Medicinal plants of Nepal: ethnomedicine, pharmacology, and phytochemistry

• Main Author: Taylor, Robin S. L.
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/6195

Information about the medicinal uses of forty-two plant species was collected from traditional healers and knowledgeable villagers from a variety of different ethnic groups in Nepal. Illnesses for which these plants are used are those perceived in western style medicine to be caused by bacterial, fungal or viral pathogens. Methanol extracts of the species were screened for activity against a variety of bacteria, fungi and viruses, under various light conditions to test for photosensitizers. Thirty-seven extracts showed activity against bacteria and thirty-five showed activity against fungi. Only eight were active against Gram-negative bacteria. The exposure to UV-A light had a considerable effect on the activities of some extracts, with eight extracts being active only when exposed to light. The antibacterial and antifungal effects of fifteen extracts were enhanced upon exposure to light. Fifteen extracts showed 100% inactivation of at least one virus, and fifteen showed partial activity. Eight extracts were active only when exposed to light, and the antiviral effect of eight extracts was enhanced upon exposure to light. A species showing antibacterial activity, Centipeda minima (Asteraceae), and one showing antiviral activity, Carissa carandas (Apocynaceae) were the focus of bioactivity guided fractionation. Centipeda minima was found to contain three sesquiterpene lactones, identified as 6-O-methylacrylylplenolin, 6-O-isobutyroylplenolin, and 6-O-angeloylplenolin. 6-O-Methylacrylylplenolin had not been previously isolated from C. minima. All three of these sesquiterpene lactones had activity against Bacillus subtilis and Staphylococcus aureus. A fraction from the methanol extract of Carissa carandas was quite active against herpes simplex virus. This fraction was found to contain a derivative of 3,4,5-trimethoxycinnamic acid.