Antioxidant Mechanism Studies on Ferulic Acid: Isolation and Structure Identification of the Main Antioxidation Product from Methyl Ferulate

As a part of our research project on the elucidation of the chain-breaking antioxidant mechanism of natural phenolic compounds in food components, ferulic acid, a phenolic acid widely distributed in edible plants, especially grains, was investigated. An antioxidation reaction of ferulic acid methyl ester produced a main product when ethyl linoleate was used as the oxidation substrate. Isolation and structure determination of the main product revealed that it was a dimer having a dihydrobenzofuran moiety. On the basis of the formation pathway for the product, a radical scavenging reaction was suggested to occur between the 5′-position of one of the ferulate radicals and the 2-position of another of the ferulate radicals to terminate the radical chain oxidation of linoleate.