RAPID SCREENING OF THE ANTIMICROBIAL ACTIVITY OF EXTRACTS AND NATURAL-PRODUCTS

A spectrophotometric method has been developed for the rapid measureme nt of the antimicrobial activity of natural products, including crude extracts or pure materials. The assay depends on the measurement of no n-specific esterase activity using fluorescein diacetate (FDA) hydroly sis in broth cultures of microbes after they have been treated with te st compounds. The assay is accurate, reproducible and economical in bo th time and materials. The speed and economy of the method make it sui table for the rapid screening of many samples and the bioassay directe d purification of antimicrobial substances. The assay can also be used with a wide variety of micro-organisms since most micro-organisms are FDA positive. Applications are described in the fields of marine natu ral products chemistry and essential oils research.