Herbs (Global Traditional) · Amazonian
Uña de Gato (Uncaria tomentosa) (Uncaria tomentosa)
Moderate Evidencebotanical
Hermetica Superfood Encyclopedia
Uña de Gato (Uncaria tomentosa) is an Amazonian vine containing pentacyclic oxindole alkaloids that modulate immune system function. Clinical studies demonstrate its ability to preserve white blood cell counts during chemotherapy and reduce cancer-related fatigue.
Uña de Gato (Uncaria tomentosa) is a woody vine native to the Amazon rainforest in Peru, Brazil, and other tropical regions of South America. The medicinal parts are primarily the inner bark of the stem and roots, traditionally harvested from wild vines and prepared as aqueous, hydroethanolic, or dry powdered extracts through decoction, maceration, or freeze-drying processes.
Clinical evidence includes RCTs in 40 breast cancer patients (PMID: 22811748) and 43 colorectal cancer patients (PMID: 21869902) receiving chemotherapy, showing hematological protection and safety at 300mg/day. A 2024 systematic review confirmed anti-inflammatory effects in animal models (PMID: 38881881), though no meta-analyses of human RCTs were identified.
Clinically studied doses include 300 mg/day of dry extract (single or divided doses) for cancer patients undergoing chemotherapy, and 100 mg three times daily for advanced solid tumors. Freeze-dried extracts have shown efficacy for osteoarthritis, though specific dosages were not detailed. Consult a healthcare provider before starting any new supplement.
Uña de Gato (Uncaria tomentosa) is a medicinal bark/root preparation rather than a dietary food, so macronutrient content is not nutritionally significant in typical therapeutic doses. Key bioactive compounds are the primary focus: Oxindole alkaloids (0.5–2.5% dry weight of bark) are the dominant pharmacologically active constituents, including pentacyclic oxindole alkaloids (POAs) — mitraphylline (~0.1–0.9% dry bark), isomitraphylline, pteropodine, isopteropodine, speciophylline, and uncarine F — alongside tetracyclic oxindole alkaloids (TOAs) — rhynchophylline and isorhynchophylline; POA:TOA ratios vary significantly by chemotype and sourcing, which affects immunomodulatory vs. CNS activity (POA chemotype preferred for immune applications). Quinovic acid glycosides (triterpene saponins, ~1–3% dry bark): including quinovic acid 3-beta-O-beta-D-glucopyranoside and related esters; contribute anti-inflammatory activity. Polyphenols and tannins: procyanidins (condensed tannins, ~2–4% dry bark), catechins, and epicatechin; contribute antioxidant capacity with ORAC values estimated at 1,000–2,000 µmol TE/g for concentrated extracts. Sterols: beta-sitosterol, stigmasterol, and campesterol present in small amounts (<0.5%). Carboxyl alkyl esters (CAEs): including quinic acid derivatives, thought to contribute immunomodulatory and DNA repair effects. Polysaccharides: small amounts of immunostimulatory polysaccharides detected. Minerals: bark contains trace calcium (~200–400 mg/100g dry weight), potassium (~300–600 mg/100g), magnesium (~80–150 mg/100g), and iron (~10–20 mg/100g), though these are not meaningful at typical supplement doses (300–350 mg extract). Fiber: present as structural plant fiber (~20–35% dry bark weight) but not bioavailable at supplemental doses. Bioavailability notes: Alkaloid bioavailability is moderate; standardized hydroethanolic extracts (70% ethanol) yield superior alkaloid extraction vs. water decoctions. POA absorption is enhanced with food; first-pass hepatic metabolism is significant. TOAs competitively inhibit POA immunostimulatory effects, making chemotype standardization critical. Commercial standardized extracts typically guarantee minimum 1.3–3% total oxindole alkaloids or minimum 8% carboxy alkyl esters depending on preparation type (C-Med-100 standardization targets CAEs).
Uña de Gato's pentacyclic oxindole alkaloids, particularly isopteropodine and pteropodine, enhance T-helper cell proliferation and macrophage activation. The alkaloids stimulate nuclear factor kappa B (NF-κB) signaling pathways, promoting cytokine production and immune cell differentiation. Quinovic acid glycosides provide additional anti-inflammatory effects by inhibiting cyclooxygenase and lipoxygenase enzymes.
A randomized controlled trial (n=40) showed Uña de Gato significantly reduced chemotherapy-induced neutropenia in breast cancer patients receiving FAC treatment, preserving white blood cell counts. A Phase II study demonstrated improvements in quality of life scores and reduced fatigue in advanced solid tumor patients. Most clinical evidence focuses on cancer supportive care, with limited data on other health conditions. Current research involves relatively small sample sizes, requiring larger studies for broader therapeutic claims.
Uña de Gato is generally well-tolerated with mild gastrointestinal upset being the most common side effect. It may enhance immune system activity, potentially interfering with immunosuppressive medications used in organ transplants or autoimmune conditions. The herb can lower blood pressure and may interact with antihypertensive drugs, requiring medical monitoring. Safety during pregnancy and breastfeeding has not been established, making it inadvisable for these populations.
