Botanical Name: Harpagophytum procumbens, Pedaliaceae

Common names: Devil's Claw (from the German Teufelskralle), Grapple plant, Wood Spider, Windhoeks' root. Although similarly named, Devil's Club (Oplopanax horridus) is unrelated to Devil's Claw.

Plant description: Devil's Claw is a weedy, perennial plant with creeping stems that spreads from a tuberous rootstock.  The leaves are grayish-green, alternate or oppositely arranged.  The flowers are red-violet, yellow-violet or violet flowers that arise from the leaf axils.  The flowers give way to an octopus-shaped fruit with long barbed tentacles called a trample bur, a lignified fruit shell with spikes and barbs that stick to the soft parts of ruminant animals ensuring the distribution of its seed.  The primary roots of Devil's Claw may descend more than 2 m into the soil, with secondary roots spreading out on all sides up to 1.5 m from the plant.

Habitat, ecology and distribution: Devil's Claw is native to the savannah of the Kalahari region of South Africa, Namibia and Botswana.

Part used: secondary storage roots, tuber; root.

History: Devil's Claw has long been used by the indigenous people of southern Africa, such as by the Khoisan peoples of the Kalahari Desert who used Devil's Claw to treat pain and complications of pregnancy, as well as in topical medicaments to heal sores, boils, and other skin problems. Its usage in Western herbal medicine however stems from a German farmer named G.H. Menhert who observed its efficacy in treating casualties of the Hottentot rebellion of 1904.  Apparently the soldiers were given up for lost, when a local shaman prepared a medicine that cured them. Menhert later followed the shaman and discovered the plant that had been used, and then began to distribute it.  Devil's Claw is for the most part wildcrafted in South Africa, and thus measures should be taken to ensure that the herb has been ethically and sustainable harvested.

Constituents: Devil's Claw is noted for its iridoid glycosides that comprise upwards of 0.5-3% of the crude herb.  The iridoids have been found to be significantly higher in the secondary tubers.  Among the iridoids is the bitter-tasting harpagoside, as well as isoharpagoside, harpagide and procumbide.  In addition to these constituents are the phenolic glycosides acetoside and isoacetoside, as well as triterpenes, phytosterols and flavonoids (lutein, kaempferol). Devil's Claw contains upwards of 50% carbohydrates, of which stachyose comprises about 46%, as well as raffinose, fructose, galactose, sucrose and glucose in lesser amounts (Bradley 1992, 78; Newall et al 1996, 98; Mills and Bone 2000, 346). Commercial sources of Devil's Claw may be adulterated with other bitter-tasting African species of the Elephantorrhiza and Acanthosicyos genera (Kemper 1999, 1).

Medical Research:
•Arthritis and pain: Several clinical trials have demonstrated the efficacy of Devil's claw in the treatment of muscle and joint pain. In one clinical study 250 patients suffering from nonspecific low back pain or osteoarthritic pain in the knee or hip took an 8-week course of a proprietary product called Doloteffin, comprising a dose equal to 60 mg of harpagoside per day.  In a multivariable analysis of the results any improvements noted tended to be observed when the initial pain and disability score was more.  Further, older patients tended to improve less than younger patients, the hip group tended to improve more than the back group, whereas those suffering from knee pain obtained similar results with those suffering back pain. Between 50% and 70% of those patients that continued with the study were found to benefit from Doloteffin, with few adverse effects. The researchers concluded that Devil's Claw is an important therapy in osteoarthritic knee and hip pain, and nonspecific low back pain (Chrubasik et al 2002). In a randomized, double-blind, placebo controlled study the effects of Devil's Claw on sensory, motor and vascular mechanisms of lower back pain were studied, as well as possible action mechanisms action.  In the study group patients were given two 480 mg capsules of Devil's Claw on a daily basis.  Compared with placebo, the study group clearly showed beneficial results in both patient and physician ratings, with no serious side effects.  Researchers postulate that Devil's Claw has an effect on sensory and vascular muscular response, reducing muscle stiffness without acting on the central nervous system (Gobel et al 2001). In an open, multicenter study the clinical effectiveness and tolerance of the Devil's Claw extract in patients suffering from non-radicular back pain was studied over a period of 6 months. A total of 130 patients were treated twice a day with tablets containing 480 mg of Devil's Claw extract for eight weeks. The results demonstrated a significant improvement of pain symptoms and mobility in the affected sections of the patient's spine during the course of treatment, without any serious side effects were observed (Laudahn and Walper 2001).  "In a double-blind, randomized, multicentre clinical study, the efficacy and tolerance of a herbal medicine product, Harpadol (6 capsules/day, each containing 435 mg of powdered cryoground powder Devil's Claw), was compared with diacerhein 100 mg/day in the treatment, for 4 months, of 122 patients suffering from osteoarthritis of the knee and hip.  Spontaneous pain showed a significant improvement during the course of the study and there was no difference in the efficacy of the two treatments. Similarly, there was a progressive and significant reduction in the Lequesne functional index and no statistical difference was found between Harpadol and diacerhein. At completion of the study, patients taking Harpadol were using significantly less NSAIDs and antalgic drugs. The frequency of adverse events was significantly lower in the Harpadol group. The most frequent event reported was diarrhea, occurring in 8.1% and 26.7% of Harpadol and diacerhein patients respectively. The global tolerance assessment by patients at the end of treatment favoured Harpadol. The results of this study demonstrate that Harpadol is comparable in efficacy and superior in safety to diacerhein" (Chantre et al 2000).
•Inflammation: Devil's Claw extract and its marker substance harpagoside were investigated with respect to its activity on leukotriene and thromboxane biosynthesis in vitro and ex vivo.  Different fractions of Devil's Claw extracts were tested in vitro in human whole blood samples for effects on basal and ionophore A23187-stimulated cysteinyl-leukotriene (Cys-LT) and thromboxane synthesis.  Human male volunteers were also administered a Devil's Claw extract orally and tested in whole blood samples for Cys-LT and thromboxane B2 (TXB2) biosynthesis and for the determination of pharmacokinetic parameters of harpagoside. Devil's Claw extract demonstrated a stronger inhibitory effect on ionophore A23187-stimulated Cys-LT levels compared with pure harpagoside or other extract fractions. Fractions without harpagoside had no pronounced inhibitory effect. When Cys-LT levels were measured after oral intake of Devil's Claw extract, a biphasic but dose-independent decrease of 28% and 58%, respectively, in basal Cys-LT formation was observed. Researchers suggest that there is a strong indication of a close relation between serum harpagoside levels and the inhibition of leukotriene biosynthesis (Loew et al 2001). The anti-inflammatory properties of a Devil's Claw extract on primary human monocytes was investigated.  After eliminating lipopolysaccharides (LPS) of bacterial origin, the Devil's Claw extract prevented the LPS-induced synthesis of tumour necrosis factor alpha (TNFalpha) in stimulated primary human monocytes in a dose-dependent manner. Harpagide and harpagoside had no effect on LPS-induced TNFalpha-release (Fiebich et al 2001). Devil's Claw was investigated in healthy humans for its effect on eicosanoid synthesis during spontaneous blood clotting. Volunteers took 4 50 mg capsules of Devil's Claw powder standaridzed 3% iridoid glycosides for a period of 21 days.  Each subject served as her own control, and no statistically significant differences were observed between before and after Devil's Claw intake. The results indicated that Devil's Claw lacks the biochemical effects on arachidonic acid metabolism of antiarthritic drugs such as NSAIDs (Moussard 1992). A dried aqueous extract of Devil's Claw and its main iridoid glycoside, harpagoside, were evaluated for their respective anti-inflammatory and analgesic effects in mice and rats. The aqueous extract exerted a significant and dose-dependent anti-inflammatory and analgesic effect in carrageenan-induced edema test in rats and chemical stimulus induced writhing in mice. Harpagoside did not protect against carrageenan inflammatory effects when it was used at 5 and 10 mg/kg; 5 mg corresponding to the quantity contained in 400 mg of dried secondary roots. The authors conclude that harpagoside appears to be implicated in peripheral analgesic properties, but other compounds are likely to be involved (Lanhers et al 1992).
•Cardiovascular: A crude methanolic extract of Devil's Claw secondary roots and harpagoside showed a significant, dose-dependent, protective action against hyperkinetic ventricular arrhythmias induced by reperfusion (Costa et al 1985). A methanolic extract of Devil's Claw secondary roots was found to demonstrate a significant dose-dependent reduction of arterial blood pressure and decrease in heart rate in rats. The decrease was significant only at doses of 400mg/kg given by gavage.  The Devil's Claw extract also demonstrated a protective action against arrhythmias induced by aconitine and chloroform (Circosta et al 1984).

Toxicity: The oral LD50 for Devil's Claw in. rats is stated to be more than 13.5 g/kg.  Other studies have confirmed the safety of Devil's Claw (Mills and Bone 2000, 348).
Herbal action: bitter tonic, analgesic, anti-inflammatory, antirrheumatic

Indications: poor appetite, dyspepsia, rheumatism, arthritis, gout, fever, chronic pain

Contraindications and cautions: High doses may aggravate gastric and duodenal ulcers.

Medicinal uses: Devil's Claw has increasingly become a popular herbal remedy in the West for the treatment of joint and muscle pain, based primarily on its usage among European settlers in Africa, who in turn learned of some of its uses from the indigenous African herbalists.  In some respects Devil's Claw is similar to other bitter-tasting herbs such as Salix and Populus that have a profound analgesic and antirheumatic activity.  Devil's Claw of course lacks the same phenolic glycosides as these Salicales, and despite the iridoid harpagoside being fingered initially as the 'active' ingredient, several studies have shown that a crude extract of the whole herb is more effective as an analgesic.  How Devil's Claw works is still a matter of some debate, especially since other less-studied constituents such as the triterpenes may offer some interesting answers.  From a herbalists perspective Devil's Claw is a bitter tonic, on par with Gentian, and like many other bitter tonics Devil's Claw promotes glandular secretions and the elimination of wastes.  In this respect Devil's Claw can be thought of as an alterative, gently acting upon the tissues, eliminating cellular wastes in joint and muscle tissues by stimulating hepatic metabolism and kidney output. It combines this however with a well-studied analgesic effect, making Devil's Claw an important medicament in most forms of arthritis, including gouty, rheumatoid and osteo arthritis.  Weiss reports that Devil's Claw may also be helpful in pain associated with spondylosis, neuralgia and headaches (1988, 266).  In the treatment of dyspeptic conditions Weiss indicates that Devil's Claw may be helpful in epigastric pain and abdominal distension, as well as in gall-bladder disease, with or without pancreatic involvement.  Weiss also provides evidence that Devil's Claw has a general ability to reduce serum cholesterol and triglycerides, and that it is suitably indicated in older patients suffering from rheumatic diseases, dyslipidemia and obesity (1988, 266-7).

Pharmacy and dosage:
•Tincture: dried secondary tubers, 1:5, 25% alcohol, 20-60 gtt, 3-10 mL
•Decoction: 1:2, 60-120 mL
•Powder: 3-6 g

REFERENCES

Bradley, Peter R. ed. 1992. British Herbal Compendium. Bournemouth, UK: British Herbal Medicine Association.
Chrubasik S, Thanner J, Kunzel O, Conradt C, Black A, Pollak S. 2002. Comparison of outcome measures during treatment with the proprietary Harpagophytum extract doloteffin in patients with pain in the lower back, knee or hip. Phytomedicine Apr;9(3):181-94
Circosta C, Occhiuto F, Ragusa S, Trovato A, Tumino G, Briguglio F, de Pasquale A. 1984. A drug used in traditional medicine: Harpagophytum procumbens DC. II. Cardiovascular activity. J Ethnopharmacol Aug;11(3):259-74
Costa De Pasquale R, Busa G, Circosta C, Iauk L, Ragusa S, Ficarra P, Occhiuto F. 1985. A drug used in traditional medicine: Harpagophytum procumbens DC. III. Effects on hyperkinetic ventricular arrhythmias by reperfusion. J Ethnopharmacol. May;13(2):193-9
Fiebich BL, Heinrich M, Hiller KO, Kammerer N. 2001. Inhibition of TNF-alpha synthesis in LPS-stimulated primary human monocytes by Harpagophytum extract SteiHap 69. Phytomedicine. Jan;8(1):28-30
Gobel H, Heinze A, Ingwersen M, Niederberger U, Gerber D, Schmerz. 2001. Effects of Harpagophytum procumbens LI 174 (devil's claw) on sensory, motor und vascular muscle reagibility in the treatment of unspecific back pain. Neurologisch-verhaltensmedizinische. Feb;15(1):10-8
Kemper, Kathi. 1999. Devil's Claw. Longwood Herbal Task Force.  Available from http://www.mcp.edu/herbal/default.htm
Lanhers MC, Fleurentin J, Mortier F, Vinche A, Younos C. 1992. Anti-inflammatory and analgesic effects of an aqueous extract of Harpagophytum procumbens. Planta Med Apr;58(2):117-23
Laudahn D, Walper A. 2001. Efficacy and tolerance of Harpagophytum extract LI 174 in patients with chronic non-radicular back pain. Phytother Res Nov;15(7):621-4
Loew D, Mollerfeld J, Schrodter A, Puttkammer S, Kaszkin M. 2001. Investigations on the pharmacokinetic properties of Harpagophytum extracts and their effects on eicosanoid biosynthesis in vitro and ex vivo. Clin Pharmacol Ther. May;69(5):356-64
Mills, Simon and Kerry Bone. 2000. Principals and Practice of Phytotherapy. London: Churchill Livingstone
Moussard C, Alber D, Toubin MM, Thevenon N, Henry JC. 1992. A drug used in traditional medicine, harpagophytum procumbens: no evidence for NSAID-like effect on whole blood eicosanoid production in human. Prostaglandins Leukot Essent Fatty Acids 1992 Aug;46(4):283-6
Newall, Carol A., Linda A. Anderson and J.D. Phillipson. 1996. Herbal Medicines: A Guide for Health-Care Professionals. London: The Pharmaceutical Press.
Weiss, Rudolf. 1988. Herbal Medicine. Translated by A.R. Meuss. Beaconsfield, England: Beaconsfield Publishers