摘要ABSTRACT Objective:To evaluate the antioxidant and cytotoxic effects of hexane extract ofMorinda pubescens leaves and to find the primary bioactive compound responsible for antioxidant and cytotoxic activities.Methods: The individual compounds were isolated using column chromatography and were characterized by spectroscopic techniques. The antioxidant activity was evaluated for all individual isolated compounds byDPPH method usingL-Ascorbic acid as standard and cytotoxicity was assessed for the extract and the hyoscyamine byMTT assay, caspase test andRT-PCR study.Results:The antioxidant activity of the isolated compounds and the extract increased as the concentration increased. One of the isolated compound hyoscyamine showed the high antioxidant activity. The extract and the hyoscyamine dose-dependently decreased the cell viability in HepG2 cells. Hyoscyamine induced caspase-3mediated apoptosis. Up regulation of p53 gene expression provides cue for apoptotic activity of hyoscyamine. Conclusions: The results indicate that hexane extract possessed potent antioxidant and cytotoxic activity and hyoscyamine is the principal bioactive compound in hexane extract.