Perovskatone A: a novel C23 terpenoid from Perovskia atriplicifolia

Perovskatone A (1), a novel C23 terpenoid with unique 6/7/7 carbon rings was isolated from Perovskia atriplicifolia, together with nine known compounds involving an rearranged diterpenoid demethylsalvicanol (2) and 7-methoxy-epirosmanol (3), hinokiol (4), isorosmanol (5), rosmanol (6), atuntzensin A (7), 7-methoxyrosmanol (8), oleanic acid (9), and ursolic acid (10). By detailed analyses of the MS, IR, and NMR data, the structure of perovskatone A (1) was definitely characterized. In vitro anti-HBV bioassay suggested perovskatone A (1) possessed superior inhibitory hepatitis B virus surface antigen (HBsAg), with a high selectivity index (SI) value of 7.56.