Discovery of novel indole derivatives containing dithioacetal as potential antiviral agents for plants.

Thirty unreported indole derivatives containing dithioacetal moiety were synthesized and evaluated for anti-plant viral activity. Bioassay results displayed that some of the target compounds showed better activities against tobacco mosaic virus (TMV) than the commercial Ribavirin in vivo. In particular, anti-TMV curative, protective and inactivating activity of 4p were 55.1, 57.2, and 80.3%, respectively, and EC50 value for inactivating activity was 88.5 μg/mL. The observation of transmission electron microscope showed that 4p may have a certain destructive effect on TMV particles. To further study, microscale thermophoresis analysis result also demonstrated that 4p powerfully interacted with TMV coat protein in vitro. Hence, this study provides a strong evidence suporting that indole derivatives might be applied as new antiviral agents.