Research on the antibacterial and cytotoxic effects of four plants used for medicinal purposes in the Central African region

This study investigates the secondary metabolites of the root and stem bark of Crossopteryx febrifuga benth, Khaya anthotheca, Gardenia ternifolia, and Terminalia glaucescens, obtained through maceration, using tub reactions. Antimicrobial and cytotoxic activities were assessed using antibiogram disc tests on Pseudomonas aeruginosa (ATCC 27853), Enterobacter hormaechei (ATCC 700323), Bacillus spizizenii (ATCC 6633), Enterococcus casseliflavus (ATCC 700327), Staphylococcus aureus subsp. Rosenbach (ATCC 6538), and Salmonella Typhi (ATCC 6539). Cytotoxicity was evaluated using the MTT assay on NIH3T3 mouse fibroblast cells. Extracts from the bark of Terminalia glaucescens and Crossopteryx febrifuga Benth exhibited antimicrobial activity against four bacterial strains, notably Enterobacter hormaechei (3 ± 2 cm), Bacillus spizizenii (5 ± 2 cm), Staphylococcus aureus (5 ± 2 cm), and Salmonella Typhi (3 ± 2 cm). Extracts from Khaya anthotheca and Gardenia ternifolia demonstrated activity against only two strains: Enterobacter hormaechei (4 ± 2 cm) and Bacillus spizizenii (5 ± 2 cm). The most potent extracts were obtained via maceration (hydromethanol 90%), inhibiting cell growth by 19%, whereas supercritical water extraction (125°C, 60 ATM) resulted in the lowest cytotoxicity. Higher extract concentrations correlated with increased inhibition, with plant E extracts exhibiting the strongest effect at 1 g/ml.