Evaluation and Comparison of the Antimelanogenic Properties of Different Solvent Fractionated Cnidium japonicum Extracts in B16F10 Murine Melanoma Cells

Cnidium japonicum is a biennial halophyte found in the salt marshes and shores of Korea and widely used in traditional Korean medicine as an ingredient. This study investigated and compared the antimelanogenic effect of solventpartitioned fractions of C. japonicum extract (CJEFs) in a B16F10 mouse melanoma cell model, focusing on tyrosinase activity and production. Melanogenesis is the process in which skin pigment melanin is produced through tyrosinase activity. Overproduction of melanin is the primary reason behind several skin disorders such as freckles, spots, and hyperpigmentation. The antimelanogenic capacity of CJEFs was initially screened by their tyrosinase inhibitory effects, prevention of dihydroxyphenylalanine (DOPA) oxidation, and suppression of melanin production. The inhibition of tyrosinase activity and DOPA oxidation by CJEFs was suggested to be related to the downregulation of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2, which was confirmed using mRNA and protein expression levels. Moreover, the glycogen synthase kinase 3 beta- and cyclic adenosine monophosphate response element-binding protein-related signaling pathways were inhibited by treatment with CJEFs, indicating their action mechanism. All the tested CJEFs exerted similar effects on tyrosinase activity and production. However, among those, 85% aq. MeOH was the most active fraction to suppress the signaling pathway that produces tyrosinase. These results suggest that especially the MeOH fraction of C. japonicum extract serves as a potential source of bioactive substances, with effective antimelanogenesis properties.