Possible Health Benefits of Coenzyme Q 10

Ubiquinone, or coenzyme Q (CoQ), was discovered in 1957 by Fred Crane. Its chemical structure was determined a few years later by Karl Folkers, who later won the Priestley medal from the American Chemical Society. CoQ plays an important role in the production of chemical energy in the mitochondria. In its reduced form, ubiquinol, CoQ also serves as an antioxidant. Ubiquinol inhibits lipid peroxidation in biological membranes and in low-density lipoprotein (LDL), and it also protects membrane proteins against oxidative damage. While ubiquinol does not require vitamin E for its antioxidant activity, it can regenerate the vitamin from its oxidized form, the alpha-tocopheroxyl radical, a process that otherwise relies on water-soluble vitamin C. This interaction with vitamin E is thought to be particularly important for the protection of LDL and other lipoproteins from oxidative damage, and we now have evidence that directly supports an antioxidant function of ubiquinol against LDL oxidation in blood vessels. On the other hand, the discovery of the semiquinone form of CoQ in the mitochondria raises the question of a possible role of the ubisemiquinone radical in the generation of superoxide radicals in the course of respiration. However, to date there is no convincing evidence that CoQ acts as a pro-oxidant in vivo.