1 ANTIBACTERIAL ACTIVITY OF AQUEOUS, ETHANOL, AND ETHYL ACETATE EXTRACTS OF BLIGHIA SAPIDA LEAVES AGAINST LISTERIA MONOCYTOGENESS

14 ABSTRACT The rising resistance of pathogens to conventional antibiotics has driven interest in medicinal plants as alternative antimicrobial sources. This study evaluated the antibacterial potential of Blighia sapida leaf extracts against Listeria monocytogenes, a major foodborne pathogen. Fresh leaves of B. sapida were extracted with distilled water, ethanol, and ethyl acetate, followed by phytochemical screening, fractionation by TLC, and antibacterial testing using agar well diffusion, MIC, and MBC assays. Active fractions were identified by bioautography and characterized using GC–MS, while 15 physicochemical and ADMET properties of detected metabolites were predicted in silico. Phytochemical screening confirmed alkaloids, flavonoids, terpenoids, tannins, cardiac glycosides, and saponins. Only ethanol and ethyl acetate extracts inhibited L. monocytogenes (9 mm zones; MIC 12.5 mg/ml), while aqueous extract was inactive and no bactericidal effect was observed. GC–MS revealed dibutyl phthalate as the dominant metabolite, alongside camphene, neophytadiene, and eicosane. ADMET predictions showed most compounds complied with Lipinski’s Rule of Five, with camphene exhibiting the most favorable pharmacokinetic and safety profile, while neophytadiene indicated cautionary blood–brain barrier penetration. These findings suggest that B. sapida leaves contain bioactive compounds with bacteriostatic effects against L. monocytogenes. Camphene, in particular, represents a promising antimicrobial lead, warranting further in vitro and in vivo studies to validate its therapeutic potential.