Screening of Brazilian medicinal plants for antiviral activity against rotavirus

Brazilian medicinal plants traditionally used for the treatment of diarrhoea were investigated for their in vitro antiviral activity against the simian rotavirus SA11. The ethanolic crude extracts of plants collected in the cerrado of Minas Gerais, Brazil were submitted to phytochemical screening. The cytotoxicity of the extracts was inferred by cellular morphologic alterations. Antiviral activity was assessed by the ability of the extracts to inhibit the cytopathic effect (CPE) of rotavirus on the treated cells. RT-PCR was performed to confirm and/or confront antiviral assay data. The maximum non-toxic concentration ranged from 50 to 500μg/mL. All extracts were toxic at a concentration of 5000μg/mL but no extract showed cytotoxicity at 50μg/mL. The species Byrsonima verbascifolia, Myracrodruon urundeuva, Eugenia dysenterica and Hymenaea courbaril exhibited the strongest in vitro activity against rotavirus. Their extracts prevented the formation of CPE, and RT-PCR analysis detected no amplification of genetic material from rotavirus. Tannins, flavonoids, saponins, coumarins and terpenes were the major classes of natural products found in the leaf extracts that showed antiviral activity. Among the species studied, Byrsonima verbascifolia, Eugenia dysenterica, Hymenaea courbaril and Myracrodruon urundeuva showed potential activity against rotavirus and are worthy of further study. The present study corroborates ethnopharmacological data as a valuable source in the selection of plants with antiviral activity and to some extent validates their traditional uses.