Differential responses of Vibrio sp. to young and mature leaves extracts of Terminalia catappa L.

Young and mature leaves of Terminalia catappa of alcoholic and aqueous extracts were evaluated for in vitro antibacterial activity against Vibrio sp. isolated from aquatic animals. Young leaves of T. catappa showed higher antibacterial activity when compared to mature leaves against Vibrio parahemolyticus, with methanolic and aqueous extracts exhibited the largest inhibition zones, 23 and 24 mm, respectively as determined by disc diffusion technique. Ethanolic extract of young leaves showed the lowest MIC and MBC at 3.13 mg/ml and 6.25 mg/ml, respectively. Both alcoholic and aqueous extracts of young and matures leaves exhibit variations in protein, RNA as well as pyrine and pyrimidines leakage of Vibrio sp. Cell membrane disruption is proposed as the mechanism of action of T. catappa leaves extract against Vibrio sp.