Abstract: Candida albicans have closely related with many oral diseases, and probiotics can inhibit the virulence of pathogenic bacteria through its metabolites. Therefore, this study explored the inhibitory effect and mechanism of the supernatant of Lactiplantibacillus plantarum HB13-2 on the bacteria of C. albicans. Firstly, the minimum inhibitory concentration of C. albicans in supernatant was determined by double dilution method. Then, CFW fluorescent dye was used to stain the cell wall，and the results showed that the supernatant treatment enhanced the fluorescence intensity and damaged the cell wall . Flow cytometry and fluorescence microscopy showed that the supernatant of L. plantarum HB13-2 changed the membrane permeability of C. albicans. The transmembrane potential was detected by DiSC3(5), and the fluorescence intensity was enhanced, indicating that the supernatant improved the transmembrane potential. Reactive oxygen species accumulation and mitochondrial membrane potential were detected by DCFH-DA and Rhodamine-123 fluorescence staining. The results showed that the supernatant resulted in a large amount of intracellular reactive oxygen species accumulation and increased mitochondrial membrane potential. The microstructures were observed by scanning electron microscopy. In conclusion, the supernatant of L. plantarum HB13-2 can deform cells by destroying cell wall and cell membrane, leading to mitochondrial damage, and thus play an inhibitory role in C. albicans. This suggested L. plantarum HB13-2 has the potential to be used as an oral probiotic

Key words: Candida albicans, Lactiplantibacillus plantarum, Antifungal mechanism