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A kinetic-based stopped-flow DPPH• method.
- Source :
-
Scientific Reports . 5/10/2023, Vol. 13 Issue 1, p1-8. 8p. - Publication Year :
- 2023
-
Abstract
- The reaction kinetics of antioxidants with free radicals is crucial to screen their functionality. However, studying antioxidant-radical interactions is very challenging for fast electron-donor substances, such as ascorbic acid, because the reaction ends in a few seconds. Accordingly, this work proposes a rapid and sensitive method for the determination of the absolute rate constant of the reaction between fast antioxidants and DPPH•. The method consists of a stopped-flow spectrophotometric system, which monitors the decay of DPPH• during its interaction with antioxidants. A kinetic-based reaction mechanism fits the experimental data. Kinetic parameters include a second order kinetics (k1) and, depending on the type of antioxidant, a side reaction (k2). Ascorbic acid was the fastest antioxidant (k1 = 21,100 ± 570 M−1 s−1) in comparison with other eleven phenols, showing k1 values from 45 to 3070 M−1 s−1. Compounds like catechin, epicatechin, quercetin, rutin, and tannic, ellagic and syringic acids presented a side reaction (k2 from 15 to 60 M−1 s−1). Among seven fruit juices, strawberry was the fastest, while red plum the slowest. Overall, the proposed kinetic-based DPPH• method is simple, rapid, and suitable for studying the activity and capacity of different molecules, and food samples rich in fast antioxidants, like fruit juices. [ABSTRACT FROM AUTHOR]
- Subjects :
- *SYRINGIC acid
*VITAMIN C
*FRUIT juices
*ELLAGIC acid
*CHEMICAL kinetics
*EPICATECHIN
Subjects
Details
- Language :
- English
- ISSN :
- 20452322
- Volume :
- 13
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Scientific Reports
- Publication Type :
- Academic Journal
- Accession number :
- 163725363
- Full Text :
- https://doi.org/10.1038/s41598-023-34382-7