Protective Effects of Pleurotus Species on UVB-Induced Skin Disorders at Clinically Relevant Plasma Concentrations of the Antioxidant Ergothioneine in Hairless Mice

Ergothioneine (ERGO) has antioxidant and anti-inflammatory activities in UV-irradiated skin cells in vitro; however, there is no evidence about the effects of dietary ERGO on UV-induced skin damage or ERGO skin distribution in vivo. This study examined the protective effects of ERGO-rich edible mushrooms Pleurotus species against UVB-induced skin damage and the exposure to ERGO in the plasma and skin. Hos : HR-1 hairless mice were fed with or without freeze-dried cross-bred Pleurotus species (PS) or Pleurotus eringii (PE) and were exposed to UVB. Dietary intake of PS or PE significantly alleviated UVB-induced reductions in skin moisture content, increases in transepidermal water loss and oxidative stress markers, and epidermal thickening at plasma ERGO concentrations of 30-40 μM. Additionally, ingestion of PS significantly suppressed UVB-induced expression of pro-inflammatory cytokines. These results suggest that ingesting PS and PE may protect against UVB-induced skin disorders through antioxidant and anti-inflammatory activities at clinically relevant ERGO concentrations. Ingestion of PS and PE led to an increase in epidermal ERGO concentration to levels that were approx. 100 times higher than the ERGO concentration required for significant suppression of UVB-induced intracellular reactive oxygen species in immortalized human keratinocyte HaCaT cells. This suggests that the beneficial effects of PS and PE may be at least partly due to the antioxidant effects of ERGO in murine skin. Overall, ingestion of ERGO-rich Pleurotus species resulted in efficient distribution of ERGO to the skin and protective effects against UVB-induced skin damage, suggesting that these mushrooms may have beneficial effects in humans.