Amentoflavone inhibits hepatitis B virus infection via the suppression of preS1 binding to host cells

Hepatitis B virus (HBV) is a leading cause of chronic hepatitis, liver cirrhosis, andhepatocellular carcinoma. Current therapeutic drugs for chronic HBV infection useIFN and nucleos(t)ide analogs; however, their efficacy is limited. Thus, there is anurgent need to develop new antivirals for HBV therapy. In this study, we identifieda plant‐derived polyphenolic bioflavonoid, amentoflavone, as a new anti‐HBVcompound. Amentoflavone treatment dose‐dependently inhibited HBV infection inHBV‐susceptible cells with HepG2‐hNTCP‐C4 and primary human hepatocytePXB‐cells. A mode‐of‐action study showed that amentoflavone inhibits the viral entrystep, but not the viral internalization and early replication processes. Attachment ofHBV particles as well as HBV preS1 peptide to HepG2‐hNTCP‐C4 cells was inhibitedby amentoflavone. The transporter assay revealed that amentoflavone partly inhibitsuptake of sodium taurocholate cotransporting polypeptide (NTCP)–mediated bile acid.Furthermore, effect of various amentoflavone analogs on HBs and HBe productionfrom HBV‐infected HepG2‐hNTCP‐C4 cells was examined. Robustaflavone exhibitedcomparable anti‐HBV activity to that of amentoflavone and an amentoflavone‐7,4', 4‴‐trimethyl ether derivative (sciadopitysin) with moderate anti‐HBV activity. Cupressu-flavone or the monomeric flavonoid apigenin did not exhibit the antiviral activity.Amentoflavone and its structurally related biflavonoids may provide a potential drugscaffold in the design of a new anti‐HBV drug inhibitor targeting NTCP.