In this study, the phlorotannin
dieckol, which was isolated from the brown alga Ecklonia cava, was examined for its inhibitory effects on
melanin synthesis.
Tyrosinase inhibitors are important agents for cosmetic products. We therefore examined the inhibitory effects of
dieckol on mushroom
tyrosinase and
melanin synthesis, and analyzed its binding modes using the crystal structure of Bacillus megaterium
tyrosinase (PDB ID: 3NM8).
Dieckol inhibited mushroom
tyrosinase with an IC(50) of 20μM and was more effective as a cellular
tyrosinase having
melanin reducing activities than the commercial inhibitor,
arbutin, in B16F10
melanoma cells, and without apparent cytotoxicity. It was found that
dieckol behaved as a non-competitive inhibitor with
l-tyrosine substrates. For further insight, we predicted the 3D structure of
tyrosinase and used a docking algorithm to simulate binding between
tyrosinase and
dieckol. These molecular modeling studies were successful (calculated binding energy value: -126.12kcal/mol), and indicated that
dieckol interacts with His208, Met215, and Gly46. These results suggest that
dieckol has great potential to be further developed as a pharmaceutical or cosmetic agent for use in dermatological disorders associated with
melanin.