Antioxidant

An antioxidant is a molecule that inhibits the oxidation of other molecules. Oxidation is a chemical reaction that can produce free radicals, leading to chain reactions that may damage cells. Antioxidants such as thiols or ascorbic acid (vitamin C) terminate these chain reactions.

To balance the oxidative state, plants and animals maintain complex systems of overlapping antioxidants, such as glutathione and enzymes (e.g., catalase and superoxide dismutase) produced internally or vitamin C, vitamin A and vitamin E obtained by ingestion.

Antioxidants are widely used in dietary supplements and have been investigated for the prevention of diseases such as cancer or coronary heart disease. The hypothesis that antioxidant supplements might promote health has not been confirmed experimentally. Trials including beta-carotene, vitamin A, and vitamin E singly or in different combinations have indicated that supplementation has no effect on mortality or might increase it.Randomized clinical trials of taking antioxidants including beta carotene, vitamin E, vitamin C and selenium have shown no effect on cancer risk or have increased cancer risk. Supplementation with selenium or vitamin E does not reduce the risk of cardiovascular disease. Oxidative stress can be considered as either a cause or consequence of some diseases, stimulating drug development for potential antioxidant compounds for use as treatments.

Radical (chemistry)

In chemistry, a radical (more precisely, a free radical) is an atom, molecule, or ion that has unpaired valence electrons. With some exceptions, these unpaired electrons make free radicals highly chemically reactive towards other substances, or even towards themselves: their molecules will often spontaneously dimerize or polymerize if they come in contact with each other. Most radicals are reasonably stable only at very low concentrations in inert media or in a vacuum.

A notable example of a free radical is the hydroxyl radical (HO•), a molecule that has one unpaired electron on the oxygen atom. Two other examples are triplet oxygen and triplet carbene (:CH
2) which have two unpaired electrons. In contrast, the hydroxyl anion (HO−
) is not a radical, since the unpaired electron is resolved by the addition of an electron; singlet oxygen and singlet carbene are not radicals as the two electrons are paired.

Free radicals may be created in a number of ways, including synthesis with very dilute or rarefied reagents, reactions at very low temperatures, or breakup of larger molecules. The latter can be affected by any process that puts enough energy into the parent molecule, such as ionizing radiation, heat, electrical discharges, electrolysis, and chemical reactions. Indeed, radicals are intermediate stages in many chemical reactions.

Free radical (disambiguation)

Free radical is a chemistry term that describes an atomic or molecular species with unpaired electrons on an otherwise open shell configuration.

Free radical may also refer to:

Lindsay Perigo

Lindsay Perigo (born 14 December 1951) is a former New Zealand television and radio broadcasting personality, founding member and first leader of the Libertarianz political party and an Objectivist organisation called Sense of Life Objectivists (SOLO).

In 1993 he quit television work, in the process denouncing TVNZ news and current affairs as "brain dead". Thereafter he returned to radio for several years, with a libertarian show on Radio Pacific and on the now defunct Radio Liberty.

Perigo is former editor of the Free Radical, a libertarian/Objectivist magazine founded by him with backing from David Henderson in 1994. Deborah Coddington, former Free Radical assistant editor, wrote a biography of Perigo entitled Politically Incorrect in 1999, which was published by Radio Pacific.

He is a noted fan of singer Mario Lanza, and in August 2013 a collection of his writings on Lanza's life and work was released called The One Tenor. He also wrote the foreword for Armando Cesari's Lanza biography, Mario Lanza: An American Tragedy. He has interviewed José Carreras and Luciano Pavarotti, and appeared with Dame Malvina Major in a television tribute to Pavarotti in September 2007.

Scavenger (chemistry)

A scavenger in chemistry is a chemical substance added to a mixture in order to remove or de-activate impurities and unwanted reaction products, for example oxygen, to make sure that they will not cause any unfavorable reactions. Their use is wide-ranged: