Kinetics of the reactions of catechins with hypochlorite, peroxynitrite, and amino acid–derived peroxyl‐ radicals

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dc.contributor.authorGebicka, Lidia
dc.contributor.authorGebicki, Jerzy L.
dc.date.accessioned2019-07-29T06:57:29Z
dc.date.available2019-07-29T06:57:29Z
dc.date.issued2019-06-01
dc.description.abstractCatechins, one of the class of flavonoids, are known as very efficient antioxidants. Here we investigated the kinetics of the reactions of three catechins, namely, catechin, epigallocatechin, and epigallocatechin gallate (EGCG) with some oxidants, which are formed in vivo under oxidative stress, hypochlorite, peroxynitrite, and amino acid peroxyl radicals. Stopped-flow spectrophotometry and pulse radiolysis technique with absorption detection were used to observe the formation of intermediate products of oxidized catechins. We found that catechins react with hypochlorite with the rate constant of the order of 10(5)-10(6) M-1 s(-1) at pH 7.4. Experimental kinetic traces of the reaction of EGCG with valine peroxyl radicals were fitted using chemical simulation, and the rate constant of this reaction was found to be 5 x 10(5) M-1 s(-1). The rate constants of the formation of unstable catechin quinones in the reaction with peroxynitrite were comparable to that of spontaneous peroxynitrite isomerization, which indicates that catechins are oxidized indirectly by peroxynitrite. Biological consequences of these reactions are discussed.cs
dc.format.extent8 strancs
dc.identifier.doi10.1002/kin.21267
dc.identifier.urihttps://dspace.tul.cz/handle/15240/152994
dc.identifier.urihttps://onlinelibrary.wiley.com/doi/epdf/10.1002/kin.21267
dc.language.isocscs
dc.relation.ispartofINTERNATIONAL JOURNAL OF CHEMICAL KINETICS
dc.subjectpulse radiolysiscs
dc.subjectperoxynitritecs
dc.subjectperoxyl radicalscs
dc.subjectkinetic simulationcs
dc.subjecthypochloritecs
dc.subjectcatechinscs
dc.titleKinetics of the reactions of catechins with hypochlorite, peroxynitrite, and amino acid–derived peroxyl‐ radicalscs
local.citation.epage442
local.citation.spage435
local.relation.issue6
local.relation.volume51
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