This thesis describes the development of an assay for free radical scavenging (antioxidant) activity in biological fluids based on an enhanced chemiluminescent reaction. Light emission from the reaction depends on the constant production of free radical intermediates and is therefore sensitive to interference by antioxidant compounds. The time period of light suppression is directly related to the amount of antioxidant added to the reaction. In this way the antioxidant activity of biological samples can be related to a standard antioxidant solution of the vitamin E analogue, trolox. The effect of a variety of pure compounds upon light emiSSion are described. Based on these observations a mathematical model for the reaction kinetics in response to the addition of antioxidants and other compounds is developed. The impact of more complex biological fluids on the reaction is described with particular reference to serum. An assessment of the contribution of individual antioxidants to serum total antioxidant activity suggests that urate accounts for 70% while ascorbate and vitamin E each account for a further 10%. The use of the assay is extended to the measurement of antioxidant activity in solutions of plasma lipoproteins isolated by density gradient ultracentrifugation. These studies suggest that vitamin E is the major (but not exclusive) contributor to lipoprotein antioxidant activity. The distribution of antioxidant activity across different lipoprotein fractions and co-operative interaction of antioxidant activity in lipoproteins are described.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:408946 |
| Date | January 1995 |
| Creators | Maxwell, Simon Robert Jenkinson |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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