Anti-salmonella activity of aqueous and methanol extracts of Xylopia aethiopica and xylopic acid

Abstract

Enteric infections pose great havoc to the well-being of humans and animals. This study established the potential use of Xylopic aethiopica and xylopic acid in salmonellosis. Aqueous and methanol extracts of X. aethiopica were prepared and tested alongside the major constituent, xylopic acid. Phytochemical screening on the extracts conducted showed the presence of various secondary metabolites such as alkaloids, tannins, flavonoids, saponins, and coumarins, but sterols were absent. The microbroth dilution assay was used to assess the antimicrobial activity of methanol (MXA), aqueous (AXA) extracts, and xylopic acid (XYL) against seven (7) drug-resistant strains and a sensitive strain of Salmonella typhi. Out of the seven (7) drug-resistant strains, 4 were multidrug-resistant, and 3 were ciprofloxacin-resistant. Xylopic acid (XYL) had better antimicrobial activity than MXA and AXA with MICs ranging from 26.8 to 118.9 µg/mL, 9.4 to 20.8 mg/mL, and 4.7 to 12.5 mg/mL, respectively. The time-kill kinetics profile of MXA, AXA, and XYL showed a reduction in the log count of viable cells, but the reduction in the microbial population was less than 99.9%, indicative of bacteriostatic action. MXA, AXA, and XYL had antimicrobial activity against drug-resistant S. typhi strains.