ABSTRACT
The rise of antibiotic-resistant bacterial infections has created an urgent need for alternative antimicrobial agents. Alstonia boonei, a medicinal plant widely used in traditional African medicine, has demonstrated promising antimicrobial properties. This study evaluates the antibacterial activity of aqueous leaf extracts of A. boonei against selected clinical bacterial isolates, including Staphylococcusaureus, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa. The study employed the agar well diffusion method to assess bacterial susceptibility to varying concentrations (1000 mg/ml, 500 mg/ml, 250 mg/ml, and 125 mg/ml) of A. boonei leaf extract. Results showed significant inhibition zones against E. coli (27 mm at 1000 mg/ml), K. pneumoniae (20 mm at 1000 mg/ml), and S. aureus (16 mm at 1000 mg/ml), while P. aeruginosa exhibited complete resistance. The antibacterial activity observed is attributed to the presence of bioactive compounds such as alkaloids, flavonoids, tannins, and saponins, which may disrupt bacterial cell membranes and metabolic functions. These findings highlight the potential of A. boonei as a natural antimicrobial agent, particularly against Gram-positive and some Gram-negative bacteria. However, the resistance of P. aeruginosa suggests further research is needed to determine possible synergistic applications with conventional antibiotics. Future studies should focus on the plant's mechanism of action, toxicity profile, and potential clinical applications
