Orcinol Inhibits Melanogenesis in B16F10 Cells via the Upregulation of the MAPK/ERK Signaling Pathway

Background: Orcinol (3,5-dihydroxytoluene) has been reported to demonstrate inhibitory activity against mushroom tyrosinase. This study aims to investigate the inhibitory effect of orcinol on melanogenesis and its mechanism in B16F10 murine melanoma cells. Methods: The effects of orcinol on melanogenesis were determined spectrophotometrically by the intracellular tyrosinase activity and melanin content. The expression of melanogenesis-related gene and signaling pathways was analyzed by Western blot and/or qRT-PCR analyses. Results: Orcinol reduced intracellular tyrosinase activity and melanin content and attenuated the protein expression and mRNA levels of melanogenesis-related genes, such as tyrosinase, tyrosinase-related protein-1, dopachrome tautomerase, and microphthalmia-associated transcription factor (MITF). Orcinol increased the phosphorylation of extracellular signal-regulated kinase (ERK), which decreased MITF expression levels. Conclusion: Orcinol reduces melanogenesis by inhibiting MITF expression, then the ERK signaling pathway, and that orcinol has the potential to become a functional cosmetic compound for skin whitening.