This research investigated the phytochemical constituents and antibacterial activity of Allium cepa (onion) leaves extracts as a potential source of natural antimicrobial agents. Several analyses were conducted, beginning with qualitative phytochemical screening, followed by antibacterial evaluation using some selected bacterial strains. Standard antibiotic (ceftriaxone) served as a control. The phytochemical analysis revealed the presence of alkaloids, flavonoids, tannins, saponins, steroids, and cardiac glycosides with some amount of carbohydrates and proteins, while anthraquinones were absent. Antibacterial assays showed concentration-dependent inhibition zones, with maximum activity at 100 mg/mL: Staphylococcus aureus (3.04 mm), Escherichia coli (2.68 mm), and Bacillus subtilis (2.35 mm), while Shigella showed no inhibition. By contrast, ceftriaxone (50 mg/mL) produced higher zones ranging from 3.28 – 4.85 mm across all organisms. The MIC and MBC values confirmed inhibitory and bactericidal effects at 75 mg/mL for Staphylococcus aureus and Escherichia coli, 50 mg/mL for Bacillus subtilis, and 25 mg/mL for Shigella.
Muhammad et al. (Tue,) studied this question.