Mechanisms of antioxidant protection of low-density lipoprotein particles against free radical oxidation

It was found that when patients with atherosclerosis are orally administered ubiquinon Q10 (CoQ10), the oxidation (lipohydroperoxide content) of low-density lipoprotein (LDL) particles sharply decreases, which confirms the important role of this natural antioxidant in protecting LDL particles from free radical oxidation in vivo. The influence of lipophilic natural antioxidants ubiquinol Q10 (CoQ10H2) and α-tocopherol (α-TOH) on the kinetic parameters of Cu2+-initiated free radical oxidation of LDL particles was investigated. In this model system, the possible synergism of the antioxidant action of CoQ10H2 and α-TOH is shown. The probable mechanisms of bioregeneration of the lipophilic antioxidants in LDL particles, including regeneration of α-TOH from the tocopheroxyl radical (α-TO•) with the participation of CoQ10H2 and/or ascorbate, are discussed.