Sasanquasaponin from Camellia oleifera Abel. induces apoptosis via Bcl-2, Bax and caspase-3 activation in HepG2 cells.

The present study aimed to elucidate the molecular mechanisms underlying the induction of cytotoxic effects by sasanquasaponin (SQS) in HepG2 cells. Following SQS treatment, time- and dose-dependent increases in the apoptotic rate were observed. The induction of cell death by SQS mainly occurs via programmed cell death, as indicated by Annexin V-fluorescein isothiocyanate and propidium iodide staining, where up to 30% apoptotic cells were detected following 12 h SQS treatment. Reverse transcription-polymerase chain reaction analysis demonstrated that SQS treatment upregulated B-cell lymphoma-2 (Bcl-2)-associated x protein and caspase-3 mRNA expression and downregulated Bcl-2 mRNA expression. Greater alterations in Bax, Bcl-2 and caspase-3 expression were observed with increasing treatment duration. The decrease in Bcl-2, increase in Bax and, finally, the activation of caspase-3 in HepG2 cells indicated that the apoptotic process induced by SQS was irreversible. The results of the present study therefore suggested that SQS induced HepG2 cell apoptosis via the activation of mitochondrial apoptotic pathways.