Hydrolyzable tannins punicalin and geraniin block hepatitis C virus life cycle

Hydrolyzable tannins were reported to exert inhibitory effects on the infection and replication of several viruses such as HBV, HSV, HIV and leukemia virus. Here we found antiviral effects of two hydrolyzable tannins, punicalin and geraniin, on the HCV life cycle. Our results showed the two hydrolyzable tannins inhibit both attachment and penetration steps of HCV entry. We also verified they suppressed the infection of HCV pseudo-particles. Intriguingly, punicalin and geraniin were found to exert antiviral activities on HCV replicon system. Further study showed HCV NS3/4A serine protease activity was inhibited by the compounds at both the molecular level and the cellular level. Moreover, the two hydrolyzable tannins impeded infectious virion production into culture supernatants. Taken together, hydrolyzable tannins punicalin and geraniin block at least two stages of the HCV life cycle and may be promising lead compounds for the development of anti-HCV agents.