Antiproliferative Effects - Uncaria tomentosa is a Rubiaceae species widely used in South-American folk medicine for the treatment of cancer, arthritis, gastritis and epidemic diseases. Extracts of the plant have been shown to possess cytostatic and anti-inflammatory activity as well as mutagenic and antimutagenic properties. he bioassay-directed fractionation from barks and leaves resulted in the isolation of two active fractions, which displayed an IC50 of 10 mg/ml and 20 mg/ml, respectively and an antiproliferative effect, with about 90% of inhibition at a concentration of 100 mg/ml.

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Furthermore, its growth-inhibitory and cytotoxic effects on glioma GAMG and neuroblastoma SKN-BE(2) cell lines were studied using cyclophosphamide and vincristine as controls.

It inhibited the growth of the two cell lines studied in a dose-dependent manner. The IC₅₀ values were 12.3 μM (30 h) for SKN-BE(2) and 20 μM (48 h) for GAMG, respectively. This action suggests that mitraphylline is a new and promising agent in the treatment of human neuroblastoma and glioma.

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Anti-Tumor - Growth inhibitory activities of novel water extracts of Uncaria tomentosa (C-Med-100) were examined in vitro using two human leukemic cell lines (K562 and HL60) and one human EBV-transformed B lymphoma cell line (Raji).

The suppressive effect of Uncaria tomentosa extracts on tumor cell growth appears to be mediated through induction of apoptosis which was demonstrated by characteristic morphological changes, internucleosomal DNA fragmentation after agarose gel electrophoresis and DNA fragmentation quantification.

The induction of DNA strand breaks coupled to apoptosis may explain the growth inhibition of the tumor cells by Uncaria tomentosa extracts. These results provide the first direct evidence for the antitumor properties of Uncaria tomentosa extracts to be via a mechanism of selective induction of apoptosis.

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Use of cat's claw might be beneficial in patients with advanced cancer by improving their quality of life and reducing fatigue. The mechanism of action does not seem to be related to the anti-inflammatory properties of this plant.

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Anti-Cancer - Preparations from Uncaria tomentosa, a South American Rubiaceae, have been used in the Peruvian traditional medicine for the treatment of infective, inflammatory and tumor processes.<