Antiviral activities of Nepalese medicinal plants.

In a screening of plants used traditionally in Nepal to treat diseases that could be caused by viruses, methanol extracts from 21 species were assayed for activity against three mammalian viruses: herpes simplex virus, Sindbis virus and poliovirus. Assays were performed in UV-A or visible light, as well as dark. Individual species of Hypericum, Lygodium, and Maesa exhibited impressive antiviral activities, although their selective effects on the three viruses suggested that the antiviral ingredients were different in each extract. In addition, many of the other extracts showed partial inactivation of one or more test viruses.