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Published on: June 10, 2022
A cobalt-based tetrazolium salts reduction test to assay polyphenols
Erez Koren1, Ron Kohen, Isaac Ginsburg
1The Faculty of Dental Medicine, Institute for Dental Sciences, Hebrew University, Hadassah Medical Center, Jerusalem 91120, Israel.
Journal of Agricultural and Food Chemistry
|September 3, 2009
Summary
A new assay measures polyphenol antioxidant capacity by detecting their ability to chelate cobalt(II). This method effectively quanties polyphenols in various sources, offering a sensitive alternative to existing antioxidant assays.
Area of Science:
- Analytical Chemistry
- Biochemistry
- Food Science
Background:
- Polyphenols are key antioxidants with diverse health benefits.
- Accurate quantification of polyphenol antioxidant capacity is crucial for food and health research.
- Existing antioxidant assays have limitations in specificity and scope.
Purpose of the Study:
- To develop a novel assay for measuring the cobalt(II) chelating capacity of polyphenols.
- To establish a method for quantifying polyphenol antioxidant activity based on cobalt chelation.
- To compare the sensitivity and applicability of the new assay with existing antioxidant assays.
Main Methods:
- Utilized tetrazolium salts (NBT, MTT, XTT) reduction to formazan products.
- Initiated salt reduction using a cocktail of cobalt(II), hydrogen peroxide, and selenium(IV).
- Measured the inhibition of formazan production by polyphenols chelating cobalt(II) in a dose-dependent manner.
Main Results:
- The novel assay demonstrated that cobalt(II) is essential for tetrazolium salt reduction.
- A wide range of antioxidant polyphenols and fruit beverages effectively chelated cobalt(II).
- The assay showed sensitivity comparable to FRAP, DPPH, and chemiluminescence assays, but is unsuitable for low molecular weight antioxidants without chelating properties.
Conclusions:
- A new, sensitive, and practical assay for quantifying polyphenol antioxidant capacity based on cobalt(II) chelation has been developed.
- This method offers a valuable tool for assessing polyphenol content in various natural sources.
- The assay's specificity for chelating compounds makes it distinct from methods measuring other antioxidant mechanisms.
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