Linked Life Data

11750019

Source:http://linkedlifedata.com/resource/pubmed/id/11750019

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2001-12-25
pubmed:abstractText
The acid dissociation of (-)-epigallocatechin gallate (abbreviated as egcg) and its complexation with Al(3+) were studied by potentiometric titrations, and were compared with those of (-)-epicatechin (ec) and (-)-epigallocatechin (egc). In Al(3+)-ec and Al(3+)-egc reaction systems, [Al(LH(-2))](+), [Al(LH(-2))(OH)](0), and [Al(LH(-2))(2)](-) are formed, as reported for Al(3+)-catechin (c). Reactions between Al(3+) and egcg at pH <4.1 yield AlLH(-2) and AlLH(-3) species. The 1H NMR studies have shown that two hydroxyl groups of the gallate (D) ring are deprotonated and coordinated to an Al(3+) ion in [Al(egcgH(-2))](+). The AlLH(-3) species of egcg is supposed to be formulated as [Al(egcgH(-3))](0) in which one hydroxyl group of the pyrogallol (B) ring and two hydroxyl groups of the D ring are deprotonated; an Al(3+) ion is coordinated to two oxygen atoms of the D ring and one oxygen atom from the B ring of the neighboring chelate molecule, resulting in the formation of a polymeric structure. In the Al(3+) complex of egcg, the gallate group forms major coordinate bonds and results in solution properties that are different from those of ec, egc and c which have no gallate group.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0162-0134
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
88
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7-13
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Potentiometric and (1)H NMR studies of complexation of Al(3+) with (-)-epigallocatechin gallate, a major active constituent of green tea.
pubmed:affiliation
Department of Chemistry, University of Arizona, Tucson, AZ 85721-0041, USA. minoue@u.arizona.edu
pubmed:publicationType
Journal Article