Botanical Adulterants Monitor: Turmeric Root/Rhizome

The turmeric root/rhizome and root/rhizome extract Botanical Adulteration Bulletin (BAB), issued in May 2018, is the 14th in the series of bulletins published by the Botanical Adulterants Prevention Program (BAPP). Turmeric is one of the most important spices, and also among the most popular dietary supplement ingredients globally. The increased demand for turmeric extracts and the improvement of laboratory analytical test methods have led to new ways to adulterate the ingredient, such as the addition of synthetically-made curcumin or curcuminoid mixtures. The turmeric bulletin assists lab directors, quality control managers, and others in staying informed on these challenges in order to adjust the identity testing protocols in quality control laboratories.

In July, BAPP released the BAB on Boswellia (Boswellia serrata) oleogum resin and its extracts. Boswellia dietary supplements have shown consistently high sales growth rates over the past five years, and have been ranked as the 22nd best-selling herbal dietary supplement in the United States in 2017. The main issue regarding Boswellia authenticity is the substitution with oleogum resin extracts from other Boswellia species. The BAB provides Boswellia manufacturers with a useful overview of the authenticity issues surrounding the ingredient.

Reports on the adulteration of ginkgo dietary supplements have received the attention of the Center for Science in the Public Interest (CSPI), a “Food Watchdog” according to their website. Based on ConsumerLab’s 2018 ginkgo report and BAPP’s ginkgo leaf extract Botanical Adulterants Bulletin, CSPI sent a letter to Steven Tave, Director of the Office of Dietary Supplement Programs at the US Food and Drug Administration requesting more enforcement action by the agency against adulterated ginkgo products. The letter also questioned the efficacy and safety of ginkgo dietary supplements, in line with a letter CSPI sent in 2013 to Michael Landa, then the Director of the Center for Food Safety and Applied Nutrition (CFSAN), in which CSPI urged FDA to remove all ginkgo products from retail shelves because a study showed that extended ingestion of very high doses of ginkgo extracts had led to tumor growth in mice and rats.1 A short review of CSPI’s letter and a brief comment on the topic can be read in the Regulatory Alerts section.

The results of a preliminary report on adulteration of commercial ginkgo dietary supplements by researchers from Network Nutrition-IMCD in Australia have been included in the previous issue of the Botanical Adulterants Monitor. The group has now summarized the data in a “Ginkgo biloba Market Report,” and made it available by request to interested parties. A note on the report and details on how to access it is provided in the Industry Alert section of this newsletter.

Summaries of six scientific papers can be found in the Science section. With the exception of the HPTLC paper on Angelica and related Apiaceae species, these papers all included analytical data on a fairly large number of commercial dietary supplement samples, ranging from nine to 53 products. The first summary details a particularly sophisticated means of adulteration of saw palmetto, where fatty acids are blended together at the same ratio found in authentic saw palmetto extracts. A combination of isotopic fingerprinting, gas chromatography (GC), and nuclear magnetic resonance (NMR) was used to assess nine commercial samples labeled to contain saw palmetto. Ten commercial cranberry products from the French market were analyzed by high-performance thin-layer chromatography (HPTLC) and ultra high-performance liquid chromatography with mass spectrometric detection (UHPLC-MS). Since many of the selected products contained additional plant extracts, the HPTLC fingerprints were highly variable, complicating accurate determination of the presence of cranberry in these dietary supplements. The HPLC-UV analysis of over 50 commercial ginkgo dietary supplements marketed in Europe, published by Czigle et al., found quality issues in ca. 80% of the tested products, in agreement with other recent publications on the quality and authenticity of ginkgo.2-4 A similarly large sample set (N = 53) of echinacea dietary supplement products was evaluated by HPTLC and DNA metabarcoding. A vast majority of the products (between 80-90%) contained echinacea as claimed on the label. With the goal to harmonize analytical methods for the identification of medicinal plant members of the family Apiaceae, Frommenwiler et al., developed an HPTLC method that can be used for Angelica gigas and the roots of 26 other Apiaceae species. The fingerprints of the roots of these species could be distinguished using various detection reagents, suggesting that the method is suitable for authentication of these materials. The last paper summarized in this newsletter looked into the use of low field nuclear magnetic resonance (NMR) to detect adulteration of patchouli essential oil. NMR proved to be a useful tool for determination of admixture for most of the potential adulterants, but not as useful as gas chromatography-mass spectrometry (GC-MS). Of the 10 commercial patchouli samples measured by NMR, four were found to be adulterated.

We hope that the information included in this issue of the Botanical Adulterants Monitor will be useful. Feel free to circulate the information among your colleagues with the goal that the information will help to avoid adulterated ingredients finding their way into the supply chain for herbal dietary supplements and other finished botanical products.

Stefan Gafner, PhD
Chief Science Officer
American Botanical Council
Technical Director, ABC-AHP-NCNPR Botanical Adulterants Program

References

  1. Jacobson MF, Schardt D (CSPI). Letter to Landa MM (USFDA). June 3, 2013. https://cspinet.org/sites/default/files/attachment/ginkgo-fda-letter-6-3-2013.pdf. Accessed June 6, 2018.
  2. Ma Y-C, Mani A, Cai Y, et al. An effective identification and quantification method for Ginkgo biloba flavonol glycosides with targeted evaluation of adulterated products. Phytomedicine. 2016;23(4):377-387.
  3. A clear majority of European food supplements containing Ginkgo biloba extract found to be adulterated [white paper]. Bella Vista, NSW, Australia; Network Nutrition-IMCD; 2018.
  4. Avula B, Sagi S, Gafner S, Upton R, Wang YH, Wang M, Khan IA. Identification of Ginkgo biloba supplements adulteration using high-performance thin layer chromatography and ultra high-performance liquid chromatography-diode arrau detector quadrupole time of flight mass spectrometry. Anal bioanal Chem. 2015;407(25):7733-7746.
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