Objective To explore the effects of hypericin on inhibition of hepatitis 15 virus (HBV) replication.Methods The concentration gradient hypericin was added to HepG2.2.15 cell culture system and lamivudine was used as control.Enzyme-linked immunosorbent assay (ELISA) and Southern blot were used to examine HBsAg,HBeAg and HBV DNA level in the culture supernatant,respectively.Half inhibitory concentration (IC50) and half effective concentration (EC50) of hypericin were calculated.The effects of hypericin on HBV DNA polymerase were detected by 32p marked deoxy-ribonucleoside triphosphate as the substrate. Independent sample t-test and single factor analysis of variance were used to compare the data between two groups and among multiple groups.Results The inhibition rates of hypericin on HBsAg, HBeAg were enhanced with hypericin concentration increasing and those were higher than lamivudine control group when the concentration was higher than 0.5 μmol/L (t=-0.127,P＜0.05).Southern blot confirmed that hypericin was stronger in inhibition of HBV DNA (EC50=0.2 μmol/L) than lamivudine (t=-0.058,P＜0.05).Hypericin was non-toxic on HepG2.2.15 cells in the range of test with EC50 of 0.2 μmol/L and IC50 of 200 μmol/L.Hypericin did not act on HBV DNA polymerase which was quite different from lamivudine.Conclusions Hypericin can effectively inhibit HBV replication as well as antigen synthesis and is non-toxic on HepG2.2.15 cell.The anti-HBV target of hypericin is different from nucleos(t)ide analogues.

At present, traditional methods on statistics have limitations in controlling time- varying confounding. This paper introduces an analysis method, parametric g-formula, which would adjust time-varying confounding, and also exemplifies the steps of its implementation for purpose to provide a new reference for researchers to deal with long-term observational data.