Ethanolic extract from Sargassum serratifolium attenuates hyperpigmentation through CREB/ERK signaling pathways in α-MSH-stimulated B16F10 melanoma cells

Hyperpigmentation is an increased deposition of melanin in the skin. The effects of ethanolic extract from the brown alga Sargassum serratifolium (ESS) on melanogenic protein expressions in B16F10 mouse melanoma cells were examined to elucidate its hypopigmenting properties. ESS remarkably reduced melanin synthesis in α-melanocyte stimulating hormone (α-MSH)-stimulated B16F10 cells. Western blot analysis revealed that ESS attenuated the expression of melanogenic enzymes, tyrosinase, and tyrosinase-related protein 1, by cyclic adenosine monophosphate (cAMP)-responsive element-binding protein (CREB)-mediated downregulation of microphthalmia-associated transcription factor (MITF). ESS inhibited accumulation of cellular cAMP that leads to inhibition of CREB phosphorylation. Moreover, ESS activated extracellular signal-regulated kinase (ERK), but not Akt and other mitogen-activated protein kinases, which is responsible for posttranslational downregulation of MITF. Therefore, ESS attenuated α-MSH-stimulated hyperpigmentation in B16F10 cells through modulation of CREB/ERK signaling pathways. Three antimelanogenic compounds such as sargahydroquinoic acid, sargachromenol, and sargaquinoic acid were identified in ESS depending on inhibition of melanin synthesis. These findings suggest that ESS could be a potential agent in the treatment of hyperpigmentation-related skin disorders.