Resumo

Glioblastoma multiforme is the most common and lethal primary brain tumor. It exhibits excessive proliferation and spreading, resistance to apoptotic stimuli, neovascularization and suppression of the immune system, which are characteristics of malignant gliomas. The necessity to give new perspectives in glioma therapy has stimulated the development of new drugs and innovations. Screening studies, especially those with polyphenolic compounds have increased significantly in recent years. In this work, we studied the toxicity to human glioblastoma GL-15 cells of the methanolic extract of seeds obtained from Bixa orellana L. which are composed by phenolic compounds and bixin. The cytotoxicity and viability were measured by the MTT and Tripan staining. The contents of bixin and total phenols in the methanolic extract of Bixa orellana L. were 0.17 mg ⁄ mg of extract and 0.05 mg ⁄ mg of extract, respectively. Data were fitted to nonlinear regression plots to determine the concentration that kills 50 % of cells (EC50). Cell morphology was evaluated by phase contrast microscopy. The extract killed cells in a dose-dependent manner. Medians, percentiles 25 th and 75 th values were 218 μg ⁄ mL; 207 μg ⁄ mL; 227 μg ⁄ mL after 24 h exposure, and 108 μg ⁄ mL; 93 μg ⁄ mL; 137 μg ⁄ mL after 72h. The 72 h treatment decreased the cell number and changed cell morphology. In conclusion, these data suggest the potential cytotoxic effect of substances present in seeds of Bixa orellana L. and their ability to decrease cell viability and cellularity in neoplastic glial cells. The methanolic extract seems to be a good source for the purification of the cytotoxic compounds.