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Evaluation of the antioxidant activity and characterization of extracts from three edible Chinese mushrooms.

Cheung Lai Ming. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 153-161). / Abstracts in English and Chinese. / THESIS COMMITTEE --- p.i / ACKNOWLEDGEMENTS --- p.ii / ABSTRACT --- p.iii / ABSTRACT (Chinese version) --- p.v / CONTENTS --- p.vi / LIST OF TABLES --- p.xi / LIST OF FIGURES --- p.xiii / LIST OF ABBREVIATIONS --- p.xv / Chapter CHAPTER ONE: --- INTRODUCTION --- p.1 / Chapter 1.1 --- Free radical --- p.2 / Chapter 1.1.1 --- Definition --- p.2 / Chapter 1.1.2 --- Reaction mechanism --- p.3 / Chapter 1.1.3 --- Sources of oxygen reactive species --- p.4 / Chapter 1.1.3.1 --- Enzymes --- p.4 / Chapter 1.1.3.2 --- The auto-oxidation of small molecules --- p.4 / Chapter 1.1.3.3 --- Haem proteins --- p.5 / Chapter 1.1.3.4 --- Endoplasmic reticulum sources --- p.5 / Chapter 1.1.3.5 --- Mitochondrial sources --- p.5 / Chapter 1.1.3.6 --- Nucleus --- p.6 / Chapter 1.1.4 --- Lipid peroxidation --- p.6 / Chapter 1.1.4.1 --- Initiation of lipid peroxidation --- p.7 / Chapter 1.1.4.2 --- Propagation of lipid peroxidation --- p.8 / Chapter 1.1.4.3 --- Products of lipid peroxidation --- p.9 / Chapter 1.1.5 --- Human diseases associated with free radicals --- p.10 / Chapter 1.2 --- Antioxidants --- p.12 / Chapter 1.2.1 --- Definition --- p.12 / Chapter 1.2.2 --- Defence against free radical damage --- p.13 / Chapter 1.2.2.1 --- Catalytic free radical removal --- p.13 / Chapter 1.2.2.2 --- Free radical scavenging --- p.14 / Chapter 1.2.2.3 --- Removal of catalytic iron and copper ions --- p.14 / Chapter 1.2.3 --- Synthetic vs. natural antioxidant --- p.15 / Chapter 1.2.3.1 --- Synthetic antioxidants --- p.15 / Chapter 1.2.3.2 --- Natural antioxidants --- p.16 / Chapter 1.3 --- Measurement of antioxidant activity --- p.17 / Chapter 1.3.1 --- Loss of substrate --- p.17 / Chapter 1.3.1.1 --- Beta-carotene bleaching method --- p.17 / Chapter 1.3.2 --- Measurement of free radical scavenging --- p.17 / Chapter 1.3.2.1 --- "Scavenging of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH´Ø)" --- p.17 / Chapter 1.3.2.2 --- Superoxide scavenging --- p.18 / Chapter 1.3.2.3 --- Hydrogen peroxide scavenging --- p.18 / Chapter 1.3.2.4 --- Hydroxyl radical scavenging --- p.19 / Chapter 1.3.2.5 --- Peroxyl radical --- p.19 / Chapter 1.3.3 --- Measurement of end product --- p.21 / Chapter 1.3.3.1 --- Diene conjugation --- p.21 / Chapter 1.3.3.2 --- Light emission --- p.21 / Chapter 1.3.3.3 --- The thiobarbituric acid (TBA) test --- p.22 / Chapter 1.3.4 --- Low-density lipoprotein oxidation --- p.22 / Chapter 1.4 --- Phenolic antioxidant --- p.24 / Chapter 1.4.1 --- Chemistry --- p.24 / Chapter 1.4.2 --- Mechanism of action of phenolic antioxidants --- p.25 / Chapter 1.4.3 --- Isolation and characterization --- p.25 / Chapter 1.4.3.1 --- Extraction --- p.25 / Chapter 1.4.3.2 --- Analysis of phenolic compounds --- p.27 / Chapter 1.4.3.2.1 --- Colorimetric method --- p.27 / Chapter 1.4.3.2.2 --- Enzymatic method --- p.28 / Chapter 1.4.3.2.3 --- Paper chromatography --- p.28 / Chapter 1.4.3.2.4 --- Thin-layer chromatography --- p.29 / Chapter 1.4.3.2.5 --- UV-Vis absorption spectroscopy --- p.29 / Chapter 1.4.3.2.6 --- High-performance liquid chromatography --- p.30 / Chapter 1.4.4 --- Natural sources of phenolic antioxidants --- p.31 / Chapter 1.4.4.1 --- Olive oil --- p.31 / Chapter 1.4.4.2 --- Berry --- p.32 / Chapter 1.4.4.3 --- Cherry --- p.32 / Chapter 1.4.4.4 --- Red wine --- p.32 / Chapter 1.4.4.5 --- Herb --- p.33 / Chapter 1.4.4.6 --- Vegetables --- p.33 / Chapter 1.5 --- Mushroom Sample --- p.34 / Chapter 1.5.1 --- Pleurotus tuber-regium --- p.34 / Chapter 1.5.2 --- Lentinus edodes --- p.34 / Chapter 1.5.3 --- Volvariella volvacea --- p.35 / Chapter 1.5.4 --- Antioxidants in fungi or mushroom --- p.37 / Chapter 1.5.5 --- Phenolic compounds in mushrooms --- p.39 / Chapter 1.6 --- Objectives --- p.42 / Chapter CHAPTER TWO: --- MATERIALS AND METHODS --- p.43 / Chapter 2.1 --- Sample Collection --- p.43 / Chapter 2.2 --- Sample Preparation --- p.43 / Chapter 2.3 --- Moisture Content --- p.43 / Chapter 2.4 --- Solvent Extraction --- p.44 / Chapter 2.4.1 --- Scheme I (Aqueous extraction only) --- p.44 / Chapter 2.4.2 --- Scheme II (Methanol and water extraction) --- p.45 / Chapter 2.4.3 --- Scheme III (Differential solvent extraction) --- p.46 / Chapter 2.4.4 --- Scheme IV (Scaled-up extraction) --- p.47 / Chapter 2.5 --- Antioxidant activity assays --- p.50 / Chapter 2.5.1 --- Beta-carotene bleaching method --- p.50 / Chapter 2.5.2 --- "Scavenging activity on 1,1 -diphenyl-2-picrylhydrazyl radicals" --- p.51 / Chapter 2.5.3 --- Assay for erythrocyte hemolysis --- p.51 / Chapter 2.5.4 --- Assay of lipid peroxidation using rat brain --- p.52 / Chapter 2.5.5 --- LDL oxidation (TBARS) --- p.53 / Chapter 2.5.5.1 --- LDL Isolation --- p.53 / Chapter 2.5.5.2 --- Calculation of density --- p.54 / Chapter 2.5.5.3 --- Lowry Method for Protein Determination --- p.55 / Chapter 2.5.5.4 --- Reagents for TBARS assay --- p.55 / Chapter 2.5.5.5 --- TBARS formation --- p.56 / Chapter 2.6 --- Determination of total polyphenolic compounds --- p.56 / Chapter 2.7 --- Fractionation --- p.57 / Chapter 2.7.1 --- Fractionation of the methanol crude extracts obtained under reflux by solvent --- p.57 / Chapter 2.7.2 --- Fractionation of boiling water crude extracts by ultrafiltration --- p.57 / Chapter 2.8 --- Crude Protein Content (Kjeldahl method) --- p.58 / Chapter 2.9 --- Total carbohydrate content --- p.59 / Chapter 2.10 --- Thin-layer chromatography --- p.59 / Chapter 2.11 --- High performance liquid chromatography --- p.60 / Chapter 2.11.1 --- Analysis of methanol fractions --- p.60 / Chapter 2.11.2 --- Analysis of water fractions --- p.61 / Chapter 2.12 --- Liquid chromatography-Mass spectrometry --- p.61 / Chapter 2.12.1 --- Liquid chromatography --- p.61 / Chapter 2.12.2 --- Mass spectrometric analysis --- p.62 / Chapter 2.13 --- Data analysis --- p.62 / Chapter CHAPTER THREE: --- RESULTS AND DISCUSSION --- p.63 / Chapter 3.1 --- Mushroom sample --- p.63 / Chapter 3.2 --- Extraction scheme I --- p.65 / Chapter 3.2.1 --- Antioxidant activity --- p.65 / Chapter 3.2.1.1 --- Effect of extraction temperature --- p.65 / Chapter 3.2.1.2 --- Effect of concentration of extracts --- p.66 / Chapter 3.3 --- Extraction scheme II --- p.69 / Chapter 3.3.1 --- Antioxidant activity --- p.69 / Chapter 3.3.1.1 --- Effect of extraction temperature --- p.69 / Chapter 3.3.1.2 --- Effect of concentration of extracts --- p.72 / Chapter 3.3.1.3 --- Effect of solvent --- p.72 / Chapter 3.4 --- Extraction scheme III --- p.75 / Chapter 3.4.1 --- Extraction yield --- p.75 / Chapter 3.4.2 --- Total phenolic content --- p.76 / Chapter 3.4.3 --- Antioxidant activity --- p.80 / Chapter 3.4.3.1 --- Beta-carotene bleaching method --- p.80 / Chapter 3.4.3.1.1 --- Effect of extract concentration --- p.80 / Chapter 3.4.3.1.2 --- Relation between total phenolic content and antioxidant activity --- p.82 / Chapter 3.4.3.2 --- "Scavenging activity of 1,1 -diphenyl-2-picrylhydrazyl (DPPH) radical" --- p.85 / Chapter 3.4.3.3 --- Assay for erythrocyte hemolysis --- p.88 / Chapter 3.5 --- Extraction scheme IV --- p.91 / Chapter 3.5.1 --- Yield and Fractionation --- p.91 / Chapter 3.5.2 --- Chemical characterization of fractions --- p.93 / Chapter 3.5.2.1 --- Protein content --- p.93 / Chapter 3.5.2.2 --- Total carbohydrate content --- p.93 / Chapter 3.5.2.3 --- Total phenolic content --- p.94 / Chapter 3.5.3 --- Antioxidant activity --- p.99 / Chapter 3.5.3.1 --- Assay for lipid peroxidation of rat brain --- p.99 / Chapter 3.5.3.2 --- LDL oxidation --- p.118 / Chapter 3.5.4 --- Identification of antioxidant by chromatographic methods --- p.126 / Chapter 3.5.4.1 --- Thin-layer chromatography --- p.126 / Chapter 3.5.4.2 --- High-performance liquid chromatography --- p.132 / Chapter 3.5.4.3 --- Liquid chromatography-Mass spectrometry --- p.142 / Chapter CHAPTER FOUR: --- CONCLUSION --- p.148 / REFERENCES --- p.153 / RELATED PUBLICATION --- p.161

Identiferoai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_323451
Date January 2001
ContributorsCheung, Lai Ming., Chinese University of Hong Kong Graduate School. Division of Food and Nutritional Sciences.
Source SetsThe Chinese University of Hong Kong
LanguageEnglish, Chinese
Detected LanguageEnglish
TypeText, bibliography
Formatprint, xvi, 161 leaves : ill. (some col.) ; 30 cm.
RightsUse of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/)

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