Vitamin E

Abstract

Vitamin E has a bicyclic hydroxychromane ring attached to a long phytyl tail that anchors it in cellular membrane spaces. The hydroxychromane, in functional analogy to the structurally different vitamin C enediolate, is a low energy donor of one electron to radical species, yielding the stable phenoxy/chromanoxy radical. Like ascorbate this radical is stable enough to be formed readily but does not propagate chain reactions. Thus, vitamin E can scavenge RO˙ and ROO˙ radicals. The most abundant ones in membrane phases are the polyunsaturated fatty acid hydroxy and peroxy radicals and they would rapidly spread via radical chain reactions if not interdicted by vitamin E. Vitamin C can re-reduce the vitamin E chromanoxy radical at aqueous/membrane interfaces in cells and so E and C combine and complement as surveillance vitamins.