3.2. Induction of caspase-3 gene expression in HepG2 cells by hexane extract Semi-quantitative RT-PCR revealed that the mRNA expression of caspase-3 in HepG2 cells was significantly induced and reached a peak after 4h of exposure to the hexane extract, when an increase in its expression of approximately 1.7-fold(po0.001) was observed (Fig. 2), which then declined drastically to levels below the baseline from 8h, reaching the lowest level after 16h of treatment (a decrease of approximately 0.7-fold).This decrease was followed by a slight elevation in its expression over the next 8h post-stimulation.Therefore, these results clearly suggested that the mechanism of cell death elicited by the hexane extract of Murdannia bracteata was mainly attributed to the activation of caspase-3 in a biphasic manner.