Anti-melanogenic effects of hot-water extracts from via MAPKs and cAMP signaling pathway on B16F10 cells.

is an evergreen tree in the family , the seeds, leaves, and stems of which have long been used as edible products and herbal medicines in Korea. Previous studies of biological activity have shown that has antioxidant and anti-inflammatory effects. However, the effect of leaves on melanogenesis are yet to be studied. In this investigation, we used B16F10 melanoma cells to test the efficacy of leaf hot water extract (TLWE). α-melanocyte stimulating hormone (α-MSH) stimulated B16F10 melanoma cells were treated with various concentrations of TLWE (50, 100, and 200 μg/mL). The results showed that TLWE reduced the melanin content and cellular tyrosinase activity in a concentration-dependent manner. It also inhibited the phosphorylation of p38 mitogen-activated protein kinase (p38) and c-Jun N-terminal kinase (JNK) in the mitogen-activated protein kinase (MAPK) signaling pathway. The compounds catechin and ρ-coumaric acid, which are known to have a whitening effect on skin, were detected by HPLC analysis. These results suggest that TLWE has an anti-melanogenic effect. In addition, the safety of TLWE was tested. The results of the skin irritation test showed that TLWE is harmless to the human skin, even at higher concentrations than those used in the experiment. Therefore, we suggest that the water extract of leaves has potential for use as a skin-whitening agent.