Effects of Radicals - Oxidation

The statement that free radicals act by oxidation might not mean very much to you, but don't worry. The matter is really very simple. Oxidation is a kind of burning and is always damaging to whatever is oxidized. It can be fast or it can be slow.

If a bright iron nail is left outside it will soon rust. If you strike a match and let is burn, the firm white wood turns to a brittle, blackened ash. If you star your car, a little petrol gets turned to a mixture of gases and soot that come out of the exhaust pipe. These are all examples of oxidation. Inn all these cases the element oxygen which makes up about 20% of the atmospheric air links up chemically with the original substance, whether iron, cellulose or hydrocarbon, to form an entirely new compound. If the nail rusts completely which it will eventually do if exposed to air ad water it turns to a pile of red powdery stuff called 'iron oxide'. When the match and the petrol are oxidized, equally major changes occur in which the carbon, hydrogen and oxygen of which they are made combines with oxygen from the air to form new compounds. These are mostly gases water vapors (hydrogen and oxygen) and carbon dioxide ( carbon and oxygen). The ash of the match and the soot from the exhaust are mostly carbon that has not linked with oxygen to form carbon dioxide.

Although the term 'oxidation' originally meant adding oxygen as in these examples, it has now been extended to have a wider meaning. Chemists now define oxidation as any chemical reaction that involves the loss of an electron from an atom. And, as you have seen, removing electrons from atoms is exactly what free radicals are particularly good at doing.   Read More