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ABTS/PP Decolorization Assay of Antioxidant Capacity Reaction Pathways
Igor R Ilyasov1, Vladimir L Beloborodov1, Irina A Selivanova1
1Department of Chemistry, Sechenov First Moscow State Medical University, Trubetskaya Str. 8/2, 119991 Moscow, Russia.
International Journal of Molecular Sciences
|February 13, 2020
Summary
The ABTS assay for antioxidant capacity has two main reaction pathways, involving coupling or direct oxidation. Coupling is specific to certain antioxidants and can affect results, but the assay remains useful with reservations.
Area of Science:
- Analytical Chemistry
- Biochemistry
Background:
- The 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation assay is widely used for determining antioxidant capacity.
- It is frequently compared to the DPPH assay in scientific literature.
Purpose of the Study:
- To clarify the reaction mechanisms of the ABTS/potassium persulfate decolorization assay.
- To understand the role of coupling reactions in antioxidant capacity measurements.
Main Methods:
- Literature review and comparative analysis of existing studies on ABTS assay reaction pathways.
- Identification of key antioxidant reaction products and marker compounds.
Main Results:
- Two primary reaction pathways were identified: antioxidant coupling with ABTS radical cation and direct oxidation without coupling.
- Phenolic antioxidants, in particular, can form coupling adducts.
- These adducts can degrade into marker compounds like 3-ethyl-2-oxo-1,3-benzothiazoline-6-sulfonate and 3-ethyl-2-imino-1,3-benzothiazoline-6-sulfonate.
Conclusions:
- The contribution of coupling reactions to total antioxidant capacity needs further investigation.
- The specificity and relevance of oxidation products may influence the interpretation of ABTS assay results.
- ABTS assays are recommended with caution, especially for monitoring antioxidant systems during storage and processing.
