scholarly journals EPR Study of KO2 as a Source of Superoxide and •BMPO-OH/OOH Radical That Cleaves Plasmid DNA and Detects Radical Interaction with H2S and Se-Derivatives

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1286
Author(s):  
Anton Misak ◽  
Vlasta Brezova ◽  
Miroslav Chovanec ◽  
Karol Luspai ◽  
Muhammad Jawad Nasim ◽  
...  
Keyword(s):  
Plasmid Dna ◽  
Water Solution ◽  
Biological Effects ◽  
Physiological Solution ◽  
Oh Radicals ◽  
Paramagnetic Resonance ◽  
Superoxide Radical Anion ◽  
Epr Spin Trapping ◽  
Electron Paramagnetic ◽  
Radical Interaction

Superoxide radical anion (O2•−) and its derivatives regulate numerous physiological and pathological processes, which are extensively studied. The aim of our work was to utilize KO2 as a source of O2•− and the electron paramagnetic resonance (EPR) spin trapping 5-tert-butoxycarbonyl-5-methyl-1-pyrroline N-oxide (BMPO) technique for the preparation of •BMPO-OOH and/or •BMPO-OH radicals in water solution without DMSO. The method distinguishes the interactions of various compounds with •BMPO-OOH and/or •BMPO-OH radicals over time. Here, we show that the addition of a buffered BMPO-HCl mixture to powdered KO2 formed relatively stable •BMPO-OOH and •BMPO-OH radicals and H2O2, where the •BMPO-OOH/OH ratio depended on the pH. At a final pH of ~6.5–8.0, the concentration of •BMPO-OOH radicals was ≥20 times higher than that of •BMPO-OH, whereas at pH 9.0–10.0, the •BMPO-OH radicals prevailed. The •BMPO-OOH/OH radicals effectively cleaved the plasmid DNA. H2S decreased the concentration of •BMPO-OOH/OH radicals, whereas the selenium derivatives 1-methyl-4-(3-(phenylselanyl) propyl) piperazine and 1-methyl-4-(4-(phenylselanyl) butyl) piperazine increased the proportion of •BMPO-OH over the •BMPO-OOH radicals. In conclusion, the presented approach of using KO2 as a source of O2•−/H2O2 and EPR spin trap BMPO for the preparation of •BMPO-OOH/OH radicals in a physiological solution could be useful to study the biological effects of radicals and their interactions with compounds.

Photodegradation of 4-chloronitrobenzene in the presence of aqueous titania suspensions in different gas atmospheres

2011 ◽  
Vol 64 (7) ◽  
pp. 1466-1472 ◽  
Author(s):  
Miaomiao Ye ◽  
Tuqiao Zhang ◽  
Zhiwei Zhu ◽  
Yan Zhang ◽  
Yiping Zhang
Keyword(s):  
Spin Trapping ◽  
Photocatalytic Efficiency ◽  
Liquid Chromatography Mass Spectrometry ◽  
Paramagnetic Resonance ◽  
Mineralization Processes ◽  
Degussa P25 ◽  
Epr Spin Trapping ◽  
Electron Paramagnetic ◽  
Nitrate Anions ◽  
Spin Trapping Technique

The photocatalytic degradation of 4-chloronitrobenzene (4-CNB) was carried out using Degussa P25 TiO2 as photocatalyst in three different gas atmospheres: nitrogen, oxygen, and ozone. The total organic carbon (TOC) and inorganic anions including chloride, nitrite, and nitrate anions were measured to monitor the mineralization processes, while the degradation of 4-CNB and the formation of intermediates were followed by liquid chromatography–mass spectrometry (LC/MS). Results showed that the photocatalytic efficiency followed the order of TiO2/UV/N2 < TiO2/UV/O2 < TiO2/UV/O3, which was further proved by evaluating the reaction activities using electron paramagnetic resonance (EPR) spin trapping technique. Chlorine atom, nitro group and hydrogen atom of the benzene ring could be displaced by hydroxyl radical (•OH) leading to the formation of chloride, nitrite (III) anions and a variety of phenols, then the nitrite (III) anions were further oxidized to nitrate (V) anions. 4-Nitrophenol and 5-chloro-2-nitrophenol were identified and quantified in both of the TiO2/UV/N2 and TiO2/UV/O2 processes while no aromatic intermediates were monitored in the process of TiO2/UV/O3.

First Synthesis of C-Phenyl N-tert-Butyl [15N]nitrone (PBN-15N) for the EPR Spin Trapping Methodology

1996 ◽  
Vol 51 (1) ◽  
pp. 139-143 ◽  
Author(s):  
Yong-Kang Zhang
Keyword(s):  
Hyperfine Splitting ◽  
Spin Trap ◽  
Spin Trapping ◽  
Paramagnetic Resonance ◽  
Tert Butyl ◽  
Hyperfine Splitting Constant ◽  
Percent Increase ◽  
Splitting Constant ◽  
Epr Spin Trapping ◽  
Electron Paramagnetic

As compared to normal PBN, about fifty percent increase of electron paramagnetic resonance (EPR) spin trapping sensitivity has been gained by using a new 100% 15N-enriched spin trap, C-phenyl N-tert-butyl[15N]nitrone (PBN-15N). PBN-15N has been prepared by a convenient four-step route using ammonium-15N chloride as the starting material. This synthetic method produces 2-methyl-2-[15N]nitropropane which is useful for the synthesis of many other PBN-15N type spin traps for the purpose of increasing spin trapping sensitivity. EPR spin trapping with PBN-15N in benzene and in phosphate buffer has been investigated. The 15N hyperfine splitting constant (15N-hfsc) is larger than 14N-hfsc by 40%. The larger 15N-hfsc gives more opportunity to identify different radical addends within the same system.

Evaluation of Methanol Induced Free Radicals in Mice Liver

2017 ◽  
Vol 70 (5) ◽  
pp. 499 ◽  
Author(s):  
Lifang Zhou ◽  
Hongli Zhao ◽  
Tieying Pan ◽  
Adrian Trinchi ◽  
Minbo Lan ◽  
...  
Keyword(s):  
Free Radicals ◽  
Harmful Effect ◽  
Spin Trapping ◽  
Enzyme Assays ◽  
Paramagnetic Resonance ◽  
Mice Liver ◽  
Epr Spin Trapping ◽  
Electron Paramagnetic ◽  
Trapping Agent ◽  
Spin Trapping Technique

Methanol induced oxidative stress (OS) models in mice were successfully established and evaluated by the electron paramagnetic resonance (EPR) spin trapping technique. The capacity for removal of reactive oxygen species (ROS) free radicals by rhubarb and vitamin C (Vc) as candidate materials was also investigated. EPR was employed to determine the free radicals generated from a spin trapping agent, α-phenyl-N-tert-butylnitrone (PBN), that reacted with the ROS. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX), and the level of malondialdehyde (MDA) were also evaluated by enzyme assays. The results indicated that methanol clearly promoted the generation of ROS free radicals in the liver of mice. The activity of SOD and GSH-PX was reduced significantly, although the level of MDA was increased as a result of the harmful effect of methanol. In addition, rhubarb and Vc exhibited a protective effect on the mice liver under acute OS.

scholarly journals Impact of selected polyphenolics on the structural properties of model lipid membranes – a review

2017 ◽  
Vol 6 (2) ◽  
Author(s):  
Nataša P. Ulrih ◽  
Ajda Ota ◽  
Veronika Abram
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Membrane Fluidity ◽  
Phenolic Acids ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Biological Effects ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Model Lipid Membranes ◽  
Electron Paramagnetic

This review is a presentation of data gathered on the interactions of several polyphenolics (i.e., phenolic acids, stilbenes, flavonoids) with lipid bilayers of different lipid compositions. These polyphenolics have been investigated through a combination of fluorescence spectroscopy, electron paramagnetic resonance spectroscopy, and differential scanning calorimetry, to detect changes in membrane fluidity. Among the investigated phenolic acids, the least polar phenolic acid, p-coumaric acid, has the greatest effect on lipid membrane structure. It appears to have a greater ability to cross membranes by passive transport than more polar phenolic acids. On the other hand, among the flavonoids that have been studied, the anthocyanins cyanidin 3-glucoside and its aglycone are inactive. All of the flavonols tested, except for epigallocatechin-3-gallate, promote small decreases in membrane fluidity. Computer simulation of electron paramagnetic resonance spectra for flavonoids indicated two or three regions in the phosphatidylcholine/ phosphatidylserine (2.4:1) membrane with different fluidity characteristics. The effects of the different flavonoids are correlated to their structural characteristics, whereby even the difference in one -OH group can be important, as can the number of H-bonds they form. The role of membrane composition and flavonoid structure in these interactions with lipid membranes are of great importance for bioavailability of these compounds and for their biological effects in an organism

scholarly journals Lawsone Derivatives as Efficient Photopolymerizable Initiators for Free-Radical, Cationic Photopolymerizations, and Thiol—Ene Reactions

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2015
Author(s):  
Christine Elian ◽  
Vlasta Brezová ◽  
Pauline Sautrot-Ba ◽  
Martin Breza ◽  
Davy-Louis Versace
Keyword(s):  
Free Radical ◽  
Paramagnetic Resonance ◽  
Ene Reactions ◽  
Ene Reaction ◽  
Free Radical Photopolymerization ◽  
Abstraction Reaction ◽  
Epoxy Monomer ◽  
Iodonium Salt ◽  
Epr Spin Trapping ◽  
Electron Paramagnetic

Two new photopolymerizable vinyl (2-(allyloxy) 1,4-naphthoquinone, HNQA) and epoxy (2-(oxiran-2yl methoxy) 1,4-naphthoquinone, HNQE) photoinitiators derived from lawsone were designed in this paper. These new photoinitiators can be used as one-component photoinitiating systems for the free-radical photopolymerization of acrylate bio-based monomer without the addition of any co-initiators. As highlighted by the electron paramagnetic resonance (EPR) spin-trapping results, the formation of carbon-centered radicals from an intermolecular H abstraction reaction was evidenced and can act as initiating species. Interestingly, the introduction of iodonium salt (Iod) used as a co-initiator has led to (1) the cationic photopolymerization of epoxy monomer with high final conversions and (2) an increase of the rates of free-radical polymerization of the acrylate bio-based monomer; we also demonstrated the concomitant thiol–ene reaction and cationic photopolymerizations of a limonene 1,2 epoxide/thiol blend mixture with the HNQA/Iod photoinitiating system.

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