Screening of seven selected Rwandan medicinal plants for antimicrobial andantiviral activities

Aqueous EtOH (80%) extracts of seven plants used by Rwandan traditional hea lers to treat infections, were screened for antibacterial, antifungal, and antiviral activities. Only two of the selected plants showed a true antivir al activity against herpes simplex virus type 1, while all of them exhibite d virucidal properties against several enveloped viruses including herpes s implex, measles, Semliki forest, and vesicular stomatitis viruses. Four pla nts were diversely active against Gram-positive bacteria, two of these show ing bactericidal effect against the acid-fast Mycobacterium fortuitum. None of the selected plants was active against Gram-negative bacteria or the ye ast Candida albicans. From a bioassay-guided fractionation procedure using herpes simplex virus type 1 as the target model, a virucidal mixture, the m aesasaponin mixture A, was isolated from the MeOH extract of Maesa lanceola ta. The maesasaponin mixture A exhibited a virucidal activity against herpe s simplex types 1 and 2, and vesicular stomatitis viruses. (C) 1999 Elsevie r Science Ireland Ltd. All rights reserved.