Helpful!

Several methods have been developed to measure the total antioxidant capacity of a biological sample. The use of peroxyl or hydroxyl radicals as pro-oxidants in the oxygen radical absorbance capacity (ORAC) assay makes it different and unique from the assays that involve oxidants that are not necessarily pro-oxidants. An improvement in quantitation is achieved in the ORAC assay by taking the reaction between substrate and free radicals to completion and using an area-under-curve technique for quantitation compared to the assays that measure a lag phase. The interpretation of the changes in plasma or serum antioxidant capacity becomes complicated by the different methods used in detecting these changes. The interpretation also depends upon the conditions under which the antioxidant capacity is determined because the measurement reflects outcomes in a dynamic system. An increased antioxidant capacity in plasma or serum may not necessarily be a desirable condition if it reflects a response to increased oxidative stress. Similarly, a decrease in plasma or serum antioxidant capacity may not necessarily be an undesirable condition if the measurement reflects decreased production of reactive species. Because of these complications, no single measurement of antioxidant status is going to be sufficient, but a “battery” of measurements, many of which will be described in Forum articles, will be necessary to adequately assess oxidative stress in biological systems.

 REFERENCE:

Trolox equivalent antioxidant capacity of different geometrical isomers of α-carotene, β-carotene, lycopene, and zeaxanthin

V Böhmet al  Journal of Agricultural …, 2002 - ACS Publications

... Carotenoids as biological antioxidants are currently the focus of numerous ... the antioxidant activity of different carotenoids, using the TEAC (Trolox equivalent antioxidant capacity) test. ... Figure 1 Trolox equivalent antioxidant capacities (TEAC) of (9Z)-α-carotene, (13Z)-α-carotene ...

Thank Mr @Ram Nath Mishra, but my condition does not support me to do another assay and I find some advantage in TEAC assay. I'm finding the progress for TEAC assay but in many article the progress was shortened. So it's hard to conduct the experiment...

Anyway thank for your help.

Hy Dr. Nguyen, we used the TEAC assay in some studies, e.g. http://www.ncbi.nlm.nih.gov/pubmed/17572100. Hope this will help. Anyway feel free to ask for more detail.

Best!

Article Estrogenic activity of 7-hydroxymatairesinol potassium aceta...

Hi there, 

I would like to ask about the calculation of the Trolox Equivalent. I had the standard curve, but I am stuck in how to calculate the TE of the sample.

Many thanks,

Hi,

The link given below, is a beautiful piece to understand calculation of TEAC. I think it will help you.

https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma/Bulletin/1/mak187bul.pdf