Antibacterial activity of crude leaf and seed extracts of Solanum melongena on Escherichia coli and Staphylococcus aureus.
Abstract
The study was carried out to compare the antibacterial activity of the ethanolic extracts of seed and leaf extracts of solanum melongena, a traditional plant commonly for food and medicinal purposes among local communities in different parts of the world. The microorganisms tested were Escherichia coli (gram negative) and staphylococcus aureus (gram positive) Which are common etiological agents of diarrheal diseases. Crude extracts were used and the method used for extraction was solvent extraction technique using ethanol as the extracting solvent. Antibacterial activity of the extracts was tested using agar-well diffusion technique on Mueller Hinton (MH) media.. Of the two bacteria tested, Escherichia coli turned out to be relatively more susceptible than Staphylococcus aureus with a mean diameter of zone of inhibition 14mm for Escherichia coli and 12mm for Staphylococcus aureus. The results showed ethanolic leaf extracts of solanum melongena to be more active at inhibiting both Escherichia coli and Staphylococcus aureus than ethanolic seed extracts of solanum melongena. Leaf extracts of Solanum melongena produced a ZOI of 14 while seed extracts produced a ZOI of 12 on Escherichia coli. For Staphylococcus aureus, leaf extracts produced a Zone Of Inhibition of 13.7 while seed extracts of Solanum melongena produced a Zone Of Inhibition of 11.9mm. Data analysis was by Analysis of Variance, ethanolic leaf extracts had more antibacterial activity compared to ethanolic seed extracts of Solanum melongena on Escherichia coli with a P-value 0.00864 at 95% level of confidence. Similarly, for Staphylococcus aureus, leaf extracts still exhibited more activity compared to their seed counterparts with a P-value 0.0231 at 95% level of confidence.
In conclusion, Solanum melongena possessed antibacterial activity against Escherichia coli and Staphylococcus aureus. Leaf extracts were significantly better at inhibiting growth of Escherichia coli and Staphylococcus aureus.