ANTIBACTERIAL ACTIVITIES AND PHYTOCHEMICAL SCREENING OF GINGER EXTRACT AGAINST SALMONELLA SPP AND STAPHYLOCOCCUS AUREUS

This study investigated the antibacterial activities and phytochemical constituents of ginger (Zingiber officinale) extract against Salmonella spp. and Staphylococcus aureus. The aim was to evaluate the antibacterial efficacy and phytochemical profile of ginger extracts against isolates obtained from Sabon Iche, Kagarko LGA, Kaduna State, Nigeria. Fresh rhizomes were collected and authenticated at the Herbarium Unit of Ahmadu Bello University, Zaria. They were processed into powdered form and subjected to aqueous and ethanolic extraction. Extracts were analysed for phytochemicals using standard methods, while antibacterial activity was determined through agar well diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays. Phytochemical analysis revealed that ethanol extract showed strong positivity for flavonoids and phenols, with moderate levels of alkaloids, tannins, and steroids. The aqueous extract presented a weaker profile but contained saponins as an additional compound. Glycosides were absent in both extracts. Bacterial confirmation was carried out by Gram staining and biochemical tests: S. aureus appeared as Gram-positive cocci in clusters, while Salmonella spp. were Gram-negative rods with typical biochemical reactions. Antibacterial assays demonstrated that both extracts exhibited dose-dependent inhibitory effects. Ethanol extract was more effective, producing inhibition zones of 16 mm against Salmonella spp. and 12 mm against S. aureus at 500 mg/mL, while aqueous extract recorded 14 mm and 11 mm, respectively. MIC and MBC results showed that ethanolic extract achieved bacterial inhibition at lower concentrations (250–500 mg/mL), unlike aqueous extract which required higher doses. The findings suggest that ginger contains bioactive compounds with promising antibacterial activity, particularly in ethanolic extracts, supporting its ethnomedicinal use as a natural alternative to conventional antibiotics.