scholarly journals The Reactive Oxygen Species Singlet Oxygen, Hydroxy Radicals, and the Superoxide Radical Anion—Examples of Their Roles in Biology and Medicine

Oxygen ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 77-95
Author(s):  
Ruth Edge ◽  
T. George Truscott
Keyword(s):  
Reactive Oxygen Species ◽  
Singlet Oxygen ◽  
Radical Anion ◽  
Superoxide Radical ◽  
Reactive Oxygen ◽  
High Energy ◽  
Oxygen Species ◽  
Superoxide Radical Anion ◽  
Hydroxy Radicals ◽  
Electronically Excited

Reactive oxygen species comprise oxygen-based free radicals and non-radical species such as peroxynitrite and electronically excited (singlet) oxygen. These reactive species often have short lifetimes, and much of our understanding of their formation and reactivity in biological and especially medical environments has come from complimentary fast reaction methods involving pulsed lasers and high-energy radiation techniques. These and related methods, such as EPR, are discussed with particular reference to singlet oxygen, hydroxy radicals, the superoxide radical anion, and their roles in medical aspects, such as cancer, vision and skin disorders, and especially pro- and anti-oxidative processes.

scholarly journals Mechanism of the Formation of Electronically Excited Species by Oxidative Metabolic Processes: Role of Reactive Oxygen Species

Biomolecules ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 258 ◽  
Author(s):  
Pavel Pospíšil ◽  
Ankush Prasad ◽  
Marek Rác
Keyword(s):  
Reactive Oxygen Species ◽  
Molecular Oxygen ◽  
Reactive Oxygen ◽  
High Energy ◽  
Oxygen Species ◽  
Human Beings ◽  
Metabolic Processes ◽  
Excited Species ◽  
Electronically Excited

It is well known that biological systems, such as microorganisms, plants, and animals, including human beings, form spontaneous electronically excited species through oxidative metabolic processes. Though the mechanism responsible for the formation of electronically excited species is still not clearly understood, several lines of evidence suggest that reactive oxygen species (ROS) are involved in the formation of electronically excited species. This review attempts to describe the role of ROS in the formation of electronically excited species during oxidative metabolic processes. Briefly, the oxidation of biomolecules, such as lipids, proteins, and nucleic acids by ROS initiates a cascade of reactions that leads to the formation of triplet excited carbonyls formed by the decomposition of cyclic (1,2-dioxetane) and linear (tetroxide) high-energy intermediates. When chromophores are in proximity to triplet excited carbonyls, the triplet-singlet and triplet-triplet energy transfers from triplet excited carbonyls to chromophores result in the formation of singlet and triplet excited chromophores, respectively. Alternatively, when molecular oxygen is present, the triplet-singlet energy transfer from triplet excited carbonyls to molecular oxygen initiates the formation of singlet oxygen. Understanding the mechanism of the formation of electronically excited species allows us to use electronically excited species as a marker for oxidative metabolic processes in cells.

scholarly journals COVID-19 and the ethnicity link – is there a photochemical link?

2021 ◽  
Vol 20 (1) ◽  
pp. 183-188
Author(s):  
Ruth Edge ◽  
T. George Truscott
Keyword(s):  
Reactive Oxygen Species ◽  
Singlet Oxygen ◽  
Bond Cleavage ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Peroxy Radicals ◽  
Superoxide Radical Anion ◽  
Black Skin ◽  
Oxygen Addition ◽  
Minority Ethnic

AbstractA hypothesis is proposed to explain the increased detrimental effect of COVID-19 for Black, Asian and Minority Ethnic (BAME) men and women compared to Caucasian individuals. This is based on the differing photochemistry of phaeomelanin in fair skin and eumelanin in dark/black skin. It is suggested that a range of reactive oxygen species, including, singlet oxygen and the superoxide radical anion, derived via direct photolysis of phaeomelanin, may escape the melanocyte and cause subsequent damage to the SARS-CoV-2 virus. It is further suggested that (large) carbon and sulphur peroxy radicals, from oxygen addition to radicals formed by carbon–sulphur bond cleavage, may assist via damage to the cell membranes. It is also speculated that light absorption by phaeomelanin and the subsequent C-S bond cleavage, leads to release of pre-absorbed reactive oxygen species, such as singlet oxygen and free radicals, which may also contribute to an enhanced protective effect for fair-skinned people.

UV-Vis Spectrophotometrical and Analytical Methodology for the Determination of Singlet Oxygen in New Antibacterials Drugs

2007 ◽  
Vol 2 ◽  
pp. 117739010700200 ◽  
Author(s):  
Tamara Zoltan ◽  
Franklin Vargas ◽  
Carla Izzo
Keyword(s):  
Reactive Oxygen Species ◽  
Singlet Oxygen ◽  
Nalidixic Acid ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Inexpensive Method ◽  
Analytical Methodology ◽  
First Time

We have determined and quantified spectrophotometrically the capacity of producing reactive oxygen species (ROS) as 1O2 during the photolysis with UV-A light of 5 new synthesized naphthyl ester derivates of well-known quinolone antibacterials (nalidixic acid (1), cinoxacin (2), norfloxacin (3), ciprofloxacin (4) and enoxacin (5)). The ability of the naphthyl ester derivatives (6-10) to generate singlet oxygen were detecting and for the first time quantified by the histidine assay, a sensitive, fast and inexpensive method. The following tendency of generation of singlet oxygen was observed: compounds 7 >10 > 6 > 8 > 9 >> parent drugs 1-5.

scholarly journals Molecular Characterization of Reactive Oxygen Species in Myocardial Ischemia-Reperfusion Injury

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Tingyang Zhou ◽  
Chia-Chen Chuang ◽  
Li Zuo
Keyword(s):  
Reactive Oxygen Species ◽  
Myocardial Ischemia ◽  
Energy Demand ◽  
Heart Diseases ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
High Energy ◽  
Protective Mechanism ◽  
Oxygen Species ◽  
Myocardial Ischemia Reperfusion

Myocardial ischemia-reperfusion (I/R) injury is experienced by individuals suffering from cardiovascular diseases such as coronary heart diseases and subsequently undergoing reperfusion treatments in order to manage the conditions. The occlusion of blood flow to the tissue, termed ischemia, can be especially detrimental to the heart due to its high energy demand. Several cellular alterations have been observed upon the onset of ischemia. The danger created by cardiac ischemia is somewhat paradoxical in that a return of blood to the tissue can result in further damage. Reactive oxygen species (ROS) have been studied intensively to reveal their role in myocardial I/R injury. Under normal conditions, ROS function as a mediator in many cell signaling pathways. However, stressful environments significantly induce the generation of ROS which causes the level to exceed body’s antioxidant defense system. Such altered redox homeostasis is implicated in myocardial I/R injury. Despite the detrimental effects from ROS, low levels of ROS have been shown to exert a protective effect in the ischemic preconditioning. In this review, we will summarize the detrimental role of ROS in myocardial I/R injury, the protective mechanism induced by ROS, and potential treatments for ROS-related myocardial injury.

scholarly journals Generation of reactive oxygen species by promoting the Cu(II)/Cu(I) redox cycle with reducing agents in aerobic aqueous solution

2018 ◽  
Vol 78 (6) ◽  
pp. 1390-1399 ◽  
Author(s):  
Wenshu Li ◽  
Peng Zhou ◽  
Jing Zhang ◽  
Yongli Zhang ◽  
Gucheng Zhang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Aqueous Solution ◽  
Superoxide Radical ◽  
Reactive Oxygen ◽  
Reducing Agents ◽  
Oxygen Species ◽  
Redox Cycle ◽  
Copper Species ◽  
Chain Reactions ◽  
H2o2 Generation

Abstract This study investigated the generation of reactive oxygen species (ROS) (O2−•, H2O2, and HO•) by promoting the Cu(II)/Cu(I) redox cycle with certain reducing agents (RAs) in aerobic aqueous solution, and benzoic acid (BA) was employed as indicator for the hydroxyl radical (HO•). Hydroxylamine (HA) can reduce Cu(II) to Cu(I) to induce chain reactions of copper species resulting in the generation of the superoxide radical (O2−•) and hydrogen peroxide (H2O2), and the intermediate Cu(I) can further activate H2O2 via a Fenton-like reaction to produce HO•, creating the remarkable BA degradation. O2 is indispensable, and unprotonated HA is the motive power in the O2/Cu/HA system. Moreover, pH is a crucial factor of the O2/Cu/HA system due to the protonated HA not being able to reduce Cu(II) into Cu(I). The oxidation of HA can be effectively induced by trace amounts of Cu(II), and both a higher HA dosage and a higher Cu(II) dosage can enhance H2O2 generation and BA degradation. In addition, some other RAs that can reduce Cu(II) into Cu(I) could replace HA in the O2/Cu/HA system to induce the generation of these ROS in aerobic aqueous solution.

scholarly journals Studies on Production and Chemical Property of Singlet Oxygen and Superoxide Radical by Dyestuffs

2009 ◽  
Vol 6 (s1) ◽  
pp. S79-S86 ◽  
Author(s):  
Vikesh Kumar ◽  
M. R. Tripathi ◽  
Manish Kumar ◽  
Gopal Shukla ◽  
Sarvesh Dwivedi ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Chemical Property ◽  
Superoxide Radical ◽  
Skin Diseases ◽  
Food Additives ◽  
Reactive Oxygen ◽  
Superoxide Radicals ◽  
Photochemical Oxidation ◽  
Oxygen Species ◽  
Metanil Yellow

There are several low lying singlet oxygen (1O2) and superoxide radical (O-2) which are important in photochemical oxidation. In our present analysis we are studying chemical property of singlet oxygen (1O2) and super oxide radical (O-2) and some dyestuffs species to produce reactive oxygen such as singlet oxygen1O2and superoxide radicals. Irradiation with sun lightin vitrothe dyestuff like benzanthrone, metanil yellow andp-aminodiphenylamine were found to produce reactive oxygen species such as singlet oxygen (1O2) and/or superoxide radicals (O-2) .The dose response relationship between singlet1O2production when sunlight expose of those dyestuffs (0-25 min), and (0-12 min) for super oxide (O-2) production were studied. However benzanthrone produces detectable amount of1O2, Although metanil yellow andp-aminodiphenylamine (p-ADPA) did not produce detectable amounts of1O2under similar conditions. The above dye stuffs are routinely used in textiles, cosmetics, detergents, leather industries as well as food additives and role of these activated oxygen species in the development of skin diseases.

scholarly journals PGC-1α, Inflammation, and Oxidative Stress: An Integrative View in Metabolism

2020 ◽  
Vol 2020 ◽  
pp. 1-20 ◽  
Author(s):  
Sergio Rius-Pérez ◽  
Isabel Torres-Cuevas ◽  
Iván Millán ◽  
Ángel L. Ortega ◽  
Salvador Pérez
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Metabolic Syndrome ◽  
Inflammatory Response ◽  
Reactive Oxygen ◽  
High Energy ◽  
Low Grade ◽  
Oxygen Species ◽  
Antioxidant Genes ◽  
Integrative View

Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is a transcriptional coactivator described as a master regulator of mitochondrial biogenesis and function, including oxidative phosphorylation and reactive oxygen species detoxification. PGC-1α is highly expressed in tissues with high energy demands, and it is clearly associated with the pathogenesis of metabolic syndrome and its principal complications including obesity, type 2 diabetes mellitus, cardiovascular disease, and hepatic steatosis. We herein review the molecular pathways regulated by PGC-1α, which connect oxidative stress and mitochondrial metabolism with inflammatory response and metabolic syndrome. PGC-1α regulates the expression of mitochondrial antioxidant genes, including manganese superoxide dismutase, catalase, peroxiredoxin 3 and 5, uncoupling protein 2, thioredoxin 2, and thioredoxin reductase and thus prevents oxidative injury and mitochondrial dysfunction. Dysregulation of PGC-1α alters redox homeostasis in cells and exacerbates inflammatory response, which is commonly accompanied by metabolic disturbances. During inflammation, low levels of PGC-1α downregulate mitochondrial antioxidant gene expression, induce oxidative stress, and promote nuclear factor kappa B activation. In metabolic syndrome, which is characterized by a chronic low grade of inflammation, PGC-1α dysregulation modifies the metabolic properties of tissues by altering mitochondrial function and promoting reactive oxygen species accumulation. In conclusion, PGC-1α acts as an essential node connecting metabolic regulation, redox control, and inflammatory pathways, and it is an interesting therapeutic target that may have significant benefits for a number of metabolic diseases.

scholarly journals Rapid evaluation of oxygen vacancies-enhanced photogeneration of the superoxide radical in nano-TiO2 suspensions

RSC Advances ◽  
2020 ◽  
Vol 10 (49) ◽  
pp. 29082-29089
Author(s):  
Wanchao Yu ◽  
Fengjie Chen ◽  
Yarui Wang ◽  
Lixia Zhao
Keyword(s):  
Reactive Oxygen Species ◽  
Photocatalytic Degradation ◽  
Oxygen Vacancies ◽  
Superoxide Radical ◽  
Surface Defects ◽  
Reactive Oxygen ◽  
Rapid Evaluation ◽  
Oxygen Species ◽  
Nano Tio2 ◽  
Degradation Of Pollutants

Reactive oxygen species (ROS) play an important role in the photocatalytic degradation of pollutants and are closely related to the surface defects of a semiconductor.

scholarly journals Reactivity of Several Reactive Oxygen Species (ROS) with the Sesquiterpene Cacalol

2008 ◽  
Vol 3 (4) ◽  
pp. 1934578X0800300
Author(s):  
Manuel Jiménez-Estrada ◽  
Ricardo Reyes-Chilpa ◽  
Arturo Navarro-Ocaña ◽  
Daniel Arrieta-Báez
Keyword(s):  
Reactive Oxygen Species ◽  
Hydroxyl Radical ◽  
Singlet Oxygen ◽  
Furan Ring ◽  
Reactive Oxygen ◽  
Antioxidant Effect ◽  
Oxygen Species ◽  
Site Reaction ◽  
Hexanedioic Acid ◽  
Antioxidant Effects

To analyze the antioxidant effects of cacalol we determined its reactivity with different reactive oxygen species (ROS). Cacalol gave rise to cacalone by a specific site reaction with a hydroxyl radical. Singlet oxygen reacted only with the double bond of the furan ring, causing its rupture. On the other hand, ozone reacted with all double bonds in cacalol affording 2-methyl-hexanedioic acid as an end product. No reaction was observed with either superoxide or hydrogen peroxide. The potential antioxidant effect of cacalol as a scavenger of hydroxyl radical and singlet oxygen could be related to its function in the plant roots.

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