Grapple plant, wood spider
Derived from the root or tuber. Clinical studies reveal conflicting data about efficacy of devil's claw as an anti-inflammatory or analgesic. It has been thought that the iridoid glucosides may be responsible for activity, but they are not active when administered separately from whole root extract. The basis for chemical standardization is unknown. Analysis of commercial products reveals wide variance in chemical components. Limited side effects have been reported; diarrhea and bradycardia also occur (1). An open clinical study suggests that Devil's claw may benefit patients with osteoarthritis of the hip or knee (6). A systematic review of clinical trials suggests that it may also be effective in treating low back pain (7). Devil's claw increases gastric acid secretions and may interfere with the activity of antacids and histamine-2 blockers (e.g. ranitidine and famotidine) (3). Other possible drug interactions include increased activity of anticoagulants and cardiac and anti-arrhythmic drugs (1).
- GI disorders
- Muscle pain
- Iridoid glucosides: Harpagoside, harpagide and procumbide
- Phytosterols: B-sitosterol, oleanolic acid
- Flavonoids: Kaempferol and luteolin
- Phenolic acids
- Glycosidic phenylpropanoic esters: Verbascoside and isoacteoside
Mechanism of Action
In animal studies, an aqueous extract containing chiefly harpagoside showed significant dose-dependent anti-inflammatory and analgesic effects. Harpagoside is not implicated in the anti-inflammatory action, but, along with other constituents, it does appear to be involved in the peripheral analgesic properties. Devils claw also has antioxidant effects by scavenging both superoxide and peroxyl in a dose dependent manner (5). The bitter iridoids are responsible for the use of the herb as a stomachic. In vitro and in vivo animal studies have shown some evidence that devil's claw might be cardioactive. Lower doses seem to cause bradycardia and increase the strength of contraction, and high doses seem to weaken heart contractions and coronary blood flow (2).
Antacids / H2 Antagonists: Devil's claw may reduce efficacy due to increased production of stomach acid.
Beta blockers / Digoxin: Devil's claw may cause bradycardia and weaken heart contractions and coronary blood flow.
Anticoagulants: Devil's claw may have additive anticoagulant activity.
Cytochrome P450 enzymes: Devil's claw root can inhibit CYP1A2/2C8/2C9/2C19/2D6 and 3A4, and may interact with substances metabolized by these enzymes (8).
Literature Summary and Critique
Dosage (Inside MSKCC Only)
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- Newall CA, et al.Herbal Medicine: A Guide for Healthcare Professionals. London: Pharmaceutical Press; 1996.
- Wichtl MW. Herbal Drugs and Phytopharmaceuticals. Boca Raton: CRC Press; 1994.
- Schulz V, et al. Rational Phytotherapy: A Physicians Guide to the Use of Herbs and Related Remedies, 3rd ed. Berlin (Germany): Springer; 1998.
- Fiebich BL, et al. Inhibition of TNF-alpha synthesis in LPS-stimulated primary human monocytes by Harpagophytum extract SteiHap 69. Phytomedicine 2001;8:28-30.
- Langmead L, et al. Antioxidant effects of herbal therapies used by patients with inflammatory bowel disease: an in vitro study. Aliment Pharmacol Ther 2002;16:197-205.
- Wegener T, Lupke NP. Treatment of patients with arthrosis of hip or knee with an aqueous extract of devil's claw (Harpagophytum procumbens DC.). Phytother Res. 2003 Dec;17(10):1165-72.
- Gagnier JJ, van Tulder MW, Berman B, et al. Herbal medicine for low back pain. Spine 2007;32(1):82-92.
- Unger M, Frank A. Simultaneous determination of the inhibitory potency of herbal extracts on the activity of six major cytochrome P450 enzymes using liquid chromatography/mass spectrometry and automated online extraction. Rapid Commun Mass Spectrom. 2004;18(19):2273-81.