Hibicuslide C-induced cell death in Candida albicans involves apoptosis mechanism

Aim To provide the observation that hibicuslide C-induced cell death in yeast Candida albicans involves apoptosis mechanism. Methods and Results Hibicuslide C was isolated from Abutilon theophrasti by column chromatography. In reactive oxygen species (ROS) assay, C. albicans treated with hibicuslide C showed increase in ROS, and its accumulation induced fungal cell death. In particular, hydroxyl radicals were a large part of the ROS. Mitochondrial dysfunction including mitochondrial depolarization and release of cytochrome c, which is a pro-apoptotic factor, was detected by JC-1 assay and Western blot. CaspACE FITC-VAD-FMK staining using caspase inhibitor showed metacaspase activation. Also, the increase in intracellular Ca2+, which is a signal molecule of apoptosis, was detected by Fura-2AM and Rhod-2AM assays. Finally, annexin V-FITC and PI double staining and TUNEL assay confirmed that hibicuslide C induces early apoptosis followed by secondary necrosis in C. albicans. Conclusions Hibicuslide C exerts antifungal activity against C. albicans through new mechanism inducing apoptosis. Significance and Impact of the Study Candida albicans is the common cause of nosocomial infections with high mortality. Our findings provide that hibicuslide C can be a model molecule that induces apoptosis in C. albicans.