RESUMO
UNLABELLED: ETHNOPHARMAGOLOGICAL RELEVANCE: Medicinal plants are an important source of antitumor compounds. This study evaluated the acute toxicity in mice, as well as the cytotoxic and antitumoral effects of methanolic extracts of Croton lechleri leaves (CLE). MATERIALS AND METHODS: The cytotoxicity of CLE on human cancer cell lines and human non-cancerous cells was evaluated using the MTT and apoptosis assays. Apoptosis induced by CLE on human cancer cell lines was determined using flow cytometry with annexin-Alexa 488/propidium iodide. The acute toxicity in mice was performed according to the Lorke procedure. Different doses of CLE were injected intraperitoneally daily into athymic mice bearing tumor during 18 days. The growth and weight of tumors was measured. RESULTS: CLE showed low IC(50) values on HeLa (17µg/ml) cells but lack toxic effects against human normal cells. Induction of cell death in HeLa cells by CLE was confirmed by an increase of apoptosis (Annexin/PI) by 30% compared to untreated cells. The LD(50) was 356mg/kg by intraperitoneal route (i.p.) and 500mg/kg by oral route. CLE administrated at 1, 10 and 50mg/kg i.p. inhibited the tumor growth by 38%, 48% and 59%, respectively, in mice bearing HeLa tumor. CONCLUSION: Croton lechleri shows moderate toxic effects in vivo, exerts cytotoxic effects on HeLa cells and has antitumor effects in mice bearing HeLa tumor.
