In vitro antifungal activity of epigallocatechin 3-O-gallate against clinical isolates of dermatophytes

Previously, we reported that epigallocatechin 3-O-gallate (EGCg) has growth-inhibitory effect on clinical isolates of Candida species. In this study, we investigated the antifungal activity of EGCg and antifungal agents against thirty-five of dermatophytes clinically isolated by the international guidelines (M38-A2). All isolates exhibited good susceptibility to EGCg (MIC₅₀, 2-4 µg/mL, MIC₉₀, 4-8 µg/mL, and geometric mean (GM) MICs, 3.36-4 µg/mL) than those of fluconazole (MIC₅₀, 2-16 µg/mL, MIC₉₀, 4-32 µg/mL, and GM MICs, 3.45-25.8 µg/mL) and flucytosin (MIC₅₀, MIC₉₀, and GM MICs, >64 µg/mL), although they were less susceptible to other antifungal agents, such as amphotericin B, itraconazole, and miconazole. These activities of EGCg were approximately 4-fold higher than those of fluconazole, and were 4 to 16-fold higher than flucytosin. This result indicates that EGCg can inhibit pathogenic dermatophyte species. Therefore, we suggest that EGCg may be effectively used solely as a possible agent or combined with other antifungal agents for antifungal therapy in dermatophytosis.