Chemical constituents of Swertia mussotii and their anti-hepatitis B virus activity.

Three new secoiridoid aglycones of (-)-swermusic acid A (1) and B (3), and (-)-swerimuslatone A (2), and four new secoiridoid glycosides of 6'-O-formylsweroside (4), 6'-O-formylgentiopicroside (5), 6'-O-acetylamarogentin (6) and 6'-O-acetylamaronitidin (7), along with 40 known compounds (8-47) were isolated from Swertia mussotii. Their structures were elucidated on the basis of extensive spectroscopic analyses including MS, IR, UV, 1D- and 2D-NMR. Forty-five compounds from S. mussotii were evaluated for their anti-HBV activity on the HepG 2.2.15 cell line in vitro inhibiting the secretions of HBsAg and HBeAg, as well as HBV DNA replication. Six of the nine phenols 26-29, 31 and 32 exhibited activities inhibiting HBsAg and HBeAg secretion with IC50 values from 0.23 to 5.18mM, and HBV DNA replication with IC50 values from <0.06 to 2.62mM. Moreover, isooriention (45) displayed significant anti-HBV activities against secretions of HBsAg and HBeAg with IC50 value of 0.79 and 1.12mM, as well as HBV DNA replication with IC50 value of 0.02mM.