An in Vitro Hydroxyl Radical Generation Assay for Microdialysis Sampling Calibration

Chen, Rui; Stenken, Julie A.

doi:10.1006/abio.2001.5702

Cited by 13 publications

(10 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One of the most important properties of an ideal • OH scavenging capacity assay is a source of • OH without interference from other ROS. There are five categories of • OH-generating systems described by previous researchers based on the reaction used for radical generation including (1) the classic Fenton reaction including the pH 7.4 buffered ferric iron-EDTA/ ascorbic acid/H 2 O 2 system used in the "deoxyribose assay" (17) and several alternatives (18)(19)(20); (2) the superoxide-driven Fenton reaction known also as the Haber-Wilstatter or the Haber-Weiss reaction (21)(22)(23)(24) using the hypoxanthine/xanthine oxidase system to generate • OH and its alternative proposed by Yang and Guo (25); (3) use of "Fenton-like" reagents to produce • OH including the Co(II)/H 2 O 2 (26) and the Cu(II)/H 2 O 2 systems (27,28); (4) pulse radiolysis of water to generate • OH (15); and (5) "photo-Fenton" systems using photosensitizers to create • OH (29). The radiolysis and photosensitization systems do not measure the • OH scavenging capacity under physiologically relevant conditions.…”

Section: Introductionmentioning

confidence: 99%

Novel Fluorometric Assay for Hydroxyl Radical Scavenging Capacity (HOSC) Estimation

Moore

Yin

2006

J. Agric. Food Chem.

136

130

View full text Add to dashboard Cite

A novel fluorometric method was developed and validated for hydroxyl radical scavenging capacity (HOSC) estimation using fluorescein as the probe. A constant flux of pure hydroxyl radical is generated under physiological pH using a Fenton-like Fe3+/H2O2 reaction. The generation of pure hydroxyl radicals under the experimental conditions was evaluated and confirmed using electron spin resonance with DMPO spin-trapping measurements. The hydroxyl radical scavenging capacity of a selected antioxidant sample is quantified by measuring the area under the fluorescence decay curve with or without the presence of the antioxidant and expressed as Trolox equivalents per unit of the antioxidant. The assay may be performed using a plate reader with a fluorescence detector for high-throughput measurements. The assay was validated for linearity, precision, accuracy, reproducibility, and its correlation with a popular peroxyl radical scavenging capacity assay using selected pure antioxidant compounds and botanical extracts. This method may provide researchers in the food, nutrition, and medical fields an easy to use protocol to evaluate free radical scavenging capacity of pure antioxidants and natural extracts in vitro against the very reactive hydroxyl radical, which may be linked to numerous degenerative diseases and conditions.

show abstract

Section: Introductionmentioning

confidence: 99%

Novel Fluorometric Assay for Hydroxyl Radical Scavenging Capacity (HOSC) Estimation

Moore

Yin

2006

J. Agric. Food Chem.

136

130

View full text Add to dashboard Cite

show abstract

“…The ligand 3,4-dihydroxybenzoic acid (3,4-DHBA) (Figure 1), 1 , is known to be produced in the reaction of radicals, which are formed in pathophysiological cases (e.g., ischemic stroke [1, 2], traumatic brain injury [3], and Huntington's disease [4]), the 4-hydroxybenzoic acid or salicylic acid acting as radical-trapping agent [5]. It is used for assisting the Fenton reaction in effluent treatment [6] and in dechlorination of polychlorinated dioxins [7].…”

Section: Introductionmentioning

confidence: 99%

Reaction of Chromium(III) with 3,4‐Dihydroxybenzoic Acid: Kinetics and Mechanism in Weak Acidic Aqueous Solutions

Zavitsanos

Tampouris²,

Petrou³

2008

Bioinorganic Chemistry and Applications

View full text Add to dashboard Cite

The interactions between chromium(III) and 3,4-dihydroxybenzoic acid (3,4-DHBA) were studied resulting in the formation of oxygen-bonded complexes upon substitution of water molecules in the chromium(III) coordination sphere. The experimental results show that the reaction takes place in at least three stages, involving various intermediates. The first stage was found to be linearly dependent on ligand concentration k 1(obs)′ = k 0 + k 1(obs)[3, 4-DHBA], and the corresponding activation parameters were calculated as follows: ΔH 1(obs) ≠ = 51.2 ± 11.5 kJ mol−1, ΔS 1(obs) ≠ = −97.3 ± 28.9 J mol−1 K−1 (composite activation parameters) . The second and third stages, which are kinetically indistinguishable, do not depend on the concentrations of ligand and chromium(III), accounting for isomerization and chelation processes, respectively. The corresponding activation parameters are ΔH 2(obs) ≠ = 44.5 ± 5.0 kJ mol−1, ΔS 2(obs) ≠ = −175.8 ± 70.3 J mol−1 K−1. The observed stages are proposed to proceed via interchange dissociative (I d, first stage) and associative (second and third stages) mechanisms. The reactions are accompanied by proton release, as is shown by the pH decrease.

show abstract

“…The negligible presence of transition metal in the buffers was determined using a well-known ascorbic acid assay that we have previously described in our work with hydroxyl radical. 25,48 A chelating agent (200 µM DTPA) was always present in the X/XO mixture. When 5 mM PP-H was delivered through the microdialysis probe, the oxidation was observed initially at 30 min and the rate for the following 30 min was ∼0.03 µM/min, which is less than that reported by Rosen for a similar hydroxylamine.…”

Section: Acknowledgmentmentioning

confidence: 99%

“…24 The recovery and delivery experiments with PP-H were originally performed in stirred media since our previous experience HO • trapping using 4-hydroxybenzoic acid and the X/XO enzyme system in a quiescent medium resulted in poor reproducibility among three replicate experiments. 25 The reproducibility for O 2 •detection using PP-H was significantly improved as compared to HO • trapping. The reasons for these differences are likely caused by the lower reactivity of O 2 •as compared to HO • toward different components in the in vitro system.…”

Section: Acknowledgmentmentioning

confidence: 99%

See 1 more Smart Citation

Microdialysis Sampling Combined with Electron Spin Resonance for Superoxide Radical Detection in Microliter Samples

2004

Self Cite

View full text Add to dashboard Cite

Quantitation of superoxide radical (O2.-) production at the site of radical generation remains challenging. Microdialysis sampling is an advantageous tool for sampling from localized environments. It is difficult to combine electron spin resonance (ESR) spin traps with microdialysis because O2.- adducts with common nitrone spin traps have shorter half-lives than typical microdialysis collection times. Furthermore, typical dialysate samples (5-15 microL) suffer significant sensitivity loss when diluted for detection in a conventional ESR flat cell (200 microL). To overcome these difficulties, a cyclic hydroxylamine, 1-hydroxy-4-phosphonooxy-2,2,6,6-tetramethylpiperidine (PP-H), which produces a stable nitroxide radical (PP.) product upon reaction with O2.- was employed. Capillary cells (1.4 microL effective volume) coupled with a loop-gap resonator were utilized to measure PP. in microliter microdialysis samples (LOD 0.36 pmol). A xanthine/xanthine oxidase (X/XO) model system provided sustained O2.- production. When PP-H was included in the X/XO medium external to the microdialysis probe, a relative recovery of 22.1 +/- 1.1 and 57.2 +/- 5.7% for PP. was achieved at perfusion fluid flow rates of 0.5 and 1.0 microL/min, respectively. The respiratory burst in interferon-gamma and zymosan-stimulated RAW 264.7 macrophages was also investigated.

show abstract

An in Vitro Hydroxyl Radical Generation Assay for Microdialysis Sampling Calibration

Cited by 13 publications

References 34 publications

Novel Fluorometric Assay for Hydroxyl Radical Scavenging Capacity (HOSC) Estimation

Novel Fluorometric Assay for Hydroxyl Radical Scavenging Capacity (HOSC) Estimation

Reaction of Chromium(III) with 3,4‐Dihydroxybenzoic Acid: Kinetics and Mechanism in Weak Acidic Aqueous Solutions

Microdialysis Sampling Combined with Electron Spin Resonance for Superoxide Radical Detection in Microliter Samples

Contact Info

Product

Resources

About