Kalopanaxsaponin A induces reactive oxygen species mediated mitochondrial dysfunction and cell membrane destruction in Candida albicans

Candidiasis causes high morbidity and mortality among immunocompromised patients. Antifungal drug resistance and cytotoxicity highlight the need of effective antifungal therapeutics. In this study, we found that kalopanaxsaponin A (KPA), a triterpenoid saponin natural product, could inhibit the proliferation of various Candida species, and exerted a fungicidal effect against C. albicans. To further explore its antifungal action mode, spectro-fluorophotometer, fluorescence microscopy and transmission electron microscopy were performed, showing that KPA treatment induced the accumulation of intracellular reactive oxygen species (ROS), resulting in mitochondrial dysfunction. Meanwhile, KPA treatment also broke down the membrane barrier of C. albicans causing the leakage of intracellular trehalose, the entrance of extracellular impermeable substance and the decrease of ergosterol content. Both ROS accumulation and membrane destruction contributed to the death of C. albicans cells. Our work preliminarily elucidated the potential mechanisms of KPA against C. albicans on a cellular level, and might provide a potential option for the treatment of clinical candidiasis.