Phytochemical composition, antioxidant, antibacterial, and antifungal activities of the methanoic extract of neem seeds (Azadirachta indica) grown in El Oued

Abstract

This study investigates the phytochemical composition, antioxidant, and antimicrobial activities of methanolic extracts from the aerial parts of neem (Azadirachta indica) seeds. The extract yielded 4.95% and exhibited total phenolic and flavonoid concentrations of 58.32±0.87 µg QE/mg and 49.03±0.99 µg GAE/mg, respectively. The antioxidant activity was evaluated using the β-carotene bleaching assay, DPPH assay, and ABTS radical scavenging assay, with results presented as IC50 values, demonstrating substantial antioxidant potential despite being lower than that of synthetic antioxidants such as BHT and BHA. Antifungal activity was assessed against pathogenic fungi, revealing significant inhibition rates, while antibacterial activity tests indicated very high concentrations (VHC) required for effective inhibition of various bacterial strains, including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis. LC-MS analysis identified a range of bioactive compounds, with catechin being the most predominant, suggesting the extract's therapeutic potential. These findings highlight the significance of neem seeds as a source of natural antioxidants and antimicrobial agents, supporting their traditional medicinal applications and potential use in food preservation and health products. Further research is warranted to explore their mechanisms of action and efficacy in clinical settings.