Posted on 10/22/2012 at 01:53:19 PM by Student BloggerBy Stefano Vendrame
Harpagophytum procumbens, commonly known as the Devil's claw, is a perennial South African plant whose roots have long been known for their medicinal properties. In an extensive review published in October 2012 (1), a team of South African researchers looked at the available evidence regarding the biological effects of this plant. The ability to alleviate joint pain is the effect most associated with Harpagophytum procumbens.
Osteoarthritis is an extremely common chronic inflammatory condition characterized by the breakdown and eventual loss of cartilage in the joints, which reduces the ‘cushion' effect of cartilage between the two bones of a joint. This leads to reduced joint mobility and - perhaps even more invalidating - joint pain.
Unfortunately, conventional medicine offers very limited help for osteoarthritis. There is no known cure, and the only possible treatment involves managing pain with painkillers such as acetaminophen and NSAIDs. There are, however, four complementary and alternative medicine treatments which are often recommended to help manage osteoarthritic pain: acupuncture, glucosamine/chondroitin, fish oil, and of course, the Devil's claw (2).
More than 30 clinical trials have tested the validity of Harpagophytum procumbens as an anti-inflammatory and analgesic botanical, especially for relieving arthritic symptoms. Devil's claw supplementation has been consistently shown to be safe and effective for managing pain in patients suffering from knee or hip osteoarthritis and non specific low back pain (3).
It has been tested in double-blind trials, against placebos but also against conventional medications such as rofecoxib. Harpagophytum has been shown to work better than a placebo (4), and substantially equivalent to other medications, but with less side effects (5). After a few weeks of daily Devil's claw supplementation, most patients were able to reduce or stop concomitant use of NSAIDs (5).
But how does the Devil's claw do it? Since the progression of osteoarthritis is mostly sustained by inflammation, the well-known anti-inflammatory effect of Harpagophytum is likely the key to its effectiveness, resulting both in pain reduction and in improved joint function. But what is responsible for this effect? The active components are believed to be its iridoid glycosides, and in particular the monoterpene harpagoside. Indeed, harpagoside is associated to a strong anti-inflammatory activity via NF-kB (nuclear factor kappa b) inhibition (6). As recently reviewed, however, harpagoside alone doesn't explain the whole story. Harpagophytum also contains unique triterpenoids, phytosterols, aromatic acids and sugars. Yet none of them, taken alone, account for the whole effect of the botanical.
Like the authors of the review concluded, “when the constituents deemed to be the biologically active compounds [are] isolated, the efficacy [is] lower than that of the whole extract” (1). If anything, this shows once more that botanicals, just like food, are more than just the sum of their components, and certainly much more than a single ‘active' compound, much to the frustration of food pharmacologists.
In conclusion, it looks like the ‘claw of the Devil' is indeed able to kill the pain, though it takes some time to do it (at least a few weeks). But how it does that, we still don't know for sure. What else did you expect? It can't be so easy to figure out the Devil's tricks.
(1) Mncwangi N, Chen W, Vermaak I, Viljoen AM, Gericke N. Devil's Claw-A review of the ethnobotany, phytochemistry and biological activity of Harpagophytum procumbens. J Ethnopharmacol. 2012;143(3):755-71.
(2) Sanders M, Grundmann O. The use of glucosamine, devil's claw (Harpagophytum procumbens), and acupuncture as complementary and alternative treatments for osteoarthritis. Altern Med Rev. 2011;16(3):228-38.
(3) Warnock M, McBean D, Suter A, Tan J, Whittaker P. Effectiveness and safety of Devil's Claw tablets in patients with general rheumatic disorders. Phytother Res. 2007;21(12):1228-33.
(4) Chrubasik S, Thanner J, Künzel O, Conradt C, Black A, Pollak S. Comparison of outcome measures during treatment with the proprietary Harpagophytum extract doloteffin in patients with pain in the lower back, knee or hip. Phytomedicine. 2002;9(3):181-94.
(5) Chantre P, Cappelaere A, Leblan D, Guedon D, Vandermander J, Fournie B. Efficacy and tolerance of Harpagophytum procumbens versus diacerhein in treatment of osteoarthritis. Phytomedicine. 2000;7(3):177-83.
(6) Huang TH, Tran VH, Duke RK, Tan S, Chrubasik S, Roufogalis BD, Duke CC. Harpagoside suppresses lipopolysaccharide-induced iNOS and COX-2 expression through inhibition of NF-kappa B activation. J Ethnopharmacol. 2006;104(1-2):149-55.