(-)-Epigallocatechin-3-gallate inhibits entry of hepatitis B virus into hepatocytes

Hepatitis B virus (HBV) is a major cause of liver disease and hepatocellular carcinoma. Chronic HBV infection is currently managed with either nucleoside/nucleotide-based or interferon-based therapies, but fails to clear infection in a substantial proportion of cases, and antiviral strategies targeting the early stages of infection are therefore required for the prevention of HBV infection. In this study, we examined some common phytochemicals and identified epigallocatechin-3-gallate (EGCG) as a new inhibitor of HBV entry. EGCG, a flavonoid present in green tea extract, belongs to the subclass of catechins. We demonstrated that EGCG at a concentration of 50μM inhibited HBV entry into immortalized human primary hepatocytes by more than 80%, whereas the other four catechins tested had much weaker inhibitory effects. DMSO-differentiated HuS-E/2 cells expressed sodium taurocholate cotransporting polypeptide (NTCP), which is a receptor for HBV. Application of EGCG during HBV inoculation markedly inhibited infection in both DMSO-differentiated HuS-E/2 cells and HA-NTCP-expressing Huh7 cells. Interestingly, EGCG induced clathrin-dependent endocytosis of NTCP from the plasma membrane followed by protein degradation. In addition, EGCG inhibited the clathrin-mediated endocytosis of transferrin. Treatment of cells with EGCG had no effect on HBV genome replication or virion secretion. Moreover, the characteristic of HBV virion and the expression of known HBV entry factors were unaltered by EGCG. Finally, the antiviral activity of EGCG on HBV entry was observed using four different genotypes, A to D. These results show that the green tea-derived molecule EGCG potently inhibits HBV entry and could be used in prevention of HBV reinfection.