Figure 4.

Inhibitory effect of excoecarianin (open bars) and ACV (dotted bars) against HSV-2 infection in Vero cell as determined by plaque reduction assay. Vero cells were incubated with 100 pfu of HSV-2 and different concentrations of excoecarianin or ACV. After 1 h, an overlay medium containing 1% methylcellulose was added. On Day 3 post-infection, the cell monolayer was stained with crystal violet and the virus plaques formed were counted. The percentage of inhibition was calculated by comparing the plaque number of compound-treated group to that of the untreated group. The concentrations of excoecarianin and ACV that inhibited 50% of HSV-2 infection (IC₅₀) were determined. Each bar represents the mean ± SD of three independent experiments. The asterisk indicates significant difference between test sample and solvent control (P < .05).