Antiviral activity of chemical compound isolated from Artemisia morrisonensis against hepatitis B virus in vitro

•A major component (PHAP) from Artemisia morrisonensis was found to have antiviral activity against HBV.•The PHAP significantly reduced HBsAg and HBeAg secretion and virion DNA level from cultured HepG2 2.2.15 cells.•PHAP regulates viral surface gene expression and causes overexpression of large surface protein in Huh7 cells.•PHAP blocks HBV virion secretion by interfering ER stress regulated chaperone GRP78 gene expression in vitro.

The compound p-hydroxyacetophenone (PHAP) isolated from Artemisia morrisonensis was found to have potential anti-HBV effects in HepG2 2.2.15 cells. We clarified its antiviral mode further and HBV-transfected Huh7 cells were used as the platform. During viral gene expression, treatment with PHAP had no apparent effects on the viral precore/pregenomic RNA. However, the 2.4-kb preS RNA of viral surface gene increased significantly relative to the 2.1-kb S RNA with PHAP. Promoter activity analysis demonstrated that PHAP had a potent effect on augmenting the viral preS promoter activity. The subsequent increase in the large surface protein and induce endoplasmic reticular (ER) stress has been reported previously. Interestingly, PHAP specifically reduced ER stress related GRP78 RNA/protein levels, but not those of GRP94, in treated Huh7 cells while PHAP also led to the significant intracellular accumulation of virus. Moreover, treatment with the ER chaperone inducer thapsigargin relieved the inhibitory effect of PHAP based on the supernatant HBV DNA levels of HBV-expressed cells. In conclusion, this study suggests that the mechanism of HBV inhibition by PHAP might involve the regulation of viral surface gene expression and block virion secretion by interference with the ER stress signaling pathway.