from your breath and skin.

Note that therapeutic doses of garlic may increase bleeding, interact with blood thinners, and should not be taken before surgery or if you have a bleeding disorder. Some sensitive people get skin irritation, stomach upset, and gas from garlic.

Hypertension Support

Many things can cause high blood pressure, including serious conditions like kidney disease and preeclampsia that require medical attention. Even everyday hypertension can create wear and tear on the kidneys and increase the risk of stroke. Herbal and natural therapies tend to work best in mild to moderate cases of hypertension, and some people simply do not respond well enough to the herbs and need medication. Nonetheless, there are some promising antihypertension herbs to consider.

Minerals, including potassium, calcium, and magnesium, play an important role in maintaining blood pressure, and you may find that taking a multi-mineral supplement and eating more mineral-rich herbs {nettle, dandelion, burdock, parsley} and foods {vegetables, especially green leafies} keep your blood pressure in check. Limiting sodium, especially sodium-based additives in processed and restaurant food, and eating five to 10 servings of fruits and vegetables daily can also prove extremely helpful for controlling high blood pressure.


Hibiscus {Hibiscus sabdariffa} is a specific species of hibiscus with an anthocyanin-rich flower calyx that you can steep to make a blood-red, tart tea. Hibiscus has long been a popular ingredient in teas – sweetened and sipped as “Rosa de Jamaica” tea in the Caribbean and in North America as a key ingredient in commercial berry “zinger” and fruit-flavored teas. Recent research has found it’s one of our more impressive antihypertensive herbs, boasting a strong safety record. In several human studies, hibiscus has performed as well as popular hypertension drugs, including lisinopril, captopril, and the diuretic hydrochlorothiazide. The herb also seems to reduce cholesterol, triglycerides, urinary tract infections, and blood sugar, and may even modestly aid weight loss.

You do need to drink relatively large amounts of the herb to lower blood pressure: steep 10-30 grams {up to 1-ounce} of the dried flowers in one liter {approximately one quart} of water for 30 minutes or longer and sip in divided doses throughout the day. While generally safe, it’s a tad corrosive to tooth enamel due to the fruits acids {not unlike lemon water} and may have very mild anti-fertility effects.

The herb rooibos has also been shown to benefit hypertension and heart health and can be blended into the tea as well.

Herbal Diuretics: We’ve long used diuretics medications safely to lower blood pressure, and we can also turn to diuretic herbs for similar but much milder effects. Eating four ribs of organic celery per day, fresh or juiced, offers diuretic and blood vessel dilating effects. Dandelion leaf and root have sodium-leaching diuretic properties that work fabulously for some people – but not at all for others. Interestingly, my mentor, herbalist Michael Moore, noted that dandelion is more effective for people of Latin America decent, and I’ve also found this to be true. The related chicory and burdock roots seem to act similarly, and you can combine all three roots into a tasty coffee-like tea.

Parsley, a relative of celery, is both mineral rich and diuretic. While parsley and celery seeds are more potent, they can also irritate the kidneys more so than the stalks and greens.

Cholesterol Support

When your cholesterol and triglyceride levels soar, first start by scrutinizing sugar and carbohydrate intake, overall excess calorie consumption, and lack of exercise. Excess sugars in the bloodstream are packaged up with fat to make triglycerides, which ultimately increases your LDL and other “bad” cholesterol, including very low-density lipoprotein {VLDL} formation.

Limit simple sugars and refined carbohydrates, as well as bad fats from factory-farmed animal products and fried foods. Eat more vegetables; protein {especially plant protein}; and “slow burn” low-to-moderate glycemic high-fiber foods {which include oats and whole grains. beans, apples, and pears for their pectin, and nopales, a tasty Mexican prickly pear cactus}.

An increase in exercise also helps by burning sugar for fuel and improving insulin sensitivity of the cells. Also look to bitter-tasting and blood-sugar balancing herbs. Besides the two herbs mentioned below, also consider cinnamon.

Artichoke leaf {Cynara scolymus} is one of the best-researched herbs in the category of “bitters” for high cholesterol and related issues, including blood sugar and obesity. Its strength lies in reducing LDL cholesterol and fasting blood glucose levels while also increasing good HDL cholesterol levels.

Because artichoke leaf is so intensely bitter, you don’t want to drink it as a tea. Take it as a tincture {tasting it increases the benefits} or capsule {still effective}. Excessive amounts may cause stomach upset and nausea, and it’s best taken with food to limit stomach upset and hypoglycemia.

fenugreek botanical art

Fenugreek {Trigonella foenumgraecum} is among our best-researched herbs for controlling blood sugar and diabetes, and these benefits translate to triglyceride management, as well. While most of the early research involved large quantities of the fiber-rich ground seeds –  two 25 gram doses per day {if poured into capsules, this would mean 50 pills a day} -other studies have found benefits with lesser quantities as well as with extracts. In one study of people with type 2 diabetes, those who consumed 10 grams per day of the powdered whole seeds had significantly better fasting blood glucose, hemoglobin A1c, insulin, total cholesterol, and triglycerides compared to those taking a placebo, even though LDL and HDL cholesterol did not change significantly. A similar study found that fenugreek reduced VLDL cholesterol and that it worked better when added to hot water rather than yogurt.

Fenugreek imparts a maple fragrance to the urine, but this is harmless. If you have type 1 diabetes or take insulin and other blood-sugar regulating medications, work with a healthcare practitioner to ensure that you safely introduce fenugreek without inducing hypoglycemia.

Circulation Support

Herbs like gotu kola, ginger, garlic, rosemary, and very small amounts of cayenne or prickly ash increase blood flow.  Think of ginger, cayenne, and prickly ash if you’re chronically cold with poor circulation to the hands and feet.

The others improve the quality of blood vessel lining, making them smoother and less prone to breakage. The pigments and precursors we discussed as heart tonics – blue berries, gotu kola, dark purple grapes, Japanese knotweed roots, and hibiscus – work well for this.

Other beneficial herbs include horse chestnut, yarrow, and again gotu kola, which are often used for vascular insufficiency, varicose veins, and hemorrhoids topically and internally and may also help prevent deep vein thrombosis {DVT}. Herbs that thin the blood and help break down clots and fibrin include ginger and garlic. Be very careful combining these herbs with medications, and work with a practitioner if you take pharmaceuticals, as serious herb-drug interactions could occur.

Gotu-Kola-ExtractGotu Kola {Centella asiatica} has many uses and is probably better known for its stress-relieving adaptogenic, nerve tonic, and brain-boosting effects, as well as its ability to improve the healing and integrity of various types of tissues in the body {gut lining, skin, collagen, blood vessels}.

In addition to these benefits, gotu kola has a gentle yet profound ability to improve circulation and the quality of blood vessel lining, decreasing the risk of breakage and sluggish blood. Studies show benefit in venous hypertension, ankle edema, foot swelling, chronic venous insufficiency, varicose veins, post-thrombotic syndrome following DVT, and in preventing circulation issues on long flights. Most of the studies have focused on a specific standardized extract od gotu kola called “total triterpenic fraction of Centella asiatica {TTF-CA},” with higher doses {120 to 180 mg} achieving better results, though this extract product does not appear to be commercially available. When buying gotu kola tincture or capsules, follow the label’s dosage recommendations.

You can consume crude gotu kola in relatively large quantities – fresh leaves are commonly eaten as food in the plant’s native lands – and long-term use is recommended. You may not see benefits for one or more months, but the long flight study of TTFCA did note improvements when taken just two days prior to flying.

Gotu kola is generally safe, though it may modestly inhibit fertility and interact with a few medications. Quality on the market varies, and because it favors sewage and sludge-like growing conditions, contamination with fecal bacteria poses a concern. Purchase organic gotu kola from reputable companies or grow your own.

Gladden the Heart

While it may seem “hippie-dippy,” people have used herbs to ‘gladden the heart” for centuries. It goes back to the concept of the heart as the emotional center of the body.

These herbs uplift the spirits and boost the sensation of good vibes emanating from the heart. They’re useful when your heart feels heavy if you’re broken hearted, need to open your heart to others {or yourself}, or are overcome with grief. These herbs tend to be rich in essential oils, engaging the senses in a variety of aromatic and tasty ways to lift your spirits.

rose illustrationRose blossoms, particularly the rosy-scented heirloom and wild species, are one of my favorite herbs in this category. The aromatics of rose have cardiotonic properties and work best as a sprinkle of rose petals in a tea blend, a glycerite or honey extract, a cold water extract steeped for several hours, a flower essence, or simply a bouquet on the table. Also, consider them for the workaholic who needs to stop and smell the roses.

Linden blossoms have a delicate yet heady aroma of honey, and although very little research exists, we often turn to linden for stress-related hypertension and to gladden the heart. Europeans often sip tea made from this fragrant herb.

Holy basil is another favorite of mine. The leaves and flowers have diverse health benefits, including anti-inflammatory qualities as well as “calm energy” adaptogenic, nervine, and cognition-enhancing properties.

Motherwort’s aerial parts harvested in flower are less obviously aromatic, but they do target anxiety that manifests in the heart –  the kind of panic that makes you feel like you’re having a heart attack, palpitations, or tachycardia – though it also has mild mood-boosting properties.

Because it’s so terribly bitter, we usually take motherwort fresh in tincture form, but you can also make an extract in vinegar or glycerine if you want to avoid alcohol.

Lemon balm bridges the benefits of its relatives holy basil and motherwort and makes for a tasty and soothing tea to feed the heart.