Cytotoxic activity of schisandrolic and isoschisandrolic acids involves induction of apoptosis

Abstract

Cycloartane triterpenoid schisandrolic acid and isoschisandrolic acid were isolated from Schisandra propinqua (Wall.) Baill (Schisandraceae). Their cytotoxicity was evaluated in several cancer cell lines and primary cultured normal mouse hepatocytes. The two triterpenoids showed moderate cytotoxic activity on all tested cell lines. Fluorescence staining and cell cycle analyses were employed to elucidate the primary mechanisms of their cytotoxicity. Our results showed that two triterpenoids exerted their cytotoxic activity via G(0)/G(1) arrest and subsequent apoptosis. Furthermore, proteolytic cleavage of poly-ADP-ribose polymerase (PARP), substrate of the caspase family, was detected and associated with apoptosis in HepG2 cells induced by the two compounds.