The antifungal effect of light emitting diode on Malassezia yeasts

BackgroundMalassezia (M.) species are members of the normal part of the skin flora, but they might induce or be involved with various cutaneous diseases. Although the role of Malassezia in the pathogenesis of cutaneous diseases is not fully understood, recent studies have shown that decreased density of Malassezia led to improvement of these diseases.ObjectiveTo identify the antifungal effect of light emitting diode (LED) against Malassezia, its antifungal mechanisms and the impact on the keratinocytes.MethodsLED with various wavelengths (370–630 nm) on Malassezia furfur, Malassezia sympodialis and Malassezia globosa was irradiated according to dose and then the antifungal effects were thereafter assessed. After irradiating LED with 392.5 ± 1 nm of wavelength according to dose on Malassezia species, reactive oxygen species (ROS) and lipid hydroperoxide production assay were measured. In addition, cell viability and inflammatory cytokines (IL-1α, IL-1β, TNF-α, TGF-β, TLR-2 and COX-2) expressions in normal human epidermal keratinocytes (NHEKs) by LED irradiation were evaluated.ResultsThe growth of Malassezia species was dose-dependently suppressed by both LED with 380 ± 2 and 392.5 ± 1 nm wavelengths. The increases of intracellular and extracellular ROS by LED irradiation with 392.5 ± 1 nm wavelengths were significantly observed compared to control group. The cell viability and cytokines in NHEKs were not significantly affected by LED irradiation under 5 J/cm2in vitro.ConclusionLED irradiation with 380 ± 2 and 392.5 ± 1 nm wavelengths proved to have antifungal effect against Malassezia species and no impact on NHEKs under 5 J/cm2. The findings suggest that LED might be an adjunctive therapeutic light tool against Malassezia yeasts related cutaneous diseases.