What is devil’s claw

Devil’s Claw (Harpagophytum procumbens) is a perennial herb from the Kalahari region of Southern Africa and may be found in Namibia, Botswana, South Africa, Angola, Zambia, and Zimbabwe. The botanical name, Harpagophytum, means “hook plant” in Greek. Devil’s Claw plant gets its name from the appearance of its fruit, which is covered with hooks meant to attach onto animals in order to spread the seeds. Devil’s Claw roots and tubers are used to make medicine. Historically, Devil’s Claw has been used as anti-inflammatory, analgesic, anti-oxidant, anti-diabetic, antimicrobial, anti-malarial, anticancer, hypotensive and cardiodepressant, anticonvulsant, “hardening of the arteries” (atherosclerosis), arthritis, gout, muscle pain (myalgia), back pain, fibromyalgia, tendonitis, chest pain, gastrointestinal (GI) upset or heart burn (dyspepsia), fever, and migraine headache and uterotonic activities ¹⁾, as well as appetite stimulation, wounds and skin rashes, liver and kidney disorders, as diuretic and sedative, and to treat degenerative disorders of the musculoskeletal system ²⁾. Devil’s Claw plant has been also used as an appetite modulator but most evidences are anecdotal ³⁾ and no clear scientific studies relating to appetite modulation have been done to this date ⁴⁾. Devil’s Claw is also used for difficulties in childbirth, menstrual problems, allergic reactions, kidney and bladder disease.

British Herbal Pharmacopoeia recommends devil’s claw as a diuretic and sedative ⁵⁾ and the German Commission E, the German counterpart to the U.S. Food and Drug Administration (FDA), approves devil’s claw for dyspepsia, appetite stimulation, and degenerative disorders of the musculoskeletal system ⁶⁾.

Extracts made from the tubers of Devil’s Claw (Harpagophytum procumbens) are known to relieve symptoms of inflammation and pain ⁷⁾ but there has been some argument about whether medicinal properties of Harpagophytum zeyheri are sufficient for the acceptance of this species for use in anti-inflammatory preparations ⁸⁾. The pharmacological actions of Devil’s Claw root tubers have been attributed to the presence of iridoid glycosides and verbascoside ⁹⁾. Studies have demonstrated anti-inflammatory properties such as inhibition of COX-2, inhibition of NF-kB activation, and downregulation of iNOS ¹⁰⁾. However, the effects of Devil’s Claw have also been associated with the presence of other compounds such as flavonoids ¹¹⁾.

Devil’s claw belongs to the Pedaliaceae family and is also known as grapple plant, wood spider, and harpago. Devil’s claw is a ground trailing, weedy perennial about 18 inches long with a stout central taproot growing up to two meters deep. Secondary storage tubers, resembling elongated sweet potatoes, branch off horizontally. Leaves are large, have 3-5 lobes, and are covered in white mucilaginous cells, making them appear a grayish-green color. Flowers are trumpet shaped and pink, red, or purple with a yellowish center. The fruit grows from the flower and is woody, radiates numerous long, barbed spines, and gives the plant its commonly known names.

Figure 1. Devil’s claw plant

Devil’s claw anti inflammatory

Currently Devil’s Claw is mainly used as an anti-inflammatory agent and as an analgesic ¹²⁾.

The major chemical constituents of Devil’s claw are iridoid glycosides (primarily harpagoside, harpagide, and procumbide), sugars (mainly the tetrasaccharide, stachyose), triterpenoids (oleanolic and ursolic acid), phytosterols (primarily β-sitosterol), aromatic acids (caffeic, cinnamic, and chlorogenic acids), and flavonoids such as luteolin and kaempferol ¹³⁾. Harpagoside, harpagide, and procumbide, found in the tubers of the plant, appear to be the most therapeutically important constituents. Whole-plant extracts appear to have a better therapeutic effect than those prepared from isolated parts ¹⁴⁾. A large body of evidence indicates that Devil’s claw may be an effective treatment for osteoarthritis because of its pain-relieving and anti-inflammatory actions. Higher concentrations of serum oxygen-free radicals prevalent with arthritis may alter the oxidant/antioxidant balance, thus facilitating lipid peroxidation and leading to tissue damage ¹⁵⁾. Devil’s claw extract has been shown to increase superoxide dismutase, catalase, glutathione peroxidase enzyme activities in a dose-dependent manner and a reduction in lipid peroxidation was also noted in vivo, which contribute to its antioxidant effects ¹⁶⁾. The flavonoids and plant phenols present in Devil’s claw extracts may be the constituents responsible for the observed antioxidant activity ¹⁷⁾. Devil’s claw has been found to scavenge both superoxide and peroxyl radicals ¹⁸⁾. A recent study also showed that both root tuber extract of Devil’s claw and tincture are effective as free radical scavengers and inhibit LPS-induced nitrite levels in RAW 264.6 macrophages ¹⁹⁾. Significant antioxidant effects by an aqueous extract of Devil’s claw and by the flavonoid constituents lutteolin and kaempferol have also been noted ²⁰⁾. A dried aqueous extract (5 and 10 mg/kg) of Devil’s claw has been shown to exert a significant dose-dependent analgesic and anti-inflammatory effect in rats. However, carrageenan-induced paw edema was not affected by harpagoside, suggesting harpagoside may not have an anti-inflammatory effect at least in the doses used in vivo ²¹⁾. In vitro data also demonstrated that the active principle (sum of coactive constituents) of Devil’s claw inhibits not only inflammatory mediators such as iNOS and COX-2 mediated PGE2 production ²²⁾ or leukotriene release ²³⁾ but also mediators of cartilage destruction, such as TNFα, IL-1β, IL-6, MMPs, NO ²⁴⁾, and elastase ²⁵⁾. Reported chondroprotective effects of Devil’s claw may be due to suppression of NF-κB activation, thereby inhibiting inflammation ²⁶⁾.

Devil’s claw extract appears to be safe when used in appropriate dosages. The side effects are few, usually limited to gastrointestinal upset, dyspepsia and loss of taste; no long-term toxicities or drug-interactions are known ²⁷⁾. Devil’s claw extract exerts a peripheral analgesic effect as it has been demonstrated to decrease pain in knee and hip osteoarthritis ²⁸⁾. The effectiveness of certain Devil’s claw preparations has been tested with a daily dose of 360 mg of harpagoside (a coactive ingredient) in the treatment of painful osteoarthritis of the hip, knee and nonspecific low back pain. Multivariate analysis confirmed that in all groups, both the generic and disease-specific outcome measures improved by week 4 and further by week 8 ²⁹⁾. Devil’s claw powder was equally effective as diacerhein (a slow-acting drug for osteoarthritis that is not available in the U.S.) in reducing pain as measured using a 100 mm VAS. This study constitutes moderate evidence that 4 months’ daily use of 2610 mg Devil’s claw powder is not significantly different from 100 mg diacerhein, producing comparable improvements in pain ³⁰⁾. Studies on Devil’s claw extracts, containing 50–100 mg harpagoside daily, have shown the best results ³¹⁾]. In a clinical study, 89 patients with osteoarthritis were randomized to receive placebo or devil’s claw at a total daily dose of 2010 mg/day for 8 weeks. The study identified that after 30 and 60 days of treatment, patients who received devil’s claw had a significant reduction in pain compared with placebo ³²⁾. Effectiveness, safety and tolerability of Devil’s claw was studied in rheumatic disorders including osteoarthritis for 8 weeks (259 patients). There were statistically significant improvements in patient assessment of global pain, stiffness, function and quality of life. There were also statistically significant reductions in mean pain scores for hand, wrist, elbow, shoulder, hip, knee and back pain ³³⁾. Numerous trials have been conducted using several Devil’s claw extracts for osteoarthritis. Unfortunately, the results of many of the studies are of questionable value because of methodological flaws. However, Devil’s claw appears to be effective in the reduction of pain. More high-quality trials are needed to assess the effectiveness and efficacy of Devil’s claw to determine whether this is a beneficial remedy for the treatment of osteoarthritis.

What is devil’s claw used for?

Devil’s claw is possibly effective for:

• Back pain: Taking Devil’s claw by mouth seems to reduce low-back pain. Devil’s claw seems to work about as well as some non-steroidal anti-inflammatory drugs (NSAIDs).
• Osteoarthritis: Taking Devil’s claw alone or along with nonsteroidal anti-inflammatory drugs (NSAIDs) seems to help decrease osteoarthritis-related pain. Some evidence suggests that devil’s claw works about as well as diacerhein (a slow-acting drug for osteoarthritis that is not available in the U.S.) for improving osteoarthritis pain in the hip and knee after 16 weeks of treatment. Some people taking devil’s claw seem to be able to lower the dose of NSAIDs they need for pain relief.

Insufficient evidence to rate effectiveness for:

• Rheumatoid arthritis. Early research suggests that taking devil’s claw extract by mouth might not improve rheumatoid arthritis.
• Gout.
• High cholesterol.
• Loss of appetite.
• Muscle pain.
• Migraine headache.
• Skin injuries and conditions.
• Upset stomach.
• Other conditions.

More evidence is needed to rate Devil’s claw for these uses.

Devil’s claw dosage

Devil’s claw extracts can be administered in several forms; dosage varies with each, depending on concentration of active constituents present. The following
are typical dosages used historically and clinically ³⁴⁾.

• Dried Root: 0.5-1.0 g dissolved in water given orally three times daily for appetite stimulation and stomach upset.
• Dried root powder (tablet or capsule): 1,800-2,400 mg (50-100 mg harpagoside) daily for arthritis and musculoskeletal pain and inflammation.
• Crude aqueous root extract: 2-9 g daily for low-back pain and osteoarthritis.

The following Devil’s claw doses have been studied in scientific research:

By mouth:

• For osteoarthritis: 2-2.6 grams of Devil’s claw extract have been taken in up to three divided doses daily for up to 4 months. A specific combination product providing 600 mg of devil’s claw, 400 mg of turmeric, and 300 mg of bromelain has been taken 2-3 three times daily for up to 2 months.
• For back pain: 0.6-2.4 grams of Devil’s claw extract has been taken daily, usually in divided doses, for up to 1 year.

Devil’s claw side effects

Devil’s claw is possibly safe for most adults when taken by mouth in appropriate doses for up to a year. In a review of 28 clinical trials of Devil’s claw extracts, adverse events occurred at a rate of about three percent and did not exceed the rate of those experienced with placebo. Long-term use appears to be safe and without toxicity. The side effects are few, usually limited to gastrointestinal upset, dyspepsia and loss of taste. The most common side effect is diarrhea. About 8% of the people participating in one research study developed diarrhea. Other possible side effects include nausea, vomiting, stomach pain, headaches, ringing in the ears, loss of appetite, and loss of taste. Devil’s claw can also cause allergic skin reactions, menstrual problems, and changes in blood pressure. But these events are uncommon.

Not enough is known about the safety of using Devil’s claw long-term or applying it to the skin.

Devil’s claw Harpagoside has been found to be of low toxicity with an LD50 (lethal dose 50 where 50% of the test subjects die) >13.5 g/kg in mice ³⁵⁾.

Special precautions and warnings

Patients with duodenal ulcers should probably avoid using Devil’s claw due to its effect on gastric pH ³⁶⁾. Because of reported oxytocic properties, Devil’s claw extracts are contraindicated during pregnancy ³⁷⁾.

Pregnancy and breast-feeding: Devil’s claw is possibly UNSAFE. It might harm the developing fetus. Avoid use in pregnancy. It is also best to avoid using Devil’s claw while breast-feeding. Not enough is known yet about its safety during breast-feeding.

Heart problems, high blood pressure, low blood pressure: Since Devil’s claw can affect heart rate, heartbeat, and blood pressure, it might harm people with disorders of the heart and circulatory system. If you have one of these conditions, talk with your healthcare provider before starting Devil’s claw.

Diabetes: Devil’s claw might lower blood sugar levels. Using it along with medications that lower blood sugar might cause blood sugar to drop too low. Monitor blood glucose levels closely. Your healthcare provider might need to adjust your dose of diabetes medications.

Gallstones: Devil’s claw might increase bile production. This could be a problem for people with gallstones. Avoid using devil’s claw.

Peptic ulcer disease: Since Devil’s claw might increase the production of stomach acids This might harm people with stomach ulcers. Avoid using Devil’s claw.

Interactions with medications

Moderate

Be cautious with this combination.

Medications changed by the liver (Cytochrome P450 2C19 (CYP2C19) substrates)

Some medications are changed and broken down by the liver. Devil’s claw might decrease how quickly the liver breaks down some medications. Taking Devil’s claw along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking Devil’s claw talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include omeprazole (Prilosec), lansoprazole (Prevacid), and pantoprazole (Protonix); diazepam (Valium); carisoprodol (Soma); nelfinavir (Viracept); and others.

Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)

Some medications are changed and broken down by the liver. Devil’s claw might decrease how quickly the liver breaks down some medications. Taking Devil’s claw along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking Devil’s claw talk to your healthcare provider if you take any medications that are changed by the liver.

Some medications that are changed by the liver include diclofenac (Cataflam, Voltaren), ibuprofen (Motrin), meloxicam (Mobic), and piroxicam (Feldene); celecoxib (Celebrex); amitriptyline (Elavil); warfarin (Coumadin); glipizide (Glucotrol); losartan (Cozaar); and others.

Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)

Some medications are changed and broken down by the liver. Devil’s claw might decrease how quickly the liver breaks down some medications. Taking Devil’s claw along with some medications that are broken down by the liver can increase the effects and side effects of some medications. Before taking Devil’s claw, talk to your healthcare provider if you are taking any medications that are changed by the liver.

Some medications changed by the liver include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and many others.

Warfarin (Coumadin)

Warfarin (Coumadin) is used to slow blood clotting. Devil’s claw might increase the effects of warfarin (Coumadin) and increase the chances of bruising and bleeding. Be sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.

Minor

Be watchful with this combination.

Medications moved by pumps in cells (P-glycoprotein Substrates)

Some medications are moved by pumps into cells. Devil’s claw might make these pumps less active and increase how much of some medications get absorbed by the body. This might increase the side effects of some medications.

Some medications that are moved by these pumps include etoposide, paclitaxel, vinblastine, vincristine, vindesine, ketoconazole, itraconazole, amprenavir, indinavir, nelfinavir, saquinavir, cimetidine, ranitidine, diltiazem, verapamil, corticosteroids, erythromycin, cisapride (Propulsid), fexofenadine (Allegra), cyclosporine, loperamide (Imodium), quinidine, and others.

Medications that decrease stomach acid (H2-blockers)

Devil’s claw might increase stomach acid. By increasing stomach acid, Devil’s claw might decrease the effectiveness of some medications that decrease stomach acid, called H2-blockers.

Some medications that decrease stomach acid include cimetidine (Tagamet), ranitidine (Zantac), nizatidine (Axid), and famotidine (Pepcid).

Medications that decrease stomach acid (Proton pump inhibitors)

Devil’s claw might increase stomach acid. By increasing stomach acid, Devil’s claw might decrease the effectiveness of medications that are used to decrease stomach acid, called proton pump inhibitors.

Some medications that decrease stomach acid include omeprazole (Prilosec), lansoprazole (Prevacid), rabeprazole (Aciphex), pantoprazole (Protonix), and esomeprazole (Nexium).