Photoprotective Effects of Cycloheterophyllin Isolated from Artocarpus heterophyllus against UVA‐Induced Damage and Oxidative Stress in Human Dermal Fibroblasts

Ultraviolet (UV) radiation is considered a cause of skin aging and may result in pathological changes in the skin. Particularly, ultraviolet A (UVA), a long known aging ray and a significant source of oxidative stress, plays a major role in the photoaging of human skin. In the past, many studies have documented that skin cells produce reactive oxygen species after UV exposure. The mitogen‐activated protein kinase (MAPK) pathway would be activated, resulting in phosphorylation of JNK, ERK, and p38 kinase in human skin cells. Previous studies also demonstrated that cycloheterophyllin, a prenylflavone isolated from the root bark of Artocarpus Heterophyllus, has an antioxidant effect and can effectively scavenge free radicals. Although cycloheterophyllin has been studied, the molecular mechanisms involved in the protection of human skin cells from photoaging have not been investigated. Therefore, we used human dermal fibroblasts to investigate protective effect of cycloheterophyllin on UV‐induced damage. We found that cycloheterophyllin significantly increased cell viability and attenuated the phosphorylation of MAPK after UVA exposure. Furthermore, cycloheterophyllin could reduce H 2 O 2 generation. In the in vivo studies, we found that the topical application of cycloheterophyllin before UVA irradiation significantly decreased the value of trans‐epidermal water loss (TEWL), erythema, corneometer and the speed of blood flow. These results indicate that photoprotective effects of cycloheterophyllin inhibited UVA‐induced oxidative stress and damage, and may be beneficial in the prevention of skin photoaging.