CLINICAL BACTERIAL ISOLATES

The increasing prevalence of antibiotic-resistant bacteria has heightened the interest in medicinal plants as potential sources of bioactive compounds. This study evaluated the phytochemical composition, antioxidant potential, and antibacterial activity of ethanol leaf extracts of Jatropha tanjorensis (commonly known as Hospital-too-far) against selected clinical bacterial isolates. Leaves of J. tanjorensis were collected from the University of Benin Botanical Garden and authenticated in the herbarium of the Department of Plant Biology and Biotechnology. Clinical isolates of Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli were obtained from the University of Benin Teaching Hospital. Qualitative phytochemical analysis revealed the presence of phenols, flavonoids, and alkaloids in high concentrations, while tannins and saponins were present at lower levels. Quantitative analysis showed phenols as the most abundant compound (129.31 µg/ml), followed by tannins (100.57 µg/ml), flavonoids (46.97 µg/ml), alkaloids (9.33%), and saponins (3.17%). Antioxidant evaluation demonstrated significant activity, with Total Antioxidant Capacity (TAC) of 219.08 µg/ml and Ferric Reducing Antioxidant Potential (FRAP) of 2607.27 µM. The extract also exhibited dose-dependent DPPH radical scavenging activity, with 48.97% inhibition at 10 µg/ml and 69.60% at 100 µg/ml. Antibacterial assessment revealed broad-spectrum activity, with Klebsiella pneumoniae being most susceptible (zone of inhibition: 18 mm at 30 µg/ml), while Escherichia coli and S. aureus showed moderate inhibition. The Minimum Inhibitory Concentration (MIC) ranged from 20–30 µg/ml, indicating bacteriostatic effects at lower concentrations and bactericidal activity at higher doses. Antibiotic susceptibility testing of the isolates confirmed high resistance to commonly used antibiotics, emphasizing the therapeutic potential of the plant extract. Overall, Jatropha tanjorensis leaves contain bioactive compounds with potent antioxidant and antibacterial properties, supporting its traditional use and potential application in combating resistant bacterial infections.