Aryl boronic acid inhibition of synthetic melanin polymerization

Inhibitors of melanin formation are sought after for a range of applications. Boronophenylalanine is known to inhibit melanogenesis via boronic acid-catechol interactions. A spectroscopic assay was developed to study the polymerization of l-dopa to synthetic melanin in the presence of para-substituted aryl boronic acids. The best inhibition was observed for aryl boronic acids with electron-withdrawing substituents. The IC50 values exhibit a correlation with the Hammett σp parameter (ρ = 0.97, r2 = 0.92).