Fish skin collagen peptides inhibit melanogenesis by directly regulating the melanocortin 1 receptor

Excessive exposure to ultraviolet (UV) radiation can induce skin erythema, inflammation, barrier dysfunction, and dryness. Melanin protects against skin dysfunction by absorbing UV light; however, overexposure to UV light causes hyperpigmentation via melanogenesis. Collagen is a major component of the skin barrier and collagen peptides derived from fish skin have been developed as functional ingredients to improve skin health. In this study, we confirmed that collagen peptides inhibit melanogenesis. Collagen peptides significantly reduced melanin content in murine melanoma cells. Furthermore, collagen peptides downregulated the protein expression of tyrosinase, Trp-1, and Trp-2, which are associated with melanin synthesis. Collagen peptides inhibited the cAMP/CREB/MITF and MAPK signaling pathways. Additionally, collagen peptides bind to the melanocortin 1 receptor (MC1R), which upregulates the cAMP/CREB/MITF and MAPK pathways. These findings revealed that collagen peptides exert an anti-melanogenic effect through a direct effect on MC1R. These results suggest that collagen peptides are a promising whitening material for the functional food, skin care, and pharmaceutical industries.