Oxidative Stress Feature
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Oxidative Stress Feature
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Oxidative stress occurs when the ability of an organism to effectively remove free radicals (eg reactive oxygen species) is insufficient to reduce the generation of reactive intermediates or is unable to repair the resulting cellular damage.

Free radicals are so reactive and short-lived that direct measurement is usually not possible. However, hundreds of biomolecules are known to be derived from the interaction of free radicals with biomolecules. Assays for some of these oxidative stress biomarkers, as well as assays for several of the body’s antioxidant defence mechanisms, have been widely used. Although there are numerous tools on the market, a small number of oxidised lipids, as well as by products of DNA and protein oxidation, have withstood the test of time. Oxford Biomedical Research provides researchers with straightforward, reliable assays for oxidative stress biomarkers and for the measurement of the antioxidant capacity of biological fluids.
Products for Oxidative Stress Measurement
Go to GSH/GSSG Assays GSH/GSSG Assays
Go to Isoprostane Assays Isoprostane Assays
Go to TBARS Assays TBARS Assays
Go to Assay Prices Assay Prices
Literature and Technical Requests
Technical Literature Request Request Technical Literature
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Assay Protocols
Size File
GSH/GSSG Assay (Microplate) 497KB Download Protocol
GSH/GSSG Assay (Cuvette) 494KB Download Protocol
Urinary Isoprostane EIA Assay 325KB Download Protocol
Isoprostane EIA Assay 193KB Download Protocol
TBARS Assay (Colorimetric, microplate) 1.0MB Download Protocol
TBARS Assay (Colorimetric/Fluorometric, cuvette) 412KB Download Protocol
Antioxidant Measurement
Total Antioxidant Power Assay
Go to Oxford Biomedical Research websiteImproved Total Antioxidant Power Assay provides a broad dynamic range and is suitable for an expanded range of sample types. This assay provides accurate determination of the total antioxidant activity in a sample that results from the combined activities of the  constituents, including vitamins, proteins, glutathione etc of the sample.

The assay works with both hydrophobic and hydrophilic compounds and can be used on many sample types including serum, tissue culture supernatant (TCS), foods etc.
Go to Oxford Biomedical Research websiteReduced glutathione (GSH) is a tripeptide (γ-glutamylcysteinylglycine) that contains a free thiol group.  GSH is a major tissue antioxidant that provides reducing equivalents for the glutathione peroxidase (GPx) catalysed reduction of lipid hydroperoxides to their corresponding alcohols and hydrogen peroxide to water.

When cells are exposed to increased levels of oxidative stress, GSSG will accumulate and the ratio of GSH to GSSG will decrease.  Therefore, the determination of the GSH/GSSG ratio and the quantification of GSSG are useful indicators of oxidative stress levels in cells and tissues.

Assay Principle
Scavenging of Free Thiols:This assay employs a pyridine derivative as a thiol-scavenging reagent thereby overcoming the shortfalls of both prior methods.  At the concentration employed in the assay, this derivative reacts quickly with GSH but does not interfere with the glutathione reductase (GR) activity. Reaction of the scavanger with a thiol forms a pyridinium salt.

Thiol Quantification: The quantitative determination of the total amount of glutathione (GSH + GSSG) employs the enzymatic method. Briefly, the reaction of GSH with Ellman’s reagent (5,5’-dithiobis-2-nitrobenzoic acid (DTNB)) gives rise to a product that can be quantified spectrophotometrically at 412 nm.  This reaction is used to measure the reduction of GSSG to GSH.  The rate of the reaction is proportional to the GSH and GSSG concentration.
Isoprostane Measurement
Isoprostane Assays
Go to Oxford Biomedical Research websiteThere is increasing evidence that isoprostanes play a causative role in artherogenesis and are a novel class of prostaglandin-like compounds which are produced following the peroxidation of lipoproteins.  In normal humans, levels of the isoprostane 15-F2t-Isoprostane α (formerly 8-epi-Prostaglandin F2) range from 5-50 pg/mL plasma and 500 to 3000 pg/g urinary creatinine, respectively. The in vivo concentration of F2- isoprostanes increases dramatically in animal models of lipid peroxidation. Measurement of isoprostane concentrations is likely to have significant diagnostic potential for assessment of oxidative stress and several disorders such as atherosclerosis, rheumatoid arthritis, and carcinogenesis. Urine and tissue culture supernatants can usually be assayed directly by diluting them with the EIA buffer using Urinary Isoprostane EIA kit (EA85). Alternatively, 15-F2t-Isoprostane α can be extracted from plasma using Sep-Pak columns following the protocol provided with the kit.
Oxidised Lipid Measurment
TBARS Assays
Go to Oxford Biomedical Research websiteThe TBARS (Thiobarbituric Acid Reactive substances) assay was developed for the measurement of MDA (malondialdehyde) production via lipid peroxidation and is a well established and widely used method for assessment of oxidative damage. However, as typically performed, the traditional method for TBARS analysis is often criticised for lack of specificity and sensitivity. Indeed, currently available TBARS assays require boiling the sample with strong acid which also generates interfering chromophores.

Oxford Biomedical Research has recently developed a room temperature TBARS method that eliminates the requirement for a high concentration of a strong acid and cuts reaction time in half. By running the assay at room temperature, low levels of interfering substances are generated. This results in more accurate, precise and reliable TBARS measurements.
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Assay Prices
Item Code1 Product Description Samples2 Prices3
OB-GT40 GSH/GSSG Assay (Microplate) 40/kit $880.00
OB-GT35 GSH/GSSG Assay (Cuvette) 100/kit $820.00
OB-EA85 Urinary Isoprostane EIA Assay 39/kit $830.00
OB-EA85.5 Urinary Isoprostane EIA Assay (5 kit pack) 5 x 39/kit $2,200.00
OB-EA84 Isoprostane EIA Assay 39/kit $860.00
OB-FR35 Enhanced TBARS Assay, (Colormetric/Fluorometric) Cuvette Format 100/kit Request P&A
OB-FR40 Enhanced TBARS Assay, (Colorimetric) Microplate Format 40/kit Request P&A
OB-FR40.5 Enhanced TBARS Assay, (Colorimetric) Microplate Format (5 kit pack) 5 x 40/kit Request P&A
OB-FR45 Enhanced TBARS Assay, (Fluorometric) Microplate Format 40/kit Request P&A
Note 1: Click on the Item Code to go to Online Prices and Ordering
Note 2: Total number of samples per kit according to the protocol. See assay protocol for details of the number of replicates per sample/standard
Note 3: Prices are exclusive of GST and local packing, handling and delivery charges
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