Antioxidizing Processes

Two forms of chemical reactions, oxidation and reduction, occur widely in nature. Oxidation is the loss of electrons, and reduction is the gain of electrons.Oxidation and reduction reactions always occur in pairs. Highly reactive molecules can oxidize molecules that were previously stable and may cause them to become unstable species, such as free radicals. A free radical is a chemical with an unpaired electron that can be neutral, positively charged, or negatively charged. Thus,without termination by an agent such as an antioxidant, a single free radical can damage numerous molecules. A certain amount of oxidative function is necessary for proper health. For example, oxidation processes are used by the body’s immune systems to kill microorganisms [5].

Cells contain a number of antioxidants that have various roles in protecting against free radical reactions. The major water-soluble antioxidant metabolites are glutathione (GSH) and vitamin C (ascorbic acid),which reside primarily in the cytoplasm and mitochondria. Many water-soluble enzymes also catalyze these reactions. Glutathione peroxidase catalyzes the reaction between GSH and hydrogen peroxide to form water and oxidized GSH, which is stable [6].Vitamin E and the carotenoids are the principal lipid-soluble antioxidants. Vitamin E is the major lipid-soluble antioxidant in cell membranes that can break the chain of lipid peroxidation. Therefore, theoretically, it is the most important antioxidant in preventing oxidation of these fatty acids.Vitamin E is recycled by a reaction with vitamin C [7].

Despite the actions of antioxidant nutrients, some oxidative damage will occur, and accumulation of this damage throughout life is believed to be a major contributing factor to aging and disease [6].