Linked Life Data

7635358

Source:http://linkedlifedata.com/resource/pubmed/id/7635358

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-9-14
pubmed:abstractText
Concurrent pulse-radiolytic generation of flavonoid aroxyl radicals and ascorbyl radicals causes a complex kinetic interplay of competing and parallel reactions. Evaluation by "kinetic modelling," that is, taking into account all possible reactions by a set of differential equations, allowed us to determine equilibria constants for the univalent steps by a novel method. From these kinetic data we were able to calculate the redox potentials for dihydroquercetin, quercetin, rutin (a quercetin 3-glycoside), kaempferol, fisetin, and luteolin. Despite the limited number of substances, two structural criteria became apparent: all substances containing the B-ring catechol group and the 2,3-double bond have a higher redox potential than ascorbate and are consequently able to oxidize it to the ascorbyl radical. With fisetin and kaempferol having values very similar to ascorbate, only the flavanone dihydro-quercetin was capable of reducing the ascorbyl radical, thus fulfilling the so-called "ascorbate-protective" function, originally proposed by Szent-Györgyi. While flavonoids are effective radical scavengers, these rather high redox potentials for most flavonols may explain their occasional prooxidative behavior.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0891-5849
pubmed:author
pubmed:issnType
Print
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
45-52
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Interaction of flavonoids with ascorbate and determination of their univalent redox potentials: a pulse radiolysis study.
pubmed:affiliation
Institut für Strahlenbiologie, GSF Forschungszentrum für Umwelt und Gesundheit Neuherberg, Oberschleissheim, Germany.
pubmed:publicationType
Journal Article