[8]-Gingerol inhibits melanogenesis in murine melanoma cells through down-regulation of the MAPK and PKA signal pathways.

[8]-Gingerol is an active component of Zinger and shows several pharmacological activities, such as antipyretic and anti-inflammation characteristics. To identify a potential skin-whitening agent, the inhibitory effects of [8]-gingerol on melanogenesis and its mechanism of action were investigated. In the present study, the effects of [8]-gingerol on mushroom tyrosinase, tyrosinase activity and melanin content were determined spectrophotometrically; the expression of melanogenesis-related proteins in B16F10 and B16F1 melanoma cells were determined by Western blotting. Furthermore, the possible signaling pathways involved in [8]-gingerol-mediated depigmentation were also investigated using specific inhibitors. The results revealed that [8]-gingerol (5-100μM) effectively suppressed intracellular tyrosinase activity and decreased the amount of melanin in B16F10 and B16F1 cells. In addition, [8]-gingerol also effectively decreased intracellular reactive species (RS) and reactive oxygen species (ROS) levels at the same dose range. Our results indicated that [8]-gingerol inhibited melanogenesis in B16F10 and B16F1 cells by down-regulation of both mitogen-activated protein kinases (MAPK) and protein kinase A (PKA) signaling pathways or through its antioxidant properties. Hence, [8]-gingerol could be used as an effective skin-whitening agent.