Antiviral and antimicrobial activities of Colombian medicinal plants

Strong antiviral and antimicrobial activities were detected in methanolic e xtracts of 24 plants used medicinally in the treatment of skin infections i n four different regions of Colombia. Thirteen extracts displayed activity against herpes simplex virus (HSV) whereas none was active against poliovir us. The antiviral activity was indicated by a total inhibition of viral cyt opathic effects (CPE) at a non-cytotoxic concentration of the extract. The most potent extract was obtained from Byrsonima verbascifolia (L.) HBK. whi ch showed anti-HSV activity at a concentration as low as 2.5 mug/ml. Antimi crobial screening was conducted using the disc diffusion assay against Kleb siella pneumoniae, Escherichia coli, Streptococcus faecalis, Mycobacterium phlei, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Sa lmonella typhimurium and the human pathogenic yeast, Candida albicans. Anti -Candida activity was observed for Piper lanceaefolium HBK. and Juglans neo tropica Diels. Twenty-two extracts displayed activity against Gram-positive bacteria whereas none was active against the Gram-negative species. We con cluded that these Colombian medicinal plants represent an untapped source o f potentially useful antivirals and are worthy of further study. (C) 2001 E lsevier Science Ireland Ltd. All rights reserved.