Anti-Candida albicans Effects and Mechanisms of Theasaponin E1 and Assamsaponin A

Candida albicansis an opportunistic human fungal pathogen, and its drug resistance is becoming a serious problem.Camellia sinensisseed saponins showed inhibitory effects on resistantCandida albicansstrains, but the active components and mechanisms are unclear. In this study, the effects and mechanisms of twoCamellia sinensisseed saponin monomers, theasaponin E1 (TE1) and assamsaponin A (ASA), on a resistantCandida albicansstrain (ATCC 10231) were explored. The minimum inhibitory concentration and minimum fungicidal concentration of TE1 and ASA were equivalent. The time–kill curves showed that the fungicidal efficiency of ASA was higher than that of TE1. TE1 and ASA significantly increased the cell membrane permeability and disrupted the cell membrane integrity ofC. albicanscells, probably by interacting with membrane-bound sterols. Moreover, TE1 and ASA induced the accumulation of intracellular ROS and decreased the mitochondrial membrane potential. Transcriptome and qRT-PCR analyses revealed that the differentially expressed genes were concentrated in the cell wall, plasma membrane, glycolysis, and ergosterol synthesis pathways. In conclusion, the antifungal mechanisms of TE1 and ASA included the interference with the biosynthesis of ergosterol in fungal cell membranes, damage to the mitochondria, and the regulation of energy metabolism and lipid metabolism. Tea seed saponins have the potential to be novel anti-Candida albicansagents.Keywords:Camellia sinensisseeds;theasaponin E1;assamsaponin A;antifungal activity;transcriptome