Kinetic of Mushroom Tyrosinase Inhibition by Benzaldehyde Derivatives

Polyphenol oxidase (PPO), also known as tyrosinase (EC 1.14.18.1), is a copper-containing enzyme widely distributed in microorganisms, animals, and plants. This enzyme is responsible not only for browning in plants but also for melanization in animals. Thus, tyrosinase inhibitors have a huge impact on industry and the economy. In the current study, we first purified the enzyme, then evaluated inhibitory potency of three benzaldehyde derivatives: 2,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzaldehyde and 4-dimethylaminobenzaldehyde on diphenolase activity of the purified mushroom tyrosinase, compared to kojic acid. Despite their close structural similarity, 2,4-dihydroxybenzaldehyde was found as potent competitive inhibitor while uncompetitive inhibition was observed for 4-dimethylaminobenzaldehyde. Further complementary studies on these types of inhibitors, as potential drugs for treating abnormal melanin pigmentation, are needed.