Mangiferin Exerts Antifungal Activity against <i>Candida albicans</i> through Dual Targeting of Cell Wall and Vacuole

Fungal infections caused by <i>Candida albicans</i> remain a significant clinical challenge, particularly with increasing resistance to conventional antifungal drugs. The present study aimed to elucidate the antifungal mechanism of mangiferin, a natural polyphenol, against <i>C. albicans</i>. Mangiferin was found to impair both cell wall integrity and vacuolar function. Its minimum inhibitory concentration (MIC) was determined to be 156 μg/ml, increasing to 312 μg/ml in the presence of the osmotic protectant sorbitol, suggesting cell wall-specific activity. Fluorescence microscopy with Calcofluor White (CFW), a dye that selectively binds to chitin and β-glucans, revealed weakened staining intensity upon mangiferin treatment, indicating structural alterations of the cell wall. Quantitative analysis showed a 63.9% reduction in CFW fluorescence, consistent with changes in cell wall polysaccharides. Enzymatic assays further showed reduced glucan synthase activity, with (1,3)-β- and (1,6)-β-D-glucans reduced to 82.8% and 94.2%, respectively, confirming inhibition of glucan biosynthesis. In parallel, vacuolar function was compromised. BCECF-AM staining demonstrated diminished vacuolar localization, and ratiometric fluorescence measurements indicated a decrease in intracellular pH from approximately 7.0 to 6.6, reflecting cytosolic acidification and impaired pH homeostasis. Neutral red retention decreased by 20.7%, and morphological observations showed cell enlargement and dye mislocalization, supporting the loss of vacuolar function and osmotic imbalance. Collectively, these findings indicate that mangiferin simultaneously impairs the fungal cell wall and vacuolar systems, leading to compromised turgor maintenance and pH homeostasis. This dual-targeted mechanism underscores mangiferin as a promising multitarget antifungal agent and supports its further development against <i>Candida</i> infections.