Prooxidant Actions of Vitamin

Although various mechanisms have been proposed to explain the ability of Cu(II) to promote LDL modification, the precise reactions involved in initiating the process remain a matter of contention in the literature. In a critical overview of the chemistry of copper-dependent LDL oxidation Burkitt (2001) discusses the key role of a-tocopherol. In addition to its protective, radical-scavenging action, a-tocopherol can also behave as a prooxidant via its reduction of Cu(II) to Cu(I). Generation of Cu(I) greatly faciUtates the decomposition of hpid hydroperoxides to chain carrying radicals, but the mechanisms by which the vitamin promotes LDL oxidation in the absence of preformed hydroperoxides remain more speculative. 

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