The role of EPR spectroscopy in studies of the oxidative status of biological systems and the antioxidative properties of various compounds

Spasojević, Ivan; Mojović, Miloš; Ignjatović, Aleksandar; Bačić, Goran

doi:10.2298/jsc101015064s

Cited by 23 publications

(10 citation statements)

References 134 publications

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“…The scavenging capacity of PEG-HCCs was evaluated by EPR with the spin trap 5-(diethoxyphosphoryl)-5-methylpyrrole-N-oxide (DEPMPO). DEPMPO produces relatively stable paramagnetic adducts upon reaction with • OH (3,4,28,29) and O 2…”

Section: Significancementioning

confidence: 99%

Highly efficient conversion of superoxide to oxygen using hydrophilic carbon clusters

Samuel¹,

Marcano

Berka

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

184

182

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Many diseases are associated with oxidative stress, which occurs when the production of reactive oxygen species (ROS) overwhelms the scavenging ability of an organism. Here, we evaluated the carbon nanoparticle antioxidant properties of poly(ethylene glycolated) hydrophilic carbon clusters (PEG-HCCs) by electron paramagnetic resonance (EPR) spectroscopy, oxygen electrode, and spectrophotometric assays. These carbon nanoparticles have 1 equivalent of stable radical and showed superoxide (O 2•− ) dismutase-like properties yet were inert to nitric oxide (NO • ) as well as peroxynitrite (ONOO − ). Thus, PEG-HCCs can act as selective antioxidants that do not require regeneration by enzymes. Our steadystate kinetic assay using KO 2 and direct freeze-trap EPR to follow its decay removed the rate-limiting substrate provision, thus enabling determination of the remarkable intrinsic turnover numbers of O 2 •− to O 2 by PEG-HCCs at >20,000 s −1 . The major products of this catalytic turnover are O 2 and H 2 O 2 , making the PEG-HCCs a biomimetic superoxide dismutase.superoxide | antioxidant | carbon nanoparticles | hydrophilic carbon clusters | superoxide dismutase mimetic R eactive oxygen species (ROS), such as superoxide (O 2 •− ), hydrogen peroxide (H 2 O 2 ), organic peroxides, and hydroxyl radical ( • OH), are a consequence of aerobic metabolism (1, 2). These ROS are necessary for the signaling pathways in biological processes (3, 4) such as cell migration, circadian rhythm, stem cell proliferation, and neurogenesis (5). In healthy systems, ROS are efficiently regulated by the defensive enzymes superoxide dismutase (SOD) and catalase, and by antioxidants such as glutathione, vitamin A, ascorbic acid, uric acid, hydroquinones, and vitamin E (6). When the production of ROS overwhelms the scavenging ability of the defense system, oxidative stress occurs, causing dysfunctions in cell metabolism (7)(8)(9)(10)(11)(12)(13)(14)(15)(16).In addition to ROS, reactive nitrogen species (RNS) such as nitric oxide (NO • ), nitrogen dioxide, and dinitrogen trioxide can be found in all organisms. NO • can act as an oxidizing or reducing agent depending on the environment (17), is more stable than other radicals (half-life 4-15 s) (18), and is synthesized in small amounts in vivo (17)(18)(19)(20)(21)(22). NO • is a potent vasodilator and has an important role in neurotransmission and cytoprotection (17,18,22,23). Owing to its biological importance and the low concentration found normally in vivo, it is often important to avoid alteration of NO • levels in biological systems to prevent aggravation of acute pathologies including ischemia and reperfusion.One way to treat these detrimental pathologies is to supply antioxidant molecules or particles that renormalize the disturbed oxidative condition. We recently developed a biocompatible carbon nanoparticle, the poly(ethylene glycolated) hydrophilic carbon cluster (PEG-HCC), which has shown ability to scavenge oxyradicals and protect against oxyradical damage in rodent models and thus far h...

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Section: Significancementioning

confidence: 99%

Highly efficient conversion of superoxide to oxygen using hydrophilic carbon clusters

Samuel¹,

Marcano

Berka

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

184

182

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“…All oxidizing species with higher redox potentials can be repaired by ascorbate, leading to the generation of the ascorbyl radical. This property makes ascorbyl radical probably the best endogenous marker of the oxidative status in biosystems, which can be easily detected by EPR spectroscopy since it gives a characteristic doublet (Spasojević et al, 2011). More stable radical species are also formed by adding exogenous spin traps, molecules that react with primary radical species to give more enduring radical adducts, such as lipid radicals, with characteristic EPR signatures (Malanga and Puntarulo, 2012).…”

Section: Introductionmentioning

confidence: 99%

Assessment of antioxidant responses and trace metal accumulation by digestive gland of ribbed mussel Aulacomya atra atra from Northern Patagonia

Giarratano

Gil

Malanga

2013

Ecotoxicology and Environmental Safety

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Seasonal variations of trace metals did not appear to influence those of biochemical parameters, which generally showed an opposite trend with higher enzymatic activities in summer when trace metal concentrations were lower. Organisms from Punta Cuevas (control site) showed higher induction of reactive oxygen species production than those from both considered impacted sites, suggesting the possibility of some biochemical adaptation in organisms or a higher modulation of environmental and physiological factors on antioxidant responses than levels of trace metals. This study, which is the first in the area in this matter, showed that seasonal variations of potential biomarkers should be incorporated into interpretation of long-term biomonitoring studies in this marine coastal ecosystem.

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“…Ascorbate radicals are long lived and thus convenient to detect directly by EPR spectrometry 14 . Stability of ascorbate radicals makes them the best non-toxic endogenous marker of oxidative stress in the biological systems 28 . In the present study, the level of ROS products and ascorbate radicals were evaluated in real time scenario using healthy mice before and after treatment with NATG using ex vivo EPR spin trapping spectrometry and direct EPR spectrometry (Figs.…”

Section: Discussionmentioning

confidence: 99%

Electron Paramagnetic Resonance Spectrometry-based Assessment of Free Radicals Scavenging Potential of N-acetyl Tryptophan Glucoside

et al. 2017

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Gamma radiation generates free radicals in biological system by inducing cellular water radiolysis. If not neutralised, free radicals oxidise vital bio-macromolecules causing structural and functional impairment and contribute to cell death. In present study, free radical scavenging activities of a novel bacterial secondary metabolite, N-acetyl tryptophan glucoside (NATG) was assessed against gamma-radiation induced damage in vitro and in vivo models. Effect of irradiated NATG (UV and gamma radiation 8 Gy and 20 Gy) on its free radical (DPPH radicals) and SOD-like activity was evaluated using EPR spectrometry. To assess the effect of NATG irradiation on its antioxidant potential, EPR based ascorbate, PBN and NO radicals scavenging activities were evaluated in blood and spleen tissue of strain A male mice. Results of the study indicated significant (p < 0.05) increase in DPPH radicals scavenging ability of irradiated NATG as compared to un-irradiated NATG. Similarly, irradiated NATG exhibited significant (p < 0.05) elevation in SOD-like activity as compared to control. Subsequently, NATG treatment displayed enhanced antioxidant activity as evident by significant (p < 0.05) decline in ascorbate, PBN and NO radicals at 1 h and 2h in blood and spleen tissues homogenate of treated mice as compared to control group. In conclusion, NATG possesses significant free radicals scavenging and radio protective capabilities against gamma radiation induced oxidative stress.

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The role of EPR spectroscopy in studies of the oxidative status of biological systems and the antioxidative properties of various compounds

Cited by 23 publications

References 134 publications

Highly efficient conversion of superoxide to oxygen using hydrophilic carbon clusters

Highly efficient conversion of superoxide to oxygen using hydrophilic carbon clusters

Assessment of antioxidant responses and trace metal accumulation by digestive gland of ribbed mussel Aulacomya atra atra from Northern Patagonia

Electron Paramagnetic Resonance Spectrometry-based Assessment of Free Radicals Scavenging Potential of N-acetyl Tryptophan Glucoside

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