Linked Life Data

8399214

Source:http://linkedlifedata.com/resource/pubmed/id/8399214

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
40
pubmed:dateCreated
1993-11-24
pubmed:abstractText
d-alpha-Tocopherol and d-alpha-tocotrienol are two vitamin E constituents having the same aromatic chromanol "head" but different hydrocarbon "tails". alpha-Tocotrienol has been shown to be more potent in protecting against free radical-induced oxidative stress than alpha-tocopherol. Simple models of phospholipid membrane systems were used to investigate the mechanism of the antioxidant potency of alpha-tocotrienol in terms of its effects on membrane order and reorientation dynamics. Chemiluminescence and fluorescence measurements demonstrated that alpha-tocotrienol exhibits significantly greater peroxyl radical scavenging potency than alpha-tocopherol in phosphatidylcholine liposomes, whereas both antioxidants have identical activity in hexane. This suggests that the antioxidant potency of alpha-tocotrienol requires the membrane environment. When alpha-tocopherol and alpha-tocotrienol were examined for their effects on phospholipid molecular order using conventional ESR spin labeling with 5- and 16-position-labeled doxylstearic acid, although both vitamin E constituents disordered the gel phase and stabilized the liquid-crystalline phase, no differences were observed between the effects of the two compounds. A slightly greater increase (19% vs 15%) in ordering of the liquid-crystalline state due to alpha-tocopherol, however, was discerned in noninvasive 2H NMR experiments. The difference is most noticeable near C10-C13 positions of the phospholipid chain, possibly suggesting alpha-tocotrienol is located closer to the membrane surface. Saturation-transfer ESR, furthermore, revealed that on the time scale tau c = 10(-7)-10(-3) s the rates of rotation about the long molecular axis and of the wobbling motion of the axis are modified to differing extents by the two forms of the vitamin E.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10692-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Structural and dynamic membrane properties of alpha-tocopherol and alpha-tocotrienol: implication to the molecular mechanism of their antioxidant potency.
pubmed:affiliation
Department of Molecular and Cell Biology, University of California, Berkeley 94720.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't