[7] Methods for the study of superoxide chemistry in nonaqueous solutions

Valentine, Joan Selverstone; Miksztal, Andrew R.; Sawyer, Donald T.

doi:10.1016/s0076-6879(84)05010-2

Cited by 72 publications

(43 citation statements)

References 26 publications

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“…DMPO with O 2 gives an adduct nitroxide whose ESR spectrum could be detected at room temperature. 21 Superoxide anion radicals were generated by two different systems: (1) according to the procedure given by Valentine et al, 22 (2) using the hypoxanthine/xanthine oxidase reaction. 23 In the first method 60 mg 18-crown-6 was dissolved in 10 ml dry DMSO and then 7 mg KO 2 was added quickly to avoid contact with air humidity.…”

Section: Methodsmentioning

confidence: 99%

Scavenging effects of phenolic compounds on reactive oxygen species

et al. 2007

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Phenolic compounds are widely present in plants and they have received considerable attention due to their antioxidant property. In this article we report the results of a study of the reactivity of 10 selected phenolics (sesamol, three phenolic acids, three flavonols, one flavone, and two flavanones) with superoxide anion radical (O(2) (*)), hydroxyl radical (HO(*)) and singlet oxygen ((1)O(2)). The following generators of reactive oxygen species were used: 18-crown-6/KO(2)/dimethylsulfoxide (DMSO) or hypoxanthine/xanthine oxidase as sources of O(2) (*), the Fenton reaction carried out in a sodium trifluoroacetate (pH 6.15) for HO(*), and a mixture of alkaline aqueous H(2)O(2) and cobalt ions for (1)O(2). We have employed chemiluminescence, electron spin resonance spin trapping, and spectrophotometry techniques to examine an antioxidative property. All tested compounds acted as scavengers of various reactive oxygen species. The reactivity indexes (beta) for the reaction of the phenolic compounds with HO(*) were calculated.

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Section: Methodsmentioning

confidence: 99%

Scavenging effects of phenolic compounds on reactive oxygen species

et al. 2007

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“…A known standard curve of superoxide radical (using potassium superoxide, KO 2 , Sigma Chemical Co.) was used (Valentine et al, 1984) to determine the concentrations. The specific intracellular ROS level was obtained by normalizing the intracellular ROS concentrations with the corresponding viable cell concentrations.…”

Section: Determination Of Specific Intracellular Ros (Siros)mentioning

confidence: 99%

Reactive oxygen species induced by shear stress mediate cell death in Bacillus subtilis

Sahoo

Rao

Suraishkumar

2006

Biotech & Bioengineering

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Exposure of Bacillus subtilis to a shear rate of 1,482/s leads to a rapid loss of cell viability after 10 h of growth. Biochemical and molecular evidences provided below strongly suggest that cell death under high shear results from an apoptosis-like process similar to that described in eukaryotes, with activation of a caspase-3-like protease (C(3)LP) followed by DNA fragmentation. Shear stress leads to an increase in specific intracellular reactive oxygen species (siROS), possibly through activation of NADH oxidase (NOX). The formation of siROS precedes the activation of C(3)LP and DNA fragmentation, thus establishing siROS as the molecular link between shear stress and apoptosis-like cell death. A model is proposed in which NOX is viewed as being strategically placed on the plasma membrane of B. subtilis that senses and converts a mechanical force arising from shear stress into a chemical signal leading to activation of C(3)LP, DNA fragmentation, and thus, apoptosis-like cell death.

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“…Superoxide anion radical (O 2 •− ) was prepared according to the following procedure: 60 mg 18-crown-6 was dissolved in 10 mL dry DMSO and then 7 mg KO 2 was added quickly to avoid contact with air humidity (11). The mixture was stirred with a magnetic stirrer for 1 h to give a pale yellow solution of 10 mmol/L O 2…”

Section: Methodsmentioning

confidence: 99%

Anti‐oxidant and pro‐oxidant behaviour of bucillamine

et al. 2006

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Bucillamine (BUC) is used clinically for the treatment of rheumatoid arthritis. Some of the pharmacological action of BUC has been reported as being dependent on the production of reactive oxygen species (ROS). In this paper the reactivity of BUC with superoxide anion radical (O(2) (*-)) generated from potassium superoxide/18-crown-6 ether dissolved in DMSO, hydroxyl radical (HO(*)) produced in the Cu(2+)-H(2)O(2) reaction, peroxyl radical (ROO(*)) from 2,2'-azobis (2-amidino-propane) dichloride decomposition, and singlet oxygen ((1)O(2)) from a mixture of alkaline aqueous H(2)O(2) and acetonitrile, have been investigated. Chemiluminescence, fluorescence, electron paramagnetic resonance (EPR) spin-trapping techniques and the deoxyribose and oxygen radical absorbance capacity towards ROO(*) (ORAC(ROO)) assays were used to elucidate the anti- and pro-oxidative behaviours of BUC towards ROS. The results indicated that BUC efficiently inhibited chemiluminescence from the O(2) (*-)-generating system at relatively high concentrations (0.5-2 mmol/L); however, at lower concentrations (<0.5 mmol/L) the drug enhanced light emission. The behaviour of BUC was correlated with a capacity to decrease the chemiluminescence signal from the Cu(2+)-H(2)O(2) system; scavenging HO(*) was effective only at high concentrations (1-2 mmol/L) of the drug. Bucillamine also prevented deoxyribose degradation induced by HO(*) in a dose-dependent manner, reaching maximal inhibition (24.5%) at a relative high concentration (1.54 mmol/L). Moreover, BUC reacts with ROO(*); the relative ORAC(ROO) was found to be 0.34 micromol/L Trolox equivalents/micromol sample. The drug showed quenching of (1)O(2)-dependent 2,2,6,6-tetramethylpiperidine-N-oxide radical formation from 2,2,6,6-tetramethyl-piperidine (e.g. 90% inhibition was found at 1 mmol/L concentration). The results showed that BUC may directly scavenge ROS or inhibit reactions generating them. However, the drug may have pro-oxidant activity under some reaction conditions.

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[7] Methods for the study of superoxide chemistry in nonaqueous solutions

Cited by 72 publications

References 26 publications

Scavenging effects of phenolic compounds on reactive oxygen species

Scavenging effects of phenolic compounds on reactive oxygen species

Reactive oxygen species induced by shear stress mediate cell death in Bacillus subtilis

Anti‐oxidant and pro‐oxidant behaviour of bucillamine

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