In vitro antibacterial activity and the minimum inhibitory concentration of aqueous seeds extract of Cucumis melo L. grown in Sri Lanka on common urinary tract infective bacteria

Abstract

In this study, in vitro antibacterial activity of aqueous seeds extract of Cucumis melo L. grown in Sri Lanka was evaluated on common urinary tract infective bacteria (E. coli, S. aureus, P. aeruginosa, P. mirabilis and E. faecalis). Disc diffusion assay and the macro broth dilution method were used to determine the antibacterial activity and the minimum inhibitory concentration (MIC) respectively. Gentamicin and ampicillin were used as the positive controls. The results showed that seeds extract exhibited concentration dependent t marked antibacterial activity against uropathogens at all the concentrations (500 µg/ mL, 1000 µg/ mL and 2000 µg/ mL). Statistical analysis revealed that the results were equipotent to gentamicin and ampicillin which is a novel finding. The highest antibacterial activity was shown against E. coli at 2000 µg/ mL (22.0±2.64 mm). Least inhibition zones were showed by E. faecalis. The highest MIC was shown by E. faecalis (1000 µg/ mL) and the least by P. aeruginosa (125 µg/ mL). The results of qualitative phytochemical analysis revealed the presence of alkaloids, phenols, saponins, flavonoids and tannins. Therefore, the extract is likely to mediate its antibacterial activity by synergistic mechanisms. In addition, the results scientifically justified the claim made by Sri Lankan traditional and folk medicine. Findings also indicated the potential of developing a drug for urinary tract infections based on the seeds of Cucumis melo L.