The Luteolinidin and Petunidin 3-O-Glucoside: A Competitive Inhibitor of Tyrosinase.

The enzyme tyrosinase plays a key role in the early stages of melanin biosynthesis. This study evaluated the inhibitory activity of anthocyanidin (1) and anthocyanins (2-6) on the catalytic reaction. Of the six derivatives examined, 1-3 showed inhibitory activity with IC50 values of 3.7 ± 0.1, 10.3 ± 1.0, and 41.3 ± 3.2 µM, respectively. Based on enzyme kinetics, 1-3 were confirmed to be competitive inhibitors with Ki values of 2.8, 9.0, and 51.9 µM, respectively. Molecular docking analysis revealed the formation of a binary encounter complex between 1-3 and the tyrosinase catalytic site. Luteolinidin (1) and petunidin 3-O-glucoside (2) may serve as tyrosinase inhibitors to block melanin production.