Abstract

ANTIBACTERIAL ACTIVITY OF EXTRACTS OF THALASSIA HEMPRICHII, HALODULA PINIFOLIA, HALODULA UNINERVIS AGAINST HUMAN AND FISH PATHOGENS

Shani T. John*

ABSTRACT

In vitro screening of organic solvent extracts of three marine sea grasess viz.,Thalassisa hemprichii, Halodula pinifolia, Halodula uninervis, were were carried out using the standard procedures, all the tested crude extracts showed good activity in inhibiting the growth of six fish pathogens viz., Vibrio parahaemolyticus, Vibrio harveyi, Vibrio fischeri, Serratia marcescens, Micrococcus sp and Aeromonas hydrophila and also 10 human pathogens like Escherichia coli, Staphylococcus epidermidis, Pseudomonas mirabilis, Klebsiella pneumonia, Pseudomonas aerugenosa, Salmonella typhi, Vibrio cholera,Streptococcus pneumonia, Bacillus cereus, and Enterobacter aerogenes Compara tively the methanol extracts of Thalassia hemprichii was active against most of the human pathogens and fish pathogens, whereas H. pinifolia, H. uninervis were active against some of the human pathogens and fish pathogens. The maximum zone of inhibition of 7mm was exhibited by T.hembrichii (methanol) extract against the human pathogen Streptococcus epidermidis and 8mm against the fish pathogen V. parahaem olyticus and 7mm against Aeromonas hydrophila. The extract which showed promising activity was partitioned and separated by column chromatographic technique and its activity was also assessed. The 100 % methanol extract showed good antibacterial activity of 6 mm against Salmonella typhi and 5 mm against Pseudomonas mirabilis and an inhibition of 6mm observed against fish pathogens like V.fischeri and A.hydrophila. MIC values were found to be lower for 100% methanol fractions for the pathogens E.coli, S.typhi (0.05mg), P.aeruginosa (0.1mg) and for V.fischeri, V.harveyi (0.1mg)).

Keywords: Sea grass, antibacterial assay, column fractions MIC, Human and Fish pathogens.