Joachim O. Ezeadila, Michael O. Nwande, Gideon I. Ogu and Francis A. Aneke
The practice of chemotherapeutic medicine has long been in battle with the development of multiple resistant strains, providing the avenue for advancement in the research for an alternative medicine with possible low or no toxicity to human, animal and environment. This study focuses on the in vitro determination of the antibacterial activities of ethyl acetate and n-hexane extracts of Vernonia amygdalina and Moringa oleifera leaves. The disc diffusion method was used to test for in vitro effect of different concentrations (400, 200, 100, 50, 25 and 12.5mg/ml) of the extracts against Staphylococcus aureus and Escherichia coli isolated from urine samples. Septrin (25mg/ml) was used as the positive control while drug free and extract-free solutions of ethyl acetate and n-hexane as negative controls. Ethyl acetate extracts of both leaves showed inhibitory activity on both test organisms, when compared with the positive control, whereas both test organisms were resistant to n-hexane extract of both plants. The inhibitory zone diameters of V. amygdalina against E. coli and S. aureus were 25mm and 10.3mm at 400mg/ml respectively, while that of M. oleifera at same concentration were 15mm and 10mm respectively. V. amygdalina and M. oleifera showed bactericidal activity against S. aureus at 100mg/ml and 200mg/ml respectively but were only bacteriostatic against E. coli. The MIC of V. amygdalina and M. oleifera ranged from 25-200 mg/ml and 50- 200mg/ml respectively. This study justifies the use of both plants as potential sources of antibiotics, and the use of highly effective organic solvents for plant extraction is recommended.
