Several types of antioxidants

Broadly speaking antioxidants as the body's defenses can be divided into 2, namely the exogenous and endogenous antioxidants. Exogenous antioxidants are antioxidants that come from outside the body is of intake of food or natural products that contain antioxidants such as vitamin E, viatamin C, vitamin A and phenolic components. Endogenous antioxidant enzyme known as an intracellular antioxidant contained in the cell.
Based on the nature, function and mechanism of action atioksidan can be classified in 2 major categories namely primary antioxidants and secondary antioxidants (Rajalakshmi & Narasimhan 1996).

1. Primary antioxidants (primary antioxidants) is an antioxidant that works by stopping the chain reaction of free radicals by donating hydrogen or electrons to free radicals and transform into a stable product. The reaction can be seen in the process of delay stages with free radical initiation or propagation phase with peroxy and aloksi.Antioxidants are included in the primary antioxidants such as tocopherols (vitamin E), phenolic compounds such as flavonoids, eugenol, vanillin, gallat, BHT, BHA. Primary antioxidants are more effective at low concentrations, at high concentrations can be prooksidan.
2. Antioxidants secondary (secondary antioxidant) is an antioxidant that is preventing the formation of free radicals, working with prevention or lipid peroxide decomposition to produce a stable final product or not free radicals, does not alter the free radical becomes stable, but as a chelating (chelating) prooksidan metal ( M (n-1)) so that it becomes inactive (MA), to an inactive singlet oxygen, absorbs ultraviolet radiation, they work as oxygen scavenger, usually work synergistically with primary antioxidants. Secondary antioxidants are thiodipropinat, dilauril, distearil ester, EDTA (pengelat metal), binding proteins (transferrin), flavonoids, and inositol olifosfat.
   

Imbalance between the amount of free radicals both ROS and RNS with antioxidants can cause oxidative stress, due to the reactive nature of free raadikal that could result in damage to the cell until the RNA (ribonukleotida acid / ribonucleic acid which is a constituent of genes.