(Willd. ex Schult.) DC.
Uncaria tomentosa (popularly known in English as cat's claw, although that name is also used for other plants; in Spanish as uña de gato or as Indian name vilcacora) is a woody vine found in the tropical jungles of South and Central America, which derives its name from its claw-shaped thorns. It is used as an alternative medicine in the treatment of a variety of ailments. Other common names include: hawk's claw, pot hook, and sparrowhawk nail.
Uncaria tomentosa is a liana deriving its name from hook-like thorns that resemble the claws of a cat. U. tomentosa can grow up to 30 m (100 ft) tall, climbing by means of these thorns. The leaves are elliptic with a smooth edge, and grow in opposite whorls of two. Cat's claw is indigenous to the Amazon rainforest, with its habitat being restricted primarily to the tropical areas of South and Central America.
There are two species of cat's claw commonly used in North America and Europe, Uncaria tomentosa and Uncaria guianensis, each having different properties and uses. The two are frequently confused but U. tomentosa is the more heavily researched for medicinal use and immune modulation, while U. guianensis may be more useful for osteoarthritis. U. tomentosa is further divided into two chemotypes with different properties and active compounds, a fact ignored by most manufacturers that can have significant implications on both its use as an alternative medicine and in clinical trials to prove or disprove its efficacy. Another species, Uncaria rhynchophylla, has usage in Chinese medicine, and several unrelated species bear the same nickname.
According to the American Cancer Society, cat's claw is often promoted for its health benefits and has become a popular herbal supplement in the United States and Europe. However, they state:
Available scientific evidence does not support claims that this herb can treat cancer or other diseases in people. Animal and laboratory studies may show promise, but further studies are necessary to find out whether the results apply to humans. Until clinical trials in humans are completed, the true value of cat's claw remains uncertain.
Some studies on its effect on rheumatoid arthritis reported modest results, which need confirmation in standardized trials.
The indigenous peoples of South America have used cat's claw for centuries as a treatment for various disorders. In Brazilian traditional medicine it is used against dengue to reduce inflammation.
Allergies and adverse reactions
Individuals allergic to plants in the Rubiaceae family and different species of Uncaria may be more likely to have allergic reactions to cat's claw. Reactions can include itching, rash and allergic inflammation of the kidneys. In one case study, kidney failure occurred in a patient with Lupus erythematosus. The patient's kidney failure improved after stopping the herbal remedy.
There are other plants which are known as cat's claw (or uña de gato) in Mexico and Latin America; however, they are entirely different plants, belonging to neither the Uncaria genus, nor to the Rubiaceae family. Some of the Mexican uña de gato varieties are known to have toxic properties.
- "Species Information". sun.ars-grin.gov. Retrieved 2008-03-01.
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- Piscoya J, Rodriguez Z, Bustamante SA, Okuhama NN, Miller MJ, Sandoval M (2001). "Efficacy and Safety of Freeze-Dried Cat's Claw in Osteoarthritis of the Knee: Mechanisms of Action of the Species Uncaria guianensis". Inflammation Research 50 (9): 442–448. doi:10.1007/PL00000268. PMID 11603848.
- Keplinger K, Laus G, Wurm M, Dierich MP, Teppner H (1999). "Uncaria tomentosa (Willd.) DC. — Ethnomedicinal Use and New Pharmacological, Toxicological and Botanical Results" (PDF). Journal of Ethnopharmacology 64 (1): 23–34. doi:10.1016/S0378-8741(98)00096-8. PMID 10075119.
- Tyler VE (Sep–Oct 1997). "An herb to forget — Cat's Claw — Uncaria tomentosa". Nutrition Forum 14 (5).
- "Cat's Claw". American Cancer Society. 12 September 2011. Retrieved August 2013.
- Ernst E (2004). "Complementary and Alternative Therapies for Rheumatoid Arthritis". International Journal of Advances in Rheumatology 2 (1): 22–25.
- Reis SR, Valente LM, Sampaio AL, Siani AC, Gandini M, Azeredo EL, d'Avila LA, Mazzei JL, Henriques MG, Kubelka CF (2008). "Immunomodulating and Antiviral Activities of Uncaria tomentosa on Human Monocytes Infected with Dengue Virus-2". International Immunopharmacology 8 (3): 468–476. doi:10.1016/j.intimp.2007.11.010. PMID 18279801.
- "Intelihealth article discussing uses and dangers of Cat's Claw". Intelihealth.com. 2005-07-14. Retrieved 2012-09-15.
- Hilepo JN, Bellucci AG, Mossey RT (1977). "Acute Renal Failure Caused by 'Cat's Claw' Herbal Remedy in a Patient with Systemic Lupus Erythematosus" (PDF). Nephron 77 (3): 361. doi:10.1159/000190304. PMID 9375835.
- M.D. Anderson - Detailed Scientific Review of Cat's Claw
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