In-vitro Antibacterial Activity and Phytochemical Screening of Psidium guajava on Some Enteric Bacterial Isolates of Public Health Importance

Aim: The study was conducted to investigate the antibacterial activity of Psidium guajava and its major antibacterial constituents (Phytochemicals).

Materials and Methods: The aqueous and ethanol extracts from the leaves and stem bark of the plant was tested using well diffusion method for their antibacterial activity against some members Enterobacteriaceae family isolated from diarrheic stool sample (Escherichia coli, Shigella spp, Salmonella typhi and Pseudomonas aeruginosa).

Results: The result shows that the extracts were active against the microorganisms. The ethanolic extract of stem bark showed the highest zones of inhibition against tested organisms compared to aqueous extract. Statistical analysis of the result shows that the extracts demonstrated higher antibacterial activity against the isolates tested with the average zone of inhibition of 15.44 mm, 14.78 mm, 12.92 mm and 11.31 mm for E. coli, Shigella spp S. typhi and P. aeruginosa, respectively. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extracts ranges between 6.25 – 100 mg/ml. Preliminary phytochemical analyses showed that both stem bark and leaf extracts contain alkaloids, tannins, terpenoid, Anthraquinone, reducing sugar, amino acid, flavonoid, saponins, glycosides and phenols.

Conclusion: The extracts of the plant demonstrated antibacterial activity due to presence of phytochemical constituents hence, the application of the decoction of leaf and stem bark of the plants in ethno medicine is justified.