Evaluation of the Antifungal Activity of Garlic (Allium sativum) Extract Against Candida albicans Isolates

Candida albicans is the most common cause of opportunistic fungal infections in immunocompromised Nigerian patients, and rising azole resistance necessitates the investigation of alternative antifungal agents from plant sources. This study evaluates the antifungal activity of garlic (Allium sativum) extract against Candida albicans isolates obtained from oral and vaginal swab samples at the University College Hospital, Ibadan, Oyo State. Garlic bulbs were obtained from a local market, crushed, and extracted in distilled water and ethanol separately. Allicin content of the extracts was estimated by spectrophotometric measurement. Clinical Candida albicans isolates were obtained from the microbiology laboratory and identified by standard methods including germ tube formation and CHROMagar Candida growth. Antifungal sensitivity was tested by the agar well diffusion method with fluconazole as the reference antifungal drug. Minimum inhibitory concentration and minimum fungicidal concentration were determined by broth microdilution. The ethanolic garlic extract demonstrated consistent antifungal activity, producing zones of inhibition ranging from 15 to 24 millimetres across all tested isolates. Three isolates showing fluconazole resistance by disk diffusion were susceptible to the garlic ethanolic extract, suggesting potential utility against drug-resistant Candida strains. MIC values for the ethanolic extract ranged from 25 to 100 milligrams per millilitre. Allicin content was higher in the ethanolic extract than in the aqueous extract and correlated positively with antifungal potency. These findings support further pharmacological development of garlic-derived antifungal preparations. Keywords: Allium sativum, antifungal, Candida albicans, allicin, Ibadan.