**3.2 Nonenzymatic system**

This system of antioxidants consists of antioxidants that trap FR. They capture FR to avoid the radical initiation reaction. Neutralize the radicals or capture them by donating electrons, and during this process, the antioxidants become free radicals, but they are less reactive than the initial FR. FR from antioxidants are easily neutralized by other antioxidants in this group. The cells use a series of antioxidant compounds or free radical scavengers such as vitamin E, vitamin C, carotenes, ferritin, ceruloplasmin, selenium, reduced glutathione (GSH), manganese, ubiquinone, zinc, flavonoids, coenzyme Q, melatonin, bilirubin, taurine, and cysteine. The flavonoids that are extracted from certain foods interact directly with the reactive species to produce stable complexes or complexes with less reactivity, while in other foods, the flavonoids perform the function of co-substrate in the catalytic action of some enzymes.
