Abstract:
One of the major issues confronting global health today is the need for new, effective, and affordable drugs to treat microbial diseases. Plants have long been used as a source of new medicinal compounds, and they continue to be the basis for many pharmaceuticals today. The aim of the study was to evaluate the antimicrobial activity of leaves and root extract of Oncoba spinosa (Forssk) against pathogenic microorganisms. The extracts were prepared using Soxhlet apparatus for crude extracts and the antibacterial activities of extracts were evaluated using well diffusion method. The minimal inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) of the extracts against tested microorganisms were assessed using the broth dilution method. From all solvents used under this investigation, ethanol extracts were potentially against all tested pathogenic bacteria, S.aureus and S.pneumonia were the most susceptible test organisms in both leaf and root extracts of ethanol. The highest inhibition diameter (13.3±0.57mm) and the most potent MIC 1.9mg/ml and MBC 7.8mg/ml of leaf ethanol extract was against S.aureus. The maximum inhibition zone (12.60.70mm) of ethanol root extract was observed in S.pneumonia, were the same MIC 3.9mg/ml and MBC 15.65mg/ml of the extract was against S. pneumonia and S. aureus respectively. In Candida spps, root extract were only gave a minute inhibition diameter of 2.33±0.40mm, and no MIC or MFC of leaf and root of ethanol extracts were found. leaf extracts of Hexane gave the highest inhibition zone (10±0.52mm) with the lowest MIC 7.8 mg/ml and MBC 31.25 mg/ml against S.aureus, while Hexane root extract shows the highest inhibition diameter (11±1) with the lowest MIC 3.9 mg/ml and MBC 15.56 against E.coli. Hexane extracts of the leaf and root show inhibition diameters of 7.66±0.47 and 7.33±0.4 against Candida spps respectively, were the same MIC (125 mg/ml) and MFC (125 mg/ml) of the extract was observed in Candida spps. From the chloroform extracts, the root extract had the highest inhibition diameter of 9±57mm against S.pneumonia, while the leaf extract had the lowest antimicrobial activity in all tested bacterial strains except S.aureus which had a modest inhibition diameter of 7±0.66mm. The inhibition diameter of chloroform extracts of leaf and root against Candida spps was 7.00±0.47mm and 6±.330.47mm respectively, with only a MIC of 125 mg/ml. Thereby, our results indicate the possibility of using this two plant parts in the treatment of bacterial and fungal infections
