From The April 2001 Issue of Nutrition Science News
by Anthony Almada
One would not expect a plant with a diabolically painful name like devil's claw (DC) (Harpagophytum procumbens) to relieve arthritis pain. Yet several clinical studies have shown this herb to exert some pain relief for various musculoskeletal conditions. [1–4] Results of a recent German study involving 197 subjects with low back pain showed a 600 or 1,200 mg daily dose of DC extract (providing 50 or 100 mg of harpagoside, a marker constituent in DC extracts required in the German Commission E monographs) offers better pain relief than placebo.  However, subjects in the DC group experienced more frequent gastrointestinal upset.
In another study, 122 subjects with knee and hip osteoarthritis received 2.6 g/day of DC for four months while another group received an anti-osteoarthritic drug. Results revealed nearly equal symptom relief plus reduced pain reliever/anti-inflammatory medication use in the DC group.  As with many botanical extracts, the composition and chemical makeup can vary from manufacturer to manufacturer. Although we don't know the exact role harpagoside may play as an active ingredient, recent test tube studies suggest it has some influence on inflammatory processes. 
Anthony Almada is a nutritional and exercise biochemist and has collaborated on more than 50 university-based clinical trials. He is the co-founder of EAS and founder and chief scientific officer of IMAGINutrition.
Leblan D, et al. Harpagophytum procumbens in the treatment of knee and hip osteoarthritis. Four-month results of a prospective, multicenter, double-blind trial versus diacerhein.
Joint Bone Spine 2000;67:462-7
Chantre P, et al. Efficacy and tolerance of Harpagophytum procumbens versus diacerhein in treatment of osteoarthritis.
Chrubasik S, et al.. Effectiveness of Harpagophytum extract WS 1531 in the treatment of exacerbation of low back pain: a randomized, placebo-controlled, double-blind study.
Eur J Anaesthes 1999;16:118-291.
Chrubasik S, et al. Effectiveness of Harpagophytum procumbens in treatment of acute low back pain.
Benito PB, et al. Effects of some iridoids from plant origin on arachidonic acid metabolism in cellular systems.
Planta Med 2000;66:324-8
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