Ubiquinone-10 as an Antioxidant

Abstract

Ubiquinol, the reduced form of coenzyme Q, is known as a lipid antioxidant. Its fully oxidized form, ubiquinone, would theoretically not have this activity. However, we report that ubiquinone‐10, the oxidized form of coenzyme Q, demonstrated antioxidant activity in model studies against a lipid‐soluble free radical generator, 2,2′‐azobis(2,4‐dimethylvaleronitrile). This was demonstrated at both 1:100 and 1:1,000 ratios of ubiquinone‐10 to lipid (for both methyl linoleate and methyl linolenate). Ubiquinone‐10 should therefore not be discounted as a possible antioxidant in more complex systems such as food. PRACTICAL APPLICATIONS Coenzyme Q (ubiquinol/ubiquinone) is an important component of electron transport in biological tissues and is also classified as a potent antioxidant. It is generally believed that the form that is active as an antioxidant is the reduced ubiquinol. In evaluating the loss of antioxidants in mackerel light and dark muscle tissues, it was observed that the oxidized form, ubiquinone, comprised over 87% of the total coenzyme Q in light muscle and over 93% in dark muscle and this observation did not change under anaerobic conditions. This study was done to determine if the oxidized form of coenzyme Q, ubiquinone, was capable of acting as an antioxidant. In this study, it is shown that it can function in this manner.

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“…CoQ 10 is an essential component in mitochondria energy metabolism of all living cells, because it participates in energy conversion from carbohydrates and fatty acids into adenosine triphosphate (ATP) (Crane, 2007 ; Pravst et al, 2010 ). Recent studies show that Coenzyme Q 10 is a very powerful antioxidant that is able to scavenge free radicals generated under oxidative stresses in the human body (Bentinger et al, 2007 ; Petillo and Hultin, 2008 ). Ubiquinol (CoQ 10 H 2 ) has been reported to have a higher antioxidant activity than the other two redox states (fully oxidized ubiquinone (CoQ 10 ) and partially reduced ubisemiquinone (CoQ10 · − ) (Frei et al, 1990 ).…”