Docking Study on salicylaldehyde Derivatives as Anti-melanogenesis Agents

Abnormal production of melanin pigment which causes melasma, freckles, ephelides, and age spots, are esthetic problems. Polyphenol oxidase (PPO), a copper-containing enzyme, is involved in melanin biosynthesis and the abnormal accumulation of melanin pigments. Thus, its inhibitors are of great importance in the medical and cosmetic fields. The aim of this study was to investigate some salicylaldehyde Analogues as Polyphenol oxidase inhibitors.
Material & In the present study, thirty five derivatives of salicylaldehyde scaffold were subjected to molecular docking studies to investigate the mode of interaction of the compounds with tyrosinase active site. Docking study was performed by AutoDock 4.2 program and the resulting docking poses were analyzed in AutoDockTools, DS Visualizer 3.5 and Ligplot softwares.
Among the all studied compounds, Ligand 4-isopropylsalicylaldehyde displayed good docking results. In fact, this compound had the most negative ΔGbind (-4.01 Kcal/mol) that indicated favorable interactions with the key amino acid residues at active site of Polyphenol oxidase. Docking results for this compound are in accordance with the docking results of Co-crystallized ligand (tropolone). In this compound, the oxygen of a carbonyl group has an efficient metal-ligand interaction with the Cu2 ion in the active site.
The presence of non-polar moiety in salicylaldehyde Analogues increases the inhibitory property.