The Luteolinidin and Petunidin 3-<i>O</i>-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