In Vitro and In Vivo Biological Evaluation of Indole-thiazolidine-2,4-dione Derivatives as Tyrosinase Inhibitors

Abstract

Tyrosinase is an important rate-limiting enzyme in melanin biosynthesis. To find potential tyrosinase inhibitors with anti-melanogenic activity, a series of indole-thiazolidine-2,4-dione derivatives 5a~5z were synthesized by incorporating indole with thiazolidine-2,4-dione into one compound and assayed for their biological activities. All compounds displayed tyrosinase inhibitory activities and 5w had the highest anti-tyrosinase inhibitory activity with an IC50 value of 11.2 μM. Inhibition kinetics revealed 5w as a mixed-type tyrosinase inhibitor. Fluorescence quenching results indicated that 5w quenched tyrosinase fluorescence in a static process. CD spectra and 3D fluorescence spectra results suggested that the binding of 5w with tyrosinase could change the conformation and microenvironment of tyrosinase. Molecular docking also represented the binding between 5w and tyrosinase. Moreover, 5w could inhibit tyrosinase activity and melanogenesis both in B16F10 cells and the zebrafish model. Therefore, compound 5w could serve as a tyrosinase inhibitor with anti-melanogenic activity.

Inhibition mechanism investigation of quercetagetin as a potential tyrosinase inhibitor

“…The first reaction process is monophenolase activity, in which L-tyrosine is hydroxylated into L-dopa and the second reaction process is diphenolase activity, in which L-dopa is subsequently oxidized into dopaquinone ( Djafarou et al, 2023 ; Lee et al, 2023 ; Zargaham et al, 2023 ). In the organism, melanin acts crucial roles to protect the skin from UV radiation ( Lu et al, 2023a ; Znajafi et al, 2023 ). But, excessive elevated melanin content leads to lots of pigmentation disorders, including age spots and melanoma ( Broulier et al, 2023 ; De Barros et al, 2023 ; Xue et al, 2023 ).…”