Harpagophytum procumbens Common name: Devils Claw
Parts used: Tuber (secondary roots)
Constituents: Iridoid glycosides [mainly harpagoside (1.4%-2.0%), harpagide, procumbide], Flavonoids, Phenolic acids, Harpagoquinone, Phytosterols [beta-sitosterol, stigmasterol], sugars
Medicinal actions: Anti-inflammatory, anti-rheumatic, analgesic, sedative, antioxidant
Medicinal use: Devils claw is used in the treatment of arthritis, and has significant anti-inflammatory activity. Other actions of Harpagophytum that aid in its anti-arthritic application are its analgesic and vasodilatory effects. Can be used in tendonitis and to treat degenerative diseases of the musculoskeletal system.
Pharmacology: Anti-inflammatory effect varies with the route of administration and nature of the condition (acute or subacute). The pharmacokinetics of devil’s claw and the iridoid glycosides have not been established. Indeed, there is some controversy on the action of the stomach or acid hydrolysis on the extract and its active ingredients. Some authors suggest that the substances obtained after acid hydrolysis, especially harpagogenin, are the active compounds producing the anti-inflammatory and anti-arthritic properties, whereas other studies suggest that the extract, and harpagoside in particular, may be partially inactivated by the acid milieu of the stomach.
Most NSAIDs act by inhibiting prostaglandin biosynthesis. Both in vitro and in vivo studies have demonstrated that devil’s claw has minimal effects on production of these compounds. Studies indicate that devil’s claw is unlikely to act by a similar mechanism to NSAIDs and further suggest that devil’s claw will not have the same irritant effects on the stomach which these drugs have.
Pharmacy: Powdered tuber: 100-250 mg TID (note: for analgesic effects should be taken in enteric coated capsules with meals). Tincture (1:2, 25%), 6-12 ml QD. Decoction: 1 tsp/cup, simmer 15 min, 1 cup TID for at least 1 month.
Contraindications: Caution with peptic ulcers, congestive heart failure, gallstones
Toxicity: Higher doses may cause transient mild GIT disturbances such as diarrhea & flatulence. Frontal headaches, conjunctivits, tinnitus, tachycardia, rhinitis have been reported.
Interactions: Caution with anti-arrhythmic and blood pressure medications (theoretical). Less effective if taken with antibiotics (needs intestinal bacteria for activation).