ASSESSMENT OF THE ANTIBACTERIAL POTENTIAL OF GINGER AND GARLIC EXTRACTS AGAINST CLINICALLY RELEVANT BACTERIAL ISOLATES FROM OKADA, NIGERIA

Abstract

The increasing prevalence of antimicrobial resistance (AMR) has necessitated the exploration of plant-derived alternatives as potential sources of antibacterial agents. This study evaluated the antibacterial activity of aqueous extracts of ginger (Zingiber officinale) and garlic (Allium sativum) against selected clinical bacterial isolates (Escherichia coli, Staphylococcus aureus, and Klebsiella spp.). Fresh ginger and garlic were obtained from Okada community, Edo State, Nigeria, processed into powdered form, and extracted using sterile distilled water. The extracts were tested at varying concentrations (stock, 1:2, 1:4, and 1:8) using the Kirby-Bauer disc diffusion method. Ofloxacin served as the control antibiotic. Results showed that garlic extract exhibited minimal inhibitory activity against S. aureus at the highest concentration (8 mm and 3 mm zones at stock and 1:2 respectively), while no activity was observed against Klebsiella spp. and most concentrations of E. coli. Ginger extract showed no observable inhibitory effect against all tested isolates across all concentrations. In contrast, ofloxacin demonstrated significant antibacterial activity with inhibition zones ranging from 16–24 mm. The findings indicate that aqueous extracts of ginger and garlic possess limited antibacterial activity under the conditions used in this study, suggesting that extraction method, concentration, and compound stability may significantly influence their efficacy. This study highlights the need for further research using alternative extraction solvents and optimized processing methods to better evaluate the antimicrobial potential of these medicinal plants.