ANTIBACTERIAL ACTIVITY OF CUCUMIS SATIVUS (CUCUMBER) PEEL AND LEAF ON SOME CLINICAL ISOLATES

This study investigates the antibacterial properties of Cucumis sativus (cucumber) peel and leaf extracts against clinical isolates of Klebsiella spp., Staphylococcus aureus, and Escherichia coli. Clinical isolates were obtained from Aminu Kano Teaching Hospital and identified using Gram staining and a series of biochemical tests. The cucumber peel and leaf were collected, air-dried, and then extracted with both methanol and chloroform to recover bioactive compounds. Phytochemical screening confirmed the presence of secondary metabolites—including flavonoids, tannins, alkaloids, and saponins—known for their antimicrobial effects. The antibacterial activity of the extracts was evaluated using the agar well diffusion method by measuring the zones of inhibition produced against each bacterial strain. In addition, the minimum inhibitory concentration (MIC) was determined via serial dilution techniques, and the minimum bactericidal concentration (MBC) was assessed by subculturing onto nutrient agar plates to evaluate bacterial viability after treatment. Statistical analysis, employing one-way ANOVA, was conducted to compare the efficacy of the different extracts. The results revealed that both peel and leaf extracts of cucumber exhibited antibacterial properties, with the methanol extracts producing significantly larger zones of inhibition than the chloroform extracts. Notably, the most pronounced antibacterial effect was observed against Staphylococcus aureus, while Klebsiella spp. showed the greatest resistance. MIC testing indicated that lower concentrations of the methanol extracts were necessary to inhibit bacterial growth. However, the MBC results demonstrated that none of the extracts achieved complete bactericidal activity at the concentrations tested. In summary, the findings support the notion that Cucumis sativus contains bioactive compounds with promising antimicrobial potential, particularly against Gram-positive bacteria. Nevertheless, the inability to fully eradicate the bacteria underscores the need for further research to optimize extraction techniques, enhance extract potency, and clarify the mechanisms underlying these antibacterial effects. Future studies should also examine potential synergistic interactions with conventional antibiotics to improve therapeutic outcomes.