Phytochemical and antibacterial studies of the ethanolic stem barks extract of Anthocleista vogelii planch, and the in silico study of its secondary metabolites on two bacteria strains Staphylococcus aureus and Salmonella typhi.

Abstract

This study investigates the phytochemical composition, antibacterial efficacy, and molecular interactions of Anthocleista vogelii stem barks extracts. Phytochemical screening revealed the presence of flavonoids, alkaloids, triterpenes, phenols, saponins, and other bioactive compounds in 95 % ethanol and hydro-ethanol extracts, while coumarins, steroids, and anthraquinones were absent in aqueous extracts. The 95 % ethanol extract demonstrated significant antibacterial activity against Esherichia coli (MIC: 64 μg/mL) and Klebsiella pneumoniae (MIC: 8 μg/mL), with moderate effects against Staphylococcus aureus, A. baumannii, and Salmonella Spp. (MIC: 512 μg/mL). Bactericidal activity (MBC/MIC ≤ 4) paralleled ciprofloxacin, particularly against Gram-positive pathogens. LC-MS analysis identified nine bioactive flavone derivatives, including fabiatrin, kaempferitrin, quercitrin, and naringin. Molecular docking revealed these compounds exhibited superior binding affinities (-6.6 to -11.7 kcal mol^-1) to S. aureus and Salmonella typhi targets compared to ciprofloxacin (-3.6 to -5.4 kcal mol^-1), forming hydrogen bonds and π-interactions critical for inhibition. ADMET predictions indicated poor gastrointestinal absorption and AMES toxicity risks but favorable plasma protein binding and cardiac safety. Frontier Molecular Orbital (FMO) analysis highlighted quercetin's high reactivity (ΔEgap: 3.70 eV) and naringin's stability. These findings position A. vogelii as a rich source of antimicrobial phytochemicals, though further optimization is needed to address pharmacokinetic limitations.