Anti-melanogenic effects of epigallocatechin-3-gallate (EGCG), epicatechin-3-gallate (ECG) and gallocatechin-3-gallate (GCG) via down-regulation of cAMP/CREB /MITF signaling pathway in B16F10 melanoma cells.

Tea catechins, the main bioactive polyphenols in green tea, are well known for their health promoting effects. Previous studies have shown that gallocatechin-3-gallate (GCG), epigallocatechin-3-gallate (EGCG) and epicatechin-3-gallate (ECG) exerted strong inhibitory effects on mushroom tyrosinase activity in vitro, whilst EGCG inhibited melanogenesis in vivo, yet the underlying mechanisms are not entirely clear. In this study, we (i) evaluated and compared the inhibitory effects of the main tea catechins (GCG, EGCG, and ECG) on melanogenesis in B16F10 melanoma cells, and (ii) explain the underlying mechanisms. The results showed that the tea catechins significantly suppressed tyrosinase activity and melanin synthesis in B16F10 cells, where the effects of ECG > EGCG > GCG. Interestingly, the inhibitory effects of the catechins were stronger than those of arbutin (AT), a well-known depigmenting agent. Moreover, GCG, EGCG, and ECG regulated the melanogenesis of B16F10 cells through the cAMP/CREB/MITF pathway. These results revealed catechins could be used as anti-melanogenic agents to protect cells from abnormal melanogenesis.