Antioxidant Enzymes

To aid in biodefense, a system of antioxidants exists to neutralize radicals after they have formed. Vitamin C (ascorbic acid) which reacts with superoxide in the aqueous phase and vitamin E (a family of molecules comprising four types of tocopherols (alpha, beta, gamma, delta) and the same four types of tocotrienols) in the lipophilic phase, will directly react with peroxy radicals to destroy them and form inorganic or organic hydroperoxides.

When this happens, vitamin E or vitamin C themselves become free radicals. But these antioxidants have aromatic ring structures, which delocalize the unpaired electron and they are less-reactive, longer-lived and less dangerous than the radicals they have quenched. Thus they are able to minimize biological damage caused by oxygen-derived radicals.