In vitro anti-hepatitis B virus effect of Hypericum perforatum L.

The anti-hepatitis B virus (HBV) effects and its mechanisms of the ethanol extracts of Hypericum perforatum L. (EHP) in vitro were explored. HepG2 2.2.15 cells, a stable HBV-producing cell line, were cultured as the model system to observe the anti-HBV effect. The viral antigens of cellular secretion, HBsAg and HBeAg, were determined by enzyme linked immunosorbent assay (ELISA). The quantity of HBV-DNA released in the supernatant was assayed by real-time PCR. In order to understand the mechanisms of the suppression of HBV replication, all HBV promoters (Cp, Xp, S1p, S2p and Fp) with luciferase reporter gene were transfected into HepG2 cells respectively. Then the activities of viral promoters were examined by luciferase reporter assay. It was found EHP effectively suppressed the secretion of HBsAg and HBeAg from HepG2 2.2.15 cells in a dose-dependent manner, as well as the extracellular HBV DNA. And EHP could selectively inhibit the activity of HBV promoter Fp. Our data suggest that EHP exerts anti-HBV effects via inhibition of HBV transcription, which helps to elucidate the mechanism underlying the potential therapeutic value of EHP.