PHYTOCHEMICAL ANALYSIS AND ANTIBACTERIAL ACTIVITY OF STEM BARK EXTRACT OF GUAVA (PSIDIUM GUAJAVA)

This study investigates the phytochemical composition and antibacterial efficacy of Psidium guajava (guava) stem bark against Escherichia coli and Staphylococcus aureus, two common bacterial pathogens. Qualitative phytochemical analysis identified the presence of tannins, saponins, terpenoids, and phenolic compounds, while alkaloids, flavonoids, and glycosides were absent. These bioactive compounds are known to exhibit significant antimicrobial activity. The antibacterial assay demonstrated that the ethanolic extract of P. guajava stem bark exhibited inhibitory effects against both bacteria, with higher efficacy at increased concentrations. The zones of inhibition for E. coli and S. aureus at 30 mg/ml were 25 mm and 20 mm, respectively. The minimum inhibitory concentration (MIC) was determined to be 1.23 µ/ml for E. coli and 0.9 µ/ml for S. aureus. Although the extract exhibited antibacterial properties, its efficacy was slightly lower compared to standard antibiotics. The findings suggest that Psidium guajava stem bark could serve as a natural antibacterial agent, particularly in the search for alternative treatments against antibiotic-resistant bacteria.