Cat'�s Claw

Common names: Cat's claw also is known aslife-giving vine of Peru, samento, and u�ña de gato.

Efficacy-safety rating:

●●...Ethno or other evidence of efficacy.

Safety rating:

What is Cat'�s Claw?

Cat's claw, or u�ña de gato (Spanish), is a high climbing, twining woody vine (liana). The name describes the small curved-back spines on the stem at the leaf juncture. Cat's claw is found throughout the tropics, mainly in Southeast Asia, the Asian continent and South America. The genus Uncaria is found throughout the tropics, mainly in Southeast Asia, the Asian continent and South America. There are 34 reported species of Uncaria. The two species of current interest, Uncaria tomentosa and U. guianensis, are found in South America. Both species are known in Peru as u�ña de gato.

What is Cat'�s Claw used for?

U. guianensis has had folkloric use in South America for wound healing and for treating intestinal ailments. Large amounts of U. guianensis are collected in South America for the European market, while American sources prefer U. tomentosa. By 1997, over 50 dietary supplement manufacturers offered cat's claw products in the United States. The part used medicinally is in the inner bark of the vine. In Peru, a boiled decoction of U. guianensis is used therapeutically as an anti-inflammatory, antirheumatic, and contraceptive agent, as well as in treating gastric ulcers and tumors, gonorrhea (by the Bora tribe), dysentery (by the Indian groups of Colombia and Guiana), and cancers of the urinary tract in women. The center of the U. tomentosa range is in Peru. Its uses are similar to those of U. guianensis and include treatment of arthritis, gastric ulcers, intestinal disorders, and some skin problems and tumors.

The Ashanica Indians believe that samento (also U. tomentosa) has “�life-giving” properties and use a cup of the decoction each week or two to ward off disease, treat bone pain, and cleanse the kidneys.

Several chemical and pharmacological investigations have verified that the alkaloids have immune-stimulating effects (pteropodine and isopteropodine). Reviews and scientific studies by the National Cancer Institute in the last decade have led to verification of some of the anticancer and immunostimulant properties. Because of potential immunostimulating effects, cat�'s claw should not be used in patients scheduled for organ transplants, skin grafts, or immunosuppressive therapy, and in patients with autoimmune disorders. More clinical studies are needed to determine the medical benefits of cat�'s claw. Some of the demand for the bark has been attributed to European reports on its clinical use with zidovudine in AIDS treatment. More clinical studies are needed to understand the full benefits of cat'�s claw in HIV/AIDS treatment.

Cat�'s claw has been found to have antihypertensive properties (rhynchophylline), diuretic effects (mytraphylline), and smooth muscle relaxant and local anesthetic properties (hirsutine). The major alkaloid rhynchophylline has been shown in animal studies to be anti-hypertensive, to relax the blood vessels of endothelial cells, dilate peripheral blood vessels, inhibit sympathetic nervous system activities, and lower the heart rate and lower blood cholesterol. There are no human clinical studies available at this time to verify these medical uses.

The demand for the bark in the United States is based on the purported usefulness of its tea in treating diverticulitis, hemorrhoids, peptic ulcers, colitis, gastritis, parasites, and leaky bowel syndrome. �Other reported therapeutic uses include treatment for abscesses, asthma, chemotherapy side effects, fever, hemorrhage, rheumatism, skin impurities, urinary tract inflammation, weakness, and wounds, and for disease prevention and recovery from childbirth. � There are no clinical data available to support these uses.

What is the dosage of Cat'�s Claw?

One gram of root bark given 2 to 3 times is a typical dose, while 20 to 30 mg of a root bark extract has been recommended. A standardized extract containing 8% to 10% carboxy alkyl esters and less than 0.5% oxindole alkaloids has been used for clinical trials as an immunostimulant in doses of 250 to 300 mg.

Is Cat'�s Claw safe?

None well documented.

Cat's claw should not be used during pregnancy and nursing.

Cat's claw may potentiate the action of antihypertensive drugs. Because of potential immunostimulating effects, it would be prudent to avoid cat'�s claw in patients receiving immunosuppressive therapy.

Low incidence.

Historical ethnomedicinal evidence and current use by health care consumers suggest low toxicity. In rats, the LD 50 of a single dose of a water extract of U. tomentosa was determined to be greater than 8 g/kg. In humans, there were no toxic side effects observed at a repeated dose of 350 mg/day for 6 consecutive weeks.

References

Copyright © 2006 Wolters Kluwer Health

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