Abstract
Abstract Background and aims: Multidrug-resistant (MDR) Candida auris and Candida albicans are critical hospital-associated threats, causing difficult-to-treat infections worldwide. Escalating resistance and limited antifungal options highlight the urgent need for alternatives, with plant-derived compounds offering promise. This study aimed to evaluate the antifungal activity and time–kill kinetics of Calotropis procera and Bridelia ferruginea leaf extracts against C. auris and C. albicans. Methods: Extraction of plant materials was carried out by the maceration method. Antifungal activity of the extracts was assessed using agar well diffusion and minimum inhibitory concentration (MIC) assays, while time–kill assays were conducted over 42 h at different concentrations. Results: Both extracts inhibited the Candida species with identical MIC values (3.125 mg/mL), though their inhibitory potency differed between species. C. procera showed greater inhibition against C. albicans (16.33 ± 0.33 mm) than B. ferruginea (12.67 ± 0.33 mm), whereas B. ferruginea was more effective against C. auris (16.33 ± 0.33 mm vs. 12.67 ± 0.33 mm). Time–kill studies showed concentration- and time-dependent fungicidal activity for both extracts. C. procera rapidly reduced C. albicans counts, achieving ≥3-log₁₀ reduction by 26–30 h, while B. ferruginea caused gradual, sustained declines in C. auris viability over 42 h. Conclusion: Both extracts displayed species-specific fungicidal activity. The rapid effect of C. procera against C. albicans and the sustained activity of B. ferruginea against C. auris underscore their complementary antifungal potential. These findings suggest that the plants may serve as promising sources of antifungal agents, warranting further phytochemical characterization and in vivo evaluation.