ANTIOXIDANT AND ANTIMICROBIAL ACTIVITY OF GARLIC ON SOME CLINICAL ISOLATES

ABSTRACT This study aimed to evaluate the antioxidant and antimicrobial effects of garlic extract against Escherichia coli, Staphylococcus spp., and Candida spp. The study was conducted in Bauchi, Nigeria, where garlic cloves were sourced from Mudalawa Market and clinical isolates were obtained from Federal Teaching Hospital, Bauchi. Aqueous and ethanolic garlic extracts were prepared, and their antimicrobial activity was tested by measuring zones of inhibition and determining the minimum inhibitory concentration (MIC). The antioxidant capacity of the garlic extract was evaluated using the DPPH radical scavenging assay, and total phenolic and flavonoid contents were measured spectrophotometrically. Data analysis was performed using ANOVA with SPSS software. The results revealed that garlic extract exhibited significant antioxidant activity, with the scavenging effect increasing from 9.69% at 100 mg/ml to 24.68% at 400 mg/ml, supported by high levels of total phenolics (8.29 mg/dm³) and flavonoids (26.31 mg/dm³). Antimicrobial tests demonstrated that garlic extract was effective against both bacterial and fungal pathogens, with higher concentrations showing greater inhibition. The extract was particularly effective against Staphylococcus spp. (inhibition zones up to 23.00 mm) and Candida albicans (up to 27.20 mm), with MIC values lower for these pathogens than for E. coli. In conclusion, garlic extract possesses substantial antioxidant and antimicrobial activities, making it a promising candidate for natural therapeutic applications. The study recommends further research to elucidate the specific mechanisms of action, optimization of garlic extract formulations, and clinical trials to assess its safety and efficacy in humans.