Determination of the antioxidant capacity in blood.
BACKGROUND
A vast amount of scientific research is directed towards the beneficial effects of antioxidants on health. For this reason, several assays have been developed to determine the total antioxidant capacity of blood.


METHODS
In this study two procedures based on the use of the green-blue 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS(*+)) were compared. In the first (commercially available) procedure, ABTS(*+) was generated in the presence of the blood sample. In the second procedure, referred to as the decolorization assay, antioxidants react with preformed ABTS(*+).


RESULTS
It was found that the first procedure leads to greater underestimation of the actual antioxidant capacity and is more prone to artifacts than the second procedure. Therefore, only the latter procedure was evaluated in detail and it appeared that (i) plasma is preferred over serum, (ii) the high background produced by albumin can be circumvented by deproteination, (iii) samples can be stored at -80 degrees C for 12 months, and (iv) the assay has high precision. Due to poor linearity, the procedure has to be standardized to allow sample comparison.


CONCLUSIONS
The decolorization assay is a reliable and robust assay that can be applied routinely to predict the antioxidant capacity of blood.
Fischer
Marc A J G
MA
Department of Pharmacology and Toxicology, Faculty of Medicine, Maastricht University, Maastricht, The Netherlands. m.fischer@farmaco.unimaas.nl
Gransier
Theo J M
TJ
Beckers
Lenie M G
LM
Bekers
Otto
O
Bast
Aalt
A
Haenen
Guido R M M
GR
D000975:Antioxidants / Q000378:metabolism*; D052160:Benzothiazoles; D001769:Blood / Q000378:metabolism*; D001774:Blood Chemical Analysis / Q000379:methods / Q000706:statistics & numerical data; D005609:Free Radicals / Q000737:chemistry; D006801:Humans; D066298:In Vitro Techniques; D010949:Plasma / Q000378:metabolism; D013451:Sulfonic Acids / Q000737:chemistry
D000975:Antioxidants; D052160:Benzothiazoles; D005609:Free Radicals; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid