Applied Cosmetic Science and Technology Applied Cosmetic Science and Technology

The skin is under constant stress from external factors such as ultraviolet (UV) and dryness. In addition, photoaging, such as darkness, spots, and wrinkles, caused by blue light (BL), a visible light source, was recently reported. Therefore, protecting the skin not only from UV but also from damage caused by BL is important. The roots of Paeonia lactiflora Pallas and their constituents, paeoniflorin and albiflorin, have blood circulation–promoting and anti-inflammatory effects; however, few studies have reported their effects on BL–induced skin damage. In the present study, we examined the effects of P. lactiflora Pallas root extract (PE) on BL–induced skin damage. BL caused dose-dependent human dermal fibroblast damage. BL irradiation increased mitochondrial singlet oxygen levels and decreased cell viability, mitochondrial content, and mitochondrial membrane potential. In contrast, PE, paeoniflorin, and albiflorin ameliorated BL damage in BL–irradiated cells. Furthermore, BL induced damage in the skin model at the same irradiation intensity as that in the monolayer condition, while PE improved adenosine triphosphate (ATP) production and mitochondrial content by reducing BL–induced mitochondrial singlet oxygen levels. Collectively, these findings suggest that PE aids in the prevention of skin aging by downregulating mitochondrial singlet oxygen levels, which are increased by BL, and by improving mitochondrial content, mitochondrial membrane potential, and ATP production.