Theoretical studies on the spin trapping of the 2-chloro-5-hydroxy-1,4-benzoquinone radical by 5,5-dimethyl-1-pyrroline N-oxide (DMPO): the identification of the C–O bonding spin adduct

RSC Advances ◽  
2016 ◽  
Vol 6 (53) ◽  
pp. 48099-48108 ◽  
Author(s):  
Wenling Feng ◽  
Cong Ren ◽  
Weihua Wang ◽  
Chao Guo ◽  
Qiao Sun ◽  
...  
Keyword(s):  
Spin Trapping ◽  
Spin Adduct ◽  
Theoretical Studies

The C–O bonding spin adduct has been identified in the spin trapping of 2-chloro-5-hydroxy-1,4-benzoquinone radical by DMPO.

Spin trapping by use of nitrosodurene and its derivatives

1982 ◽  
Vol 60 (12) ◽  
pp. 1532-1541 ◽  
Author(s):  
Ryusei Konaka ◽  
Shigeru Terabe ◽  
Taiichi Mizuta ◽  
Shigeru Sakata
Keyword(s):  
Hydrogen Peroxide ◽  
Esr Spectra ◽  
Spin Trapping ◽  
Nitroso Compounds ◽  
Spin Adduct ◽  
Spin Traps ◽  
Spectral Pattern ◽  
Alkyl Radicals ◽  
Alkyl Hydroperoxides ◽  
Tert Butyl Hydroperoxide

In spin trapping the N-methyl-N-phenylaminomethyl radical with nitrosodurene, an esr spectmm exhibiting line width alternation was observed despite the normal spectral pattern found with the use of nitroso-tert-butane. Nitrosodurene derivatives, N-duryl nitrone and methyl N-duryl nitrone, have been revealed to be other excellent spin traps for the N-, 0-, and S-centered radicals. Spin adducts of these radicals, which can be independently prepared by spin trapping with nitrosodurene, are stable and can be easily discriminated by large differences in β-hydrogen splittings or characteristic patterns. Methyl N-duryl nitrone reacted with tert-butyl hydroperoxide to give a spin adduct which could be clearly distinguished in the esr spectra from the tert-butoxy adducts prepared independently from other sources. Accordingly, it seems to be the tert-butylperoxy adduct. Similarly, hydrogen peroxide gave a different spectrum from the hydroxy adducts. Alkyl hydroperoxides caused molecule-induced homolysis with the nitroso compounds to produce alkoxy adducts of the respective nitroso compounds. Some phenyl and duryl alkoxy nitroxides undergo decomposition to give alkyl radicals which were trapped by the nitroso compounds.

scholarly journals Hemoglobin Toxicity in Experimental Bacterial Peritonitis Is Due to Production of Reactive Oxygen Species

1999 ◽  
Vol 6 (6) ◽  
pp. 938-945 ◽  
Author(s):  
Yeong-Min Yoo ◽  
Ki-Mo Kim ◽  
Sung-Soo Kim ◽  
Jeong-A Han ◽  
Ho-Zoo Lea ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Peritoneal Fluid ◽  
Oxygen Radicals ◽  
Lethal Effect ◽  
Spin Trapping ◽  
Spin Adduct ◽  
E Coli ◽  
Bacterial Peritonitis ◽  
Bacterial Proliferation ◽  
Iron Administration

ABSTRACT Hemoglobin (Hb) is a toxic molecule responsible for the extreme lethality associated with experimental Escherichia coliperitonitis, but the mechanism has yet to be elucidated. Hb, but not globin, showed toxic effects in a live E. coli model but not in a model using killed E. coli. Methemoglobin, hematin, and the well-known Fenton reagents iron and iron-EDTA demonstrated the same lethal effect in E. coli peritonitis as Hb, while the addition of the Fenton inhibitors desferrioxamine (DF) and diethylenetriamine pentaacetate removed most of the cytotoxic activity of iron. Administration of a combined dose of superoxide dismutase and catalase minimized the action of Hb and iron-EDTA, suggesting that both O2 ⋅ − and H2O2 are involved in the toxic action of Hb in this rat model. The combination of the antioxidative enzymes and DF further suppressed iron-mediated lethality. An electron spin resonance technique with the spin-trapping reagent 5,5-dimethyl-1-pyroline-N-oxide (DMPO) showed O2 ⋅ − generation in the peritoneal fluid of rats injected with E. coli alone or E. coliplus iron-DF, and ⋅OH generation was detected in the peritoneal fluid of the rats injected with iron-EDTA. Hb did not show any spin adduct of oxygen radicals, suggesting that Hb produces non-spin-trapping radical ferryl ion, which decayed the spin adduct of DMPO. In the presence of Hb or iron-EDTA, O2 −-generating activity and viability of phagocytes decreased, whereas lipid peroxidation of peritoneal phagocytes increased. Generation of oxygen radicals and lipid peroxidation did not differ in the live and dead bacterial models. Bacterial numbers in the peritoneal cavity and blood were markedly increased in the live bacterial model with Hb and iron-EDTA. The Fenton inhibitor iron-DF prevented the loss of phagocyte function, lipid peroxidation, and bacterial proliferation. These results led us to conclude that the lethal toxicity of Hb in bacterial peritonitis is associated with a Fenton-type reaction, the products of which decrease phagocyte viability, through the induction of lipid peroxidation, allowing bacterial proliferation and resulting in mortality.

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