PHARMACEUTICAL MICROBIOLGY

This study evaluated the antimicrobial activity and chemical constituents of the aqueous extract of Azadirachta indica stem bark using standard antimicrobial methods and GC-MS analysis. The antimicrobial activity was tested against clinical isolates, including Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Candida albicans, Klebsiella spp., and Aspergillus niger, using the agar-well diffusion method. The extract, a dark brown substance with a yield of 12%, exhibited inhibition zones ranging from 13 to 40 mm. Gas Chromatography-Mass Spectrometry (GC-MS) analysis identified nine bioactive compounds, with 9-Octadecenoic acid (Z)-, methyl ester being the most abundant (64.56%). Other identified compounds include Pyrazine, tetramethyl-; 9- Tetradecenal, (Z)-; Di-n-octyl phthalate; Hexadecanoic acid, methyl ester; Ethanone, 1- cyclododecyl-; Methyl stearate; N,N-bis[2-trimethylsiloxyethyl] ethanamine; and Hexadecanoic acid, 1-[(2-aminoethoxy) hydroxy] derivatives. Some of these compounds have documented antimicrobial properties, which align with the observed inhibitory activity against Gram-positive and Gram-negative bacteria, as well as fungi. These findings support the ethnomedicinal use of Azadirachta indica in managing infections caused by the testedclinical isolates