Two new alkaloids and active anti-hepatitis B virus constituents from Hypserpa nitida

Two new alkaloids, hypserpanines A and B (1, 11), together with eleven known compounds, phenolbetain (2), acutumine (3), acutumidine (4), dechloroacutumine (5), dauricumine (6), dauricumidine (7), pronuciferine (8), glaziovine (9), S-reticuline (10), magnoflorine (12) and laurifoline(13), were isolated from Hypserpa nitida Miers. (Menispermaceae) and chemically elucidated through spectral analyses. All the isolated alkaloids were evaluated for their anti-HBV activities in vitro using the HBV transfected Hep G2.2.15 cell line. The most active compound, dauricumidine (7), exhibited an IC50 value of 0.450 mM (SI = 4.13) on hepatitis B virus (HBV) surface antigen (HBsAg) secretion of the Hep G2.2.15 cell line.