Antimicrobial activities of southern Nepalese medicinal plants.

In an ethnopharmacological screening of selected medicinal plants used in Nepal, methanol extracts from 20 plant species were assayed for activity against eleven strains of bacteria and four strains of fungi. Duplicate assays were conducted with and without exposure to ultraviolet (UV)-A radiation to test for light-activated or light-enhanced activity. Fifteen of the extracts showed activity against bacteria and fourteen showed activity against fungi. Five extracts were active only when exposed to UV-A light, and the antibiotic or antifungal effect of five extracts was enhanced upon exposure to light. Two of the most active extracts were from plants used to treat diarrhoea and dysentery. Bark from both Terminalia alata (Combretaceae) and Mallotus phillppensis (Euphorbiaceae) was active against Gram-positive and Gram-negative bacteria.