Abietane diterpenes from the twigs and leaves of Cephalotaxus oliveri Mast. with antitumor activity

Twenty one abietane diterpenes were isolated from Cephalotaxus oliveri Mast. The structures of 7 undescribed diterpenoids, named cephaloliverins A-G, were elucidated via spectroscopic data interpretation and electronic circular dichroism (ECD) analysis. The isolated diterpenoids were evaluated for their cytotoxicity against three kinds of human tumor cell lines (MCF-7, HepG2, and A549). Metaglyptin A was the most active with IC50 values of 16.34, 15.63 and 21.33 μM and was further investigated for colony formation and apoptosis in HepG2 cells.