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 usable lifetimes. Foods 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.
Flavonoids are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans.
Flavan-3-ols are a subgroup of flavonoids. They are derivatives of flavans that possess a 2-phenyl-3,4-dihydro-2H-chromen-3-ol skeleton. Flavan-3-ols are structurally diverse and include a range of compounds, such as catechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, proanthocyanidins, theaflavins, thearubigins. They play a part in plant defense and are present in the majority of plants.
Polyphenols are a large family of naturally occurring phenols. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some of which have been used historically as dyes and for tanning garments.
Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. The name comes from Greek φυτόν (phyton) 'plant'. Some phytochemicals have been used as poisons and others as traditional medicine.
Catechin is a flavan-3-ol, a type of secondary metabolite providing antioxidant roles in plants. It belongs to the subgroup of polyphenols called flavonoids.
Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; capers, red onions, and kale are common foods containing appreciable amounts of it. It has a bitter flavor and is used as an ingredient in dietary supplements, beverages, and foods.
Oxygen radical absorbance capacity (ORAC) was a method of measuring antioxidant capacities in biological samples in vitro. Because no physiological proof in vivo existed in support of the free-radical theory or that ORAC provided information relevant to biological antioxidant potential, it was withdrawn in 2012.
The vitamin E family comprises four tocotrienols and four tocopherols. The critical chemical structural difference between tocotrienols and tocopherols is that tocotrienols have unsaturated isoprenoid side chains with three carbon-carbon double bonds versus saturated side chains for tocopherols.
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.
A polyphenol antioxidant is a hypothetized type of antioxidant, in which each instance would contain a polyphenolic substructure; such instances which have been studied in vitro. Numbering over 4,000 distinct chemical structures, such polyphenols may have antioxidant activity {{{1}}} in vitro (although they are unlikely to be antioxidants in vivo). Hypothetically, they may affect cell-to-cell signaling, receptor sensitivity, inflammatory enzyme activity or gene regulation, although high-quality clinical research has not confirmed any of these possible effects in humans as of 2020.
The MRC Mitochondrial Biology Unit is a department of the School of Clinical Medicine at the University of Cambridge, funded through a strategic partnership between the Medical Research Council and the University. It is located at the Addenbrooke’s Hospital / Cambridge Biomedical Campus site in Cambridge, England. The unit is concerned with the study of the mitochondrion, as this organelle has a varied and critical role in many aspects of eukaryotic metabolism and is implicated in many metabolic, degenerative, and age-related human diseases.
Masayoshi Yamaguchi is a distinguished biomedical scientist and researcher. He is notable for discovering the novel protein and genes named Regucalcin and RGPR-p117, respectively.
Victor Darley-Usmar is a free-radical biologist and biochemist, the UAB Endowed Professor in Mitochondrial Medicine and Pathology at the University of Alabama at Birmingham. Darley-Usmar also contributed to a book titled Microbes, Bugs & Wonder Drugs, a science book written for young readers and their families.
Secondary metabolism produces a large number of specialized compounds that do not aid in the growth and development of plants but are required for the plant to survive in its environment. Secondary metabolism is connected to primary metabolism by using building blocks and biosynthetic enzymes derived from primary metabolism. Primary metabolism governs all basic physiological processes that allow a plant to grow and set seeds, by translating the genetic code into proteins, carbohydrates, and amino acids. Specialized compounds from secondary metabolism are essential for communicating with other organisms in mutualistic or antagonistic interactions. They further assist in coping with abiotic stress such as increased UV-radiation. The broad functional spectrum of specialized metabolism is still not fully understood. In any case, a good balance between products of primary and secondary metabolism is best for a plant’s optimal growth and development as well as for its effective coping with often changing environmental conditions. Well known specialized compounds include alkaloids, polyphenols including flavonoids, and terpenoids. Humans use many of these compounds for culinary, medicinal and nutraceutical purposes.
David Chaim Rubinsztein FRS FMedSci is the Deputy Director of the Cambridge Institute of Medical Research (CIMR), Professor of Molecular Neurogenetics at the University of Cambridge and a UK Dementia Research Institute Professor.
Barry Halliwell is an English biochemist, chemist and university administrator, specialising in free radical metabolism in both animals and plants. His name is included in the "Foyer–Halliwell–Asada" pathway, a cellular process of hydrogen peroxide metabolism in plants and animals, named for the three principal discoverers, with Christine Foyer and Kozi Asada. He moved to Singapore in 2000, and served as Deputy President of the National University of Singapore (2006–15), where he continues to hold a Tan Chin Tuan Centennial professorship.
Nutritional immunology is a field of immunology that focuses on studying the influence of nutrition on the immune system and its protective functions. Indeed, every organism will under nutrient-poor conditions "fight" for the precious micronutrients and conceal them from invading pathogens. As such, bacteria, fungi, plants secrete for example iron chelators (siderophores) to acquire iron from their surrounding
Helmut Sies is a German physician, biochemist and university professor. He was the first to demonstrate the existence of hydrogen peroxide as a normal attribute of aerobic life in 1970, and he introduced the concept of Oxidative stress in 1985. He also worked on the biological strategies of antioxidant defense and the biochemistry of nutritional antioxidants.
