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Ubiquinol-10 is an Effective Lipid-Soluble Antioxidant at Physiological Concentrations
Balz Frei, Mike C. Kim and Bruce N. Ames
Proceedings of the National Academy of Sciences of the United States of America
Vol. 87, No. 12 (Jun., 1990), pp. 4879-4883
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/2354427
Page Count: 5
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It is well known that ubiquinone-10 (coenzyme Q10, ubiquinone 50) acts as an electron carrier of the respiratory chain in mitochondria. In this paper we show that ubiquinol-10, the reduced form of ubiquinol-10, also efficiently scavenges free radicals generated chemically within liposomal membranes. Ubiquinol-10 is about as effective in preventing peroxidative damage to lipids as α-tocopherol, which is considered the best lipid-soluble antioxidant in humans. The number of radicals scavenged by each molecule of ubiquinol-10 is 1.1 under our experimental conditions. In contrast to α-tocopherol, ubiquinol-10 is not recycled by ascorbate. However, it is known that ubiquinol-10 can be recycled by electron transport carriers present in various biomembranes and possibly by some enzymes. We also show that ubiquinol-10 spares α-tocopherol when both antioxidants are present in the same liposomal membranes and that ubiquinol-10, like α-tocopherol, does not interact with reduced glutathione. Our data together with previous work on the antioxidant function of ubiquinol reported in the literature strongly suggest that ubiquinol-10 is an important physiological lipid-soluble antioxidant.
Proceedings of the National Academy of Sciences of the United States of America © 1990 National Academy of Sciences