Nanotheranostic agents for neurodegenerative diseases. Emerging Topics in Life Sciences, 4 6 Thomas, M. Cancers, 12 12 ,
Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals.
In turn, these radicals can start chain reactions. When the chain reaction occurs in a cellit can cause damage or death to the anti age expert oxidative stress.
Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions. They do this by being oxidized themselves, so antioxidants are often reducing agents such as thiolsascorbic acidor polyphenols.
A simple guide to protecting your skin in a polluted world
Substituted phenols and derivatives of phenylenediamine are common antioxidants used to inhibit gum formation in gasoline petrol. Although oxidation reactions are crucial for life, they can also be damaging; plants and animals maintain complex systems of multiple types of antioxidants, such as glutathionevitamin Cvitamin Aand vitamin E as well as enzymes such as catalasesuperoxide dismutase and various peroxidases.
Insufficient levels of antioxidants, or inhibition of the antioxidant enzymes, cause oxidative stress and may damage or kill cells. Oxidative stress is damage to cell structure and cell function by overly reactive oxygen-containing molecules and chronic excessive inflammation. Oxidative stress seems to play a significant role in many human diseases, including cancers.
The use of antioxidants in pharmacology is intensively studied, particularly as treatments for stroke and neurodegenerative diseases. For these reasons, oxidative stress can be considered to be both the cause and the consequence of some diseases.
Antioxidants are widely used in dietary supplements and have been investigated for the prevention of diseases such as cancer, coronary heart disease and even altitude sickness. Although initial studies suggested that antioxidant supplements might promote health, later large clinical trials with a limited number of antioxidants detected no benefit and even suggested that excess supplementation with certain putative antioxidants may be harmful.
Int J Mol Sci. Published online Jan 8. Copyright © by the authors. This article has been cited by other articles in PMC. Abstract Royal jelly RJ is a yellowish-white and acidic secretion of hypopharyngeal and mandibular glands of nurse bees used to feed young worker larvae during the first three days and the entire life of queen bees.
Antioxidants also have many industrial uses, such as preservatives in food and cosmetics and to prevent the degradation of rubber and gasoline Free-radical theory of aging From Wikipedia, the free encyclopedia The free radical theory of aging FRTA states that organisms age because cells accumulate free radical damage over time.
A free radical is any atom or molecule that has a single unpaired electron in an outer shell. While a few free radicals such as melanin are not chemically reactivemost biologically-relevant free radicals are highly reactive.
For most biological structures, free radical damage is closely associated with oxidative damage.
LIST OF PUBLICATIONS
Antioxidants are reducing agentsand limit oxidative damage to biological structures by passivating them from free radicals. Strictly speaking, the free radical theory is only concerned with anti age expert oxidative stress radicals such as superoxide O2—but it has since been expanded to encompass oxidative damage from other reactive oxygen species such as hydrogen peroxide H2O2or peroxynitrite OONO—.
Denham Harman first proposed the free radical theory of aging in the s, and in the s extended the idea to implicate mitochondrial production of reactive oxygen species.
In some model organisms, such as yeast and Drosophilathere is evidence that reducing oxidative damage can extend lifespan. In mice, interventions that enhance oxidative damage generally shorten lifespan. However, in roundworms Caenorhabditis elegansblocking the production of the naturally occurring antioxidant superoxide dismutase has recently been shown to increase lifespan.
Whether reducing oxidative damage below normal levels is sufficient to extend lifespan remains an open and controversial question. There you get free radicals from That is free radicals can damage Background The free radical theory of aging was conceived by Denham Harman in the s, when prevailing scientific opinion held that free radicals were too unstable to exist in biological systems.
New Insights into the Biological and Pharmaceutical Properties of Royal Jelly
This was also before anyone invoked free radicals as a cause of degenerative diseases. In later years, the free radical theory was expanded to include not only aging per se, but also age-related diseases.
Haematologica ; 86 3 :Mar.
There has been some evidence to suggest that free radicals and some reactive nitrogen species trigger and increase cell death mechanisms within the body such as apoptosis and in extreme cases necrosis. InHarman modified his original theory to what Svájci automata anti aging tojáskeltető known as the mitochondrial theory of aging. In its current form, this theory proposes that reactive oxygen species that are produced in the mitochondriacauses damage to certain macromolecules including lipidsproteins and most importantly mitochondrial DNA.
This damage then causes mutations which leads to an increase of ROS production and greatly enhances the accumulation of free radicals within cells.
This mitochondrial theory has been more widely accepted that it could play a major role in contributing to the aging process.
Since Harman first proposed the free radical theory of aging, there have been continual modifications and extensions to his original theory. Processes In chemistry, a free radical is any atom, molecule, or ion with an unpaired valence electron Free radicals are atoms or molecules containing unpaired electrons.
Electrons normally exist in pairs in specific orbitals in atoms or molecules. Free radicals, which contain only a single electron in any orbital, are usually unstable toward losing or picking up an extra electron, so that all electrons in the atom or molecule will be paired.