Ngai Lei-Ka. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 113-125). / Abstracts in English and Chinese. / List of Abbreviations --- p.ix / List of Tables --- p.x / List of Figures --- p.xii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Flavonoids --- p.1 / Chapter 1.1.1 --- The six major classes of flavonoids --- p.1 / Chapter 1.1.1.1 --- Flavonones --- p.1 / Chapter 1.1.1.2 --- Flavones --- p.2 / Chapter 1.1.1.3 --- Flavonols --- p.2 / Chapter 1.1.1.4 --- Isoflavonoids --- p.2 / Chapter 1.1.1.5 --- Anthocyanidins --- p.3 / Chapter 1.1.1.6 --- Flavans --- p.3 / Chapter 1.1.2 --- Structural variation of flavonoids --- p.3 / Chapter 1.1.3 --- The roles of flavonoids --- p.6 / Chapter 1.2 --- "Free radicals, oxidative stress and antioxidants" --- p.7 / Chapter 1.2.1 --- Oxidants and free radicals --- p.7 / Chapter 1.2.2 --- Lipid peroxidation (LPO) --- p.8 / Chapter 1.2.3 --- Oxidative stress and human diseases --- p.9 / Chapter 1.2.4 --- Role of food antioxidants --- p.10 / Chapter 1.2.5 --- Synthetic and natural food antioxidants --- p.11 / Chapter 1.3 --- Antioxidant activity of flavonoids --- p.12 / Chapter 1.4 --- Determination of antioxidant activity --- p.13 / Chapter 1.4.1 --- Trolox equivalent antioxidant capacity (TEAC) assay --- p.13 / Chapter 1.4.2 --- DPPH radical scavenging assay --- p.14 / Chapter 1.4.3 --- β-carotene bleaching assay --- p.15 / Chapter 1.5 --- Single cell gel electrophoresis assay (Comet assay) --- p.16 / Chapter 1.6 --- Determination of the genotoxicity --- p.18 / Chapter 1.7 --- Research objectives --- p.19 / Chapter 2 --- Materials and Methods --- p.26 / Chapter 2.1 --- Standards and reagents --- p.26 / Chapter 2.2 --- Sample Preparation --- p.26 / Chapter 2.3 --- Trolox equivalent antioxidant capacity (TEAC) assay --- p.27 / Chapter 2.4 --- DPPH´Ø radical scavenging assay --- p.28 / Chapter 2.5 --- β-carotene bleaching assay --- p.29 / Chapter 2.6 --- The comet assay --- p.30 / Chapter 2.6.1 --- Preparation of reagents --- p.31 / Chapter 2.6.2 --- Blood sample --- p.32 / Chapter 2.6.3 --- Optimal condition of comet assay --- p.32 / Chapter 2.6.3.1 --- Induction of DNA damage --- p.32 / Chapter 2.6.3.2 --- Antioxidant pre-treatment --- p.32 / Chapter 2.6.4 --- Hydrogen peroxide (H2O2) treatment --- p.32 / Chapter 2.6.4.1 --- Pre-incubation system --- p.32 / Chapter 2.6.4.2 --- Co-incubation system --- p.33 / Chapter 2.6.5 --- Slide preparation --- p.33 / Chapter 2.6.6 --- Cell lysis --- p.33 / Chapter 2.6.7 --- Alkaline treatment and electrophoresis --- p.34 / Chapter 2.6.8 --- Neutralization --- p.34 / Chapter 2.6.9 --- Quantification of DNA damage --- p.34 / Chapter 2.6.10 --- Cell viability analysis --- p.35 / Chapter 2.6.11 --- Statistical Analysis --- p.35 / Chapter 2.7 --- Mutatox® test --- p.36 / Chapter 2.8 --- Statistical analysis --- p.36 / Chapter 3 --- Result --- p.45 / Chapter 3.1 --- Determination of antioxidant activity using Trolox equivalent antioxidant capacity (TEAC) assay --- p.45 / Chapter 3.1.1 --- Trolox standard reference --- p.45 / Chapter 3.1.2 --- Antioxidant activity: ABTS´Ø+ scavenging capacity --- p.45 / Chapter 3.2 --- Evaluation of antioxidant activity using free radical scavenging assay --- p.46 / Chapter 3.2.1 --- Free radical scavenging abilities at 5 minutes --- p.46 / Chapter 3.2.2 --- Antiradical efficiency --- p.47 / Chapter 3.3 --- Evaluation of antioxidant activity using β-carotene bleaching assay --- p.47 / Chapter 3.3.1 --- Optimal incubation time --- p.47 / Chapter 3.2.2 --- Antioxidant activities on β-carotene bleaching assay --- p.47 / Chapter 3.4 --- Structure and antioxidant activities relationship (SAR) of flavonoids --- p.48 / Chapter 3.4.1 --- Effect of hydroxylation on the antioxidant activities of flavonoids --- p.48 / Chapter 3.4.1.1 --- Hydroxylation positions --- p.48 / Chapter 3.4.1.2 --- Polyhydroxylation --- p.48 / Chapter 3.4.2 --- Importance of B ring structure --- p.49 / Chapter 3.4.2.1 --- Increase hydroxylation in B ring --- p.49 / Chapter 3.4.2.2 --- The othro-dihydroxyl arranagement in B ring --- p.49 / Chapter 3.4.3 --- Importance of C ring structure --- p.50 / Chapter 3.4.3.1 --- The presence of a hydroxyl group at C3 --- p.50 / Chapter 3.4.3.2 --- The blockage of hydroxylation at C3 --- p.50 / Chapter 3.4.3.3 --- The presence of a double bond between C2 to C3 --- p.50 / Chapter 3.4.3.4 --- The presence of a carbonyl group at C4 --- p.50 / Chapter 3.4.3.5 --- The conjugation of a carbonyl at with a double bond between C2 to C3 --- p.51 / Chapter 3.4.4 --- Effect of glycosylation --- p.51 / Chapter 3.5 --- Evaluation of protective effects on DNA damage using comet assay --- p.51 / Chapter 3.5.1 --- Optimization of conditions fro the determination of H2O2-induced DNA damage --- p.52 / Chapter 3.5.1.1 --- H2O2 concentration & treatment temperature --- p.52 / Chapter 3.5.1.2 --- H2O2 treatment time --- p.52 / Chapter 3.5.1.3 --- Sample volume --- p.52 / Chapter 3.5.2 --- Protective effect of vitamin C on DNA damage --- p.53 / Chapter 3.5.3 --- Protective effect of selected flavonoids on DNA damage --- p.53 / Chapter 3.5.4 --- Structure and antioxidant activities relationship (SAR) of flavonoids in comet assay --- p.54 / Chapter 3.5.4.1 --- The importance of B ring structures --- p.54 / Chapter 3.5.4.2 --- The importance of C ring structures --- p.54 / Chapter 3.6 --- Evaluation of genotoxicity of flavonoids using Mutatox test --- p.55 / Chapter 4 --- Discussion --- p.96 / Chapter 4.1 --- Comparison of antioxidant activities between hydrophilic and lipophilic assays --- p.97 / Chapter 4.2 --- Structure and antioxidant activity relationship of flavonoids --- p.98 / Chapter 4.3 --- The comet assay --- p.103 / Chapter 4.4 --- Comparison of protective effect on DNA damage between pre-incubation and co-incubation systems --- p.105 / Chapter 4.5 --- Structure and protective effect of flavonoids in the comet assay --- p.106 / Chapter 4.6 --- Genotoxicity of flavonoids --- p.108 / Chapter 4.7 --- Significance and future works --- p.108 / Chapter 5 --- Conclusion --- p.111 / References --- p.113
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_323835 |
| Date | January 2002 |
| Contributors | Ngai, Lei-Ka., Chinese University of Hong Kong Graduate School. Division of Biology. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | print, xiii, 125 leaves : ill. (some col.) ; 30 cm. |
| Rights | Use 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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