ANTIBACTERIAL ACTIVITY OF CRUDE EXTRACTS OF Solanum incanum AGAINST Escherichia coli and Staphylococcus aureus

Abstract

Human pathogenic microorganisms have developed resistance in response to indiscriminative use of commercial drugs. Plants produce many secondary metabolites with microbiocidal activity hence their use in traditional medicine. Herbalists in Kenya use medicinal plants including Solanum incanum in treating microbial infections. Though S. incanum has been used to treat different diseases in humans and animals, there is little information on antimicrobial activities of its extracts against Escherichia coli and Staphylococcus aureus. In this study, phytochemical analysis and antibacterial activity of solanum incanum leaves, roots and seeds extracts were determined. Ethanolic and aqueous extracts of leaf, root and seed of concentrations 25, 50, 75 and 100, and amoxicillin 25 mg/ml (control) with three replications were used for antibacterial analysis by the agar-well diffusion method. The results were subjected to analysis of variance at P < 0.05. Phytochemical screening revealed the presence of alkaloids, flavonoids, glycosides, saponins, steroids and tannins. Solanum incanum exhibited significant antibacterial effect against the two test bacteria. Ethanol extracts were more active than extracts against the bacteria. Ethanol extracts at 100% inhibited growth of Staphylococcus aureus more than the Escherichia coli. The zones of inhibition for Staphylococcus aureus were 35.0±0.6 mm, 30.94±0.3 mm and 30.14±0.64mm for seed, root and leaves respectively.On the other hand, the zones of inhibition for Escherichia coliat 100% ethanol were 27.20±0.06, 23.14±0.12 and 21.0±0.4 seed, root and leaves respectively.The results validate the use of these plants in ethnomedicine and potential of this plant in treating infections caused by the two bacteria.