Written by Klara Rombauts, Italo M Cesari and the CAM-Cancer Consortium.
Updated March 9, 2017

Cat's claw (Uncaria spp)

Abstract and key points

  • Cat’s claw is a woody vine indigenous to the Amazon rainforest and other tropical areas of South and Central America.
  • Cat’s claw is said to treat a range of disorders, including cancer.
  • The current evidence from preclinical data suggesting anticancer activity is not confirmed by clinical trials. Two clinical trials investigating the role of cat’s claw in alleviating the adverse effects of chemotherapy are not conclusive.
  • Adverse effects are mostly gastrointestinal problems associated with high doses. Interactions with immunosuppressants and anticoagulants might theoretically occur.

Cat's claw or ‘Uña de Gato’ is a thick woody vine classified in the Rubiaceae family. For medicinal purposes, the stem bark or root from the species Uncaria tomentosa and U. guianensis are most commonly used. These have traditionally been used for allergies, asthma, wound healing, viral infections, fevers, arthritis, gastric ulcers, rheumatism, inflammation, contraception and menstrual irregularities.

Uncaria tomentosa and U. guianensis contain over 60 different biologically active compounds that could be complementary and/or synergic in their actions. Despite some positive preclinical data, there are no clinical trials investigating cat’s claw as a direct anticancer agent. There is not enough evidence for other outcomes. Only two clinical trials investigated the role of cat’s claw in alleviating the adverse effects of chemotherapy. While in the first trial cat’s claw was not effective in reducing the most prevalent adverse effects, the second trial reported reduce neutropenia caused by chemotherapy. One small uncontrolled trial suggests improvement of quality of life and fatigue but no effects on biochemical and inflammatory markers or tumour response. 

Cat’s claw seems well tolerated at normal clinical doses but larger doses have been reported to cause some abdominal pain or gastrointestinal problems, including diarrhoea. Historically cat's claw has been used as an immunostimulant as well as for its antifertility effects. It can also reduce platelet aggregation and could theoretically be an anticoagulant.

Read about the regulation, supervision and reimbursement of herbal medicine at NAFKAMs website CAM Regulation.

Citation Klara Rombauts, Italo M Cesari, CAM-Cancer Consortium. Cat's claw (Uncaria spp) [online document]. http://ws.cam-cancer.org/The-Summaries/Herbal-products/Cat-s-claw-Uncaria-spp. March 9, 2017.

References

  1. Keplinger K, Laus G, Wurm M, Dierich MP, Teppner H. Uncaria tomentosa (Willd.) DC. ethnomedicinal use and new pharmacological, toxicological and botanical results. J. Ethnopharmacol. 1999;64(1):23–24.
  2. Reinhard KH. Uncaria tomentosa (Willd.) D.C.: cat’s claw, uña de gato, or sevéntaro. J Alternative Complementary Med. 1999;5(2):143–151.
  3. Dr. Duke's Phytochemical and Ethnobotanical Databases. Uncaria tomentosa. [internet]. Available at https://phytochem.nal.usda.gov/phytochem/plants/show/2064?et=, accessed 9th March 2017.
  4. Laus G, Brossner D, Keplinger K. Alkaloids of peruvian Uncaria tomentosa. Phytochemistry. 1997;45:855-860.
  5. Sandoval M, Charbonnet RM, Okuhama NN, Roberts J, Krenova Z, Trentacosti AM, Miller MJ. Cat´s claw inhibits TNF-alpha production and scavenges free radicals: role in cytoprotection. Free Radic Biol Med. 2000;29(1):71-8.
  6. Kitajima M, Hashimoto K, Takamaya H, Shakai SI. A new gluco indole alkaloid from Peruvian Uncaria tomentosa. Chem Pharm Bull (Tokyo). 2000;48(10):1410-2.
  7. Kitajima M, Hashimoto K, Yokoya M, Takayama H, Sandoval M, Aimi N. Two new nor-triterpene gycosides from Peruvian "Una de gato" (Uncaria tomentosa). J. Nat. Prod. 2003;66(2):320-323.
  8. Ganzera M, Muhammad I, Khan RA, Khan IA. Improved method for determination of oxindole alkaloids Uncaria tomentosa by high performance liquid chromatography. Planta Med. 2001;67:447-450.
  9. Montoro P, Carbone V, Quiroz J, De Simone F, Pizza C. Identification and quantification of components in extracts of Uncaria tomentosa by HPLC-ES/MS. Phytochemistry. 2004;158(1):55-64.
  10. Gattuso M, Di Sapio O, Gattuso S, Pereyra EL. Morphoanatomical studies of Uncaria tomentosa and Uncaria guianensis bark and leaves. Phytomedicine. 2004;11(2-3):213-23.
  11. Heitzman ME, Neto CC, Winiarz E, Vaisberg AJ, Hammond GB. Ethnobotany, phytochemistry and pharmacology of Uncaria (Rubiaceae). Phytochemistry 2005;66(1):5-29.
  12. Obregon Vilches LE (1995). Cat's claw, Uncaria genus. Botanical, chemical and pharmacological studies of Uncaria tomentosa (Willd.) D.C. (Rubiaceae) and Uncaria guinensis (Aubl.) Gmel. Lima (Perú): Instituto de Fitoterapia Andina, 144 p.
  13. Tropical Plant Database: Cat’s Claw (Uncaria tomentosa). [Internet] Available from: http://www.rain-tree.com/catclaw.htm#, accessed 9th March 2017.
  14. Valerio LG Jr, Gonzales GF. Toxicological aspects of the South American herbs cat’s claw (Uncaria tomentosa) and Maca (Lepidium meyenni): A critical synopsis. Toxicol Rev 2005;24(1): 1-25.
  15. Natural Medicines Comprehensive Database. Cat’s Claw [internet] Available from: http://naturaldatabase.therapeuticresearch.com, accessed 9th March 2017.
  16. Wirth C, Wagner H. Pharmacologically active procyanidines from the bark of Uncaria tomentosa. Phytomedicine. 1997;4:265-266.
  17. Pilarski R, Zielinski H, Ciesiotka D, Gulewicz K. Antioxidant activity of ethanolic and aqueous extracts of Uncaria tomentosa (Willd.) DC. Ethnopharmacol. 2006;104: 18-23.
  18. Sheng Y, Bryngelsson C, Pero WR. Enhanced DNA repair, immune function and reduced toxicity of C-MED-100 tm, a novel aqueous extract from Uncaria tomentosa. J. Ethnopharmacol. 2000;69:115-126.
  19. De Martino L, Silva-Martinot JL, Franceschelli S, Leone A, Pizza C, De Feo V. Proapoptotic effect of Uncaria tomentosa extracts. J. Ethnopharmacol. 2006;107(1):91-4.
  20. Caballero M, Arsenak M, Abad MJ, Cesari IM, Taylor PG. Effect of 3 plant extracts on B16-BL6 melanoma cell growth and metastasis in C57BL/6 mice. Acta Científica Venezolana. 2005;55:21-27.
  21. Fazio A, Ballen D, Cesari IM, Abad M, Arsenak M, Taylor P. An ethanolic extract of Uncaria tomentosa reduces inflammation and B16-BL6 melanoma growth in C57BL/6 mice. Bol Latinoam Caribe Plant Med Arom 2008;7(4): 217-225.
  22. Sandoval-Chacon M, Thompson JH, Zhang XJ, Liu X, Mannick EE, Sadowska-Krowicka H, Charbonnet RM, Clark DA, Miller MJ. Antiinflamatory actions of cat´s claw: the role of NF-kappaB. Aliment Pharmacol Ther. 1998;12(12):1279-1289.
  23. Akesson C, Lindgreen H, Pero RW, Leanderson T, Ivars F. An extract of Uncaria tomentosa inhibiting cell division and NF-B activity without inducing cell death. Int Immunpharmacol. 2003;3(13-14):1889-900.
  24. Dreifuss AA, Bastos-Pereira AL, Avila TV, da Silva Soley B, Rivero AJ, Aguilar JL, Acco A. Antitumoral and antioxidant effects of a hydroalcoholic extract of cat’s claw (Uncaria tomentosa) (Willd. Ex Roem. & Schult) in an in vivo carcinosarcoma model. J Ethnopharmacol. 2010;130:127–133.
  25. Farias ILG, Araújo MCS, Farias JG, Rossato LV, Elsenbach LI, Dalmora SL, Flores NMP, Durigon M, Cruz IBM, Morsch VM, Schetinger MRC. Uncaria tomentosa for reducing side effects caused by chemotherapy in CRC patients: Clinical trial. Evidence-Based Complementary and Alternative Medicine Vol. 2012, Article ID 892182: 8 pages.
  26. Araújo MCS, Farias ILG, Gutierres J, Dalmora SL, Flores N, Farias J, Cruz I, Chiesa J, Morsch VM, Schetinger MRC (2012). Uncaria tomentosa – Adjuvant Treatment for Breast Cancer: Clinical trial. Evidence-Based Complementary and Alternative Medicine Vol. 2012, Article ID 676984: 8 pages.
  27. Sheng Y, Pero RW, Amiri A, Bryngelsson C. Induction of apoptosis and inhibition of proliferation in human tumor cells treated with extracts of Uncaria tomentosa. Anticancer Res. 1998;18(5A):3363-8.
  28. Pilarski R, Filip B, Wietrzyk J, Kuras M, Gulewicz K. Anticancer activity of the Uncaria tomentosa DC. preparations with different oxindole alkaloid composition. Phytomedicine. 2010;17:1133–1139.
  29. Riva L, Coradini D, Di Fronzo G, et al. The antiproliferative effects of Uncaria tomentosa extracts and fractions on the growth of breast cancer cell line. Anticancer Res. 2001;4A:2457-61.
  30. Bacher N, Tiefenthaler M, Sturm S, Stuppner H, Ausserlechner M, Kofler R. Oxindole alkaloids from Uncaria tomentosa induce apoptosis in proliferating, G0/G1-arrested and bcl-2-expressing acute lymphoblastic leukaemia cells. Br J Haematol. 2006;132:615-622.
  31. Erowele GI, Kalejaiye AO. Pharmacology and therapeutic uses of cat’s claw. Am. J. Health-Syst. Pharm. 2009;66:992-995.
  32. Garcia Prado E, Garcia Gimenez MD, De la Puerta Vazquez R, Espartero Sanchez JL, Saenz Rodriguez MT. Antiproliferative effects of mitraphylline, a pentacyclic oxindole alkaloid of Uncaria tomentosa on human glioma and neuroblastoma cell lines. Phytomedicine. 2007;14:280-284.
  33. García Giménez D, García Prado E, Sáenz Rodríguez T, Fernández Arche A, De la Puerta R. Cytotoxic effect of the pentacyclic oxindole alkaloid mitraphylline isolated from Uncaria tomentosa bark on human Ewing’s sarcoma and breast cancer cell lines. Planta Med. 2010;76(2):133-6.
  34. Sheng Y, Li L, Holmgren K, Pero RW. DNA repair enhancement of aqueous extracts of Uncaria tomentosa in a human volunteer study. Phytomedicine. 2001;8(4):275-82.
  35. Lamm S, Sheng Y, Pero RW. Persistent response to pneumococcal vaccine in individuals supplemented with a novel water soluble extract of Uncaria tomentosa, C-Med-100. Phytomedicine. 2001;8(4):267-274.
  36. Piscoya J, Rodriguez Z, Bustamante SA, Okuhama NN, Miller MJ, Sandoval M. 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): 442-8.
  37. Bright-Gbebry et al. Use of multivitamins, folic acid and herbal supplements among breast cancer survivors: the black women’s health study. BMC Complementary and Alternative Medicine 2011;11:30
  38. Rinner B et al. Antiproliferative and pro-apoptotic effects of Uncaria tomentosa in human medullary thyroid carcinoma cells. Anticancer Res. 2009;29(11):4519-28.
  39. de Paula LC, Fonseca F, Perazzo F, Cruz FM, Cubero D, Trufelli DC, Martins SP, Santi PX, da Silva EA, Del Giglio A. Uncaria tomentosa (cat's claw) improves quality of life in patients with advanced solid tumors. J Altern Complement Med. 2015;21(1):22-30.