Synthesis and biological assessment of novel 4H-chromene-3-carbonitrile derivatives as tyrosinase inhibitors

Excessive activity of the tyrosinase enzyme during melanogenesis results in hyperpigmentation in the skin. To address this issue, there is a need to develop effective tyrosinase inhibitors as a treatment for hyperpigmentation. In this study, we synthesized some novel 4H-chromene-3-carbonitrile compounds (6a-o) and assessed their inhibitory activities against tyrosinase, comparing them with kojic acid, which is known as a positive control. Compound 6f emerged as the most effective inhibitor, with an IC₅₀ of 35.38 ± 2.12 µM. Kinetic studies of 6f exhibited competitive inhibition, with K_i = 16.15 µM. Molecular docking studies highlighted the importance of π-π stacking and hydrogen bonding interactions within the binding site. Molecular dynamics simulations showed that the R-enantiomer 6f exhibited superior binding stability compared to the S-enantiomer, with a lower standard deviation of RMSD and more persistent interactions with the key active site residues. These findings underscore the potential of the R-enantiomer of compound 6f as a potent tyrosinase inhibitor and provide insights for developing effective treatments for hyperpigmentation and related skin conditions.