HSINCHU, Taiwan—It’s summer time, and things are heating up as formulators of sun care products are on the looking out for natural ingredients that thwart UVA and UVB’s damaging effects. Researchers recently found chrysin, a natural flavonoid occurring in various plants and foods such as honey, protects keratinocytes against UVA- and UVB-induced injuries, suggesting its potential use in skin photoprotection (J Agric Food Chem. July 6, 2011).
Chrysin reportedly opposes inflammation and carcinogenesis, but has rarely been applied in skin care. This study, therefore, aimed to explore the roles of chrysin in protection against UV-induced damage in HaCaT keratinocytes. Results showed chrysin can attenuate apoptosis, reactive oxygen species (ROS) production and cyclooxygenase 2 (COX-2) expression induced by UVB and UVA. Chrysin predominantly reversed the down-regulation of aquaporin 3 (AQP-3) by UVB. It predominantly reversed JNK activation and also mildly inhibited p38 activation triggered by UVA and UVB. Animal studies revealed chrysin's topical application demonstrated efficient percutaneous absorption and no skin irritation.