Cat's Claw (Uncaria tomentosa): Evidence, Dosage & Uses

Rubiaceae · Amazonian Liana

Biological Overview

Uncaria tomentosa is a woody climbing vine that can reach 30 meters in length, with a trunk up to 20 cm in diameter and stems up to 20 cm across. It bears large glossy leaves and sharp, curved thorns resembling a cat's claw. Native to the tropical Andean rainforests of Peru, Ecuador, and Colombia; the related species Uncaria guianensis is found in French Guiana.

HabitWoody Liana, up to 30m

Native RangePeru, Ecuador, Colombia

Alkaloid Chemotypes2 (Pentacyclic & Tetracyclic)

Related SpeciesUncaria guianensis

Botanical Classification

Taxonomy & Identification

Latin Name: Uncaria tomentosa (Willd. ex Roem. & Schult.) DC.
Related Species: Uncaria guianensis (Aubl.) J.F.Gmel.
Family: Rubiaceae
Common Names: Cat's Claw, Una de Gato, Vilcacora, Samento
Parts Used: Stem bark (root bark)
Origin: Andean tropical rainforests of Peru, Ecuador, Colombia

Ethnobotany & Traditional Use

History & Tradition

Cat's claw has long served as a panacea for the Ashaninka and other Peruvian peoples, used to treat serious illnesses including asthma, cancer, diabetes, and arthritis. ¹

Traditional healers are able to select plants low in tetracyclic oxindole alkaloids (TOA), believed most likely to strengthen immunity — an early, practical form of the chemotype awareness that modern research has since confirmed matters pharmacologically.

A parallel line of ethnobotanical discovery exists in Ancistrocladus korupensis (Ancistrocladaceae) of Cameroon, whose anti-HIV alkaloids (michellamines A and B) illustrate a similar pattern of Indigenous plant knowledge later validated by pharmacological research. ³

⚠ Chemotype Matters

Cat's claw exists as two distinct alkaloid chemotypes (POA and TOA) with different — and reportedly opposing — biological effects. The tetracyclic (TOA) chemotype is considered too immunosuppressive for some traditional uses; correct chemotype identification is essential to predicting a given preparation's effects.

Timeline

Ashaninka Panacea

Traditional

Used as a panacea by the Ashaninka and other Peruvian peoples for serious illnesses including asthma, cancer, diabetes, and arthritis. ¹

Traditional Chemotype Selection

Traditional

Traditional healers select plants low in TOA, believed most likely to strengthen immunity.

Alkaloid Characterization

20th Century

Two distinct alkaloid chemotypes were characterized: pentacyclic oxindole alkaloids (POA) and tetracyclic oxindole alkaloids (TOA). ⁹

Modern Chemotype-Specific Research

21st Century

Research established that chemotype identification is critical, since POA and TOA show different — and sometimes opposing — biological activity, including in immune and antitumor contexts. ¹³¹⁴

The Key Compounds

Oxindole Alkaloids — Deep Dive

The two alkaloid chemotypes that define cat's claw's immune, anti-inflammatory, and antitumor research — and why identifying the right one matters.

🧬

Two Distinct Chemotypes

Pentacyclic (POA) and tetracyclic (TOA) oxindole alkaloids define two different chemotypes of the plant, with rynchophylline, 5-carboxystrictosidine, and isopteropodine among the characterized compounds.

🎯

Selective Lymphocyte Proliferation

Pentacyclic alkaloids (not tetracyclic) increase proliferation of naive or weakly activated B and T lymphocytes, without affecting lymphoblasts or B lymphoblastoid cells. ⁸⁹

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Chemotype-Specific Antitumor Selectivity

Each chemotype shows specific selectivity toward human malignant cells, making correct chemotype identification important for understanding antitumor potential. ¹³

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Peruvian Clinical Interest in HIV

Clinical studies conducted in Peru have reported an effect in HIV/AIDS specifically with the POA chemotype, since the TOA chemotype is considered too immunosuppressive for this use.

⚠ Preparation Determines Composition

Clinical results vary by preparation, not just by dose.

Clinical data remains insufficient to draw definitive conclusions about cat's claw's effects, since results depend heavily on the nature of the preparation used, which in turn determines its alkaloid composition. ¹⁴

Pharmaceutical Preparations

Parts Used & Available Forms

The stem bark (and root bark) is used medicinally, prepared across two documented forms.

Powder

Ground stem bark, used at practitioner-directed dosing.

Powder

Extract

Standardized or freeze-dried extracts of the stem bark.

Extract

Clinical Dosimetry

Dosages

A single documented dosing ceiling applies across forms — dosing above this range should be guided by a qualified practitioner.

Form	Dose	Frequency	Context	Notes
Dried Bark / Powder	Max 1g plant material (10–30mg alkaloids)	Daily maximum	General use	Represents the upper limit cited for plant material and its corresponding alkaloid content.

Phytochemistry

Composition

Stem bark composition only — no gemmotherapy (bud) or essential-oil fraction is documented for this species.

Stem Bark — Primary Constituents

Pentacyclic & Tetracyclic Oxindole AlkaloidsRynchophylline, 5-carboxystrictosidine, isopteropodine, mitraphylline, uncarines C–F, and related indole/oxindole alkaloids — two distinct chemotypes

Present

Triterpenic AcidsOleanolic acid, ursolic acid

Present

Flavonoids, Phenolics & TanninsIncluding epicatechin and proanthocyanidins, some as pelargonidin dimers cytotoxic to gastric and colonic adenocarcinoma cell lines ⁵

Present

SterolsSitosterol, campesterol, daucosterol

Present

Plant Properties — Pharmacodynamics

Eight pharmacodynamic properties are documented for cat's claw, spanning immune, anti-inflammatory, and antitumor pathways.

8 Properties Immune-Enhancing Anti-inflammatory Clinical + Preclinical

🛡️

Antioxidant

Attributed to the alkaloids, flavan-3-ol monomers, and polyphenols.

🩹

Immune-Enhancing

Induces lymphocyte proliferation and stimulates interleukin-1 and interleukin-6, macrophages, and phagocytosis. ⁶⁷⁸⁹

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Anti-inflammatory

Inhibits TNF-alpha, to a lesser extent PGE2, and NF-κB activation. ¹⁵¹⁶¹⁷

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Anticancer (Chemotype-Dependent)

Anticancer properties documented, with each chemotype showing distinct selectivity for malignant cell lines. ¹⁰¹¹¹²¹³

🦠

Macrophage & Phagocytosis Stimulating

Stimulates macrophage activity and phagocytosis alongside apoptosis in tumor cells.

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Cytotoxic Proanthocyanidins

Cytotoxic against gastric and colonic adenocarcinoma cell lines. ⁵

🦟

Anti-Borrelia (Lyme Disease Activity)

Shows activity against Borrelia burgdorferi, evaluated alongside several other botanicals for Lyme disease potential. ¹⁹

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Neurotransmitter-Modulating

Rynchophylline is believed to increase levels of neurotransmitters such as dopamine and serotonin. ¹⁸

Clinical Applications

Clinical Indications

Cat's claw's primary use spans chronic inflammatory and degenerative disease, with additional research interest in oncology and neurological conditions.

🩺

Chronic Inflammatory & Degenerative Disease

Primary Indication

HIV/AIDS, Rheumatoid Arthritis & Ulcerative Colitis: chronic inflammatory or degenerative conditions.
Rheumatic Disease: studied in a randomized, double-blind trial for rheumatoid arthritis. ⁴²⁰

🎗️

Oncology Support

Research-Backed Indication

Breast Cancer & Chemotherapy Support: may help prevent breast cancer and reduce the effects of anticancer chemotherapy.

🧠

Neurological & Infectious Disease

Preliminary Interest

Lyme Disease: proposed based on anti-Borrelia activity. ²¹
Alzheimer's Disease: preliminary interest, including reported reduction of brain plaques and tangles in preclinical research. ²²²³²⁴

⚠️

Use Considerations

Clinical Precautions

Contraceptive Effect: avoid during pregnancy and breastfeeding.
Chemotype-Specific HIV Studies: Peruvian clinical studies reported an effect specifically with the POA chemotype, since TOA is considered too immunosuppressive.

Pharmacodynamics

Mode of Action

Cat's claw's immune and anti-inflammatory effects converge on cytokine signaling, lymphocyte activation, and NF-κB pathway inhibition.

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Interleukin & Macrophage Stimulation

Stem bark extracts stimulate in vitro production of IL-6 and IL-1 in lipopolysaccharide-stimulated alveolar macrophages. ⁷

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Selective Lymphocyte Proliferation (POA-Specific)

Pentacyclic oxindole alkaloids increase proliferation of naive or weakly activated B and T lymphocytes, without affecting lymphoblasts or B lymphoblastoid cells — a selectivity not shared by tetracyclic alkaloids. ⁸⁹

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TNF-alpha & NF-κB Inhibition

Both Uncaria species show anti-inflammatory activity through inhibition of TNF-alpha, to a lesser extent PGE2, and inhibition of NF-κB activation. ¹⁶¹⁷

🧠

Neurotransmitter Modulation via Rynchophylline

Rynchophylline is believed to increase levels of neurotransmitters such as dopamine and serotonin. ¹⁸

Risk Profile

Safety & Interactions

Cat's claw shows generally low acute toxicity, but genuine, specific precautions apply — particularly around pregnancy, Parkinson's disease, and kidney health.

⚠️

Adverse Effects

Low Acute/Subacute Oral Toxicity: demonstrated low potential for acute and subacute oral toxicity, though genotoxicity and mutagenicity remain poorly characterized. ²⁵
Suspected Nephropathy Cases: suspected cases of nephropathy have been reported. ²⁷
Parkinson's Symptom Aggravation: a documented case describes reversible, momentary worsening of Parkinson's disease motor symptoms after oral intake. ²⁶

🚫

Contraindications & Interactions

Pregnancy & Breastfeeding: avoid, given the plant's contraceptive properties.
Parkinson's Disease: avoid, given the risk of momentary symptom aggravation. ²⁶
Chemotype-Dependent Effects: immune and antitumor effects vary significantly by chemotype (POA vs TOA); preparation-dependent variability makes effects harder to predict. ¹⁴

Clinical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice. Consult a qualified healthcare provider before starting cat's claw, particularly if pregnant, breastfeeding, have Parkinson's disease, or have any kidney condition.

Common Questions

Frequently Asked Questions

What is cat's claw used for?

Cat's claw is used for chronic inflammatory and degenerative conditions including HIV/AIDS, rheumatoid arthritis, and ulcerative colitis, for rheumatic disease, as adjunctive support in breast cancer and chemotherapy, and has been studied for Lyme disease and Alzheimer's disease.

How does cat's claw work?

Stem bark extracts stimulate interleukin-6 and interleukin-1 production in macrophages, and pentacyclic oxindole alkaloids selectively increase proliferation of naive or weakly activated B and T lymphocytes. Both major Uncaria species show anti-inflammatory activity through inhibition of TNF-alpha and NF-κB activation.

What is the typical cat's claw dosage?

A maximum of 1 gram of plant material daily is cited, corresponding to roughly 10 to 30 mg of alkaloids.

Is cat's claw safe? What are the precautions?

Cat's claw shows low potential for acute and subacute oral toxicity, though its genotoxicity and mutagenicity are not well characterized. Suspected cases of nephropathy have been reported, and a case of reversible, momentary worsening of Parkinson's disease motor symptoms has been documented after oral intake.

What's the difference between the two chemotypes of cat's claw (POA vs TOA)?

Cat's claw contains two distinct alkaloid chemotypes: pentacyclic oxindole alkaloids (POA) and tetracyclic oxindole alkaloids (TOA). Only the pentacyclic alkaloids increase lymphocyte proliferation, and the tetracyclic chemotype is considered too immunosuppressive for uses like HIV support, making correct chemotype identification important.

Can cat's claw be used during pregnancy?

No. Cat's claw should be avoided during pregnancy and breastfeeding due to its documented contraceptive properties.

Does cat's claw interact with Parkinson's disease medication or symptoms?

Cat's claw should be avoided in Parkinson's disease. A documented case describes reversible, momentary worsening of motor symptoms following oral intake.

Is cat's claw the same as Uncaria guianensis?

They are closely related but distinct species. Uncaria tomentosa is the species most associated with the name cat's claw, while Uncaria guianensis, found in French Guiana, is also traditionally used and shares anti-inflammatory activity.

Sources

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