Lipase-Catalysed Synthesis of Ferulyl Oleins and Evaluation of Their Radical Scavenging Activity

The enzymatic transesterification of ethyl ferulate with triolein was investigated. Ferulyl oleins were synthesized by immobilized lipase from C. antarctica (Novozym 435) in organic phase, solvent-free system, and glycerol introduced system. The transesterification reactions in those three different solvent systems were compared. The yield in organic medium was the lowest and the selectivity to FMO was higher in glycerol introduced system than the other two system. 4Å molecular sieve was selected to control the reaction water content. The yield of ferulyl oleins increased with increasing the amount of molecular sieve to 20%. The radical scavenging activity of the products were evaluated using DPPH. Ferulyl monoolein was found to possess higher radical scavenging activity than one of the substrates, ethyl ferulate. The time to reach steady state of ferulyl monoolein also exhibited shorter than ferulyl diolein. The results showed that pure ferulyl diolein and ferulyl monoolein have antioxidant activities with IC₅₀ values of 0.012 mg/mL and 0.476 mg/mL, respectively.