Linked Life Data

17439549

Source:http://linkedlifedata.com/resource/pubmed/id/17439549

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2007-4-18
pubmed:abstractText
This study assessed the location of melatonin (N-acetyl-5-methoxytryptamine) and of a pinoline derivative (GWC22) [6-ethyl-1-(3-methoxyphenyl)-2-propyl-1,2,3,4-tetrahydro-beta-carboline], when present in lipid assemblies such as linoleate micelles, phosphatidylcholine liposomes or low density lipoproteins (LDL). The efficiency of radical scavenging by these compounds is highly dependent on their partitioning between the lipidic and aqueous phases. We determined the proportion of melatonin or GWC22 in the aqueous and lipid phases of each system (concentrations of the antioxidants ranging between 3 x 10(-5) and 10(-4) m) by assaying melatonin or GWC22 by HPLC/UV detection, or by fluorescence for melatonin in micelles. Our results show that melatonin and GWC22 were preferentially located in the aqueous phase of micelles (68.4% and 59.0%, respectively), whereas only 30.5% of melatonin and 39.0% of GWC22 were found in the lipid phase. By contrast, in phosphatidylcholine liposomes, both compounds were essentially present in the lipid phase (73.5% for melatonin and 79.1% for GWC22, versus 25.9% and 19.5% in the aqueous phase, respectively). In the case of LDL, 99.9% of the melatonin added was found in the methanol/water extracting phase containing phospholipids, unesterified cholesterol and apolipoprotein B100. The partitioning of melatonin and GWC22 in linoleate micelles gave new insights on the marked protective effect of GWC22 towards radiation-induced lipid peroxidation and allowed us to determine more accurately the lower limit values of the reaction rate constants of the two molecules studied with lipid peroxyl radicals, i.e. k(LOO.+melatonin)) >or= 9.0 x 10(4)m(-1)s(-1) and k(LOO.+GWC22) >or= 3.5 x 10(5)m(-1)s(-1).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0742-3098
pubmed:author
pubmed:issnType
Print
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
330-7
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Quantification of the water/lipid affinity of melatonin and a pinoline derivative in lipid models.
pubmed:affiliation
Laboratoire de Chimie-Physique, UFR Biomédicale des Saints-Pères, Université Paris 5, Paris, France.
pubmed:publicationType
Journal Article, In Vitro