Antifungal activity of Punicalagin-nystatin combinations against Candida albicans.

Abstract

Oral candidiasis is the most common opportunistic fungal infection of oral mucosa and results from an overgrowth ofCandida, especiallyCandida albicans.The potential anti-C.albicansand cytotoxicity of punicalagin (PCG), isolated fromPunica granatum, alone or with nystatin (NYS) were evaluated. Activity of compounds alone or in combinations wasdetermined against twoC.albicansstrains (ATCC 90028 and SC5314).Minimal inhibitory concentration (MIC)-50 and Minimum Fungicidal Concentration (MFC)were assessed by XTT assay and CFU counts, respectively. For combinations, determination of fractional inhibitory concentration index was performed. Ergosterol pathway was investigated as a possible PCG antifungal mechanism. Cytotoxicity assays were undertaken on human primary oral keratinocytes and gingival fibroblasts incubated with antifungal concentrations of PCG and/or NYS for 24hr. Combination of NYS and PCG increased antifungal efficacy, compared with compounds tested alone. Combinations 4 (PCG-6.25μg/ml; NYS-3.9μg/ml) and 5 (PCG-12.5μg/ml; NYS-1.95μg/ml) were more effective since they reduced the MIC-50 of PCG (50μg/ml)by 8 and 4 times, respectively, increased the candidal inhibition and nullified the PCG cytotoxicity for keratinocytes. PCG antifungal mechanism did not involve ergosterol biosynthesis pathway. The favorable outcomes for combination of PCG and NYS encourage further testing this therapeutic strategy against C.albicans.