Uncaria tomentosa (Willd. ex Schult.) DC.

Last updated: 10 Mar 2017

Scientific Name

Uncaria tomentosa (Willd. ex Schult.) DC.


Cinchona globifera Pav. ex DC., Nauclea aculeata Kunth, Nauclea polycephala A.Rich. ex DC., Nauclea surinamensis (Miq.) Walp., Nauclea tomentosa Willd. ex Schult., Ourouparia polycephala (A.Rich. ex DC.) Baill., Ourouparia tomentosa (Willd. ex Schult.) K.Schum., Uncaria surinamensis Miq., Uncaria tomentosa var. dioica Bremek. [1]

Vernacular Name

English Cat’s claw [2]
Latin America Rájara, rangallo, uña de gato, uña de guara [2].

Geographical Distributions

Uncaria tomentosa is native to the Amazon rainforest and is found in various tropical areas of South and Central America.  It is sometimes confused with other plants making plant identification paramount.  It requires a tropical climate to survive and other plants upon which to climb. [3]

Botanical Description

U. tomentosa is a large liana (climbing vine-like plant) that has hooked thorns which are the reason it is often called ‘cat’s claw’.  It can grow up to 30 m using the thorny hooks to support its upward growth.  The leaves grow in opposite whorls and are smooth edged and elliptic. [3]


No documentation.

Chemical Constituent

Steroidic fraction of U. tomentosa was found to contain proanthocyanidins, quinovic acids, oxindole alkaloids (pteridine, isopteridine, uncarine, mitraphylline, isomitraphylline), N-oxide, rhynocophylline, carboline alkaloid, hirustine, N-oxide triterpenes, polyphenols, phytosterols (stigmasterol and campesterol). [4]

Petroleum extract of U. tomentosa dried bark was found to contain quinovic acid glycosides and polyhydroxylated triterpenes. [5]

Plant Part Used

Roots and bark. [6]

Traditional Use

In South America, U. tomentosa has a history of use that dates back to over 2000 years.  In Peru, indigenous tribes used this herb as a treatment for rheumatic complaints and inflammation.  It was also used by various indigenous peoples to treat asthma, urinary tract infections, gastric ulcers diabetes and as an internal detoxification agent large doses were used in Peru as a contraceptive, a practice that had unwanted side effects as large doses over extended periods of time may result in sterility. [7]

Other uses include dysentery, gonorrhoea, menstrual irregularity, wounds, gastric ulcers, dysentery, fever, bone pain, cirrhosis and diabetes. [7][8]

Preclinical Data


Anti-inflammatory activity

Quinovic acid glycoside 7 isolated from U. tomentosa was found to exhibit anti-inflammatory activity using the carrageenan-induced edema in rat paw. [9]

Water extract of U. tomentosa bark was found to exhibit anti-inflammatory primary mechanism that appears to be immunomodulation via suppression of TNF-α synthesis. [10]

A study found the use of U.  tomentosa superior to placebo in people with osteoarthritis of the knee. Again, TNF-α inhibition and PGE2 production were noted as being likely responsible for the anti-inflammatory properties. [11]

U. tomentosa bark extract was found to protect against oxidative stress and inhibition of NF-kappaB activation. [12]

Immune function activity

Extract of U. tomentosa was found to enhance and stimulate phagocytosis which would be a key part of the immune function activity. [13] Phytohemagglutinin (PHA) stimulated lymphocyte proliferation was significantly increased in splenocytes of rats treated at the doses of 40 and 80 mg/kg. [14]

Immune function has also been supported by a study where a U.  tomentosa water soluble extract demonstrated immune enhancement via elevation of the lymphocyte/neutrophil ratio and also, for the 5 months measured, a decrease in the decay rate of antibody titer responses to a pneumococcal vaccine. [15]

Antimicrobial activity

Quinovic acid glycosides isolated from U. tomentosa was found to exhibit antiviral activity. [16]

Anticancer activity

One study demonstrated the antiproliferative effects of bark fractions from U. tomentosa on the MCF7 human breast cancer cell line. [17]

Another study evaluated the antitumor properties of U.  tomentosa in two human leukemic and one lymphoma cell line. The investigators associated these properties with selective induction of apoptosis. [18]

Cardiovascular activity

Procyanidins (PCOs) isolated from U. tomentosa are reported to be many times more powerful than vitamin C. They may reduce capillary fragility and inhibit platelet-activating factor (PAF), along with another phytochemical, rynchophylline, which may inhibit platelet aggregation and thrombus formation. Its anti-inflammatory activity, anti-allergic (antihistaminic) activity, and edema reducing effects lead to the claim that U.  tomentosa may be beneficial in reducing cardiovascular risk factors. [19]

Health promoting activity

Clinicians agree that the uses of pentacyclic alkaloids (POAs) from U.  tomentosa root bark are the health promoting constituents. Tetracyclic alkaloids (TOAs) do occur in the root bark, but should be kept to a minimum in the final product as to maximize the health benefits of U.  tomentosa as a dietary supplement. [20]

Anti-amnesic activity

The total alkaloids isolated in U.  tomentosa have demonstrated amnestic effects in mice. Results obtained suggest that U. tomentosa total alkaloids exert a beneficial effect on memory impairment induced by the dysfunction of cholinergic systems in the brain and that the effect of the total alkaloids is partly attributed to the oxindole alkaloids tested. [21]


No documentation.

Clinical Data

Clinical findings

A small human double-blind study involving 40 patients with active rheumatoid arthritis were treated with U. tomentosa. Patients experienced a reduction in the number of painful and swollen joints. [18]


U. tomentosa has been reported safe in recommended dosages, although there was one case report of renal failure in 35 year old Peruvian women with systemic lupus erythematosus reportedly using U. tomentosa[23]

Side effects

Based on pharmacology, use with caution in individuals with bleeding disorders. [19]

U. tomentosa is generally considered safe, with only minor side effects of stomach upset or diarrheal. [24][25]

This plant should not be taken by transplant recipients, persons who have a bleeding disorder or are currently fighting an infection, talk to your doctor before taking this dietary supplement. [19][26]

Do not use in neurological disorders, including Parkinson’s disease. There was a case report of oral U. tomentosa leading to reversible worsening of motor signs in a patient with Parkinson disease. [27]

Pregnancy/Breast Feeding

Not to be used by pregnant or breastfeeding women. [28]

Age limitation

No documentation.

Adverse reaction

No documentation.

Interaction & Depletion

Interaction with drug

Studies have reported that U. tomentosa possesses anti-inflammatory activity which may alter the effects of these medications and possibly the dose needed for treatment. Use with caution. These drugs include ibuprofen, naproxin, etodolac, flurbiprofen, indomethacin, ketorolac tromethamine, mefenamic acid, nabumetone, oxaprozin, sulindac, tolmentin, diclofenac, fenoprofen, ketoprofen, meclofenamate, meloxicam, piroxicam, celecoxib, rofecoxib, and valdecoxib. [9]

Studies have reported that U. tomentosa stimulates our immune system which may alter the effects of these medications and possibly the dose needed for treatment. Use with caution. These drugs include Hepatitis B Immune Globulin (HBIG), Tetanus Immune Globulin (TIG), Varicella-Zoster Immune Globulin (VZIG), Immune Globulin (IGIM or IGIV), Cytomegalovirus Immune Globulin (CMV-IGIV), Lymphocyte Immune Globulin, Antithymocyte Globulin (ATG equine or ATG rabbit), Rabies Immune Globulin (RIG), Respiratory Syncytial Virus Immune Globulin (RSV-IGIV), Rho(D) Immune Globulin (Rho[D] IGIM, Rho[D] IGIV or Rho[D] IG Micro-dose). [13]

Based on pharmacology, U. tomentosa may decrease effectiveness of the medication(s). Use with caution. These drugs include Cytomegalovirus Immune Globulin (CMV-IGIV), Hepatitis B Immune Globulin (HBIG), Rabies Immune Globulin (RIG), Respiratory Syncytial Virus Immune Globulin (RSV-IGIV), Tetanus Immune Globulin (TIG), and Varicella-Zoster Immune Globulin (VZIG). [13]

Studies have reported that U. tomentosa affects the blood's clotting ability and may alter the effects of these medications and possibly the dose needed for treatment. Use with caution. These drugs include warfarin, heparin, dalteparin, tinzaparin, enoxaparin, danaparoid sodium, antithrombin III, lipirudin, argatroban, bivalirudin, aspirin, dipyridamole, anagrelide, cilostazol, clopidogrel, ticlopidine, abciximab, tirofiban, and eptifibatide. [19]

Interaction with other Herbs

No documentation.


No documentation.


Dosage Range

One gram of root bark given 2 to 3 times daily is a typical dose, while 20 to 30 mg of a root bark extract has been recommended. [29]

Clinical trials are generally lacking to support appropriate dosages. [29]

A standardized extract containing 8% to 10% carboxy alkyl esters and less than 0.5% oxindole alkaloids has been used in clinical studies in doses of 250 to 300 mg. [29]

Most Common Dosage

No documentation.


The most current available medical and scientific literature indicates that this dietary supplement should be standardized to 3% alkaloids and 15% total phenols per dose.

An extract of U. tomentosa containing only pentacyclic oxindole alkaloids (mainly isomitraphylline isolated from the root) may be more beneficial as an immune enhancing product than the standard mixture of pentacyclic and tetracyclic alkaloids. When the two chemotypes are mixed, immune enhancement may be decreased. This product should be standardized to not less than 1.3% pentacyclic oxindole alkaloids and not more than 0.06% tetracyclic oxindole alkaloids per dose. [20]

Poisonous Management

No documentation.

Line drawing

No documentation.


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  2. Quattrocchi U. CRC world dictionary of medicinal and poisonous plants: Common names, scientific names, eponyms, synonyms, and etymology. Volume V R-Z. Boca Raton, Florida: CRC Press, 2012; p. 673-674.
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  11. Piscoya J, Rodriguez Z, Bustamante SA, Okuhama NN, Miller MJS, 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):442-448.
  12. Sandoval-Chacón M, Thompson JH, Zhang XJ, et al. Antiinflammatory actions of car’s claw: The role of NF-kappaB. Aliment Pharmacol Ther. 1998;12(12):1279-1289.
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  17. 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;21(4A):2457-2461.
  18. 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):3363-3368.
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  27. Cosentino C, Torres L. Reversible worsening of Parkinson disease motor symptoms after oral intake of Uncaria tomentosa (cat’s claw). Clin Neuropharmacol. 2008;31(5):293-294.
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