| Harpagophytum | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Asterids |
| Order: | Lamiales |
| Family: | Pedaliaceae |
| Genus: | Harpagophytum |
Harpagophytum procumbens, also called grapple plant, wood spider and most commonly devil's claw, is a plant of the sesame family, native to South Africa. It got its name from the peculiar appearance of its hooked fruit. The plant's large tuberous roots are used medicinally to reduce pain and fever, and to stimulate digestion. European colonists brought devil's claw home where it was used to treat arthritis.
H. procumbens are mainly found in the eastern and south eastern parts of Namibia, Southern Botswana and the Kalahari region of the Northern Cape, South Africa. H. Zeyheri is found in the northern parts of Namibia (Ovamboland) and southern Angola. The active ingredient is harpagoside (structure at PubChem [1]) with values ranging in both species from 1.0% to 3.3%.
The name "devil's claw" is also used for several species of North American plants in the genus Proboscidea, as well as Urtica dioica and certain species of Pisonia.
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The two active ingredients in Devil's Claw are harpagoside and beta-sitosterol. The British Herbal Pharmacopoeia recognises Devil's Claw as having analgesic, sedative and diuretic properties. Most studies involve chronic use, rather than acute treatment of pain.
Several studies have been performed using Doloteffin, a standardized preparation of Devil's Claw. Due to the natural variability of herbal extracts, the results of studies using different products and preparations are difficult to compare. A series of small-scale studies completed in Germany found that H. procumbens was comparable to Vioxx in the treatment of chronic low back pain,[1] and was well-tolerated after more than four years of treatment with H. procumbens alone.[2] H. procumbens also seems efficacious in the treatment of arthritis-caused hip and knee pain. An author involved in several studies on Devil's Claw and pain relief had the general conclusion that a minimum 50 mg per dose standardized extract was an alternative to synthetic analgesics with a low risk of adverse events.[3] A separate 2006 systematic review of herbal medications for low back pain reached the conclusion that a standardized daily dose between 50 and 100 mg of harpagoside performed better than a placebo, and an unspecified dose of harpagoside demonstrated relative equivalence to 12.5 mg per day of Vioxx.[4]
Devil's claw may interfere with the action of ticlopidine and warfarin, and patients should consult with a physician before combining Devil's claw with these medications. In addition, Devil's Claw promotes the secretion of stomach acid, leading to difficulties in those with peptic ulcers, gastritis or excess stomach acid. Care should also be taken for individuals with gallstones.