Antiviral activities of medicinal plants of southern Nepal.

In a screening of plants used traditionally in Nepal to treat diseases that could be caused by viruses, twenty-one methanol extracts from twenty species were quantitatively assayed for activity against three mammalian viruses: herpes simplex virus, Sindbis virus and poliovirus. Assays were performed in ultraviolet (UV)-A or visible light, as well as dark, and cytotoxicity was also noted. Impressive antiviral activities were exhibited by species of Bauhinia (Fabaceae), Carissa (Apocynaceae), Milletia (Fabaceae), Mallotus (Fabaceae), Rumex (Polygonaceae), Streblus (Moraceae), Terminalia (Combretaceae) and Tridax (Asteraceae). The Carissa extract was the most active, showing activity against all three viruses at a concentration of 12 micrograms/ml. Many of the other extracts showed partial inactivation of one or more test viruses.