Uncaria
Also known as: Cat's Claw, Una de Gato, Uncaria tomentosa
Overview
Uncaria tomentosa, commonly known as Cat's Claw or Una de Gato, is a woody vine native to the Amazon rainforest. It is traditionally used in herbal medicine for its anti-inflammatory and immunomodulatory properties. The supplement is primarily derived from the bark and roots of the plant and is available as botanical extracts. It is frequently used for managing inflammatory conditions, such as osteoarthritis, and is being explored as an adjunct in cancer therapy due to its cytotoxic potential. Research on Uncaria is ongoing, with studies focusing on its anti-inflammatory effects and potential anti-cancer properties. While preclinical data are promising, more high-quality human clinical trials are needed to fully establish its efficacy and safety across various applications.
Benefits
Uncaria tomentosa exhibits several evidence-based benefits. It possesses significant anti-inflammatory effects, with meta-analyses of animal and in vitro studies showing reductions in inflammatory markers like NF-κB and interleukin-6 (IL-6). For osteoarthritis, a large systematic review and meta-analysis of 42 RCTs found a modest but statistically significant reduction in pain intensity (SMD = −0.23, 95% CI −0.37 to −0.08, p=0.002), with longer supplementation durations showing greater effects. Certain extracts, particularly those rich in pentacyclic oxindole alkaloids (POAs), demonstrate selective cytotoxicity against various cancer cell lines (e.g., prostate, breast) while showing low toxicity to normal cells, suggesting potential in cancer research. Additionally, Uncaria is known for its immunomodulatory properties, which may be beneficial in inflammatory diseases, although human clinical data in this area are limited.
How it works
Uncaria tomentosa primarily exerts its effects through anti-inflammatory and immunomodulatory pathways. Its main mechanism involves the inhibition of NF-κB signaling, a crucial pathway in inflammation, leading to a reduction in the production of pro-inflammatory cytokines such as IL-6. The active compounds, particularly pentacyclic oxindole alkaloids (POAs), are key contributors to its biological activity. The specific profile of bioactive compounds can vary significantly depending on the plant part used and the extraction method, which in turn influences the supplement's efficacy and potential toxicity. While absorption and bioavailability data are limited, they are also likely influenced by the type of extract (e.g., aqueous vs. hydroethanolic).
Side effects
Uncaria tomentosa is generally considered to have low toxicity based on traditional use and animal studies, with a median lethal dose in rats exceeding 8 g/kg. Human studies have reported no significant adverse effects at doses around 350 mg/day for up to 6 weeks. However, there are documented cases of hepatotoxicity linked to Uncaria supplements, with one US registry reporting liver injury in 18% of single-ingredient supplement-related hepatotoxicity cases. Specific risk factors for hepatotoxicity are not fully elucidated but warrant caution. Contraindications include use before or after surgery due to potential effects on blood clotting and immune function, and during immunosuppressive therapy, as it may interfere with immune-modulating medications. Safety in children and during pregnancy or lactation has not been established, and it should be avoided in these populations. Individuals with autoimmune diseases should also exercise caution due to its immunomodulatory effects. It may interact with anticoagulant medications, increasing the risk of bleeding.
Dosage
Clinical trials typically utilize doses of Uncaria tomentosa around 350 mg/day of standardized extracts, administered for periods up to 6 weeks. However, optimal dosing is not definitively established due to significant variability in extract composition and standardization of active compounds. For conditions like osteoarthritis, longer supplementation durations, potentially exceeding 10 months, may be required to observe greater clinical benefits. There is no clearly defined maximum safe dose, and caution is advised due to reported cases of hepatotoxicity. The efficacy and safety of Uncaria are highly dependent on the extraction method and the standardization of its alkaloid content, particularly pentacyclic oxindole alkaloids (POAs). Users should prioritize products that specify their active compound content.
FAQs
Is Uncaria safe to use?
Generally, Uncaria is considered safe at moderate doses, but there is a risk of liver toxicity. It should be avoided if you are immunosuppressed or undergoing surgery.
How long does it take to see benefits from Uncaria?
Clinical effects on pain and inflammation may take several weeks to months to become noticeable. Longer-term use, especially for conditions like osteoarthritis, may lead to improved outcomes.
Can Uncaria cure cancer?
No, Uncaria does not cure cancer. While some extracts show cytotoxic effects against cancer cells in preclinical studies, these findings have not been confirmed in human clinical trials.
Can Uncaria be combined with other medications?
Caution is advised, especially when combining Uncaria with immunosuppressants, anticoagulants, or other hepatotoxic drugs. Always consult a healthcare professional before combining supplements with medications.
Research Sources
- https://www.nature.com/articles/s41598-020-78075-x – This systematic review and meta-analysis, published in 2020, evaluated 42 RCTs involving 4160 participants on various nutraceuticals, including Uncaria, for osteoarthritis. It found a small but statistically significant reduction in pain intensity (SMD = −0.23, p=0.002), with larger effects observed with longer supplementation durations. The study highlights the potential of Uncaria for pain management in osteoarthritis, despite heterogeneity among the included studies.
- https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1378408/full – This 2024 systematic review and meta-analysis focused on the anti-inflammatory effects of Uncaria extracts in animal studies. It demonstrated significant reductions in IL-6 and NF-κB, supporting the traditional use of Uncaria for inflammatory conditions. However, it noted high heterogeneity among studies and emphasized the need for human RCTs to confirm these findings.
- https://pubmed.ncbi.nlm.nih.gov/38881881/ – This publication, likely a systematic review or meta-analysis, further supports the anti-inflammatory effects of Uncaria extracts. It specifically highlights the reduction of IL-6 and NF-κB, key markers in inflammatory pathways, while noting inconsistent or non-significant effects on IL-1 and IL-10. The findings reinforce the potential of Uncaria in managing inflammatory responses.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC12116528/ – This systematic review evaluated the cytotoxic activity of various Uncaria extracts on cancer and normal cell lines. It found that extracts rich in pentacyclic oxindole alkaloids (POAs) exhibited selective cytotoxicity against cancer cells with low toxicity to normal cells. The study suggests that the extraction method and chemotype are critical for the observed activity, indicating potential for anticancer drug development.
- https://www.drugs.com/npp/cat-s-claw.html – This source provides a general overview of Cat's Claw (Uncaria tomentosa), including its traditional uses, potential benefits, and safety profile. It mentions that human studies have reported no significant adverse effects at moderate doses but also highlights documented cases of hepatotoxicity linked to Uncaria supplements, emphasizing the need for caution.
