Figure 2: Antiviral activity of serial dilutions of (a) star anise oil, phenylpropanoids and (b) sesquiterpenes against HSV-1 in viral suspension assays. Diluted drugs were tested up to the maximum noncytotoxic concentration. Number of virus plaques was determined 3 days after infection and compared to untreated control. Results are presented as percentage of plaque reduction, experiments were repeated independently and data are the mean of three experiments ± SD.