Comparative Evaluation of In Vitro Antifungal Activity of Nigella sativa Linn. and Catharanthus roseus Linn. Extracts Against Pathogenic Candida Strains

Opportunistic fungal infections caused by Candida species represent a major clinical concern due to increasing antifungal resistance to conventional synthetic drugs. This study evaluates and compares the in vitro antifungal activity of ethanolic extracts of Nigella sativa Linn. (seeds) and Catharanthus roseus Linn. (leaves) against four clinically significant Candida strains (Candida albicans, Candida glabrata, Candida tropicalis, and Candida krusei). Antimicrobial potency was determined using disk diffusion (Zone of Inhibition, mm) and broth microdilution assays (Minimum Inhibitory Concentration, MIC, μ"g/mL" ). N. sativa demonstrated significantly stronger antifungal activity across all tested strains compared to C. roseus (p<0.05). The largest zone of inhibition and lowest MIC for N. sativa were observed against C. albicans (15.2±1.4 "mm" ; "MIC"=62.5±5.3 μ"g/mL" ), whereas C. roseus exhibited a 12.8±1.6 "mm" zone of inhibition and an MIC of 125.0±7.2 μ"g/mL" . These findings indicate that N. sativa possesses higher concentrations of potent membrane-disrupting bioactive compounds—primarily thymoquinone—making it a promising candidate for plant-based antifungal drug development