Mechanisms of Antioxidant Protection of Low-Density Lipoprotein Particles Against Free Radical Oxidation

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Vadim Z. Lankin^1,a*, Konstantin B. Shumaev^1,2, Valeria A. Medvedeva¹, Alla K. Tikhaze¹, Galina G. Konovalova¹

¹Chazov National Medical Research Center of Cardiology, Ministry of Health of the Russian Federation, 121552 Moscow, Russia

²Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia

^* To whom correspondence should be addressed.

Received: September 24, 2024; Revised: December 5, 2024; Accepted: December 10, 2024

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

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KEY WORDS: low-density lipoproteins, free radical oxidation, antioxidants, ubiquinol Q₁₀, α-tocopherol, antioxidant bioregeneration

DOI: 10.1134/S0006297924603381

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