HCWEs inhibit HSV infections by targeting virus particles directly
To determine which stage HCWEs hit and identify which viral proteins or host factors mediated the anti-virus activity, we first explored whether HCWEs lead host cells to initiate anti-viral mechanisms or interfere virus particles directly to block further viral binding and penetration, Vero cells and HSV were pretreated respectively with HCWEs and the plaque reduction assay was performed to determine which stage HCWEs act on HSV infection. The pretreated Vero cells showed no obviously inhibitory effect on HSV-1 infection at a concentration of 10 mg/ml (S1 Fig.), which is 14 times higher than its EC50 (0.692 mg/ml). However, in the cases of HSV-1, HSV-2, and even HSV-AR pretreated with 0.01 mg/ml HCWEs, the plaque formation was largely inhibited (Fig. 1A). These results implied that the anti-HSV effects of HCWEs might target virus particles directly and inhibit further stages of HSV infection. To examine this hypothesis, HCWEs-pretreated HSV-1 and HSV-2 were incubated with Vero cells at 4°C to allow virus to bind onto cells but not penetrate the cells. The unbound viruses were washed out with PBS, and the cell-bound viruses were analyzed by Western blot analysis. HCWEs obviously decreased the cell binding ability of HSV-1 and HSV-2 in a dose-dependent manner (Fig. 1B). The results implied that HCWEs might affected virus particles directly and result in the inhibition HSV-1 and HSV-2 infections