oxygen radical


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Related to oxygen radical: Oxygen radical absorbance capacity

radical

 [rad´ĭ-kal]
1. thorough or sweeping; directed to the cause or root of a morbid process.
2. a group of atoms that enters into and goes out of chemical combination without change and that forms one of the fundamental constituents of a molecule.
color radical chromophore.
free radical a radical that carries an unpaired electron; such radicals are extremely reactive, with a very short half-life.
oxygen radical a toxic metabolite of oxygen, such as superoxide or singlet oxygen, capable of damaging microorganisms and normal tissues.

oxygen radical

Reactive oxygen metabolite Any molecule with an unpaired electron in its outer orbital which leads to an unstable and/or short half-life, which is capable of reducing or oxidizing other molecules. See Oxygen free radicals.

oxygen radical

Hydrogen peroxide (H2O2) or the superoxide radical (O2) produced by the incomplete reduction of oxygen. Oxygen free radicals are released during the respiratory burst phase of phagocytosis by neutrophils and macrophages during inflammation. They cause direct cell damage, increase vascular permeability through damage to the capillary endothelium, and promote chemotaxis. Oxygen free radicals are normally contained by antioxidant protective measures; however, with severe inflammation they cause significant damage. They are believed to be responsible for much of the cellular damage involved in adult respiratory distress syndrome (ARDS), in which massive neutrophil aggregation and phagocytosis occur.
See also: radical
References in periodicals archive ?
Molecular damage caused by oxygen radicals accumulates, and at some point the cells--and ultimately, the entire organism--can no longer function.
Hyperhomocysteinemia is a situation characterized by increased production of reactive oxygen radicals, and folate deficiency, which leads to reduced bioavailability of NO and endothelial dysfunction.
In the oxidative burst experiments, without stimulation neutrophils did not produce relevant amounts of oxygen radicals as indicated by a MFI of 33 AU (97.5th percentile).
For example, one mechanism through which alcohol induces liver damage is by increasing oxidative stress in the cells--that is, by producing increased amounts of highly reactive, oxygen-containing molecules (i.e., oxygen radicals) or by reducing the levels of antioxidants that scavenge those radicals.
Several factors influence the susceptibility to oxidative stress by affecting the antioxidant status or free oxygen radical generation.
The antioxidant potential of the extracts was determined using the oxygen radical absorbance capacity (ORAC) assay, which measures the antioxidant capacities of different foods.
Bilberry extract, by virtue of its exceptional antioxidant properties, proved effective in reducing the kidney levels of various oxidative stress markers and increasing the capacity to absorb free radicals (Oxygen Radical Absorbance Capacity--ORAC) in renal tissue.
After these treatments were completed, the juice was clarified by centrifugation and analyzed for its vitamin C content using the 2,6-dicloroindophenol titration method; for its antioxidant capacity using the oxygen radical absorbance capacity technique; for its total soluble phenolics using the Folin assay; and for its turbidity and color L * a * b * values.
Plant pigment anthocyanins are exceptionally potent oxygen radical scavengers that produce beneficial effects in diseases outside the cardiovascular system.
Kerry Ingredients has introduced the SuperFruit nutrition bar concept, which features high-ORAC (oxygen radical absorption capacity) fruit inclusions, such as real pomegranate fruit powder and an acai puree filling--an increasingly popular Brazilian fruit known for its "mega-antioxidants." The SuperFruit bar also contains a good source of protein and 500 mg of omega 3 (per 50 grams bar), which is virtually undetectable due to Kerry's patented encapsulation technologies.