free radicals


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free radicals

Highly chemically active atoms or group of atoms capable of free existence, under special conditions, for very short periods, each having at least one unpaired electron in the outer shell. Oxygen free radicals can be very damaging to DNA and proteins and to the fat in cell membranes where a free radical chain reaction can be set up. They are normally mopped up by ANTIOXIDANTS and associated substances such as vitamins E and C, FLAVONOIDS, selenium, copper, zinc, and manganese. Produced in excess, or insufficiently opposed, free radicals are believed to be implicated in the production of ATHEROSCLEROSIS, cancer, RHEUMATOID ARTHRITIS, radiation sickness and many other conditions. They are thought to be responsible for much of the damage to the heart during the reperfusion that follows a coronary thrombosis. They are said to be promoted by many agents including radiation, atmospheric pollutants and smoking. The body's natural antioxidants include superoxide dismutase and vitamins C and E. See also NANOPARTICLES.
References in periodicals archive ?
In this study, the researchers tested the biomimetic peptides by exposing them to intracellular free radicals triggered by hydrogen peroxide (H2O2).
But now we know that e-cigarettes do produce free radicals, and the amount is affected by the flavourants added."
DPPH free radicals scavenging assay: For this attempt of DPPH (1, 1-diphenyle-2-picrylehydrazyl) scavenging activity, the technique of Gymfi et al., (1999) with some modifications.
But recently, Reviva Skin Care Labs of Haddonfield, NJ, discovered that EMBLICA (from the Indian Gooseberry plant), was unique in neutralizing nitrogen free radicals as well as oxygen free radicals, and features it in a breakthrough new Antioxidant Serum.
"Dr Troup was one of the first scientists to discover free radicals in coffee in 1988 and so it made sense for Illycaffe -- a ...
In mouse lungs, those free radicals can swipe electrons from cellular components, creating more reactive molecules and oxidative stress, Cormier and colleagues discovered.
Many normal bodily processes create free radicals, such as when our bodies break down nutrients for energy, fight off infection or detoxify drugs.
Our DNA is the most vulnerable as it has as many as 10,000 hits per day by free radicals. Every cell would be destroyed if it weren't for our DNA repair system and our home-grown army of antioxidant defences.
The effect of high temperature on sterilized drug should not produce high amounts of free radicals in the sample.
Free radicals attack the structure of our cell membranes, creating metabolic waste products that disturb DNA and RNA production, interfere with the synthesis of protein, and destroy important cellular enzymes.
If your body is under siege from free radicals, your skin will reflect the struggle.
Though phenomenal literature and huge theories of ageing are put forward, the most recent and highly accepted theory is "Free Radical Theory of Ageing" conceived by Harman.[1] In the free radical theory of aging, there is some imbalance between production and scavenging mechanisms of free radicals.[2] The free radical theory of aging proposes that reactive oxygen species (ROS) cause oxidative damage over the lifetime of the subject which is critical in determining the life span.[3] It is the cumulative and potentially increasing amount of accumulated damage that accounts for the dysfunctions and pathologies seen in normal aging.