IN VITRO EVALUATION OF AQUEOUS AND ETHANOLIC EXTRACTS OF VERNONIA COLORATA AS AN ANTIBACTERIAL AGENT

Abstract

Recent reports have shown the increased emergence of bacteria resistance to many existing antimicrobial drugs. This has prompted the need to find alternative remedies, and plant products have proven to be vital in this search. Vernonia colorata has been reported to be active against syphilis, pneumonia, measles, dysentery and several skin infections in traditional medical practices. In the present study, aqueous and ethanolic extracts from the leaves of Vernonia colorata were evaluated in vitro for growth inhibitory activity on Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus using Agar diffusion method. Phytochemical analysis revealed the presence of reducing sugars, saponins, polyphenols, tannins, phlobatannins, alkaloids, sterols and triterpenes in both extracts. These classes of phytochemicals have widely been reported for their antibacterial properties. Of the several bacteria tested, only S. aureus and P. aeruginosa showed significant susceptibility to both ethanolic and aqueous extracts with concentrations range between 2.00 to 5.00mg/ml. The aqueous extract also showed the highest activity on S. aureus at concentration of 5mg/ml. The Minimum Inhibitory Concentration of the aqueous extract ranged between 4.00 and 6.00mg/ml while that of the ethanolic extract ranged between 5.00 and 6.00mg/ml. Following the results from the current study, it can be concluded that V. colorata has significant antibacterial activity and will be very useful in the discovery of novel antibiotics against S. aureus and P. aeruginosa