PHYTOCHEMICAL PROFILING AND ANTIMICROBIAL EFFICACY OF AZADIRACHTA INDICA STEM BARK EXTRACTS

The growing threat of antimicrobial resistance has necessitated the exploration of alternative therapeutic agents derived from natural sources. This study investigated the phytochemical composition and antimicrobial efficacy of Azadirachta indica (Neem) stem bark extracts against clinically relevant multidrug-resistant pathogens, including Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, Acinetobacter, and Enterococcus. Extraction of The stem bark was carried out using maceration unified. The crude extract was partitioned using ethanol and n-hexane to obtain two fractions: the ethanolic fraction (AIE) and the n-hexane fraction (AIH). Minimum inhibitory concentration (MIC) tests revealed that the ethanolic extract was more effective, with MIC values ranging from 100 mg/ml to 12.5 mg/ml. The ethanolic extract showed the highest efficacy against Staphylococcus aureus (MIC: 12.5 mg/ml). while the lowest activity was observed against Escherichia coli (MIC: 100 mg/ml). The n-hexane extract had MIC values ranging from 100 mg/ml to 12.5 mg/ml, with the highest activity against Staphylococcus aureus (MIC: 12.5 mg/ml) and lowest activity against Escherichia coli (MIC: 100 mg/ml). Minimum bactericidal concentration (MBC) tests showed that the lowest MBC value was observed against Staphylococcus aureus (37.5 mg/ml), while the highest was recorded against Escherichia coli (150 mg/ml) for both extracts. Antimicrobial susceptibility tests demonstrated that the ethanolic extract was more effective than the n-hexane extract, with zones of inhibition ranging from 8 mm to 20 mm. The highest inhibition was observed against Acinetobacter (20 mm at 100 mg/ml), while the lowest was recorded for Enterococcus (6 mm at 50 mg/ml). Phytochemical analysis revealed the presence of several bioactive compounds, including Gallic acid, Sinapic Acid, Caffeic Acid, Rutin Hydrate, Quercetin, Kaempferol, Nicotiflorin, and Astragalin. Quercetin had the highest concentration (361.43 ppm), while Kaempferol was found at the lowest concentration (87.12 ppm). This study demonstrates that Azadirachta indica stem bark extracts, particularly the ethanolic fraction, possess significant antimicrobial activity, making them a potential natural source for antimicrobial agents