Background: Reduced production of melanin and decreased or absence of melanocytes leads to various hypopigmentation disorders. Melanin synthesis is regulated by melanogenic proteins such as tyrosinase, tyrosinase-related protein 1 (TRP-1) and tyrosinase-related protein 2 (TRP -2), as well as their transcription factors.
Objectives: This study elucidated the effects of xanthoxylin on melanin content, dendriticity, melanogenic protein expression and its signal transduction pathways in mouse B16F10 melanoma cells (B16F10 cells).
Methods: Melanin production of B16F10 cells was measured by using a melanin content assay. The effect of xanthoxylin on the dendriticity of B16F10 cells was determined by a melanocyte dendricity assay. RT-PCR was used to investigate the effects of xanthoxylin on the melanogenic protein expression.
Results: We found that xanthoxylin increased melanin production, number of dendrites, tyrosinase, and microphthalmia-associated transcription factor (MITF) expression in cultured B16F10 cells. In addition, PKA and PKC inhibitor decreased melanin production, tyrosinase, and MITF expression in xanthoxylin-treated cells. However, xanthoxylin did not inhibit TRP-1 and TRP-2 expression.
Conclusion: These results indicated that xanthoxylin induces melanogenesis mainly via cAMP-mediated PKA activation. Other signaling pathways may also play a role in xanthoxylin-induced melanogenesis.