Ho, Ka Yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 111-124). / Abstracts in English and Chinese. / Thesis committee --- p.i / Acknowledgements --- p.ii / Abstract --- p.iii / 摘要 --- p.v / List of Tables --- p.vii / List of Figures --- p.viii / Abbreviations --- p.x / Content --- p.xiii / Chapter Chapter 1: --- Introduction --- p.1 / Chapter 1.1 --- Reactive oxygen species (ROS) --- p.1 / Chapter 1.1.1 --- Definition and examples --- p.1 / Chapter 1.1.2 --- Generation of ROS in biological systems --- p.2 / Chapter 1.1.3 --- Features of specif ic ROS --- p.3 / Chapter 1.1.3.1 --- Superoxide anion --- p.3 / Chapter 1.1.3.2 --- Peroxyl radical --- p.4 / Chapter 1.1.3.3 --- Hydrogen peroxide --- p.4 / Chapter 1.1.3.4 --- Hydroxyl radical --- p.5 / Chapter 1.1.4 --- Damaging effects of ROS on biomolecules --- p.5 / Chapter 1.1.4.1 --- Lipid peroxidation --- p.6 / Chapter 1.1.4.2 --- DNA damage --- p.8 / Chapter 1.1.4.3 --- Protein oxidation --- p.9 / Chapter 1.2 --- Antioxidants --- p.11 / Chapter 1.2.1 --- Introduction --- p.11 / Chapter 1.2.2 --- Mode of action --- p.11 / Chapter 1.2.3 --- Endogenous Antioxidants --- p.12 / Chapter 1.2.3.1 --- Antioxidant enzymes --- p.12 / Chapter 1.2.3.2 --- Antioxidant compounds --- p.15 / Chapter 1.2.4 --- Exogenous antioxidants --- p.16 / Chapter 1.3 --- Oxidative stress --- p.17 / Chapter 1.3.1 --- Balance between ROS and antioxidants --- p.17 / Chapter 1.3.2 --- Diseases associated with oxidative stress --- p.18 / Chapter 1.4 --- Previous studies on edible mushroom antioxidants --- p.19 / Chapter 1.4.1 --- Previous studies on Agrocybe aegerita --- p.20 / Chapter 1.5 --- Cell culture models for antioxidant research --- p.21 / Chapter 1.6 --- Objectives --- p.23 / Chapter Chapter 2 --- Materials and Methods --- p.24 / Chapter 2.1 --- Materials --- p.24 / Chapter 2.1.1 --- Mushroom fruiting bodies --- p.24 / Chapter 2.1.2 --- Cell lines and their subcultures --- p.24 / Chapter 2.2 --- Principle of Methods and Procedures --- p.26 / Chapter 2.2.1 --- Sample preparation and extraction --- p.26 / Chapter 2.2.2 --- Chemical assays for in vitro antioxidative properties of mushroom extracts --- p.28 / Chapter 2.2.2.1 --- ABTS + scavenging activity --- p.28 / Chapter 2.2.2.2 --- Hydroxyl radical scavenging activity --- p.30 / Chapter 2.2.2.3 --- Hydrogen peroxide scavenging activity --- p.32 / Chapter 2.2.3 --- Total phenolic content --- p.34 / Chapter 2.2.4 --- Cytotoxicity of hydrogen peroxide --- p.36 / Chapter 2.2.5 --- Cytoprotectivity of mushroom extracts --- p.36 / Chapter 2.2.6 --- "Colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay" --- p.37 / Chapter 2.2.7 --- Lactate dehydrogenase (LDH) assay --- p.39 / Chapter 2.2.8 --- Total cellular protein loss --- p.40 / Chapter 2.2.9 --- Comet assay (Single cell gel electrophresis assay) --- p.41 / Chapter 2.2.10 --- Thiobarbituric Acid Reactive Substances (TBARS) assay ..… --- p.44 / Chapter 2.2.11 --- Preparation of cell lysate for evaluating cellular antioxidant defense system --- p.45 / Chapter 2.2.12 --- Total Glutathione level --- p.46 / Chapter 2.2.13 --- Enzyme activity --- p.49 / Chapter 2.2.13.1 --- Catalase (CAT) --- p.49 / Chapter 2.2.13.2 --- Glutathione peroxidases (GPx) --- p.51 / Chapter 2.2.13.3 --- Glutathione Reductase (GR) --- p.53 / Chapter 2.2.13.4 --- Superoxide dismutase (SOD) --- p.54 / Chapter 2.2.14 --- Determination of protein --- p.56 / Chapter 2.2.15 --- Statistical analysis --- p.56 / Chapter Chapter 3 --- Results and discussions --- p.57 / Chapter 3.1 --- Extraction yield --- p.57 / Chapter 3.2 --- Chemical assays for in vitro antioxidative properties of mushroom extracts --- p.60 / Chapter 3.2.1 --- ABTS + scavenging activity --- p.60 / Chapter 3.2.2 --- Hydroxyl radicals scavenging activity --- p.61 / Chapter 3.2.3 --- Hydrogen peroxide scavenging activity --- p.64 / Chapter 3.3 --- Total phenolic content --- p.67 / Chapter 3.4 --- Cytotoxicity of hydrogen peroxide --- p.69 / Chapter 3.4.1 --- "Colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay" --- p.71 / Chapter 3.4.2 --- Lactate dehydrogenase (LDH) assay --- p.72 / Chapter 3.4.3 --- Total cellular protein loss --- p.73 / Chapter 3.4.4 --- Residual hydrogen peroxide level --- p.76 / Chapter 3.4.5 --- Lipid peroxidation --- p.77 / Chapter 3.4.6 --- DNA damage --- p.79 / Chapter 3.5 --- Cytotoxicity of extracts --- p.85 / Chapter 3.6 --- Protection of H2()2-induced oxidative damage in HDFa cells --- p.88 / Chapter 3.6.1 --- Protective effect of mushroom water extracts --- p.88 / Chapter 3.6.2 --- Protective effect of CfAa on H2()2-incluced damage to HDFa --- p.93 / Chapter 3.6.3 --- Protective effect of CfAa on DNA damage in HDFa cells --- p.96 / Chapter 3.7 --- Modulation of cellular antioxidant defense system by CfAa --- p.99 / Chapter 3.7.1 --- Intracellular total glutathione --- p.100 / Chapter 3.7.2 --- Enzyme activities --- p.102 / Chapter 3.8 --- Speculation on the possible components in CfAa --- p.108 / Chapter Chapter 4 --- Conclusion and further works --- p.109 / References --- p.111