RESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Himatanthus articulatus (Vahl) Woodson (Apocynaceae) is a tree occurring in the Amazon region. The local population uses its bark against to external tumors and cancer. AIM OF THE STUDY: Evaluated the antiproliferative activity of the crude extract and their fractions against human tumors cells. MATERIALS AND METHODS: The antiproliferative responses of the crude extract and their fractions were colorimetrically evaluated by sulforhodamine B (SRB) assay against HT-29 (colon adenocarcinoma); NCI-H460 (non-small cell lung carcinoma); MCF-7 (breast cancer); OVCAR-3 (ovarian adenocarcinoma) and RXF-393 (renal cell carcinoma) as well as against NIH-3T3 (mouse embryo fibroblast cell). RESULTS: The cytotoxicity data from the crude extract allowed considering active only in the NCI-H460 cell line. However, the antiproliferative activity was much more pronounced at the chloroformic fraction in all cell lines tested. The butanolic fraction demonstrated activity against to HT-29, MCF-7, RXF-393 and OVCAR-3 cells. The ethyl acetate fraction demonstrated activity only in RXF-393 and the aqueous residue did not present antiproliferative effect. CONCLUSIONS: Through the popular use we find that the crude extracts of Himatanthus articulatus bark displayed weak cytotoxic. However, the butanolic fraction showed to be active only against to tumor cell lines while chloroformic fraction possesses high activity being similar to the positive control. Both fractions have been selected for future bio-guided fractionation and isolation of active compounds.