Antibacterial Principle and Chemical Characterization of the Gliricidia sepium Leaves Extract

Abstract

Aim: The present study is aimed at examine the antibacterial effect of crude extract of G. sepium to human pathogenic bacteria and its contents of its chemical composition. Place and Duration of the Study: The study was conducted in the Department of Science Laboratory Technology. Ekiti State University Ado Ekiti Nigeria between May and September 2023. Methodology: The plant sample was authenticated at the Department of Plant Science and Biotechnology, Ekiti State University, Ado Ekiti, Ekiti State. Initially, the leaves were air-dried for four weeks in a cool environment, after which they were oven-dried at 61.9°C for two hours and thirty minutes. The dried leaves were then pulverized into a fine powder using an electric blender. For extract preparation, 100 grams of the powdered leaves were soaked separately in 500 ml each of distilled water, N-hexane, dichloromethane, and methanol. After soaking, the mixtures were filtered using muslin cloth to separate the liquid extract from the solid residues. Escherichia coli 70303, and Klebsiella pneumonia 700303. were obtained from the department of science laboratory technology, Nigeria. The antibacterial activity of was determined using the agar diffusion method. Results: Among the four extracts tested, methanol extract exhibited the strongest antibacterial activity against E. coli, followed by dichloromethane, n-hexane, and water extracts. The methanol extract maintained significant activity even at lower concentrations, with an MIC of 12.5 mg/ml and MBC of 50 mg/ml. The water extract also demonstrated moderate activity but with a higher MIC, indicating lower potency. Water extract exhibited the greatest antibacterial activity against Klebsiella pneumoniae with a 26.3 mm zone of inhibition at 100 mg/ml. MIC was observed at 25 mg/ml, and MBC at 50 µg/ml. Conclusion: Gliricidia sepium leaf extracts, especially those prepared with methanol, exhibit promising antibacterial activity against E. coli. Further phytochemical screening and isolation of active constituents are recommended to identify the compounds responsible for this activity.