Antibacterial activities of polyunsaturated fatty acid extracts from Sardinella longiceps and Sardinella fimbriata

Polyunsaturated fatty acids (PUFA) content of two species of fishes Sardinella fimbriata and Sardinella longiceps was examined and their antibacterial activities were compared. PUFA isolated from the tissue extracts were used to conduct Antibacterial Sensitivity Tests on pathogenic bacterial strains like Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pnuemoniae, Enterobacter aerogenes, Proteus vulgaris, Salmonella enterica and Pseudomonas aeruginosa. These extracts were subjected to Gas Chromatography for the quantitative analysis of PUFA. Extracts from both species showed inhibitory effects on the strains of S. aureus, E. faecalis, E. coli and P. aeruginosa. No inhibitory activities were observed on the strains of K. pnuemoniae, E. aerogenes, P. vulgaris and S. enterica. S. fimbriata extract showed a higher inhibitory effect on all the inhibited bacterial strains. Gas Chromatography analysis revealed higher concentrations of docosahexaenoic acid (DHA) in the extracts from S. fimbriata as compared to S. longiceps. The differences between the antibacterial activities of the two extracts could be attributed to the disparity in DHA content.