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Antioxidants are compounds that inhibit oxidation, a chemical reaction that can produce free radicals. Autoxidation leads to degradation of organic compounds, including living matter. Antioxidants are frequently added to industrial products, such as polymers, fuels, and lubricants, to extend their useable lifetimes. Food are also treated with antioxidants to forestall spoilage, in particular the rancidification of oils and fats. In cells, antioxidants such as glutathione, mycothiol or bacillithiol, and enzyme systems like superoxide dismutase, can prevent damage from oxidative stress.
Superoxide dismutase (SOD, EC 1.15.1.1) is an enzyme that alternately catalyzes the dismutation (or partitioning) of the superoxide (O−
2) radical into ordinary molecular oxygen (O2) and hydrogen peroxide (H
2O
2). Superoxide is produced as a by-product of oxygen metabolism and, if not regulated, causes many types of cell damage. Hydrogen peroxide is also damaging and is degraded by other enzymes such as catalase. Thus, SOD is an important antioxidant defense in nearly all living cells exposed to oxygen. One exception is Lactobacillus plantarum and related lactobacilli, which use a different mechanism to prevent damage from reactive O−
2.
Catalase is a common enzyme found in nearly all living organisms exposed to oxygen which catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting the cell from oxidative damage by reactive oxygen species (ROS). Catalase has one of the highest turnover numbers of all enzymes; one catalase molecule can convert millions of hydrogen peroxide molecules to water and oxygen each second.
Glutathione peroxidase (GPx) is the general name of an enzyme family with peroxidase activity whose main biological role is to protect the organism from oxidative damage. The biochemical function of glutathione peroxidase is to reduce lipid hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water.
Melatonin is a natural compound, specifically an indoleamine, produced by and found in different organisms including bacteria and eukaryotes. It was discovered by Aaron B. Lerner and colleagues in 1958 as a substance of the pineal gland from cow that could induce skin lightening in common frogs. It was subsequently discovered as a hormone released in the brain at night which controls the sleep–wake cycle in vertebrates.
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 reactive, most biologically relevant free radicals are highly reactive. For most biological structures, free radical damage is closely associated with oxidative damage. Antioxidants are reducing agents, and limit oxidative damage to biological structures by passivating them from free radicals.
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen. Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
Lipid peroxidation is the chain of reactions of oxidative degradation of lipids. It is the process in which free radicals "steal" electrons from the lipids in cell membranes, resulting in cell damage. This process proceeds by a free radical chain reaction mechanism. It most often affects polyunsaturated fatty acids, because they contain multiple double bonds in between which lie methylene bridges (-CH2-) that possess especially reactive hydrogen atoms. As with any radical reaction, the reaction consists of three major steps: initiation, propagation, and termination. The chemical products of this oxidation are known as lipid peroxides or lipid oxidation products (LOPs).
Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. Disturbances in the normal redox state of cells can cause toxic effects through the production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA. Oxidative stress from oxidative metabolism causes base damage, as well as strand breaks in DNA. Base damage is mostly indirect and caused by the reactive oxygen species generated, e.g., O2− (superoxide radical), OH (hydroxyl radical) and H2O2 (hydrogen peroxide). Further, some reactive oxidative species act as cellular messengers in redox signaling. Thus, oxidative stress can cause disruptions in normal mechanisms of cellular signaling.
Myricetin is a member of the flavonoid class of polyphenolic compounds, with antioxidant properties. Common dietary sources include vegetables, fruits, nuts, berries, tea, and red wine. Myricetin is structurally similar to fisetin, luteolin, and quercetin and is reported to have many of the same functions as these other members of the flavonol class of flavonoids. Reported average intake of myricetin per day varies depending on diet, but has been shown in the Netherlands to average 23 mg/day.
Peroxiredoxins are a ubiquitous family of antioxidant enzymes that also control cytokine-induced peroxide levels and thereby mediate signal transduction in mammalian cells. The family members in humans are PRDX1, PRDX2, PRDX3, PRDX4, PRDX5, and PRDX6. The physiological importance of peroxiredoxins is indicated by their relative abundance. Their function is the reduction of peroxides, specifically hydrogen peroxide, alkyl hydroperoxides, and peroxynitrite.
Protandim is a herbal dietary supplement marketed with unsupported claims that it can treat a number of medical conditions. The product is a patented mix of five herbal ingredients and sold by LifeVantage Corporation, a Utah-based multi-level marketing company. The manufacturers of Protandim claim it can prevent or cure a wide variety of medical conditions. In 2017, LifeVantage was issued a warning letter by the U.S. Food and Drug Administration (FDA) regarding illegal advertising claims on the company's websites suggesting that Protandim can help to cure various ailments, including cancer and diabetes.
Superoxide dismutase [Cu-Zn] also known as superoxide dismutase 1 or hSod1 is an enzyme that in humans is encoded by the SOD1 gene, located on chromosome 21. SOD1 is one of three human superoxide dismutases. It is implicated in apoptosis, familial amyotrophic lateral sclerosis and Parkinson's disease.
Superoxide dismutase 2, mitochondrial (SOD2), also known as manganese-dependent superoxide dismutase (MnSOD), is an enzyme which in humans is encoded by the SOD2 gene on chromosome 6. A related pseudogene has been identified on chromosome 1. Alternative splicing of this gene results in multiple transcript variants. This gene is a member of the iron/manganese superoxide dismutase family. It encodes a mitochondrial protein that forms a homotetramer and binds one manganese ion per subunit. This protein binds to the superoxide byproducts of oxidative phosphorylation and converts them to hydrogen peroxide and diatomic oxygen. Mutations in this gene have been associated with idiopathic cardiomyopathy (IDC), premature aging, sporadic motor neuron disease, and cancer.
Irwin Fridovich was an American biochemist who, together with his graduate student Joe M. McCord, discovered the enzymatic activity of copper-zinc superoxide dismutase (SOD),—to protect organisms from the toxic effects of superoxide free radicals formed as a byproduct of normal oxygen metabolism. Subsequently, Fridovich's research group also discovered the manganese-containing and the iron-containing SODs from Escherichia coli and the mitochondrial MnSOD (SOD2), now known to be an essential protein in mammals. He spent the rest of his career studying the biochemical mechanisms of SOD and of biological superoxide toxicity, using bacteria as model systems. Fridovich was also Professor Emeritus of Biochemistry at Duke University.
Corneal keratocytes are specialized fibroblasts residing in the stroma. This corneal layer, representing about 85-90% of corneal thickness, is built up from highly regular collagenous lamellae and extracellular matrix components. Keratocytes play the major role in keeping it transparent, healing its wounds, and synthesizing its components. In the unperturbed cornea keratocytes stay dormant, coming into action after any kind of injury or inflammation. Some keratocytes underlying the site of injury, even a light one, undergo apoptosis immediately after the injury. Any glitch in the precisely orchestrated process of healing may cloud the cornea, while excessive keratocyte apoptosis may be a part of the pathological process in the degenerative corneal disorders such as keratoconus, and these considerations prompt the ongoing research into the function of these cells.
Hara Prasad Misra is an American biochemist and Professor Emeritus of Biomedical Sciences and Pathology in the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech. Misra is currently serving as Vice President for Research & Graduate Studies at the Virginia College of Osteopathic Medicine in Blacksburg, VA. Dr. Misra is a well known teacher of undergraduate, graduate and DVM professional students for a period spanning over 30 years.
All living cells produce reactive oxygen species (ROS) as a byproduct of metabolism. ROS are reduced oxygen intermediates that include the superoxide radical (O2−) and the hydroxyl radical (OH•), as well as the non-radical species hydrogen peroxide (H2O2). These ROS are important in the normal functioning of cells, playing a role in signal transduction and the expression of transcription factors. However, when present in excess, ROS can cause damage to proteins, lipids and DNA by reacting with these biomolecules to modify or destroy their intended function. As an example, the occurrence of ROS have been linked to the aging process in humans, as well as several other diseases including Alzheimer's, rheumatoid arthritis, Parkinson's, and some cancers. Their potential for damage also makes reactive oxygen species useful in direct protection from invading pathogens, as a defense response to physical injury, and as a mechanism for stopping the spread of bacteria and viruses by inducing programmed cell death.
Superoxide dismutase (SOD) mimetics are synthetic compounds that mimic the native superoxide dismutase enzyme. SOD mimetics effectively convert the superoxide anion, a reactive oxygen species, into hydrogen peroxide, which is further converted into water by catalase. Reactive oxygen species are natural byproducts of cellular respiration and cause oxidative stress and cell damage, which has been linked to causing cancers, neurodegeneration, age-related declines in health, and inflammatory diseases. SOD mimetics are a prime interest in therapeutic treatment of oxidative stress because of their smaller size, longer half-life, and similarity in function to the native enzyme.
The mitochondrial theory of ageing has two varieties: free radical and non-free radical. The first is one of the variants of the free radical theory of ageing. It was formulated by J. Miquel and colleagues in 1980 and was developed in the works of Linnane and coworkers (1989). The second was proposed by A. N. Lobachev in 1978.
References
- ↑ McCord JM, Fridovich I (November 1969). "Superoxide dismutase. An enzymic function for erythrocuprein (hemocuprein)". J. Biol. Chem. 244 (22): 6049–55. doi: 10.1016/S0021-9258(18)63504-5 . PMID 5389100.
- ↑ Keele BB, McCord JM, Fridovich I (November 1970). "Superoxide dismutase from escherichia coli B. A new manganese-containing enzyme". J. Biol. Chem. 245 (22): 6176–81. doi: 10.1016/S0021-9258(18)62675-4 . PMID 4921969.
- 1 2 Corporation, Lifevantage (25 June 2013). "Dr. Joe McCord, LifeVantage Corporation's First Chief Science Officer, Retires From Company". GlobeNewswire News Room. Retrieved 19 April 2021.
- ↑ "SFRBM - Society for Free Radical Biology and Medicine".
- 1 2 http://secwatch.com/mccord-joe-m%5B%5D
- ↑ Nelson SK, Bose SK, Grunwald GK, Myhill P, McCord JM (January 2006). "The induction of human superoxide dismutase and catalase in vivo: a fundamentally new approach to antioxidant therapy". Free Radic. Biol. Med. 40 (2): 341–7. doi:10.1016/j.freeradbiomed.2005.08.043. PMID 16413416.
- ↑ Velmurugan K, Alam J, McCord JM, Pugazhenthi S (February 2009). "Synergistic induction of heme oxygenase-1 by the components of the antioxidant supplement Protandim". Free Radic. Biol. Med. 46 (3): 430–40. doi:10.1016/j.freeradbiomed.2008.10.050. PMID 19056485.
- ↑ Liu J, Gu X, Robbins D, et al. (2009). "Protandim, a fundamentally new antioxidant approach in chemoprevention using mouse two-stage skin carcinogenesis as a model". PLOS ONE. 4 (4): e5284. Bibcode:2009PLoSO...4.5284L. doi: 10.1371/journal.pone.0005284 . PMC 2668769 . PMID 19384424.
- ↑ Robbins D, Gu X, Shi R, et al. (2010). "The chemopreventive effects of Protandim: modulation of p53 mitochondrial translocation and apoptosis during skin carcinogenesis". PLOS ONE. 5 (7): e11902. Bibcode:2010PLoSO...511902R. doi: 10.1371/journal.pone.0011902 . PMC 2912769 . PMID 20689586.
- ↑ Bogaard HJ, Natarajan R, Henderson SC, et al. (November 2009). "Chronic pulmonary artery pressure elevation is insufficient to explain right heart failure". Circulation. 120 (20): 1951–60. doi: 10.1161/CIRCULATIONAHA.109.883843 . PMID 19884466.
- ↑ Qureshi MM, McClure WC, Arevalo NL, et al. (June 2010). "The Dietary Supplement Protandim Decreases Plasma Osteopontin and Improves Markers of Oxidative Stress in Muscular Dystrophy Mdx Mice". J Diet Suppl. 7 (2): 159–178. doi:10.3109/19390211.2010.482041. PMC 2926985 . PMID 20740052.
- ↑ Joddar B, Reen RK, Firstenberg MS, et al. (March 2011). "Protandim attenuates intimal hyperplasia in human saphenous veins cultured ex vivo via a catalase-dependent pathway". Free Radic. Biol. Med. 50 (6): 700–9. doi:10.1016/j.freeradbiomed.2010.12.008. PMID 21167278.
- 1 2 "Form 8-K for LifeVantage Corp". Yahoo.com. June 25, 2013. Retrieved November 10, 2013.
- ↑ https://www.pathwaysbio.com/
