N-(4-methoxyphenyl) caffeamide-induced melanogenesis inhibition mechanisms

Background: The derivative of caffeamide exhibits antioxidant and antityrosinase activity. The activity and mechanism of N-(4-methoxyphenyl) caffeamide (K36E) on melanogenesis was investigated. Methods: B16F0 cells were treated with various concentrations of K36E; the melanin contents and related signal transduction were studied. Western blotting assay was applied to determine the protein expression, and spectrophotometry was performed to identify the tyrosinase activity and melanin content. Results: Our results indicated that K36E reduced alpha-melanocyte-stimulating hormone (alpha-MSH)-induced melanin content and tyrosinase activity in B16F0 cells. In addition, K36E inhibited the expression of phospho-cyclic adenosine monophosphate (cAMP)-response element-binding protein, microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein-1 (TRP-1). K36E activated the phosphorylation of protein kinase B (AKT) and glycogen synthase kinase 3 beta (GSK3 beta), leading to the inhibition of MITF transcription activity. K36E attenuated a-MSH induced cAMP pathways, contributing to hypopigmentation. Conclusions: K36E regulated melanin synthesis through reducing the expression of downstream proteins including p-CREB, p-AKT, p-GSK3 beta, tyrosinase, and TRP-1, and activated the transcription factor, MITF. K36E may have the potential to be developed as a skin whitening agent.