An antifungal mechanism of curcumin lies in membrane-targeted action within Candida albicans.

The aim of this study is to investigate the antifungal mechanism of curcumin. This polyphenolic compound has been used traditionally in Asia for medicinal, culinary, and other purposes. Although antifungal effect of curcumin has been reported, this is the first study for its mode of action underlying disruption of plasma membrane in Candida albicans. The leakage of potassium ion from the fungal cytosol and dissipation in membrane potential was detected by bis-(1,3-dibutylbarbituric acid)trimethine oxonol [DiBAC4 ] staining. We also investigated an increase in membrane permeability in curcumin-treated C. albicans with influx of propidium iodide assay. Fluorescence analysis with 1,6-diphenyl-1,3,5-hexatriene supported the membrane-targeted mechanism of action indicating membrane disruption. On the basis of these results, we studied the effects of curcumin treatment on model membrane to elucidate its antifungal mechanism. Using calcein leakage assays from curcumin-treated large unilamellar vesicles and giant unilamellar vesicles, we found that curcumin has membrane-active mechanism inducing leakage of intracellular component through the flappy membrane. Therefore, this study suggests that curcumin exerts antifungal activity via inducing disruption of fungal plasma membrane.