ANTIMICROBIAL ACTIVITY IN THE COMPOSITE AND MINT FAMILIES

Abstract

The design of this project is such that extracts from identified plants can be tested for antimicrobial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Experimental plants were collected along roadsides, in fields and in wooded areas in the following counties of Georgia: Burke, Columbia, Richmond, and Thomas. Plant material from the root, stem, leaf and flower were extracted in methylene chloride (Fischer, Fair Lawn, NJ). The plants were tested for antimicrobial activity using the agar diffusion assay method. Antimicrobial activities of these plant parts were compared to solvent control bactericidal data, and then the most active plants were further tested in hopes of determining quantitatively the amounts of antimicrobial activity, as well as the minimal inhibitory concentrations and the minimal bacterial concentrations. After extensive testing, it was concluded that methylene chloride should not be used in extracting plant materials, due to its high evaporative rate, resulting in toxicity of bacteria, yielding false positive results.