In Vitro Antibacterial Activity of Extracts of Selected Marine Algae and Mangroves against Fish Pathogens

摘要

In vitro screening of organic solvent extracts of three marine algae viz., Gracilaria corticata, Ulvafasciata and Enteromorpha compressa and five mangroves viz., Aegiceras corniculatum, Aegialitis rotundifolia, Aglaia cucullata, Cynometra iripa and Xylocarpus granatum showed species specific activity in inhibiting the growth of six virulent strains of bacteria pathogenic to fish viz., Edwardsiella tarda, Vibrio alginolyticus, Pseudomonas Jluorescens, Pseudomonas aeruginosa and Aeromonas hydrophila (2strains). Three methanol extracts of C. iripa were active against all the six pathogens, whereas A. corniculatum and A. cucullata were active against four of the pathogens. The chromatographic fractionation of active extracts of A. corniculatum, C. iripa and G. corticata resulted in enriched fractions with wide spectrum activity and lowered values of minimum inhibitory concentration.