Melanogenesis Inhibitory Activity of Rhododendron weyrichii in Mouse B16 Melanoma Cells

摘要

In this study, to evaluate the usefulness of Rhododendron weyrichii Maxim, as a whitening agent, the whitening effects of its extracts were investigated in alpha-melanocyte-stimulating hormone (α-MSH)-induced B16F10 melanoma cells. No toxicity was noted in either B16F10 melanoma cells or HaCaT keratinocyte cells that were exposed to the hot water or 70% ethanol extracts of R. weyrichii Maxim. (RW-H and RW-E, respectively). Moreover, both the RW-H and RW-E extracts dose-dependently inhibited α-MSH-induced melanin production in B16F10 melanoma cells, with inhibitory effects of 52.5% and 51.6%, respectively, at a concentration of 200 μg/mL. The RW-H and RW-E extracts also inhibited intracellular tyrosinase activity in a dose-dependent fashion. Western blot analyses showed that the RW-H and RW-E extracts decreased tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2 expression. Additionally, we found that h-coumaric acid-containing RW-H and RW-E extracts could be used as hypopigmentation agents since they suppress melanogenesis. Collectively, our results suggest that RW-H and RW-E extracts have the potential to serve as functional cosmetic agents, including whitening agents.