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

Cat's claw (Uncaria spp)

What is it?

Description

Cat's claw or “Uña de Gato” is a thick woody vine (liana) belonging to the Rubiaceae family 1,2.

Names

The plant, described by its Spanish common name “Uña de Gato”, derives its name from hook-like thorns that grow along the vine 1. There are several species of cat’s claw but the two most common species used as a medicinal herb are U. tomentosa (Willd. DC.) and U. guianensis (Aubl, Gmel.). These species are indigenous to the Amazon rainforest and other tropical areas of South and Central America. Other common names include saventero, samento , vilcacora, etc. 1,2.

Ingredients/components

Fifty-six compounds have been isolated from U. tomentosa and an additional eight from U. guianensis based on a search in Reaxys (an online search and retrieval system for chemical compounds, bibliographic data, and chemical reactions) in December 2012. Among the 56 compounds isolated from U. tomentosa, pharmacological activity has been demonstrated for 27. Among the eight compounds isolated from U. guianensis pharmacological activity has been demonstrated for six 3-11. Characteristic phytochemicals belong to indole alkaloids (for instance, pentacyclic oxindoles such as pteropodine, isopteropodine, mytraphylline and tetracyclic oxindoles like rhyncophlline), triterpenes including quinovic acid and derivatives thereof, stigmasterol, sterols, flavonoids (procyanidins, catechins and flavonols, tannins), and low molecular weight carboxyl alkyl esters (CAEs).

Cat's claw is included in the United States Pharmacopeial Convention (USP) as a dietary supplement. In the pharmacopeia cat's claw consists of the inner bark of the stems of U. tomentosa (Willd.) DC. (Rubiaceae). It contains not less than 0.3% of pentacyclic oxindole alkaloids as isopteropodine, calculated on the dried basis, as the sum of speciophylline, uncarine F, mitraphylline, isomitraphylline, pteropodine and isopteropodine.

Application and dosage

In South America, about 20-30 g of the root or bark is prepared as a decoction in 1 litre of water for 20-30 minutes and the extract is consumed as tea. The dosage of a standard decoction for general health and maintenance is 0.5-1 cup of decoction once daily, up to three cups daily if necessary. Alcoholic extracts from the bark are also traditionally used 12,13.

Nowadays cat's claw is available in many different forms: dried cut-and-sifted root and stem, powdered root and stem, encapsulated powdered material or lyophilized aqueous extracts, tinctures, tablets and other types extracts. Cat’s claw is also available in preparations for external uses (ointments, gels).

History and providers

Cat’s claw has been used as a sacred plant of healing for over 2,000 years. The priests of the Asháninka Indian tribe in Central Peru considered cat's claw to have great powers and health-improving properties and used the herb to ward off disease. This tribe has the longest recorded history of use of this plant. They are also the largest commercial source of cat's claw from Peru today 13,14.

Alleged indications/claims of efficacy

Cat’s claw has been used traditionally as an anti-inflammatory, contraceptive, immunostimulant, cancer remedy and anti-viral 5.

Mechanism of action

The wide range of biological/pharmacological effects of Uncaria spp preparations are due to the concomitant presence of numerous and differently bioactive chemical structures that could be complementary and/or synergic in their actions 16. The pentacyclic oxindole alkaloids are immunostimulants and can be selectively cytostatic/cytotoxic to some cancer cells; they are considered biomarkers in alcoholic extracts of U. tomentosa; the tetracyclic oxindole alkaloids have effects on the cardiovascular system and DNA protection. Pentacyclic triterpenes are anti-microbial, anti-viral, and anti-inflammatory. Sterols appear to be anti-inflammatory only. Uncaria polyphenols (flavonoids) have strong antioxidant as well as antiviral, anti-allergic, anti-platelet, anti-inflammatory, and anti-tumour activities 13,16,17.

The suppressive effects of some aqueous U. tomentosa extracts on tumour cell growth would appear to be mediated by the induction of apoptosis 18,19. Moreover, U. tomentosa extracts are able to reduce the serum response of the proinflammatory cytokines TNF-α and IL-6, and to inhibit the nitric oxide production as well as the NF-κB activity 20-24. Dreifuss et al. 24, using an U. tomentosa hydroalcoholic extract in vivo, demonstrated that the anti-tumour activity could, at least partially, result from the ability of U. tomentosa to restore redox and metabolism homeostasis through downregulation of the NF-κB transcription factor and superoxide dismutase (SOD) activities.

Effects of cat’s claw have been shown in vitro in several cell lines of different tumour origins: breast 29,33, lung 28 and medullary thyroid carcinoma 38 as well as in glioma 32, neuroblastoma 32, melanoma 20,21, lymphoma and leukaemia cell lines 30. Although some results were confirmed in vivo in mice (metastatic melanoma 20,21 and Lewis lung carcinoma 28), more research is still needed in animal models and humans before any conclusions can be drawn 22,27,28,31.

Prevalence of use

There is no information available about the prevalence of use of cat’s claw worldwide but review papers describe it as one of the most popular herbs in the USA 13-15. In a survey on the use of herbal supplements amongst 998 black breast cancer survivors 0.9% reported using cat’s claw 37.

Legal issues

Cat's claw is not listed on the Food and Drug Administration’s Generally Regarded as Safe (GRAS) list 15. It is widely available on the internet and in pharmacies.

Costs/expenditures

The product is available in several formulations and doses and the prices vary, which makes it impossible to predict the treatment cost. A one-month supply can range from €5 to €100.

Citation

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

Document history

Revised in March 2017 by Barbara Wider.

Assessed as up to date in September 2014 by Barbara Wider.
Summary first published in February 2013, authored by Klara Rombauts and Italo M Cesari.

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.