Antibacterial potential of Thevetia peruviana leaf extracts against food associated bacterial pathogens

Objective:To isolate and characterize the food associated bacterial strains,and to evaluate the antibacterial activity and minimum inhibitory concentration of various solvents(acetone,chloroform,methanol and petroleum ether)leaf extracts of Thevetia peruviana(T.peruviana)against their respective isolated and standard bacterial strains and also to investigate the presence of various phytochemical constituents in the leaf extracts of test plant.Methods:The food associated bacterial strains were isolated from students'lunch boxes in Tesfa Tewahido Primary School.The antimicrobial activity and minimum inhibitory concentrations were determined by the disc diffusion and serial dilution methods,respectively and phytochemical constituents were also detected in various solvent leaf extracts of T.peruviana.Results:The result showed that all the tested solvent leaf extracts of T.peruviana exhibited antibacterial activity against the tested standard and isolated bacterial strains with zones of inhibition ranged from 10.0 to 17.0 mm.Amongst the tested food borne bacterial pathogens,Salmonella typhimurium was most sensitive towards petroleum ether leaf extracts of T.peruviana while,methanol leaf extracts was relatively least effective against all the tested standard and isolated bacterial strains.Minimum inhibitory concentration of various solvent leaf extracts of T.peruviana ranged from 16.67 to 50.00 mg/mL for all the tested standard and isolated bacterial strains.The phytochemical constituents screening on the leaf extracts of T.peruviana showed the presence of alkaloids,cardiac glycosides,flavonoids,polyphenols,saponins and tannins.Conclusions:The present study suggests that T.peruviana could be used as prospective aspirants against the common food borne bacterial pathogens and also provide a wide array in the development of drugs against common food borne bacterial pathogens.