Pedaliaceae
Harpagophytum procumbens
Devil’s claw · Grapple plant
- Part used
- tuberroot
- Native range
- The Kalahari of Namibia, Botswana and South Africa
- Morphology
- A trailing perennial of sandy ground with lobed leaves and trumpet flowers, producing woody fruit armed with barbed hooks that catch in animals’ feet — which is what names it. The medicine is the secondary storage tuber.
What is in it
Evidence
Trials for low back pain and osteoarthritis report modest benefit, with some suggesting comparability to low-dose conventional treatment. Cochrane and subsequent reviews describe the evidence as moderate at best and the trials as small.
Safety
Generally well tolerated; gastrointestinal upset is commonest. Contraindicated in peptic ulcer, and cautioned in gallstones. Cardiac effects reported in animal work.
Interactions: Case reports of potentiated warfarin; Possible effects on drug-metabolising enzymes
Regulatory: Permitted as a listed medicine ingredient. Harvest is regulated in Namibia and it is on CITES Appendix II for monitoring purposes in some listings.
Historical use
Used by San and Khoi peoples of the Kalahari for pain, fever and digestive complaints. Commercial export to Europe began in the mid-twentieth century and it is now a substantial German and French herbal medicine.
Recorded as history and attributed where possible. Long use establishes that a plant was widely used, not that it worked, and not that it was safe.
Worth knowing
Devil's claw is the clearest African case of the benefit-sharing problem, and one where something has actually been attempted.
The plant is harvested almost entirely from the wild by rural San and other Kalahari communities, who dig the secondary tubers by hand, and it supplies a European herbal market worth many times what the harvesters receive. Namibia has built regulated harvesting schemes and organic and fair trade certification exists for part of the trade.
Whether that constitutes benefit-sharing or a better-documented version of the same arrangement is argued about by the people involved. What is not in dispute is that harvesting the storage tuber sets the plant back years, and that demand has grown faster than anyone counted the population.
Nomenclature verified against GBIF backbone taxonomy.