Bioactivity of Excoecaria agallocha leaf extract against Pseudomonas aeruginosa infection in Labeo rohita

ABSTRACT As a natural remedy to combat bacterial diseases that arise during intensive farming practices in aquaculture, extracts of milky mangrove (Excoecaria agallocha) leaves were prepared using acetone, diethyl ether, petroleum ether, and water. Among these, petroleum ether extract has shown the highest bactericidal and antioxidant potency. This extract was purified using column chromatography and preparative TLC and further characterized using mass spectroscopy (MS). The results from MS confirmed the presence of 4-methylumbelliferone, pinellic acid, 1,2,9,10-tetramethoxy-6-methyl-5,6,6a,7-tetrahydro-4 H-dibenzo[de,g]quinolin-3-yl) methanol, and 10-hydroxy-camptothecin, which have antimicrobial and anti-inflammatory potential. Moreover, the efficiency of the extract was assessed by conducting in vivo studies on P. aeruginosa-infected Labeo rohita fingerlings. Among the five groups considered under study, Groups 4 and 5, which were treated with crude and purified extracts, recovered with 88% and 100% survival rates and also showed elevated levels of antioxidant (CAT and SOD) enzymes in the liver after the experimental period. Thus, the present investigation substantiates E. agallocha extract as an alternative medicine for existing drugs to treat bacterial infections in fishes owing to its antibacterial and antioxidant activities.