Hepatitis C is a major global health burden with 160 million infected individuals worldwide. This long-term disease, caused by a small positive-strand ribonucleic acid (RNA) enveloped virus, namely hepatitis C virus (HCV) evolves slowly. Nowadays, no vaccine is available and current treatments are unsatisfactory due to their restricted spectrum of action. For this reason, it is suggested that the combination of several drugs will prevent viral resistance and might conduct to an efficient antiviral therapy. Thus, the discovery of new direct acting antiviral agents (DAAs), with a broad spectrum of action, targeting different steps of the virus life cycle is still needed. Here, we identified (-)-epigallocatechin-3-gallate (EGCG) as a new inhibitor of HCV entry. Epigallocatechin-3-gallate, extracted from green tea, inhibits HCV infection. More precisely, this natural catechin molecule acts at a very early step of entry regardless of the genotype as illustrated with HCV pseudoparticles expressing HCV envelope glycoproteins E1 and E2 assays and cell-cultured HCV assays. Moreover, this molecule inhibits the docking of the virus to the cell surface as showed by the quantification of bound viruses during the attachment step using quantitative real-time polymerase chain reaction. Furthermore, EGCG inhibits viral cell-to-cell transmission as demonstrated by inhibiting cell-free transmission using agarose or neutralizing antibodies assays. Finally, EGCG clears HCV from cell culture supernatants after four passages.The half maximal inhibitory concentration (IC50) of EGCG in cell culture is approximately 11 µM. In order to identify new molecules exhibiting an enhanced anti-HCV activity and displaying similarities from EGCG scaffold, a series of natural compounds were selected and were tested for their anti-HCV activities. Thus, the anthocyanidin delphinidin chloride was identified as another inhibitor of HCV entry. Like EGCG, delphinidin chloride acts directly on the virus at a very early step of entry, regardless of the genotype, probably by inhibiting the docking of the virus to the cell surface without affecting replication or viral assembly/secretion. Finally, with an IC50 of 3 µM, delphinidin chloride displays a more potent anti-HCV activity.Together, these data indicate that EGCG and delphinidin chloride are new interesting anti-HCV molecules that inhibit entry and might be used as a new treatment in combination with other DAAs. Furthermore, these two inhibitors might be novel tools to further dissect the mechanisms of HCV entry into the hepatocyte.
EGCG and delphinidin : two new natural inhibitors of hepatitis C virus entry