Synthesis, screen and biological activity of potent thiosemicarbazone as a tyrosinase inhibitor
Tyrosinase plays an essential role in melanogenesis. Tyrosinase inhibition may be not only a means to alleviate skin hyperpigmentation, but also the most effective method for fruit and vegetable preservation. Thiosemicarbazone compounds have received considerable attentions because of their potential therapeutic activities, such as antitumoral, antibacterial and antimalarial properties. In this study, we focused on the screen, toxicity, interaction and inhibitory activities of potent thiosemicarbazone compounds as novel tyrosinase inhibitors. The results showed that the inhibitor effectiveness was drastically reduced by the absence of ortho-hydroxyl group and was improved through changing the substituents of benzaldehyde. To develop a pharmacophore model, we explored the binding mode of thiosemicarbazones compounds in the active site of tyrosinase. Docking analysis using an AUTODOCK program was conducted to explain the flexible thiosemicarbazone molecules binding with the active site of tyrosinase, because of their perfect match with both the active site and the substrate channel of tyrosinase in both size and hydrophobicity. Their binding was stabilized mainly via both the coordination of the sulfur and nitrogen atoms in the inhibitors to binuclear copper in the tyrosinase active site. Further complementary studies on these types of inhibitors, as potential drug candidates for treating abnormal melanin pigmentation and inhibiting food or fruit browning, are still needed.