Cat's claw
Una de gato; Uncaria tomentosa
Named after its hook-like horns, cat's claw (Uncaria tomentosa) is a woody vine native to the Amazon rainforest and other places in South and Central America. The bark and root have been used by South Americans for centuries to treat health problems including arthritis, stomach ulcers, inflammation, dysentery, and fevers. It was also used as a form of birth control.
Test tube studies indicate that cat's claw may stimulate the immune system, help relax the smooth muscles (such as the intestines), dilate blood vessels (helping lower blood pressure), and act as a diuretic (helping the body eliminate excess water).
Cat's claw also has antioxidant properties, helping the body eliminate particles known as free radicals that damage cells. Scientists believe free radicals to contribute to health problems, including heart disease and cancer. Antioxidants can help neutralize free radicals and may reduce, or even help prevent, some of the damage they cause.
Some early studies suggest cat's claw may kill tumor and cancer cells in test tubes.
Osteoarthritis
Not many scientific studies have looked at the safety and effectiveness of cat's claw, but it has been used traditionally to treat osteoarthritis (OA). One study found that it may help relieve pain from knee OA without significant side effects.
Rheumatoid arthritis
Cat's claw has been suggested as a treatment for rheumatoid arthritis (RA) because it may help reduce inflammation. One small study of people who were already taking sulfasalazine or hydroxychloroquine to treat RA found that those who also took cat's claw had fewer painful, swollen joints than those who took a placebo (dummy pill). But although cat's claw may help reduce inflammation, there is no evidence to show that it stops joint damage from getting worse. For that reason, RA should be treated with conventional medications, which can stop joint damage.
Further research
Cat's claw is being studied for a number of other possible uses, including HIV, Crohn disease, multiple sclerosis, systemic lupus erythematosus (SLE or lupus), endometriosis, kidney problems, bladder cancer, and Alzheimer disease. More research is needed before scientists can say whether it is effective.
Plant Description
Cat's claw is a thorny vine that can climb as high as 100 feet. It grows mostly in the Amazon rainforest, as well as tropical areas in South and Central America. Much of the cat's claw sold in the United States was grown in Peru.
Cat's claw got its name from the curved, claw-like thorns that grow on its stem. The root and bark of cat's claw are the parts used for medicine.
What is It Made Of?
Cat's claw contains many types of plant chemicals that help reduce inflammation, such as tannins and sterols, and fight viruses, such as quinovic acid glycosides.
Cat's claw preparations are made from the root and bark of the cat's claw vine. How effective the root and bark are may depend on what time of year the plant was harvested.
Available Forms
The bark of the cat's claw vine can be crushed and used to make tea. Standardized root and bark extracts (containing 3% alkaloids and 15% phenols) are also available in either liquid or capsule forms.
How to Take It
Pediatric
No one has studied cat's claw in children, so no one knows whether it is safe. DO NOT give a child cat's claw except under your doctor's supervision.
Adult
Speak to your health care provider regarding dosing instructions.
Precautions
The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, can trigger side effects, and can interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, under the supervision of a health care provider.
Cat's claw appears to have few side effects, however, there have not been enough scientific studies on cat's claw to determine its safety. Some people have reported dizziness, nausea, and diarrhea when taking cat's claw. The diarrhea or loose stools tend to be mild and go away with continued use of the herb.
Pregnant or nursing women should not take cat's claw because it may cause miscarriage.
People with autoimmune diseases, skin grafts, tuberculosis, or those receiving organ transplants should not use cat's claw unless specifically directed by their physician because of its possible effects on the immune system.
People with leukemia or low blood pressure should not take cat's claw.
People with kidney or liver disease should not use cat's claw without first asking their doctor.
Possible Interactions
If you are currently taking any of the following medications, you should not use cat's claw without first talking to your health care provider.
Medications that suppress the immune system: In theory, because cat's claw may stimulate the immune system, it should not be used with medications that suppress the immune system. Those include cyclosporine or other medications prescribed following an organ transplant, or to treat an autoimmune disease.
Blood-thinning medications: Cat's claw may increase the risk of bleeding, especially if you also take blood thinners such as aspirin, warfarin (Coumadin), or clopidogrel (Plavix).
Diuretics (water pills): Cat's claw may act as a diuretic, helping the body eliminate excess fluid. If you also take diuretics, which do the same thing, you could be at risk of developing an electrolyte imbalance.
Blood pressure medication: Cat's claw may lower blood pressure. If you take medication for high blood pressure, taking cat's claw may cause your blood pressure to be too low.
Other medications: Cat's claw may interfere with some medications that are processed by the liver. If you take any medications, check with your doctor before taking cat's claw.
Supporting Research
Aquino R, De Feo V, De Simone F, et al. New compounds and anti-inflammatory activity of Uncaria tomentosa. J Nat Prod. 1991;54:453-459.
de Fatima Fernandes Vattimo M, da Silva NO. Uncaria tomentosa and acute ischemic kidney injury in rats. Rev Esc Enferm USP. 2011;45(1):194-8.
Gonzales GF, Valerio LG. Medicinal plants from Peru: a review of plants as potential agents against cancer. Anticancer Agents Med Chem. 2006;6(5):429-44.
Hardin SR. Cat's claw: an Amazonian vine decreases inflammation in osteoarthritis. Complement Ther Clin Pract. 2007 Feb;13(1):25-8.
Kaiser S, Dietrich F, de Resende PE, et al. Cat's claw oxindole alkaloid isomerization induced by cell incubation and cytotoxic activity against T24 and RT4 human bladder cancer cell lines. Planta Med. 2013;79(15):1413-20.
Keplinger K, Laus G, Wurm M, et al. Uncaria tomentosa (Willd.) Dethnomedicinal use and new pharmacological, toxicological and botanical results. J Ethnopharmacol. 1999;64:23-34.
Miller MJ, Mehta K, Kunte S, Raut V, Gala J, et al. Early relief of osteoarthritis symptoms with a natural mineral supplement and a herbomineral combination: a randomized controlled trial [ISRCTN38432711]. J Inflamm (Lond). 2005 Oct 21;2:11.
Mur E, Hartig F, Eibl G, et al. Randomized double blind trial of an extract from the pentacyclic alkaloid-chemotype of uncaria tomentosa for the treatment of rheumatoid arthritis. J Rheumatol. 2002 Apr;29(4):678-81.
Nogueira N, Coelho TM, Aguiar GC, et al. Experimental endometriosis reduction in rats treated with Uncaria tomentosa (cat's claw) extract. Eur J Obstet Gynecol Reprod Biol. 2011;154(2):205-8.
Pilarski R, Zielinski H, Ciesiolka D, et al. Antioxidant activity of ethanolic and aqueous extracts of Uncaria tomentosa (Willd.) DC. J Ethnopharmacol. 2006 Mar 8;104(1-2):18-23.
Piscoya J, Rodriguez Z, Bustamante SA, et al. Efficacy and safety of freeze-dried cat's claw in osteoarthritis of the knee: mechanisms of action of the species Uncaria guianensis. Inflamm Res. 2001;50(9):442-448.
Quilez AM, Saenz MT, Garcia MD. Uncaria tomentosa (Willd. ex. Roem. & Schult.) DC. and Eucalyptus globulus Labill. interactions when administered with diazepam. Phytother Res. 2012;26(3):458-61.
Rizzi R, Re F, Bianchi A, et al. Mutagenic and antimutagenic activities of Uncaria tomentosa and its extracts. J Ethnopharmacol. 1993;38(1):63-77.
Rosenbaum CC, O'Mathúna DP, Chavez M, Shields K. Antioxidants and antiinflammatory dietary supplements for osteoarthritis and rheumatoid arthritis. Altern Ther Health Med. 2010 Mar-Apr;16(2):32-40. Review.
Sandoval M, Charbonnet RM, Okuhama NN, et al. Cat's claw inhibits TNFalpha production and scavenges free radicals: role in cytoprotection. Free Radic Biol Med. 2000;29(1):71-78.
Setty AR, Sigal LH. Herbal medications commonly used in the practice of rheumatology: mechanisms of action, efficacy, and side effects. Semin Arthritis Rheum. 2005 Jun;34(6):773-84. Review.
Sheng Y, et al. Induction of apoptosis and inhibition of proliferation in human tumor cells treated with extracts of Uncaria tomentosa. Anticancer Res. 1998;18:3,363-3,368.
Sheng Y, Pero RW, Wagner H. Treatment of chemotherapy-induced leukopenia in a rat model with aqueous extract from Uncaria tomentosa. Phytomedicine. 2000;7(2):137-143.
Spelman K, Burns J, Nichols D, et al. Modulation of cytokine expression by traditional medicines: a review of herbal immunomodulators. Altern Med Rev. 2006 Jun;11(2):128-50. Review.
Steinberg PN. Cat's claw: medicinal properties of this Amazon vine. Nutrition Science News. 1995.