Linked Life Data

15606149

Source:http://linkedlifedata.com/resource/pubmed/id/15606149

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2004-12-20
pubmed:abstractText
The nature of the products formed by reaction of all-trans retinoic acid (1) and its major metabolite, 5,6-epoxyretinoic acid (2), with the Fenton reagent was investigated. Oxidation of 1 in a vigorously stirred biphasic medium (0.1 M phosphate buffer, pH 7.4/ethyl acetate 5:1 v/v) with Fe2+/EDTA complex (2 mol equiv) and a 10-fold excess of H2O2 proceeded smoothly to give a very complex mixture of products. Repeated TLC fractionation of the reaction mixture after methylation allowed isolation of the main products which were identified as 2 methyl ester, (7E)-7,8-epoxyretinoic acid methyl ester (6), all-(E)-2,6-dimethyl-8-(2,6,6-trimethyl-2-cyclohexen-1-ylidene)-2,4,6-octatrienal (11), the novel (9E)-5,6,9,10-diepoxyretinoic acid methyl ester (7), and (9Z)-5,6,9,10-diepoxyretinoic acid methyl ester (8) (1:1 mixture of syn/anti isomers each), 5,6-epoxy-beta-ionone (9), 5,6-epoxy-beta-ionylideneacetaldehyde (10), and trace amounts of beta-ionone (12), beta-ionylideneacetaldehyde (13), and 4-oxoretinoic acid (3) methyl ester. When the oxidation was carried out with the substrate and the Fenton reagent at concentrations as low as 10 microM, the main detectable products were 2 methyl ester, 11, and 7/8. Under similar conditions, the epoxide 2 gave mainly products 7-10. A less efficient conversion of 1 and 2 but similar product patterns were observed with other oxidizing systems such as peroxidase/H2O2 and 13-hydroperoxyoctadecadienoic acid in the presence of Fe(II). Besides providing the first detailed insight into the products formed by reaction of a retinoid with the Fenton reagent, the results of this study disclose a novel nonenzymatic route from 1 to the epoxide 2 and offer an improved chemical basis to inquire into the mechanism of the antiinflammatory, antimutagenic, and cancer chemopreventive action of these retinoids.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0893-228X
pubmed:author
pubmed:issnType
Print
pubmed:volume
17
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1716-24
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Free radical oxidation of (E)-retinoic acid by the Fenton reagent: competing epoxidation and oxidative breakdown pathways and novel products of 5,6-epoxyretinoic acid transformation.
pubmed:affiliation
Department of Organic Chemistry and Biochemistry, University of Naples "Federico II", Via Cinthia 4, I-80126 Naples, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't