Linked Life Data

2340603

Source:http://linkedlifedata.com/resource/pubmed/id/2340603

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1990-6-27
pubmed:abstractText
The influence of vitamins E and C on the initial stages of lipid peroxidation in human erythrocyte membranes was assessed with the fluorescent polyunsaturated fatty acid, parinaric acid, as probe molecule. Cumene hydroperoxide was used as initiator with either haemin-Fe3+ or Cu2+ as metal ion cofactor. The effect of vitamin C (pro- or antioxidant) appeared to be determined by the localisation of the metal ions, either in the water phase or in the membrane. Vitamin C is only able to reduce metal ions in the water phase, which results in acceleration of radical generation and subsequent enhancement of parinaric acid peroxidation. Thus, interaction of vitamin C with Cu2+ in the water phase led to drastically enhanced peroxidation of parinaric acid. In contrast, when only membrane-associated haemin-Fe3+ was present, vitamin C functioned as an antioxidant at all concentrations tested (0-10 microM). In a system with haemin-Fe3+ equilibrated between the water phase and the membranes, less than 5 microM vitamin C produced an overall prooxidant, and greater than 15 microM vitamin C an overall antioxidant effect. At vitamin C concentrations of 5-15 microM, continuous measurement of parinaric acid fluorescence revealed a shift in the vitamin C effect from antioxidant to prooxidant within the time-course of an assay. Vitamin E exhibited a protective effect on peroxidation initiated by cumene (per)oxyl radicals with haemin-Fe3+ as cofactor, by inducing a concentration-dependent extension of the lag-phase in parinaric acid peroxidation. Vitamin E appeared to be much more effective compared with vitamin C in scavenging radicals in this system. This indicates that vitamin C has only a limited ability to react with cumene (per)oxyl radicals in the membrane. The combination of vitamins E and C produced a protective effect on parinaric acid peroxidation exceeding the sum of their individual contributions. Moreover, the rate of vitamin E consumption was drastically lowered in the presence of vitamin C, whereas the rate of vitamin C consumption hardly decreased in the presence of vitamin E. The results are discussed in terms of a reaction scheme where the relative contributions of a number of reactions are considered to determine the total effect of added vitamin C or E. Vitamin E radicals constitute an additional substrate for vitamin C, resulting in a more than additive shift in the overall effect to the antioxidant side.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0009-3084
pubmed:author
pubmed:issnType
Print
pubmed:volume
53
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
309-20
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
The cooperative action of vitamins E and C in the protection against peroxidation of parinaric acid in human erythrocyte membranes.
pubmed:affiliation
Centre for Biomembranes and Lipid Enzymology, State University of Utrecht, The Netherlands.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't