FREE RADICALS
Free radicals are atoms or molecules containing one or more unpaired electrons in their end orbitals. They are highly reactive and short-lived. The source of free radicals for biological systems is molecular oxygen (O2). Free radicals are essential for life An excess of Free Radicals can result in serious cell, tissue and/or organ damage. When free radicals exceed the capacity of the antioxidant defense mechanism in the body, they cause various disorders. They cause structural and metabolic changes in the cell by interacting with all classes of biomolecules such as carbohydrates, lipids, proteins and DNA, and with all cell components.
There are protective mechanisms in the organism against the harmful effects of free radicals, these are called antioxidant systems. Some of these mechanisms prevent the formation of free radicals, and some prevent the harmful effects of formed free radicals. Antioxidants are structures of endogenous and exogenous origin, and they neutralize the formed oxidant molecules with both intracellular and extracellular defense. Non-enzymatic intracellular antioxidants; GSH is alpha-tocopherol, beta-carotene, ascorbate, transferrin, ceruloplasmin and bilirubin. Intracellular free radical scavenging enzymes provide the main antioxidant defense. These enzymes are superoxide dismutase, Glutathione-S-Transferase, glutathione peroxidase, cytochrome oxidase. Trace elements such as copper, zinc and selenium are necessary for the functions of these enzymes. Considering the protective properties of antioxidants against oxidative damage to tissues or cells, they are shown as protective agents against aging, tissue damage and poisoning with toxic agents. There is a balance between the rate of formation of free radicals and the rate of their elimination in the organism, and this balance is called oxidative balance. As long as the oxidative balance is maintained, the organism is not affected by free radicals. An increase in the rate of formation or a decrease in the rate of elimination of these radicals causes the deterioration of this balance. This situation, which is called “oxidative stress”, shows the serious imbalance between the formation of free radicals and the antioxidant defense mechanism, and ultimately leads to tissue damage.
The most important fat-soluble antioxidant is vitamin E. Vitamin A and beta-carotene act as antioxidants in some cases. In addition, bioflavonoids also have antioxidant properties. Coenzyme Q is a phenol and it also acts like vitamin E in many tissues. Lipoic acid and glutathione are sulfur-containing compounds, acting as hydrogen atom donors and acting like phenols. In addition to all these, the most important and most studied antioxidant vitamins are vitamin E and vitamin C.
Specialist.Doctor.Fevzi Balkan
