Abstract:
This study was designed with the objective of the determination of the antibacterial activity of leaves of Nicotiana tabaccum which was collected from Al Fasher city . Four reference strains of bacteria were used including two Gram -positive bacteria Staphylococcus aureus ,Bacillus subtilis and two gram- negative bacteriaEscherichia coli , Pseudomonas aeruginosa .Four concentration of leaves extractsfrom water,acetone and ethanol of Nicotainatabaccum 12.5%, 25%, 50%, 100% were used testing of the extract for antibacterial activity was done onNutrient agar media byusing agar well diffution method .Antibacterial activity was determined by measuring the diameter of zone of inhibition.Water extracts of allconcentrations of leaves of Nicotaina tabaccum not caused inhibition zone against Staphylococcus aureus ,Bacillus subtilisEscherichia coliandPseudomonas aeruginosa .Four concentrations of acetone extract were shown inhibitory effect against Staphylococcus aureus,andEscherichia coli,exceptBacillus subtiliswhichshown inhibitory effectin the100% concentration.whilePseudomonas aeruginosashowed resistance to all concentrations of acetone extract.Ethanol extract caused inhibition zone againstStaphylococcus aureus,Escherichia coliwhereasBacillus subtilis (shown inhibitory effect in the50%,100% concentration)whereasPseudomonas aeruginosanotshownresistance to all concentration of ethanolic extract.
