A Review of Herbal Treatment Options for the Symptoms of Rheumatoid Arthritis
Rheumatoid arthritis (RA), a multifactorial progressive autoimmune disease, causes inflammation and hypertrophy in synovial tissue in joints, leading to joint tissue destruction. Treatment of RA includes a multicomponent regimen including herbs. Yarnell organizes herbs for RA effects as follows: inflammation-modulating, immunomodulating, and “spicy relief.” Miscellaneous Asian herbs and formulas and thunder duke vine (Tripterygium wilfordii, Celastraceae) also are covered in this review.
Inflammation modulation, distinct from suppression, aims to lower inflammatory “tone,” addressing RA causes, pathology, and symptoms. In the inflammation-modulating herbs studied in RA, omega-6 γ-linolenic acid (GLA)-rich seed oils from evening primrose (Oenothera biennis, Onagraceae), black currant (Ribes nigrum, Grossulariaceae), and borage (Borago officinalis, Boraginaceae) show promise. However, benefits of GLA are questionable in diets with high amounts of its precursor, omega-6 linoleic acid (LA). GLA is the precursor for dihomo-gamma-linolenic acid (DGLA), the precursor of anti-inflammatory series 1 prostaglandins, and for arachidonic acid (AA), the precursor of pro-inflammatory series 2 prostaglandins. Positive results in trials and lack of serious adverse effects (AEs) favor GLA-rich herbs in RA management. Adding eicosapentaenoic acid (EPA) from fish oil may prevent GLA to DGLA conversion. In some trials, fish oil alone was just as effective as fish oil with GLA.
Black cumin (Nigella sativa, Ranunculaceae) seed oil reduced disease symptoms compared to placebo in two trials, with inflammation-modulating and immunomodulating effects. Devil’s claw (Harpagophytum procumbens and H. zeyheri, Pedaliaceae) has been shown to be overall beneficial in clinical investigations. Salicylate glycosides, mainly salicin, from willow (Salix spp., Salicaceae), aspen (Populus tremula, Salicaceae), and cottonwood (Populus spp.) tree barks, have been used historically for RA. One modern trial assessing a salicin-rich extract from European violet willow (Salix daphnoides) found no difference in RA pain scores or AEs compared to placebo. Trials of two European multi-herb products containing salicylate-rich herbs report positive results. One, Phytodolor® (Steigerwald Arzneimittelwerk GmbH; Darmstadt, Germany), has strong evidence for efficacy and “seems appropriate for clinical use.” The product, unavailable in North America at time of writing, may be approximated with equal parts aspen, European goldenrod (Solidago virgaurea, Asteraceae), and European ash (Fraxinus excelsior, Oleaceae). Other potentially inflammation-modulating herbs are listed in a table.
Immunomodulating herbs are shown to help patients with RA; however, the few published studies are mostly disappointing. Randomized controlled trials (RCTs) of two formulas containing ashwagandha (Withania somnifera, Solanaceae) root, ginger (Zingiber officinale, Zingiberaceae) rhizome, and other herbs, as well as ginger on its own, and of the single Ayurvedic herb bhallataka (marking-nut tree; Semecarpus anacardium, Anacardiaceae), reported that the products had good results and excellent safety. Reishi (Ganoderma lucidum, Ganodermataceae), taken with the Chinese herbal formula Sān Miào Sǎn (Three Wonder Powder), was assessed in two trials with inconclusive results but excellent safety. Andrographis (Andrographis paniculata, Acanthaceae) aerial parts, an important Asian medicine, is an immune stimulant and immunomodulator. An RCT studied the anti-RA effect of an andrographis extract containing 30 mg andrographolide given thrice daily for 14 weeks. Results showed that while the pain scores did not show change or reduction, the severity of swelling and tenderness in joints decreased significantly.
“Spicy relief” refers to topical capsaicin from cayenne (Capsicum annuum syn. C. frutescens, Solanaceae). In a double-blind RCT of capsaicin, 31 patients used a capsaicin cream or placebo for pain. The capsaicin group showed significant improvement in pain score. Yarnell includes garlic (Allium sativum, Amaryllidaceae) under this heading, although it is taken orally and may act as an immunomodulator. In one study, Russian patients with RA taking disease-modifying drugs were randomly assigned to receive a garlic extract or no additional therapy for four to six weeks; 87% of the garlic group had at least a partial response but no information was reported for the drug-only group. Among Chinese herbs, white peony (Paeonia lactiflora, Paeoniaceae) may have both inflammation-modulating and immunomodulating effects in RA. It is also a hormone modulator and spasmolytic. Most importantly, white peony is reported to reduce hepatotoxicity of the common RA drugs methotrexate and leflunomide—”For this reason alone, white peony should be considered for use in combination with these drugs … .” RCTs of Chinese and Korean multi-herb formulas (the former including animal products and combined, in one treatment arm, with moxa) report excellent safety and many benefits.
Thunder duke vine root and stem without bark is a potent immunosuppressant. The traditional decoction was associated with high rates of serious AEs; in response, two safer extracts were developed. Not easily obtainable in North America, Yarnell states that the extracts should not be recommended without more evidence of efficacy and safety, but a meta-analysis of 10 RCTs found them safer than, and just as effective as, immunosuppressive drugs. Another meta-analysis of six RCTs comparing methotrexate alone to methotrexate with thunder duke vine extracts found the combination more effective and with similar safety compared to methotrexate alone. Chinese licorice (Glycyrrhiza uralensis, Fabaceae), an immunomodulator and inflammation modulator, is a good choice for use with thunder duke vine to reduce toxicity. A topical preparation of thunder duke vine also showed good results in an RCT.
Yarnell E. Herbs for rheumatoid arthritis. Altern Complement Ther. August 2017;23(4):149-156.