Radical Scavenging Activity of Lipophilized Products from Transesterification of Flaxseed Oil with Cinnamic Acid or Ferulic Acid

Abstract

Lipase-catalyzed transesterification of flaxseed oil with cinnamic acid (CA) or ferulic acid (FA) using an immobilized lipase from Candida antarctica (E.C. 3.1.1.3) was conducted to evaluate whether the lipophilized products provided enhanced antioxidant activity in the oil. Lipase-catalyzed transesterification of flaxseed oil with CA or FA produced a variety of lipophilized products (identified using ESI-MS-MS) such as monocinnamoyl/feruloyl-diacylglycerol, dicinnamoyl-monoacylglycerol and monocinnamoyl-monoacylglycerol. The free radical scavenging activity of the lipophilized products of lipase-catalyzed transesterification of flaxseed oil with CA or FA toward 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) were both examined in ethanol and ethyl acetate. The polarity of the solvents proved important in determining the radical scavenging activity of the substrates. Unesterified FA showed the highest free radical scavenging activity among all substrates tested while CA had negligible activity. The esterification of CA or FA with flaxseed oil resulted in significant increase and decrease in the radical scavenging activity compared with the native phenolic acid, respectively. Based on the ratio of a substrate to DPPH. concentration, lipophilized FA was a much more efficient free radical scavenger compared to lipophilized CA and was able to provide enhanced antioxidant activity in the flaxseed oil. Lipophilized cinnamic acid did not provide enhanced radical scavenging activity in the flaxseed oil as the presence of natural hydrophilic antioxidants in the oil had much greater radical scavenging activity.

Assessment of the Antioxidant Capacity and Oxidative Stability of Esterified Phenolic Lipids in Selected Edible Oils

“…On the other hand, the presence of 3,4‐dihyroxyphenyl acetoylated lipids in FSO could have improved its radical scavenging capacity, as compared to the unmodified oil, by the donation of a hydrogen atom from its ‐OH groups to the chemically unstable peroxyl radicals generated in the ORAC assay (Prior and others ; Sroka and Cisowski ). Similarly, Choo and others () reported that based on the ratio of a substrate to DPPH concentration, the lipophilized products, obtained by the lipase‐catalyzed transesterification of FSO with ferulic acid, were able to provide an enhanced AOC for the FSO. Although Karboune and others () and Sorour and others () reported that the esterification of the ‐COOH of DHPA to a MAG or DAG moiety reduced its radical scavenging ability, the 3,4‐dihydroxyphenyl acetoylated lipids demonstrated a scavenging capacity against DPPH• half of that of α‐tocopherol, hence indicating their potential as antioxidants.…”

Enzymatic Production of Biologically Active 3-Methoxycinnamoylated Lysophosphatidylcholine via Regioselctive Lipase-Catalyzed Acidolysis

“…Then we focused on selection of a reaction temperature suitable for all these lipase preparations. We analyzed literature data and description of optimum usage conditions for lipases and we found that the reaction temperature will be set at 50 °C [ 29 , 30 ].…”