Flax phenolic compounds as inhibitors of lipid oxidation: Elucidation of their mechanisms of action

•Lignans were more efficient than phenolic acids to prevent lipid oxidation.•Both classes of compounds presented a structure/antioxidant efficiency relationship.•Membrane inserted compounds significantly inhibited lipid oxidation.•The inner membrane fraction of lignans inhibited ∼70 % of lipid oxidation. Polyunsaturated fatty acids are particularly sensitive to the damages due to reactive oxygen species and lipid oxidation has been reported to be involved in the degradation of food as well as in the early stages of several diseases. Our objective was to study the mechanisms of action of flax (Linum usitatissimum) phenolic compounds to prevent membrane lipid oxidation. To do so, several biophysical techniques (oxidative stress, surface tension, fluorescence spectroscopy and HPLC) were used to investigate the ability of the compounds to prevent lipid oxidation and to interact with membranes. We evidenced a relationship between the structure and the antioxidant efficiency as aglycone compounds were significantly more efficient (p