Linked Life Data

12086683

Source:http://linkedlifedata.com/resource/pubmed/id/12086683

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2002-6-27
pubmed:abstractText
Oxidative stress is implicated in the initiation of maturity onset cataract. Quercetin, a major flavonol in the diet, inhibits lens opacification in a lens organ culture oxidative model of cataract. The aim of this research was to investigate the metabolism of quercetin in the lens and show how its metabolism affects the ability to prevent oxidation-induced opacity. The LOCH model (Free Radical Biology & Medicine 26:639; 1999) was employed, using rat lenses to investigate the effects of quercetin and metabolites on hydrogen peroxide-induced opacification. High-performance liquid chromatography analysis showed that the intact rat lens is capable of converting quercetin aglycone to 3'-O-methyl quercetin (isorhamnetin). Over a 6 h culture period no further metabolism of the 3'-O-methyl quercetin occurred. Loss of quercetin in the lens was accounted for by the increase in 3'-O-methyl quercetin. Incubation with 3,5-dinitrocatechol (10 microM), a catechol-O-methyltransferase (COMT) inhibitor, prevented the conversion of quercetin to 3'-O-methyl quercetin. The presence of both membrane-bound and soluble COMT was confirmed by immunoblotting. The results demonstrate that in the rat lens COMT methylates quercetin and that the product accumulates within the lens. Quercetin (10 microM) and 3'-O-methyl quercetin (10 microM) both inhibited hydrogen peroxide- (500 microM) induced sodium and calcium influx and lens opacification. Incubation of lenses with quercetin in the presence of COMT inhibitor revealed that the efficacy of quercetin is not dependent on its metabolism to 3'-O-methyl quercetin. The results indicate dietary quercetin and metabolites are active in inhibiting oxidative damage in the lens and thus could play a role in prevention of cataract formation.
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:day
1
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
63-70
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:12086683-Animals, pubmed-meshheading:12086683-Blotting, Western, pubmed-meshheading:12086683-Calcium, pubmed-meshheading:12086683-Cataract, pubmed-meshheading:12086683-Catechol O-Methyltransferase, pubmed-meshheading:12086683-Chromatography, High Pressure Liquid, pubmed-meshheading:12086683-Disease Models, Animal, pubmed-meshheading:12086683-Enzyme Inhibitors, pubmed-meshheading:12086683-Flavonols, pubmed-meshheading:12086683-Hydrogen Peroxide, pubmed-meshheading:12086683-Lens, Crystalline, pubmed-meshheading:12086683-Male, pubmed-meshheading:12086683-Mass Spectrometry, pubmed-meshheading:12086683-Organ Culture Techniques, pubmed-meshheading:12086683-Oxidation-Reduction, pubmed-meshheading:12086683-Quercetin, pubmed-meshheading:12086683-Rats, pubmed-meshheading:12086683-Rats, Wistar, pubmed-meshheading:12086683-Sodium
pubmed:year
2002
pubmed:articleTitle
Quercetin metabolism in the lens: role in inhibition of hydrogen peroxide induced cataract.
pubmed:affiliation
School of Biological Sciences, University of East Anglia, Norwich, Norfolk, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't