A tyrosinase inhibitor from a nitrogen enriched chemically engineered extract.

Abstract

The enzyme tyrosinase is involved in the biosynthesis of melanin and the enzymatic browning of fruits and vegetables, so its inhibitors have potential as agents to treat hyperpigmentary disorders or as food anti-browning agents. The use of hydrazine monohydrate as reagent to prepare chemically engineered extracts can lead to semisynthetic compounds that contain the portion N-N, a fragment rarely found in natural products and present in some tyrosinase inhibitors. Here, we report the tyrosinase inhibition screening of a series of chemically engineered extracts diversified by reaction with hydrazine. LC-MS was used to evaluate the change in composition produced by the reaction. Bioguided fractionation of the most active chemically engineered extract, prepared from Matricaria recutita L., led to the discovery of a pyrazole that inhibits tyrosinase with an IC50 value of 28.20 = 1,13 µM. This compound was produced by a one-pot double chemical transformation, of its natural precursor, that includes an unexpected selective removal of one -OH group.