Antibacterial Activity of Herbal Medicine Extracts against Edwardsiella tarda

The methanol extracts of 19 commercial herb medicines was analyzed to antibacterial activities against Edwardsiella tarda, causing several fish diseases. Rhus javanica showed most strong antibacterial activity against E. tarda and Escherichia coli. Methanol extract of R. javanica was further extracted using several organic solvents having different polarity. Extract from ethyl acetate fraction showed strong activity against E. tarda as well as E. coli. Minimal inhibitory concentration, MIC of R. javanica extract was measured and resulted showing for E. tarda and for E. coli. It is needed that, from these results, further purification and isolation of reposible compound of these activities and further study on the synergy effect using combination with antibiotics against pathogenic bacteria.