Free Radical and Enzymatic Oxygenation of Eicosanoids : Synthesis of Isoprostanes and 5-Hydroxyeicosanoid Dehydrogenase Photoaffinity Ligand

다국어 초록 (Multilingual Abstract)

Polyunsaturated fatty acids (PUFA) are oxidized by free radical and enzymatically. The F2-isoprostanes are unique series of prostaglandin-like compounds formed in vivo from the free radical catalyzed peroxidation of arachidonic acid (AA) 5 independent of cyclooxygenase enzyme. Recently, F3- and F4-isoprostane formations are also discovered in vivo by free-radical mechanism on phospholipids by peroxidation of eicosapentaenoic acid (EPA) 188 and docosahexaenoic acid (DHA) 189.
<그림참조>(원문을 참조하세요)
The synthesis of selected iPs, deuterated iPs and the development of GC/MS and LC/MS/MS methodology to identify and quantify were accomplished here. I have extended the initial focus of AA-derived iPs to metabolites of iPs, to provide a standard time for the measurement of the free radical oxidation in vivo by studying the mechanism of the metabolisms and the positive identity of metabolites of iPF2α-III and iPF2α-VI.
<그림참조>(원문을 참조하세요)
Moreover, I have synthesized group VI iPs derived from DHA and EPA, 356 and 370. The development of GC/MS and LC/MS/MS, as well as the syntheses of those deuterated iPs, 19,19,20,20-d4- iPF3α.VI 396 and 21,21,22,22- d4-iPF4α.VI 377 are reported here. DHA is the major polyunsaturated fatty acid (PUFA) in the brain. It is possible that the measurement of iPs derived from DHA can provide a unique index of free-radical damage in the brain and can be used for monitoring the progress of Alzheimer’s disease (AD) and the effectiveness of drug intervention. EPA is unique in that people on high fish diets (e.g. Inuits) have more EPA than AA.
<그림참조>(원문을 참조하세요)
Arachidonic acid is also metabolized by an enzymatic oxidation. 5- Lipoxygenase produces 5-hydroperoxy-6,8,11,14-eicosatetraenoic acid (5-HPETE), which is converted to 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE). 5- hydroxyeicosanoid dehydrogenase (5h-dh) is a key enzyme involved in the transformation of 5-HETE to 5-oxo-ETE. 5-Oxo-ETE is the most potent eosinophil chemotactic factor among lipid mediators. We have proposed that 5-oxo-ETE may be a causative factor in diseases such as asthma involving the infiltration of eosinophils. 5-Oxo-ETE exerts its action by activating a dedicated receptor.
Chemical synthesis of a radio photoaffinity labeled 5(S)-HETE analogs is necessary for the characterization, labeling, and purification of the enzyme 5h-dh. A photoaffinity radiolabelled trimethyl tin precursor was prepared by total synthesis and converted to the desired iodo derivative.
<그림참조>(원문을 참조하세요)

목차 (Table of Contents)

• Abstract = iii
• Acknowledgments = vii
• Dedication = viii
• Table of Contents ix
• List of Schemes = xiii
• List of Figures = xvii
• List of Abbreviations = xix
• Chapter I. Introduction and Background = 1
• 1.1. The Isoprostanes: Free Radical Oxygenation = 4
• 1.1.1 Mechanisms of Formation of Isoprostanes = 6
• 1.1.2 DHA and EPA Derived iPs = 21
• 1.1.3 Nomenclature of Isoprostanes = 26
• 1.1.4 Measurement of Isoprostanes = 29
• 1.1.5 Biological Significance of Isoprostane Formation = 32
• 1.1.6 Synthesis of Isoprostanes = 37
• 1.2. Enzymatic Oxygenation of 5-HETE = 38
• 1.2.1 Biological Activities of 5-oxo-ETE = 39
• 1.2.2 Biosynthesis of 5-oxo-ETE = 42
• 1.2.3. Synthesis of 5-Oxo-ETE = 44
• Chapter II. Objectives = 47
• Chapter III. Synthetic Strategy for the Synthesis of Isoprostanes = 51
• 3.1. Radical Cyclization Approach = 53
• 3.2. Diels Alder Approach = 58
• Chapter IV Metabolism of Isoprostanes = 61
• 4.1. Metabolic Pathways for PGF2α = 62
• 4.2. β.Oxidation of Fatty Acids = 65
• 4.3. ω. Oxidation of Fatty Acids = 66
• 4.4. Metabolism of iPF2α-III = 68
• 4.4.1 First Total Synthesis of dinor-iPF2α-III, A Primary β-Oxidation Metabolite = 70
• 4.4.2 GC/MS of dinor-iPF2α-III = 74
• 4.5 15-oxo-2,3-dinor-5,6-dihydro-8,12-iso-iPF2α-III = 78
• 4.5.1 Synthesis of 2,3-dinor-5,6-dihydro-8,12-iso-iPF2α-III = 78
• 4.5.2. Selective Oxidation; One Step Synthesis of 15-oxo-2,3-dinor-5,6-dihydro-8,12-iso-iPF2α-III = 79
• 4.6 iPF2α-VI Metabolism Study = 82
• 4.6.1 Structure Analysis of iPF2α-VI = 83
• 4.6.2 Preparation of 3H-iPF2α-VI = 84
• Chapter V ω.3 Isoprostanes = 87
• 5.1 iPs as a Selective Index of the Severity of AD = 87
• 5.2 iPs Derived from DHA and EPA = 90
• 5.3 First Total Synthesis of iPF3α-VI and iPF4α-VI = 95
• 5.4 GC/MS Analysis of iPF3α-VI and iPF4α-VI = 100
• Chapter VI Measurement of Isoprostanes = 102
• 6.1 Gas Chromatography/Mass Spectrometry (GC/MS) = 102
• 6.2 Quantitative High Performance Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS) = 106
• 6.2.1 Separation of Four Groups of iPs in Human Urine = 106
• 6.2.2 Selection of Class Specific Product Ions = 108
• 6.2.3 Assay Development = 109
• 6.3 Total Synthesis of d4-iPF3α-VI and d4-iPF4α-VI = 110
• 6.3.1 Synthetic Design for d4-iPF3α-VI and d4-iPF4α-VI = 110
• 6.3.2 Synthesis of d4-iPF3α-VI and d4-iPF4α-VI = 112
• 6.3.3 Identification of d4-iPF3α-VI in vivo = 115
• 6.4 The Development of an EnzymeImmunoassay Method for iPF2α.VI = 117
• 6.4.1 Antibody generation = 118
• Chapter VII A Photoaffinity Probe for 5-Hydroxyeicosanoid-Dehydrogenase Suitable for Radioiodination = 120
• 7.1 Design and Prelinary Studies = 122
• 7.2 Preliminary studies on Azido 5-HETE = 125
• 7.3 A Photoaffinity Probe for 5-Hydroxyeicosanoid-Dehydrogenase Suitable for Radioiodination = 127
• 7.4 HPLC Analysis of Photoaffinity Ligand Probe for 5-oxo-ETE = 137
• Chapter VIII Miscellaneous = 139
• 8.1 Improvement of isolation and separation of radical cyclized lactones = 139
• 8.2 A new method for the preparation of olefins from vicinal diols = 142
• 8.3 A Convenient strategy for the synthesis of β,γ-unsaturated aldehydes and acids. A construction of skipped dienes = 144
• Chapter IX Experimental = 146
• General = 146
• Experimental = 148
• References = 197
• Appendix = 212