HARMFUL FREE RADICALS
Free radicals are within our cells, they become toxic if they are released in high concentration.
1-What Are Free Radicals.
In chemistry, a free radical is any atom or molecule that has one or more unpaired electrons. A free radical is a relatively stable species. It can react with other molecules, either by donating its unpaired electron to another molecule or by taking it away from another molecule to increase stability.
In a biological context, reactive oxygen species (ROS) are formed as a natural by-product of cellular aerobic metabolism. A mitochondrial respiration chain is a significant cause of reactive oxygen species.
In the formulas, free radicals are represented by a dot placed in superscript which symbolizes their external electrons. By reacting with another molecule, the very active radical like OH. will certainly transform him into a free radical and contaminate everything around him. This propagation phenomenon includes three major, brief intermediate stages.
2-Free Radical In Medicine.
Firstly, free radicals are within our cells, they become toxic if they are released in high concentrations. Their toxicity usually leads to degenerative diseases from atherosclerosis, diabetes, Crohn’s disease, emphysema, asthma, hypertension, allergy, retinopathy, and cancer.
These are highly reactive species, capable in the nucleus, and in the membranes of cells of damaging biologically relevant molecules such as DNA, proteins, carbohydrates, and lipids.
3-Free radicals Formed From Oxygen Basic State.
The oxygen basic state includes two isolated electrons, hence it is named a biradical molecule. The transition from the base state to the excited state is relatively slow involving an electronic spin tilt.
4-Oxygen Is Not A Reactive Element.
If Oxygen has two electrons with the same spin, the normal compounds in counterparts have two electrons in one orbital and two opposite spins. Thus oxygen basic state can not react with a normal organic compound to form bonds: if one of the oxygen electrons could do so, the second wouldn’t because it shares the same spin with the other molecule.
However, oxygen can be excited to a higher energy state if we heat or irradiate it with radiation. In this case, this basic state can be modified to an excited state called singlet oxygen. Now singlet oxygen has paired electrons and therefore is extremely reactive.
5-Making Oxygen More Reactive.
It is widely known that in our bodies exist stable radicals transition metal ions such as zinc, copper iron, molybdenum, and manganese. All these metals have unpaired electrons, so they behave like free radicals. They can easily react with oxygen basic molecule that has unpaired electrons.
6-Radical Derivative Generated From Oxygen Basic State.
-First reaction: this step, is the reduction process that takes place from the basic state of oxygen to superoxide.
Oxygen is reduced and becomes more reactive: the addition of electrons generates a radical derivative called superoxide.
From now on, the radical derivative superoxide is not only the first product of one electron reduction but also the first of the group of very reactive oxygen species. And reactive oxygen species is the international name for what used to be called free radicals of oxygen.
Superoxide is both oxidizing and reducing.It can be generated with oxygen and by xanthine oxidase. Also, it can be destroyed by superoxide dismutase, for this reason, it is not very harmful to the cell.
-Second Reaction: The Superoxide is reduced to peroxide. By adding another electron to superoxide we will get a molecule called molecule a second derivative called peroxide. The peroxide is not a free radical but it still is a reactive oxygen species.
The third Reaction: starts with peroxide and ends with hydroxyl radical. Only one electron we have to add to peroxide and we will get the most important molecule out of these reactive oxygen species which is called hydroxyl radical.
NOTE: Hydroxyl radical can be produced from hydrogen peroxide from peroxide in the presence of iron or copper.
7-Superoxide, Peroxide, And Hydroxyl Radical.
These are the important ones. Hydroxyl radical is more reactive than superoxide because it can react with anything that it encounters.
