Abstract
A versatile microplate bioassay for quick and sensitive determination of antibacterial activity was developed for use in screening medicinal plants and identification of their active principles. This assay can be used to determine minimum inhibitory concentrations for small quantities of organic or water-soluble plant extracts. Bioassay-guided fractionation of the stem and leaves of
Peperomia galioides using this method found fractions containing grifolin and grifolic acid, which inhibited growth of
Staphylococcus aureus and
Staphylococcus epidermidis.