Biocatalytic synthesis, structural elucidation, antioxidant capacity and tyrosinase inhibition activity of long chain fatty acid acylated derivatives of phloridzin and isoquercitrin

Abstract

Our present investigation describes the regioselective enzymatic acylation of two series of acylated derivatives of phloridzin and isoquercitrin with six different long chain saturated, mono- and poly-unsaturated fatty acids. The biocatalytic synthesis was optimized to achieve 81-98% yields, using immobilized lipase B, from Candida antarctica (Novozym 435), in acetone at 45°C. The synthesized esters have been analyzed by (1)H NMR, (13)C NMR spectroscopy and evaluated for their antioxidant capacity and tyrosinase inhibition, using in vitro assays. Among all the phloridzin and isoquercitrin derivatives, the greatest potential for inhibition of tyrosinase activity (p ≤ 0.05) was exhibited by the α-linolenic acid ester of isoquercitrin.