Antibacterial Activity of Psidium Guajava Leaf and Stem Bark Extracts Against Selected Pathogenic Bacteria from Vegetables

This study investigates the percentage yield, physical characteristics, phytochemical composition, and antibacterial activity of Psidium guajava leaf and stem bark extracts. The percentage yields of 17% for the leaf extract and 21% for the stem bark extract, with characteristic dark green and light brown colors, respectively, align with prior findings, reflecting their phytochemical density and extraction efficiency. Phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, steroids, glycosides, and saponins, compounds known for their antibacterial properties. Morphological, microscopic, and biochemical characterization of bacteria isolated from contaminated vegetable samples confirmed the presence of Staphylococcus aureus and Escherichia coli. Antibacterial testing showed dose-dependent inhibitory effects, with the stem bark extract exhibiting greater potency 21.21.3 than the leaf extract 21.01.00, supported by lower Minimum Inhibitory Concentration (MIC) 25mg/ml and 12.5mg/ml against E. coli and Minimum Bactericidal Concentration (MBC) 50mg/ml and 50mg/ml for MBC was found against S. aureus. These findings corroborate the traditional use of Psidium guajava in managing bacterial infections and validate its potential as a natural antimicrobial agent. Further research should isolate and characterize specific bioactive compounds, investigate clinical applications, and explore the extracts' role in food safety to combat bacterial contamination.