Chiang Yee-Ting. / Thesis submitted in: December 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 116-130). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / List of Abbreviations --- p.iv / List of Tables --- p.v / List of Figures --- p.vi / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- "Free radical, oxidative stress and antioxidants" --- p.2 / Chapter 1.1.1 --- Free radicals and reactive oxygen species (ROS) --- p.2 / Chapter 1.1.2 --- Oxidative stress and human diseases --- p.3 / Chapter 1.1.3 --- Dietary antioxidants --- p.5 / Chapter 1.1.4 --- Synthetic antioxidants --- p.5 / Chapter 1.2 --- Flavonoids ´ؤ polyphenolic compounds in plants --- p.8 / Chapter 1.2.1 --- Sources and biosynthesis of flavonoids --- p.8 / Chapter 1.2.2 --- Classification and dietary occurrence of flavonoids --- p.11 / Chapter 1.2.3 --- Functions of flavonoids in plants --- p.15 / Chapter 1.2.4 --- Effects of flavonoids in mammals --- p.16 / Chapter 1.2.5 --- Therapeutic application of flavonoids --- p.17 / Chapter 1.2.6 --- Absorption and metabolism of flavonoids --- p.26 / Chapter 1.3 --- Plant of interest --- p.28 / Chapter 1.4 --- Method used to characterize flaovnoid antioxidants in Vigna sinensis seeds --- p.30 / Chapter 1.5 --- Method used to evaluate the antioxidant activity --- p.31 / Chapter 1.5.1 --- p-carotene bleaching method --- p.31 / Chapter 1.5.2 --- "a,a-diphenyl- --- p.32 / Chapter 1.5.3 --- Single cell gel electrophoresis assay (Comet assay) --- p.32 / Chapter 1.6 --- Research objectives --- p.34 / Chapter 2 --- Materials and Methods --- p.35 / Chapter 2.1 --- Plant materials and chemicals --- p.35 / Chapter 2.2 --- Sample preparation --- p.36 / Chapter 2.2.1 --- Methanolic extraction method --- p.36 / Chapter 2.2.2 --- Acidic methanolic extraction method --- p.36 / Chapter 2.2.3 --- Optimization of extraction time --- p.37 / Chapter 2.3 --- Standards preparation --- p.37 / Chapter 2.4 --- Characterization of flavonoid antioxidants in V. sinensis seed extracts --- p.38 / Chapter 2.5 --- Evaluation of antioxidant activity --- p.39 / Chapter 2.6 --- Determination of free radical scavenging ability --- p.41 / Chapter 2.7 --- Evaluation of the protective effects on DNA damage --- p.42 / Chapter 2.7.1 --- Preparation of reagents --- p.42 / Chapter 2.7.2 --- Blood sample --- p.43 / Chapter 2.7.3 --- Hydrogen peroxide treatment --- p.43 / Chapter 2.7.3.1 --- Co-incubation system --- p.43 / Chapter 2.7.3.2 --- Pre-incubation system --- p.43 / Chapter 2.7.4 --- Establishment of optimal assay conditions --- p.44 / Chapter 2.7.4.1 --- Hydrogen peroxide concentration --- p.44 / Chapter 2.7.4.2 --- Sample volume --- p.44 / Chapter 2.7.4.3 --- Incubation time --- p.44 / Chapter 2.7.4.4 --- Hydrogen peroxide treatment time --- p.44 / Chapter 2.7.5 --- Ethidium bromide-acridine orange cell viability determination --- p.45 / Chapter 2.7.6 --- Slide preparation --- p.45 / Chapter 2.7.7 --- Comet assay --- p.45 / Chapter 2.7.8 --- Quantification of DNA damage --- p.47 / Chapter 2.7.9 --- Statistical analysis --- p.47 / Chapter 3 --- Results / Chapter 3.1 --- Comparison on the free radical scavenging abilities on two different V. sinensis seed extracts --- p.48 / Chapter 3.1.1 --- Optimal extraction time of methanolic extraction method --- p.48 / Chapter 3.1.2 --- Optimal extraction time of acidic methanolic extraction method --- p.48 / Chapter 3.1.3 --- pH values of two different V. sinensis seed extracts --- p.49 / Chapter 3.1.4 --- Free radical scavenging abilities of the two different V. sinensis seed extracts --- p.49 / Chapter 3.2 --- Determination of the stability of the V. sinensis seed extracts --- p.50 / Chapter 3.2.1 --- Effects of storage on the free radical scavenging ability of methanolic V. sinensis seed extract --- p.50 / Chapter 3.2.2 --- Effects of storage on the free radical scavenging ability of acidic V. sinensis seed extract --- p.50 / Chapter 3.2.3 --- Effect of storage on the antioxidant activity of methanolic V.sinensis seed extract --- p.51 / Chapter 3.2.4 --- Effect of storage on the antioxidant activity of acidic V. sinensis seed extract --- p.52 / Chapter 3.3 --- Identification of the flavonoid antioxidants in the acidic V. sinensis seed extract --- p.53 / Chapter 3.4 --- Evaluation of free radical scavenging abilitiesof identified flavonoids using the DPPH radical scavenging method --- p.54 / Chapter 3.5 --- Evaluation of antioxidant activities of the identified flavonoids using the β-carotene bleaching assay --- p.56 / Chapter 3.6 --- Evaluation of protective effects on DNA damage using the Comet assay --- p.57 / Chapter 3.6.1 --- Optimal comet assay conditions --- p.57 / Chapter 3.6.1.1 --- Hydrogen peroxide concentration --- p.57 / Chapter 3.6.1.2 --- Sample volume --- p.58 / Chapter 3.6.1.3 --- Incubation time with the seed extract in the co-incubation system --- p.58 / Chapter 3.6.1.4 --- Hydrogen peroxide treatment time --- p.58 / Chapter 3.6.1.5 --- Incubation time with the seed extract in the pre-incubation system --- p.59 / Chapter 3.6.2 --- Protective effects of the V. sinensis seed extracts and phenolic compounds --- p.59 / Chapter 3.6.2.1 --- Protective effects in pre-incubation system --- p.59 / Chapter 3.6.2.2 --- Protective effects in co-incubation system --- p.60 / Chapter 3.6.3 --- Protective effects of the identified flavonoids in acidic V.sinensis seed extracts and phenolic compounds --- p.60 / Chapter 3.6.3.1 --- Protective effects in pre-incubation system --- p.60 / Chapter 3.6.3.1.1 --- At 0.5 mM concentration --- p.60 / Chapter 3.6.3.1.2 --- At 1 mM concentration --- p.61 / Chapter 3.6.3.2 --- Protective effects in co-incubation system --- p.62 / Chapter 3.6.3.2.1 --- At 0.5 mM concentration --- p.62 / Chapter 3.6.3.2.2 --- At 1 mM concentration --- p.62 / Chapter 4 --- Discussion --- p.100 / Chapter 4.1 --- Comparison on the two different extraction methods --- p.100 / Chapter 4.1.1 --- Methanolic extraction and acidic methanolic extraction --- p.100 / Chapter 4.1.2 --- Free radical scavenging abilities on the two different V sinensis seed extracts --- p.100 / Chapter 4.2 --- Stabilities of two different V. sinensis seed extracts --- p.101 / Chapter 4.2.1 --- Change in antioxidant activity during storage --- p.101 / Chapter 4.2.2 --- Comparison on the stabilities of the extracts assayed under different conditions --- p.102 / Chapter 4.3 --- Identification of flavonoid antioxidants in the acidic methanolic V sinensis seed extract --- p.103 / Chapter 4.4 --- Antioxidant activities of the individual identified flavonoid antioxidants --- p.104 / Chapter 4.4.1 --- Antioxidant activities of the identified flavonoid antioxidants and the selected phenolic compounds in hydrophilic assay system --- p.106 / Chapter 4.4.2 --- Antioxidant activities of the identified flavonoid antioxidants and the selected phenolic compounds in lipophilic assay system --- p.107 / Chapter 4.5 --- Evaluation of protective effects on DNA damage using Comet assay --- p.109 / Chapter 4.5.1 --- Optimal conditions in Comet assay --- p.109 / Chapter 4.5.1.1 --- Effect of hydrogen peroxide concentration --- p.109 / Chapter 4.5.1.2 --- Effect of sample volume --- p.109 / Chapter 4.5.1.3 --- Effect of hydrogen treatment time --- p.110 / Chapter 4.5.1.4 --- Pre-incubation and co-incubation systems --- p.110 / Chapter 4.5.2 --- Protective effects of two different V. sinensis seed extracts and six phenolic compounds --- p.111 / Chapter 4.5.3 --- Protective effects of the identified flavonoids and the phenolic compounds --- p.112 / Chapter 4.6 --- Health beneficial properties of V. sinensis seeds --- p.113 / Chapter 5 --- Conclusion --- p.114 / References --- p.116
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_324430 |
| Date | January 2003 |
| Contributors | Chiang, Yee-Ting., 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, viii, 130 leaves : ill. (col. ill.) ; 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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