ABSTRACT

The methanolic bark and leave extracts of Azadirachta indica were screened for antimicrobial activity. The extract of the barks and leaves were tested against Escherichia coli, Staphylococcus aureus and Salmonella typhi. Escherichia coli, Staphylococcus aureus, Salmonella typhi, using paper disc diffusion method and results compared with standard antibiotics discs of Gentamicin and chloramphenicol. The methanol bark extract showed activity against E.coli at concentration of I00mg/ml with zone of inhibition of 12.2mm. The same extract showed activity against S. aureus and S. typhi at concentration of I 00mg/ml showing the zone of inhibition of 17 .5mm respectively. The leave methanol extract showed activity on the test organisms of S. aureus and S. typhi at concentration of I00mg/ml with diameter zone of inhibition 11.2mm and 10.5mm respectively, while there was no activity on E. coli at lesser than I 00mg/ml.Higher concentration of greater than 25mg/ml, were required to produce bactericidal activity on the test organisms. Phytochemical screening showed that tannins, alkaloids, saponins, flavanoids and phenols were active compounds present in the methanol bark and leaves extract of Azadirachta indica.Methanol bark extract had highest inhibitory activity on the test organisms probably because they contain more compounds than the methanol leaves extracts. Bark and leaves extract of Azadirachta indica bay be useful or the treatment o some diseases whose causative agents are susceptible to its in-vitro antibacterial activity.