Anti-hepatitis B virus active constituents from Swertia chirayita.

Four new compounds swertiachiralatone A (1), swertiachoside A (2), swertiachirdiol A (3) and swertiachoside B (4), together with twenty-six known ones were isolated from the ethanol extract of Swertia chirayita. Their structures were elucidated by extensive spectroscopic analyses (1D- and 2D-NMR, HRESIMS, UV, IR and [α]D). All compounds were evaluated for anti-hepatitis B virus (anti-HBV) activities on HepG 2.2.15 cells line in vitro, of which compounds 14 and 19 showed inhibitory activity on hepatitis B surface antigen (HBsAg) secretion with IC50 values of 0.31 ± 0.045 and 1.49 ± 0.033 mM; compounds 14 and 28 exhibited activity against hepatitis B e antigen (HBeAg) secretion with IC50 values of 0.77 ± 0.076 and 5.92 ± 1.02 mM; and eight compounds (8,9,13,14,24-26,29) possessed activity against HBV DNA replication with IC50 values of 0.07-0.33 mM. In particular (+)-cycloolivil-4'-O-β-d-glucopyranoside (14) exhibited inhibition not only on the secretions of HBsAg and HBeAg with IC50 values of 0.31 ± 0.045 mM (SI=4.29) and 0.77 ± 0.076 mM (SI=1.75), respectively, but also on HBV DNA replication with an IC50 value of 0.29 ± 0.034 mM (SI=4.66).