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, [1] and he introduced the concept of Oxidative stress [2] in 1985. He also worked on the biological strategies of antioxidant defense [3] and the biochemistry of nutritional antioxidants (e.g., selenium, carotenoids, flavonoids, polyphenols).
Professor Sies was born March 28, 1942, in Goslar, Germany. He grew up in Seesen/Harz, Germany, attended Elementary School 1948-1952, and Gymnasium (Jacobson School) 1952-1961. He was a High School Exchange student (1959-1960) with the Michigan Council of Churches, in Pleasant Plain, Ohio, and in Kankakee, Illinois, where he graduated from Kankakee High School in 1960. He was married to Dr. Claudia Sies, born Neumann, (1967-1983). They have two children (Alexander, Art Gallerist (www.sieshoeke.com); Caroline). He is married to Dr. Nancy Sies, born Kim (born 1990), they also have two children (Katharina, MD; Audrey).
He was a student at Leibniz-Kolleg at Tübingen for 'studium generale' in 1961. He studied medicine at the University of Tübingen, the Ludwig Maximilians University of Munich, and in Paris. In 1967 he received his medical doctorate summa cum laude at Munich, where he worked at the Institute of Physiological Chemistry from 1968. In 1972 he habilitated in Munich for Physiological Chemistry and Physical Biochemistry with the thesis, "Biochemistry of the Peroxisome in the Liver Cell", and in 1978 became professor. From 1979 until 2008 he was professor and chairman at the Institute of Biochemistry and Molecular Biology I, Heinrich_Heine_University_Düsseldorf. He has been a visiting professor at the University of California at Berkeley, the University of Texas at Austin the Heart Research Institute in Sydney, the University of Siena, the University of Southern California, and the King Saud University in Riyadh. Since 2008 he is emeritus professor at the Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, and Senior Scientist at the Leibniz Institute for Environmental Medicine, Düsseldorf, Germany. [4]
Investigating biological redox reactions, [5] he identified hydrogen peroxide as a normal constituent of aerobic life in eukaryotic cells. [1] This finding led to developments that recognized the essential role of hydrogen peroxide in metabolic redox control. Further research included studies on glutathione, [6] toxicological aspects (the concept of "redox cycling"), [7] biochemical pharmacology (Ebselen), [8] nutritional biochemistry and micronutrients (selenium, carotenoids, flavonoids), and the concept of "Oxidative Stress". [2] [9]
He found that Lycopene, a carotenoid common in tomatoes, works as an antioxidant by quenching singlet molecular oxygen, [10] and that lycopene and other carotenoids, as well as some flavonoids, protect the skin from damage from sunlight. [11] Working with clinicians, he found that cocoa flavanols are beneficial for the cardiovascular system. [12] [13]
He pointed out that epidemiology can generate interest for further analysis, but that epidemiological association of parameters cannot prove cause-effect relationships. The striking example was the almost perfect correlation (r = 0.982) between the number of brooding storks and the number of newborn babies in then West Germany: [14] every child in Germany knows that 'storks bring babies'!
He was named "Redox Pioneer". [4]
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.
Lycopene is an organic compound classified as a tetraterpene and a carotene. Lycopene is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables.
Glutathione is an organic compound with the chemical formula HOCOCH(NH2)CH2CH2CONHCH(CH2SH)CONHCH2COOH. It is an antioxidant in plants, animals, fungi, and some bacteria and archaea. Glutathione is capable of preventing damage to important cellular components caused by sources such as reactive oxygen species, free radicals, peroxides, lipid peroxides, and heavy metals. It is a tripeptide with a gamma peptide linkage between the carboxyl group of the glutamate side chain and cysteine. The carboxyl group of the cysteine residue is attached by normal peptide linkage to glycine.
Flavonoids are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans.
Carotenoids are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, archaea, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, canaries, flamingos, salmon, lobster, shrimp, and daffodils. Over 1,100 identified carotenoids can be further categorized into two classes – xanthophylls and carotenes.
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.
In chemistry and biology, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (O2), water, and hydrogen peroxide. Some prominent ROS are hydroperoxide (O2H), superoxide (O2-), hydroxyl radical (OH.), and singlet oxygen. ROS are pervasive because they are readily produced from O2, which is abundant. ROS are important in many ways, both beneficial and otherwise. ROS function as signals, that turn on and off biological functions. They are intermediates in the redox behavior of O2, which is central to fuel cells. ROS are central to the photodegradation of organic pollutants in the atmosphere. Most often however, ROS are discussed in a biological context, ranging from their effects on aging and their role in causing dangerous genetic mutations.
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., O−
2, OH and H2O2. 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.
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 glyoxalase system is a set of enzymes that carry out the detoxification of methylglyoxal and the other reactive aldehydes that are produced as a normal part of metabolism. This system has been studied in both bacteria and eukaryotes. This detoxification is accomplished by the sequential action of two thiol-dependent enzymes; firstly glyoxalase І, which catalyzes the isomerization of the spontaneously formed hemithioacetal adduct between glutathione and 2-oxoaldehydes into S-2-hydroxyacylglutathione. Secondly, glyoxalase ІІ hydrolyses these thiolesters and in the case of methylglyoxal catabolism, produces D-lactate and GSH from S-D-lactoyl-glutathione.
Peroxiredoxin-5 (PRDX5), mitochondrial is a protein that in humans is encoded by the PRDX5 gene, located on chromosome 11.
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.
Roland Stocker is a Swiss Australian biochemist who discovered the antioxidant activity of bilirubin. He is a former Olympic rower and has represented Switzerland at the 1980 Summer Olympics.
Christine Helen Foyer is professor of plant science at the University of Birmingham, Birmingham, UK. She is President Elect of the Association of Applied Biologists, the General Secretary of the Federation of European Societies of Plant Biologists, an elected Board Member of the American Society of Plant Biologists and a Member of the French Academy of Agriculture. She has published and co-authored many papers on related subjects.
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.
Jeremy P. E. Spencer is a British biochemist, specialising in nutrition and cognitive function. He is Professor of Molecular Nutrition at the Department of Food and Nutritional Sciences of the University of Reading. He is an Institute for Scientific Information highly-cited researcher.
Carotenoid complexes are physical associations of carotenoids with other molecules.
Danyelle M. Townsend is a biomedical scientist, and academic. She is a Professor and acting Department Chair of Drug Discovery and Biomedical Sciences at the Medical University of South Carolina (MUSC).
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