Additive Antioxidant Capacity of Vitamin C and Tocopherols in Combination

Abstract

Vitamin C (ascorbic acid) and vitamin E (tocopherols) are water-soluble and fat-soluble essential nutrients, respectively, present ubiquitously in cellular membranes and plasma through dietary intake of fruits and vegetables. These vitamins act as antioxidants by virtue of their free hydroxyl groups. To quantitatively assess the vitamin C-tocopherol interaction in generating total antioxidant capacity, various binary mixtures of vitamin C and tocopherols (alpha, beta, delta, and gamma) were titrated with ABTS radicals. In this assay, the antioxidant capacity of tocopherols increased as follows: beta-tocopherol<alpha-tocopherol<delta-tocopherol<gamma-tocopherol. As the total concentration of mixed antioxidants vitamin C and tocopherols increased, the total antioxidant capacity increased linearly. The sum of the individual antioxidant capacities of vitamin C and tocopherol in the assay was very close to the total antioxidant capacity of the corresponding combination of two compounds. Using this assay system, and in the concentration ranges applied, vitamin C and tocopherols in combination displayed additive interaction.