Fungal-Host Interaction: Curcumin Modulates Proteolytic Enzyme Activity ofCandida albicansand Inflammatory Host ResponseIn Vitro

Abstract

Current treatments forCandida albicansinfection are limited due to the limited number of antifungal drugs available and the increase in antifungal resistance. Curcumin is used as a spice, food preservative, flavoring, and coloring agent that has been shown to have many pharmacological activities. Thus, this study evaluated the modulatory effects of curcumin on major virulence factors associated with the pathogenicity ofC. albicans. The minimum inhibitory concentration (MIC) of curcumin againstC. albicans(SC5314) was determined. Biofilm formation was quantified and the proteinase and phospholipase secretion was measured. The cytotoxicity was tested in oral fibroblast cells. A cocultured model was used to analyze the gene expression of proinflammatory cytokines (IL-1β, IL-1α, and IL-6) from host cells, as well SAP-1 and PLB-1 by RT-PCR. The MIC was between 6.25 and 12.5 µM, and the activity of proteinase enzyme was significantly decreased in biofilms treated with curcumin. However, proteinase gene expression was not downregulated after curcumin treatment. Furthermore, gene expressions of host inflammatory response, IL-1βand IL-1α, were significantly downregulated after exposure to curcumin. In conclusion, curcumin exhibited antifungal activity againstC. albicansand modulated the proteolytic enzyme activities without downregulating the gene expression. In host inflammatory response, curcumin downregulated IL-1βand IL-1αgene expression.