Comparing the inhibitory abilities of epigallocatechin-3-gallate and gallocatechin gallate against tyrosinase and their combined effects with kojic acid

Inhibition of tyrosinase activity contributes to the control of food browning and skin pigmentation diseases. Herein, the inhibitory mechanism of epigallocatechin-3-gallate (EGCG) and gallocatechin gallate (GCG) on tyrosinase were investigated. Both EGCG and GCG inhibited tymsinase in a mixed manner with the IC50 values of 39.4 +/- 0.54 mu M and 36.8 +/- 0.21 mu M, and showed a synergism with their combination, while EGCG and GCG combined with kojic acid (IC50 = 19.2 +/- 0.26 mu M) exhibited antagonism and additive effect, respectively. EGCG and GCG interacted with tyrosinase mainly by hydrogen bonding and hydrophobic interactions and induced a looser conformation of tyrosinase. Molecular docking indicated that EGCG and GCG bound to the active center of tyrosinase and interacted with copper ions and key amino acid residues. Molecular dynamics simulation further characterized the structure and property of EGCG/GCG-tyrosinase complex. This study provides novel insights into the mechanism of catechins as tyrosinase inhibitors.

Automated summary

The study demonstrates that EGCG and GCG inhibit tyrosinase activity in a mixed manner, interact with tyrosinase through hydrogen bonding and hydrophobic interactions, and induce a looser conformation of tyrosinase. Additionally, when combined with kojic acid, EGCG and GCG show antagonism and additive effects.