Abstract: The need to substantiate the widely acclaimed antibacterial potentials of Dialium guineense leaf informed the present study.Two extract types of Dialium guineense leaf; aqueous extract of Dialium guineense (DAE) and methanol extract of Dialuim guineense (DME) were prepared and analysed for phytochemical constituents following standard protocols. The antibacterial activities of both extracts were evaluated against clinical isolates of Staphylococcus aureus, Bacillus cereus, Enterobacter species, and Pseudomonas aeruginosa using the agar-well diffusion technique. The minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) were also determined using standard methods.The results of the phytochemical analysis revealed the presence of ten(9) bioactive compouds, which varied with extract type.The compounds include anthraquinone, tannins, terpenoids, flavonoids, carbohydrate, protein and amino acid, cardiac glycoside, saponins, and glycoside. The antibacterial analysis revealed that both leaf extracts of Dialium guineense were inhibitory to all the clinical isolates used in this study, indicating that both extracts have broad spectrum activity. The zone of inhibition(cm) ranged between 4.48± 0.13 and 1.22±0.05 with DAE having the highest inhibition against Pseudomonas aeruginosa. While DME had the lowest lowest against Staphylococcus aureus. The minimum inhibitory concentration(MIC) value ranged between 25.00mg/ML and < 0.781mg/ML  with DME having the highest value against Pseudomonas aeruginosa, while DAE had the least value against Staphylococcus aureus, Enterobacter species, and Pseudomonas aeruginosa. The minimum bactericidal concentration value ranged between >50.00mg/mL and 0.781mg/ML. The results of this work suggest further exploitation of the leaves of Dialium guineense to possibly unveil its potential use for treatment of diseases.

Keywords: Dialium guineense, aqueous and methanolic extracts, phytochemical, antibacterial.