A Novel Inhibitor Against Mushroom Tyrosinase with a Double Action Mode and Its Application in Controlling the Browning of Potato

In order to search for a new method for the anti-browning of food products, a novel hydroxypyridinone (HPO) derivative with a formyl group was evaluated for its anti-tyrosinase property. This compound was found to exhibit potent tyrosinase inhibition on the monophenolase activity of mushroom tyrosinase with an IC50 value of 1.33 mu M, indicating that this HPO derivative was 12-fold stronger than kojic acid (IC50 15.89 mu M). This molecule can inhibit tyrosinase via two action modes, namely copper reduction and chelation, and the formation of a Schiff's base with the amino group at the active site of the enzyme. A synergistic effect of these two action modes to enhance the inhibitory activity was observed. This compound was also investigated for the inhibitory effect on diphenolase activity of mushroom; the inhibitory mechanism was found to be reversible and of competitive-uncompetitive mixed-type inhibition. This hydroxypyridinone was demonstrated to effectively control the browning of vegetable products.