Antibacterial Activities and Phytochemical Screening of Extracts of Flower of Azadiracthta indica (Neem) against Some Selected Clinical Isolates

A study on the phytochemistry and antibacterial effects of petroleum ether, chloroform, and methanol extract of flower of Azadirachta indica on five clinical isolates viz: Proteus mirabilis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae was carried out using deep well agar diffusion and broth dilution methods. The results obtained showed that methanol flower extract possessed the highest antibacterial activity against P. mirabilis with an inhibition zone of 23mm at the concentration of 4000μg/ml. The minimum inhibitory concentration (MIC) of the petroleum ether flower extract was 62.5μg/ml for all the test organisms while P. mirabilis, S. aureus, and K. pneumoniae had MIC value 62.5μg/ml with the exception of E. coli and P. aeruginosa. Methanol flower extract recorded 62.5μg/ml against P. mirabilis, S. aureus. While E. coli, P. aeruginosa, and K. pneumoniae had no MIC value across all the concentrations. The minimum bactericidal concentration (MBC) for the petroleum ether extracts was 125μg/ml, for chloroform extracts was 250μg/ml, and for methanol extracts was 62.5μg/ml. Phytochemical analysis of the flower extracts showed the presence of reducing sugars, alkaloids, tannins, flavonoids, resins, and saponins, in all the extracts. Petroleum ether flower extract (PFE) showed antibacterial activities against all the test organisms while Methanol flower extract (MFE) had antibacterial activities against only two test organisms.