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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Protective effects of seaweeds against liver injury caused by carbon tetrachloride and trichloroethylene in rats.

January 2000 (has links)
Wong Chun-kwan. / Thesis submitted in: December 1999. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 127-137). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgments --- p.viii / Tables of Contents --- p.ix / List of Figures --- p.xv / List of Tables --- p.xxvi / Chapter Chapter 1: --- INTRODUCTION --- p.1 / Chapter Chapter 2: --- LITERATURE REVIEW --- p.8 / Chapter 2.1 --- Toxicology --- p.8 / Chapter 2.1.1 --- Acute toxicity test --- p.8 / Chapter 2.1.2 --- Biochemical Analysis --- p.9 / Chapter 2.1.3 --- Organ weights --- p.10 / Chapter 2.2 --- Histology --- p.11 / Chapter 2.2.1 --- Light Microscope --- p.11 / Chapter 2.2.2 --- Electron Microscopy --- p.11 / Chapter 2.3 --- Tissue injury --- p.12 / Chapter 2.3.1 --- Free-radical mechanisms --- p.12 / Chapter 2.3.2 --- Lipid peroxidation --- p.13 / Chapter 2.4 --- Carbon tetrachloride (CC14) --- p.14 / Chapter 2.4.1 --- Mechanisms of carbon tetrachloride toxicity --- p.15 / Chapter 2.5 --- Trichloroethylene (TCE) --- p.18 / Chapter 2.5.1 --- Mechanisms of trichloroethylene toxicity --- p.21 / Chapter 2.6 --- Dimethyl sulfoxide (DMSO) --- p.25 / Chapter 2.7 --- N-acetylcysteine (NAC) --- p.27 / Chapter Chapter 3: --- MATERIALS AND METHODS --- p.28 / Chapter 3.1 --- Materials --- p.28 / Chapter 3.2 --- Methods --- p.31 / Chapter 3.2.1 --- Acute hepatotoxicity test on aqueous seaweed extracts --- p.31 / Chapter 3.2.1.1 --- Preparation of aqueous extracts of seaweed --- p.31 / Chapter 3.2.1.2 --- Experimental protocol --- p.31 / Chapter 3.2.1.3 --- Biochemical assays --- p.32 / Chapter 3.2.1.4 --- Organ weights --- p.36 / Chapter 3.2.1.5 --- Histopathological examination --- p.36 / Chapter 3.2.1.6 --- Statistical analysis --- p.36 / Chapter 3.2.2 --- Curative and preventive tests of seaweed aqueous extracts against the CCl4-induced hepatotoxicity --- p.37 / Chapter 3.2.2.1 --- Preparation of aqueous extracts of seaweed --- p.37 / Chapter 3.2.2.2 --- Experimental protocol --- p.37 / Chapter 3.2.2.3 --- Biochemical assays --- p.39 / Chapter 3.2.2.4 --- Organ weights --- p.39 / Chapter 3.2.2.5 --- Histopathological examination --- p.40 / Chapter 3.2.2.6 --- Statistical analysis --- p.41 / Chapter 3.2.3 --- Acute hepatotoxicity test of TCE in rats by oral and intraperitoneal routes --- p.42 / Chapter 3.2.3.1 --- Experimental protocol --- p.42 / Chapter 3.2.3.2 --- Biochemical assays --- p.43 / Chapter 3.2.3.3 --- Organ weights --- p.43 / Chapter 3.2.3.4 --- Histopathological examination --- p.44 / Chapter 3.2.3.5 --- Statistical analysis --- p.44 / Chapter 3.2.4 --- Curative and preventive tests of seaweed aqueous extracts against the TCE effective dose-induced toxicity --- p.44 / Chapter 3.2.4.1 --- Preparation of aqueous extracts of seaweed --- p.44 / Chapter 3.2.4.2 --- Experimental protocol --- p.45 / Chapter 3.2.4.3 --- Biochemical assays --- p.46 / Chapter 3.2.4.4 --- Organ weights --- p.46 / Chapter 3.2.4.5 --- Histopathological examination --- p.46 / Chapter 3.2.5 --- Antidotal effects of dimethyl sulfoxide (DMSO) and N-acetylcysteine (NAC) against CC14- and TCE- induced poisoning in rats --- p.47 / Chapter 3.2.5.1 --- Experimental protocol --- p.47 / Chapter 3.2.5.2 --- Biochemical assays --- p.48 / Chapter 3.2.5.3 --- Organ weights --- p.48 / Chapter 3.2.5.4 --- Histopathological examination --- p.49 / Chapter 3.2.6 --- Hepatoprotective effect of seaweeds' methanol extract against CC14- and TCE-induced poisoning in rats --- p.49 / Chapter 3.2.6.1 --- Preparation of methanol extracts of seaweed --- p.49 / Chapter 3.2.6.2 --- Experimental protocol --- p.50 / Chapter 3.2.6.3 --- Biochemical assays --- p.52 / Chapter 3.2.6.4 --- Organ weights --- p.52 / Chapter 3.2.6.5 --- Histopathological examination --- p.53 / Chapter Chapter 4 --- RESULTS --- p.54 / Chapter 4.1 --- Acute hepatotoxicity test on aqueous seaweed extracts --- p.54 / Chapter 4.1.1 --- The biochemical assays of the serum transaminase activity --- p.54 / Chapter 4.1.2 --- The organ weight (Aqueous seaweed crude extracts) --- p.56 / Chapter 4.2 --- Curative and preventive tests of seaweed aqueous extracts against the CCl4-induced hepatotoxicity --- p.58 / Chapter 4.2.1 --- The biochemical assays of the serum transaminase activity (Curative) --- p.58 / Chapter 4.2.2 --- The organ weight (Curative) --- p.60 / Chapter 4.2.3 --- The biochemical assays of the serum transaminase activity (Preventive) --- p.62 / Chapter 4.2.4 --- The organ weight (Preventive) --- p.64 / Chapter 4.3 --- Acute hepatotoxicity test of TCE in rats by oral and intraperitoneal routes --- p.66 / Chapter 4.3.1 --- Oral route --- p.66 / Chapter 4.3.1.1 --- One-time oral route --- p.66 / Chapter 4.3.1.2 --- Two-time oral route --- p.66 / Chapter 4.3.2 --- Intraperitoneal route --- p.66 / Chapter 4.3.3 --- Time course of the effective dose of 20% TCE in i.p. route --- p.67 / Chapter 4.4 --- Curative and preventive tests of seaweed aqueous extracts against the TCE effective dose-induced toxicity --- p.12 / Chapter 4.4.1 --- The biochemical assays of the serum transaminase activity (Curative) --- p.72 / Chapter 4.4.2 --- The organ weight (Curative) --- p.74 / Chapter 4.4.3 --- The biochemical assays of the serum transaminase activity (Preventive) --- p.76 / Chapter 4.4.4 --- The organ weight (Preventive) --- p.78 / Chapter 4.5 --- Antidotal effects of dimethyl sulfoxide (DMSO) and N-acetylcysteine (NAC) against CC14- and TCE-induced poisoning in rats --- p.80 / Chapter 4.5.1 --- The biochemical assays of the serum transaminase activity (Curative) --- p.80 / Chapter 4.5.2 --- The organ weight (Curative) --- p.82 / Chapter 4.5.3 --- The biochemical assays of the serum transaminase activity (Preventive) --- p.84 / Chapter 4.5.4 --- The organ weight (Preventive) --- p.86 / Chapter 4.6 --- Hepatoprotective effect of methanol extract of seaweed against CC14- and TCE-induced poisoning in rats --- p.88 / Chapter 4.6.1 --- The biochemical assays of the serum transaminase activity (Curative) --- p.88 / Chapter 4.6.2 --- The organ weight (Curative) --- p.89 / Chapter 4.7 --- Histopathological examinations --- p.90 / Chapter 4.7.1 --- Acute hepatotoxicity test on aqueous seaweed extracts --- p.91 / Chapter 4.7.2 --- Curative and preventive tests of seaweed aqueous extracts against the CC14-induced hepatotoxicity --- p.92 / Chapter 4.7.3 --- Acute hepatotoxicity test of TCE in rats by oral and intraperitoneal routes --- p.99 / Chapter 4.7.4 --- Curative and preventive tests of seaweed aqueous extracts against the TCE effective dose-induced toxicity --- p.100 / Chapter 4.7.5 --- Antidotal effects of dimethyl sulfoxide (DMSO) and N-acetylcysteine (NAC) against CC14- and TCE-induced poisoning in rats --- p.100 / Chapter 4.7.6 --- Hepatoprotective effect of methanol extract of seaweed against CC14- and TCE-induced poisoning in rats --- p.102 / Chapter Chapter 5 --- DISCUSSION --- p.106 / Chapter Chapter 6 --- CONCLUSION --- p.124 / REFERENCES --- p.127 / APPENDIX --- p.138
22

Antioxidative activity of aqueous extracts from the herbal components of the traditional Chinese medicinal formula Wu-zi-yan-zong-wan.

January 2002 (has links)
by Yau Ming Hon. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 131-154). / Abstracts in English and Chinese. / Contents --- p.i / Acknowledgements --- p.ix / Abstract --- p.x / 槪論 --- p.xi / List of abbreviations --- p.xii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Reactive oxygen species (ROS) --- p.2 / Chapter 1.1.1 --- Hydrogen peroxide --- p.2 / Chapter 1.1.2 --- Superoxide anion --- p.3 / Chapter 1.1.3 --- Hydroxyl radical --- p.3 / Chapter 1.1.4 --- Carbon centered radical --- p.4 / Chapter 1.1.5 --- Nitric oxide --- p.4 / Chapter 1.2 --- Physiological roles of ROS --- p.5 / Chapter 1.2.1 --- Signal transduction --- p.5 / Chapter 1.2.2 --- Phagocytic activity --- p.6 / Chapter 1.3 --- Defense systems against ROS --- p.7 / Chapter 1.3.1 --- Endogenous antioxidant enzymes --- p.8 / Chapter 1.3.1.1 --- Catalase --- p.8 / Chapter 1.3.1.2 --- Superoxide dismutase --- p.8 / Chapter 1.3.1.3 --- Selenium-glutathione peroxidase --- p.9 / Chapter 1.3.1.4 --- Glutathione reductase --- p.10 / Chapter 1.3.1.5 --- Glutathione-S-transferases --- p.10 / Chapter 1.3.2 --- Non-enzymatic antioxidants --- p.12 / Chapter 1.3.2.1 --- Vitamin E (tocopherols and tocotrienols) --- p.12 / Chapter 1.3.2.2 --- Vitamin C (L-ascorbic acid) --- p.13 / Chapter 1.3.2.3 --- Glutathione --- p.14 / Chapter 1.3.2.4 --- Flavonoids and polyphenols --- p.15 / Chapter 1.3.2.5 --- Uric acid --- p.16 / Chapter 1.4 --- Roles of ROS in pathogenesis --- p.16 / Chapter 1.4.1 --- Liver diseases --- p.17 / Chapter 1.4.2 --- Genital malfunctioning --- p.19 / Chapter 1.5 --- "The traditional Chinese medicinal formula, Wu-zi-yan-zong-wan" --- p.19 / Chapter 1.5.1 --- Pharmacology of individual herbal components --- p.20 / Chapter 1.5.1.1 --- Semen Cuscuta --- p.20 / Chapter 1.5.1.2 --- Fructus Lycii --- p.21 / Chapter 1.5.1.3 --- Fructus Schisandrae --- p.21 / Chapter 1.5.1.4 --- Fructus Rubi --- p.22 / Chapter 1.5.1.5 --- Semen Plantaginis --- p.22 / Chapter 1.5.2 --- Effect of Wu-zi-yan-zong-wan on infertility --- p.23 / Chapter 1.5.3 --- Effect of Wu-zi-yan-zong-wan on liver disease --- p.23 / Chapter 1.6 --- Objectives of the present study --- p.24 / Chapter Chapter 2 --- Antioxidant Activity of Aqueous Extracts of the Herbal Components of Wu-zi-yan-zong-wan in in vitro Free Radical Generating Systems --- p.26 / Chapter 2.1 --- Introduction --- p.27 / Chapter 2.1.1 --- Application of in vitro ROS generating systems --- p.27 / Chapter 2.1.1.1 --- Superoxide generation --- p.27 / Chapter 2.1.1.2 --- Hydroxyl radical generation system --- p.28 / Chapter 2.1.1.3 --- "2,2'-Azobis(2-amidinopropane) dihydrochloride- induced hemolysis" --- p.28 / Chapter 2.1.1.4 --- Bleomycin-iron-dependent DNA damage --- p.28 / Chapter 2.1.2 --- Objective --- p.29 / Chapter 2.2 --- Materials and methods --- p.30 / Chapter 2.2.1 --- Materials --- p.30 / Chapter 2.2.2 --- Preparation of aqueous herbal extracts --- p.30 / Chapter 2.2.3 --- Superoxide-scavenging assay --- p.30 / Chapter 2.2.4 --- Microsome lipid peroxidation inhibition assay --- p.31 / Chapter 2.2.5 --- "2,2'-Azobis(2-amidinopropane) dihydrochloride-induced hemolysis inhibition assay" --- p.32 / Chapter 2.2.6 --- Bleomycin-iron-dependent DNA damage inhibition assay --- p.32 / Chapter 2.2.7 --- Statistical analysis --- p.33 / Chapter 2.3 --- Results --- p.34 / Chapter 2.3.1 --- Extraction yield --- p.34 / Chapter 2.3.2 --- Free radical scavenging activity of Wu-zi-yan-zong-wan extract --- p.34 / Chapter 2.3.3 --- Free radical scavenging activity of FR extract --- p.37 / Chapter 2.3.3.1 --- Superoxide-scavenging activity --- p.37 / Chapter 2.3.3.2 --- Effect on hydroxyl radical-induced lipid peroxidation --- p.37 / Chapter 2.3.3.3 --- Effect on AAPH-induced hemolysis --- p.40 / Chapter 2.3.3.4 --- Effect on bleomycin-iron-dependent DNA damage --- p.40 / Chapter 2.3.4 --- Pro-oxidant activity of FR extract --- p.40 / Chapter 2.3.5 --- Free radical scavenging activity of the remaining herbal extracts --- p.44 / Chapter 2.4 --- Discussion --- p.46 / Chapter Chapter 3 --- Effect of Aqueous Extract of the Herbal Components of Wu- zi-yan-zong-wan on tert-Butyl Hydroperoxide-Induced Oxidative Damage in Primary Rat Hepatocyte --- p.51 / Chapter 3.1 --- Introduction --- p.52 / Chapter 3.1.1 --- Primary rat hepatocyte as pharmacological model --- p.52 / Chapter 3.1.2 --- tert-Butyl hydroperoxide as an oxidative stress inducer --- p.53 / Chapter 3.1.3 --- Detection of ROS --- p.54 / Chapter 3.1.4 --- Objective --- p.55 / Chapter 3.2 --- Materials and methods --- p.56 / Chapter 3.2.1 --- Materials --- p.56 / Chapter 3.2.2 --- Primary rat hepatocyte isolation --- p.56 / Chapter 3.2.2.1 --- Liver perfusion --- p.56 / Chapter 3.2.2.2 --- Collagen pre-coated plates preparation --- p.57 / Chapter 3.2.2.3 --- Hepatocyte culture --- p.58 / Chapter 3.2.3 --- Drug treatment and oxidative stress induction --- p.58 / Chapter 3.2.4 --- Cytotoxicity assessment --- p.58 / Chapter 3.2.4.1 --- Lactate dehydrogenase leakage measurement --- p.59 / Chapter 3.2.4.2 --- MTT assay --- p.59 / Chapter 3.2.5 --- Cellular GSH content determination --- p.59 / Chapter 3.2.6 --- Protein determination by Lowry's method --- p.60 / Chapter 3.2.7 --- MDA measurement --- p.60 / Chapter 3.2.8 --- GSSG measurement --- p.61 / Chapter 3.2.9 --- ROS measurement with fluorescent dye --- p.61 / Chapter 3.2.10 --- "Vitamin C, vitamin E and butylated hydroxytoluene treatment" --- p.62 / Chapter 3.2.11 --- Antioxidant enzyme activity measurement --- p.62 / Chapter 3.2.11.1 --- Catalase activity measurement --- p.62 / Chapter 3.2.11.2 --- Superoxide dismutase activity measurement --- p.63 / Chapter 3.2.11.3 --- Glutathione peroxidase activity measurement --- p.63 / Chapter 3.2.11.4 --- Glutathione-S-transferases activity measurement --- p.63 / Chapter 3.2.11.5 --- Glutathione reductase activity measurement --- p.64 / Chapter 3.2.12 --- Statistical analysis --- p.64 / Chapter 3.3 --- Results --- p.65 / Chapter 3.3.1 --- Cytotoxicity of FR extract on rat hepatocyte --- p.65 / Chapter 3.3.2 --- Effect of tBHP and FR extract on hepatocyte viability --- p.65 / Chapter 3.3.3 --- Time-dependent effect of FR extract on tBHP-induced cytotoxicity --- p.69 / Chapter 3.3.4 --- Effect of tBHP and FR extract on hepatocyte GSH content --- p.69 / Chapter 3.3.5 --- Effect of tBHP and FR extract on GSSG formation in hepatocyte --- p.72 / Chapter 3.3.6 --- Effect of tBHP and FR extract on MDA formation in hepatocyte --- p.72 / Chapter 3.3.7 --- ROS-scavenging activity of FR extract in hepatocyte --- p.77 / Chapter 3.3.8 --- Effect of FR extract on antioxidant enzymes activities --- p.77 / Chapter 3.3.9 --- Comparison between typical antioxidants --- p.77 / Chapter 3.3.10 --- Effect of WZ and remaining herbal extracts on tBHP-induced oxidative damage in hepatocyte --- p.81 / Chapter 3.4 --- Discussion --- p.84 / Chapter Chapter 4 --- Effect of Aqueous Extract of Wu-zi-yan-zong-wan and Fructus Rubi on tert-Buty Hydroperoxide Induced Oxidative Damage in Mouse Model --- p.91 / Chapter 4.1 --- Introduction --- p.92 / Chapter 4.2 --- Materials and methods --- p.93 / Chapter 4.2.1 --- Materials --- p.93 / Chapter 4.2.2 --- Animal treatments --- p.93 / Chapter 4.2.3 --- Serum preparation --- p.94 / Chapter 4.2.4 --- Marker enzyme measurement --- p.94 / Chapter 4.2.5 --- Liver MDA and GSH determination --- p.95 / Chapter 4.2.6 --- Statistical analysis --- p.95 / Chapter 4.3 --- Results --- p.97 / Chapter 4.3.1 --- Effect of tBHP and FR extract on mouse serum ALT and AST activities --- p.97 / Chapter 4.3.2 --- Effect of tBHP and FR extract on mouse liver MDA and GSH content --- p.97 / Chapter 4.3.3 --- Effect of WZ extract on tBHP-induced increase in serum ALT and AST activities --- p.97 / Chapter 4.4 --- Discussion --- p.102 / Chapter Chapter 5 --- Characterization of the Active Antioxidant Principlein Aqueous Extract of FR --- p.105 / Chapter 5.1 --- Introduction --- p.106 / Chapter 5.2 --- Materials and methods --- p.107 / Chapter 5.2.1 --- Materials --- p.107 / Chapter 5.2.2 --- Chemical/physical treatments on FR extract --- p.107 / Chapter 5.2.3 --- Digestion with enzymes --- p.108 / Chapter 5.2.4 --- Antioxidant activity determination --- p.109 / Chapter 5.2.5 --- Chemical composition determination --- p.109 / Chapter 5.2.5.1 --- Uronic acid determination --- p.109 / Chapter 5.2.5.2 --- Hexose determination --- p.109 / Chapter 5.2.5.3 --- Tannin determination --- p.110 / Chapter 5.2.5.4 --- Protein determination --- p.110 / Chapter 5.2.6 --- Column chromatography --- p.110 / Chapter 5.2.6.1 --- Polyamide CC6 resin column chromatography --- p.111 / Chapter 5.2.6.2 --- Sephadex LH-20 gel column chromatography --- p.111 / Chapter 5.2.7 --- Antioxidant activity of commercially available tannin --- p.111 / Chapter 5.2.8 --- Bovine serum albumin precipitation --- p.112 / Chapter 5.2.9 --- Statistical analysis --- p.112 / Chapter 5.3 --- Results --- p.113 / Chapter 5.3.1 --- Effect of chemical/physical treatments on antioxidant activity of FR extract --- p.113 / Chapter 5.3.2 --- Effect of enzyme digestions on antioxidant activity of FR extract --- p.113 / Chapter 5.3.3 --- Chemical composition of FR extract --- p.118 / Chapter 5.3.4 --- Polyamide CC6 resin column chromatography --- p.118 / Chapter 5.3.5 --- Sephadex LH-20 gel column chromatography --- p.118 / Chapter 5.3.6 --- Antioxidant activity of commercially available tannin --- p.123 / Chapter 5.3.7 --- Effect of BSA precipitation on superoxide-scavenging activity --- p.123 / Chapter 5.4 --- Discussion --- p.127 / Conclusion --- p.131 / References --- p.132
23

Effects of green tea catechins and broccoli extracts on the antioxidant enzymes and life span of Drosophila melanogaster.

January 2005 (has links)
Li, Yuk Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 121-132). / Abstracts in English and Chinese. / ACKNOWLEDGMENTS --- p.i / ABSTRACT --- p.ii / LIST OF ABBREVATIONS --- p.vii / TABLE OF CONTENTS --- p.x / Chapter Chapter 1 --- General Introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Theories of aging --- p.2 / Chapter 1.2.1 --- Free radical theory of aging --- p.3 / Chapter 1.2.2 --- Free radicals reactions and their effects --- p.4 / Chapter 1.2.2.1 --- Lipid peroxidation --- p.6 / Chapter 1.2.2.2 --- Protein oxidation --- p.6 / Chapter 1.2.2.3 --- DNA oxidation --- p.8 / Chapter 1.2.2.4 --- Carbohydrate oxidation --- p.8 / Chapter 1.2.3 --- Antioxidant defense systems --- p.9 / Chapter 1.2.3.1 --- Superoxide dismutase (SOD) --- p.9 / Chapter 1.2.3.2 --- Catalase --- p.11 / Chapter 1.2.3.3 --- Glutathione peroxidase (GPx) and reductase --- p.11 / Chapter 1.3 --- Models on aging study --- p.12 / Chapter 1.3.1 --- Non-mammalian model systems --- p.12 / Chapter 1.3.1.1 --- History of Drosophila on longevity study --- p.14 / Chapter 1.3.1.2 --- Advantages of Drosophila model --- p.14 / Chapter 1.3.2 --- Mammalian model systems --- p.15 / Chapter 1.4 --- Antioxidant effects on aging process --- p.16 / Chapter 1.4.1 --- Antioxidant capacity of tea --- p.16 / Chapter 1.4.2 --- Antioxidant capacity of vegetables --- p.19 / Chapter 1.5 --- Dietary fat on longevity --- p.21 / Chapter Chapter 2 --- Anti-aging: Effects of Green Tea Catechins on Life Span and Antioxidant Enzymes of Drosophila melanogaster / Chapter 2.1 --- Introduction --- p.24 / Chapter 2.2 --- Gbjectives --- p.27 / Chapter 2.3 --- Materials and methods --- p.28 / Chapter 2.3.1 --- Materials --- p.28 / Chapter 2.3.2 --- Preparation of GTCs --- p.28 / Chapter 2.3.3 --- Feeding experiment --- p.30 / Chapter 2.3.3.1 --- Dose determination --- p.31 / Chapter 2.3.3.2 --- Paraquat treatment --- p.31 / Chapter 2.3.3.3 --- Hydrogen peroxide (H202) treatment --- p.33 / Chapter 2.3.3.4 --- Enzyme activity assay --- p.34 / Chapter 2.3.4 --- Enzyme analysis --- p.34 / Chapter 2.3.4.1 --- SOD activity --- p.34 / Chapter 2.3.4.2 --- Catalase activity --- p.35 / Chapter 2.3.4.3 --- Lipid hydorperoxies (LOOHs) formation --- p.36 / Chapter 2.3.4.4 --- Determination of protein concentration --- p.37 / Chapter 2.3.5 --- Semi-quantitative RT-PCR assay --- p.37 / Chapter 2.3.5.1 --- RNA isolation --- p.37 / Chapter 2.3.5.2 --- Primer sequences --- p.38 / Chapter 2.3.5.3 --- Reverse Transcriptase PCR --- p.40 / Chapter 2.3.6 --- Statistics --- p.40 / Chapter 2.4 --- Results --- p.42 / Chapter 2.4.1 --- Dose determination --- p.42 / Chapter 2.4.2 --- Paraquat treatment --- p.45 / Chapter 2.4.3 --- H202 treatment --- p.48 / Chapter 2.4.4 --- SOD activity --- p.51 / Chapter 2.4.5 --- Catalase activity --- p.51 / Chapter 2.4.6 --- LOOHs formation --- p.53 / Chapter 2.4.7 --- Semi-quantitative RT-PCR assay --- p.53 / Chapter 2.5 --- Discussion --- p.55 / Chapter Chapter 3 --- Anti-aging: Effects of Vegetable Extracts on Life Span and Antioxidant Enzymes of Drosophila melanogaster / Chapter 3.1 --- Introduction --- p.62 / Chapter 3.2 --- Objectives --- p.64 / Chapter 3.3 --- Materials and methods --- p.65 / Chapter 3.3.1 --- Materials --- p.65 / Chapter 3.3.2 --- Preparation of vegetables extracts --- p.65 / Chapter 3.3.3 --- Feeding experiment --- p.65 / Chapter 3.3.3.1 --- Dose determination --- p.66 / Chapter 3.3.3.2 --- Paraquat and hydrogen peroxide (H2O2) treatment --- p.67 / Chapter 3.3.4 --- Lipid hydroperoxide (LOOHs) formation --- p.67 / Chapter 3.3.5 --- Enzyme analysis --- p.67 / Chapter 3.3.6 --- Semi-quantitative RT-PCR assay --- p.67 / Chapter 3.3.7 --- Statistics --- p.68 / Chapter 3.4 --- Results --- p.69 / Chapter 3.4.1 --- Dose determination --- p.69 / Chapter 3.4.2 --- Antioxidant effect among different vegetables --- p.69 / Chapter 3.4.3 --- SOD activity --- p.76 / Chapter 3.4.4 --- Catalase activity --- p.76 / Chapter 3.4.5 --- LOOHs formation --- p.78 / Chapter 3.4.6 --- Semi-quantitative RT-PCR assay --- p.78 / Chapter 3.5 --- Discussion --- p.80 / Chapter Chapter 4 --- Anti-aging Activity of Greeen Tea Catechins and Broccoli Extracts in Drosophila melanogaster Fed a High Fat Diet / Chapter 4.1 --- Introduction --- p.85 / Chapter 4.2 --- Objectives --- p.87 / Chapter 4.3 --- Materials and methods --- p.88 / Chapter 4.3.1 --- Materials --- p.88 / Chapter 4.3.2 --- Preparation of free fatty acid --- p.88 / Chapter 4.3.3 --- Prepartion of GTCs and BEs --- p.89 / Chapter 4.3.4 --- Feeding experiment --- p.89 / Chapter 4.3.5 --- LOOHs formation --- p.90 / Chapter 4.3.6 --- Enzyme analysis --- p.91 / Chapter 4.3.7 --- Semi-quantitative RT-PCR assay --- p.91 / Chapter 4.3.8 --- Statistics --- p.91 / Chapter 4.4 --- Results --- p.92 / Chapter 4.4.1 --- Dose determination --- p.92 / Chapter 4.4.2 --- Effects of GTCs or BEs on life span with lard consumption --- p.95 / Chapter 4.4.3 --- LOOHs formation --- p.101 / Chapter 4.4.4 --- SOD activity --- p.103 / Chapter 4.4.5 --- Catalase activity --- p.107 / Chapter 4.4.6 --- Semi-quantitative RT-PCR assay --- p.110 / Chapter 4.5 --- Discussion --- p.112 / References --- p.121
24

Modulatory and antidiabetic effects of vindoline and Catharanthus roseus in type 2 diabetes mellitus induced male Wistar rats and in RIN-5F cell line

Goboza, Mediline January 2019 (has links)
Thesis (DPhil (Biomedical Science))--Cape Peninsula University of Technology, 2019. / Diabetes mellitus (DM) is a group of metabolic disorders characterised by persistent high blood glucose levels together with abnormal metabolism of macromolecules. If the hyperglycemia is not controlled, adverse metabolic changes could occur leading to the progressive development of severe complications. Formation of reactive oxygen/nitrogen species and inflammatory responses are principal mechanisms that have been implicated in the development of hyperglycemia-induced tissue damage. The commercially available drugs utilised in the treatment of diabetes have been linked to detrimental side effects hence the need to discover alternative medicines especially from medicinal plants. Catharanthus roseus is both a medicinal and ornamental plant that is traditionally used to treat various diseases. It has been reported to possess antidiabetic, anticancer, antimicrobial and antioxidant properties. The plant has been shown to possess more than 100 monotepernoid indole alkaloids which were linked to the plants’ antihyperglycemic and antioxidant effects. Therefore, this study was carried out to investigate the effect of vindoline; a bioactive compound derived from C. roseus against type 2 diabetes–induced complications. The study also investigated the effects of Catharanthus roseus extracts in RIN-5F cell line. The study was carried out in two parts: viz in vitro and the in vivo assessments. The in vitro study initially investigated the polyphenolic content and antioxidant activities of vindoline and the 3 extracts (methanolic, aqueous and the dichloromethane) of C.roseus. The assays used to evaluate the antioxidant capacity of the extracts include oxygen radical absorbance capacity (ORAC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibitory assay. Among the evaluated extracts, the methanolic extract demonstrated both high total polyphenolic content and antioxidant capacity. The HLPC analysis of the extracts was performed and showed highest concentrations of vindoline in the dichloromethane extract and the aqueous extract exhibited the least. The antioxidant activities of vindoline were determined and compared to a known antioxidant, ascorbic acid. Vindoline revealed stronger ORAC activity than ascorbic acid however the ferric reducing antioxidant power did not show any significant differences (p < 0.05). Insulin secretion studies were performed in a β-cell insulinoma cell line- RIN-5F exposed to different concentrations of glucose (high, low and in the absence of glucose). The studies were carried out to compare the β-cell stimulatory effect of vindoline to the extracts. After performing cytotoxic experiments, concentrations that resulted in about 80% cell viability were used to determine the insulin secretory effects. In cells that exposed to glucotoxicity (50 mM glucose), vindoline showed the highest β-cell stimulatory effect (p < 0.05) when compared to the untreated controls and to the cells that were treated with the methanolic extract. In cells that were exposed to a low glucose concentration, vindoline additionally showed significant β-cell stimulatory effect at p < 0.05 when compared to the aqueous and the methanolic extracts. Thereafter, the intracellular reactive oxygen species assay (ROSA) was performed in glucotoxicity-induced cells after treatment with vindoline and the respective extracts. The results were compared to the untreated control: vindoline, methanolic and the dichloromethane extracts indicated significant reduction in ROS generation (p < 0.05). Further measurement of the release of TNF-α, a pro-inflammatory cytokine in the cells following treatment, the results were not significant among the groups at p < 0.05. The carbohydrate enzymes inhibitory activity of vindoline and extracts of C.roseus (50, 25, 12.5 and 6.125 mg/ml) were measured. The alpha glucosidase inhibitory activities of the extracts at 50 mg/ml resulted in < 30% enzyme inhibition with no significant differences among the groups at p < 0.05. At lower concentrations, the dichloromethane extract exhibited significantly lower inhibitory activities when compared to the methanolic and the aqueous extract (p < 0.05). The alpha amylase inhibitory activity of the methanolic extract was significantly increased at all concentrations; recording the highest enzyme inhibition of approximately 40% (p < 0.5). However, the dichloromethane extract did not show any enzyme inhibitory activity. The enzyme inhibitory activity of vindoline was compared to acarbose-a known standard drug, for both enzymes; vindoline did not show appreciable enzyme inhibition when compared to acarbose (p < 0.05). In vivo studies were performed in a type 2 diabetes (T2DM) rat model in which T2DM was induced in 6 weeks old male Wistar rats by having them drink 10% fructose solution ad libitum for 14 days followed by a single intraperitoneal injection of streptozotocin (STZ 40 mg/kg) in freshly prepared 0.1 M citrate buffer (pH 4.5). Animals were randomly divided into six groups (n=8) and received daily treatments for 6 weeks with the vehicle, vindoline (20 mg/kg) or glibenclamide (5 mg/kg) via oral gavage. The effects of the treatments on blood glucose, insulin, body weight, organ weight, serum biochemical parameters, oxidative status, inflammatory markers and tissue histology were assessed in diabetic and non-diabetic rats. Administration of vindoline significantly (p < 0.05) reduced the fasting blood glucose in diabetic rats by 15% and significantly increased serum insulin levels when compared to the diabetic controls. Vindoline and glibenclamide significantly (p < 0.05) reduced the levels of circulating hepatic enzymes in T2DM; the results were significant when compared to the diabetic controls. Treatment with vindoline significantly improved the hepatic antioxidant status as indicated by increased ORAC, superoxide dismutase and catalase activities, indicative of the protective effect of vindoline in diabetes-induced hepatic injury. Assessment of the levels of pro-inflammatory cytokines in the hepatic tissue indicated remarkable reduction of TNF-ɑ by (-41%) and IL-6 (-28%) in diabetic rats treated with vindoline when compared to the diabetic controls (p < 0.05). The serum lipid profile showed marked increases in the levels of serum lipids (triglycerides, low density lipoproteins, total cholesterol and very low density lipoproteins) in diabetic controls when compared to all treatment groups (p < 0.05). Therefore, vindoline and glibenclamide showed possible protective effects against diabetes-induced cardiovascular disease. Kidney function assessment revealed increased levels of urea and creatinine in the diabetic control group. Vindoline and glibenclamide significantly reduced the urea and creatinine levels in diabetic rats. Vindoline additionally improved the FRAP in diabetic hearts. The SOD activity and ORAC were increased while lipid peroxidation was reduced in the kidneys of diabetic rats treated with vindoline when compared to the diabetic control (p < 0.05). Histopathological assessment in diabetic rats showed severe damage of the liver, kidney and pancreas. Treatment of diabetic rats with vindoline restored the structure of these organs which was indicated by minimum structural changes. The expression of pro-apoptotic marker caspase 9 in response to glucose stress was significantly higher in the diabetic control group when compared to all the treatment groups. Treatment with vindoline showed remarkable reduction of caspase 9 expression in the diabetic rats. In conclusion, persistent high blood glucose levels resulted in free radical induced tissue damage in the type 2 diabetes rat model. Vindoline demonstrated protective effects against diabetes induced hepatic, cardiac, pancreatic and nephritic injuries. In addition, vindoline improved insulin secretion in both in vitro and in vivo setups hence the findings suggest that vindoline could be an important agent that can be considered in the treatment and management of diabetes and diabetic complications.
25

Antioxidative and hypotensive activities of selected marine macroalgae in Hong Kong.

January 2001 (has links)
Lim Sze Nee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 165-176). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese Version) --- p.iii / Acknowledgements --- p.v / Table of Contents --- p.vi / List of Tables --- p.xi / List of Figures --- p.xiii / List of Abbreviation --- p.xvii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1. --- General Introduction --- p.1 / Chapter 1.1 --- Classification of algae --- p.2 / Chapter 1.2 --- Chemical and mineral composition of marine macroalgae --- p.4 / Chapter 1.3 --- Uses of marine macroalgae --- p.7 / Chapter 1.3.1 --- Food --- p.7 / Chapter 1.3.2 --- Industrial uses --- p.8 / Chapter 1.3.3 --- Agricultural uses --- p.9 / Chapter 1.3.3.1 --- Fertilizer --- p.9 / Chapter 1.3.3.2 --- Fodder --- p.9 / Chapter 1.3.4 --- Medicinal properties --- p.10 / Chapter 1.4 --- Pharmacological effects of marine macroalgae --- p.11 / Chapter 1.4.1 --- Antioxidant activity --- p.11 / Chapter 1.4.2 --- Hypotensive activity --- p.11 / Chapter 1.4.3 --- Antiviral activity --- p.12 / Chapter 1.4.4 --- Antimicrobial activity --- p.12 / Chapter 1.4.5 --- Antitumor activity --- p.13 / Chapter 1.4.6 --- Hypocholesterolemic activity --- p.14 / Chapter 1.5 --- Objectives --- p.14 / Chapter CHAPTER 2 --- Free Radical Scavenging and Antioxidative Activities of Marine Macroalgae --- p.16 / Chapter 2.1 --- Introduction --- p.16 / Chapter 2.1.1 --- Free radicals: definition and sources --- p.16 / Chapter 2.1.2 --- Free radical-induced damage --- p.16 / Chapter 2.1.2.1 --- Biological lipid peroxidation --- p.16 / Chapter 2.1.2.2 --- Lipid oxidation of foods --- p.18 / Chapter 2.1.3 --- Antioxidants --- p.19 / Chapter 2.1.3.1 --- Antioxidants --- p.19 / Chapter 2.1.3.2 --- Antioxidant mechanisms --- p.20 / Chapter 2.1.4 --- Synthetic antioxidants --- p.21 / Chapter 2.1.5 --- Natural antioxidants --- p.24 / Chapter 2.1.6 --- Objectives --- p.27 / Chapter 2.2 --- Methods and Materials --- p.28 / Chapter 2.2.1 --- Preparation of algae extracts --- p.28 / Chapter 2.2.2 --- Determination of free radical scavenging activities --- p.32 / Chapter 2.2.2.1 --- Superoxide anions scavenging activity --- p.32 / Chapter 2.2.3 --- Antioxidative activity using hemolysis assay --- p.33 / Chapter 2.2.3.1 --- Preparation of red blood cell (RBC) --- p.33 / Chapter 2.2.3.2 --- Hemolysis assay --- p.33 / Chapter 2.2.4 --- Lipid peroxidation assay --- p.34 / Chapter 2.2.4.1 --- Preparation of rat brain homogenates --- p.34 / Chapter 2.2.4.2 --- Measurement of lipid peroxidation --- p.34 / Chapter 2.2.5 --- Statistics --- p.35 / Chapter 2.3 --- Results --- p.36 / Chapter 2.3.1 --- Superoxide radical scavenging activity of algal extracts --- p.36 / Chapter 2.3.2 --- Effects of algae extracts on hemolysis assay --- p.41 / Chapter 2.3.3 --- Effects of algae extracts on lipid peroxidation --- p.44 / Chapter 2.4 --- Discussion --- p.50 / Chapter CHAPTER 3 --- Isolation of Antioxidative Phenolic Compounds from Sargassum siliquastrum --- p.60 / Chapter 3.1 --- Introduction --- p.60 / Chapter 3.1.1 --- Phenolic compounds --- p.60 / Chapter 3.1.2 --- Major classes of phenolic compounds --- p.60 / Chapter 3.1.3 --- Functional aspects of phenolic compounds --- p.61 / Chapter 3.1.3.1 --- Functions of phenolic compounds in plants --- p.61 / Chapter 3.1.3.2 --- Biological and pharmacological activities --- p.64 / Chapter 3.1.3.3 --- Food industry --- p.65 / Chapter 3.1.4 --- Polyphenolic compounds in brown algae --- p.66 / Chapter 3.1.5 --- Objectives --- p.68 / Chapter 3.2 --- Methods and Materials --- p.69 / Chapter 3.2.1 --- Extraction and isolation of antioxidant components from S siliquastrum --- p.69 / Chapter 3.2.2 --- Thin-Layer chromatography --- p.70 / Chapter 3.2.3 --- Antioxidant activity --- p.71 / Chapter 3.2.4 --- Determination of total phenolics --- p.71 / Chapter 3.2.5 --- Infrared spectra --- p.72 / Chapter 3.2.6 --- Ultra-violet and visible (UV-vis) spectrophotometry --- p.72 / Chapter 3.2.7 --- Statistics --- p.73 / Chapter 3.3 --- Results --- p.73 / Chapter 3.3.1 --- Identification of phenolic compounds from various solvent extracts of S. siliquastrum --- p.73 / Chapter 3.3.2 --- Isolation of dichloromethane fraction by liquid chromatography --- p.81 / Chapter 3.3.3 --- Phenolic content of isolated compounds --- p.86 / Chapter 3.3.4 --- IR and UV-vis spectra --- p.86 / Chapter 3.4 --- Discussion --- p.92 / Chapter 3.4.1 --- Antioxidative activities --- p.92 / Chapter 3.4.2 --- Relationship between phenolic contents and antioxidant activity --- p.95 / Chapter 3.4.3 --- Identification of antioxidant compounds --- p.97 / Chapter CHAPTER 4 --- Hypotensive Activities of Marine Algae in the Rat --- p.102 / Chapter 4.1 --- Introduction --- p.102 / Chapter 4.1.1 --- Basic principles of cardiovascular system --- p.102 / Chapter 4.1.2 --- Regulation of arterial pressure --- p.105 / Chapter 4.1.2.1 --- Short-term regulation of arterial pressure --- p.105 / Chapter 4.1.2.2 --- Long-term regulation of arterial pressure --- p.107 / Chapter 4.1.3 --- Hypertension --- p.108 / Chapter 4.1.3.1 --- Causes of hypertension --- p.109 / Chapter 4.1.3.2 --- Where do antihypertensive or hypotensive agents act? --- p.114 / Chapter 4.1.3.2.1 --- Sympathetic nervous system inhibitors --- p.115 / Chapter 4.1.3.2.2 --- Diuretics --- p.120 / Chapter 4.1.3.2.3 --- Vasodilators --- p.121 / Chapter 4.1.3.2.4 --- Calcium antagonist (Calcium channel blockers) --- p.121 / Chapter 4.1.3.2.5 --- Angiotensin-converting enzyme (ACE) inhibitors --- p.122 / Chapter 4.1.3.2.6 --- Antihypertensive drug combination --- p.122 / Chapter 4.1.4 --- The relationship between hypertension and free radicals --- p.123 / Chapter 4.1.5 --- Development of new antihypertensive agenrs --- p.124 / Chapter 4.2 --- Materials and methods --- p.125 / Chapter 4.2.1 --- Animal care --- p.125 / Chapter 4.2.2 --- Preparation of the blood pressure measurement in rats --- p.125 / Chapter 4.2.2.1 --- Effects of seaweed extracts on arterial blood pressure of rat --- p.126 / Chapter 4.2.2.1.1 --- Single-dose response curve --- p.126 / Chapter 4.2.2.1.2 --- Cumulative-dose response curve --- p.126 / Chapter 4.2.2.2 --- Pharmacological blocker studies --- p.128 / Chapter 4.2.3 --- Statistics --- p.131 / Chapter 4.3 --- Results --- p.131 / Chapter 4.3.1 --- Hypotensive effects of marine algal extracts --- p.131 / Chapter 4.3.2 --- Effects of pharmacological blockers on MAP --- p.135 / Chapter 4.4 --- Discussion --- p.150 / Chapter 4.4.1 --- Hypotensive effects of the marine algal extracts --- p.150 / Chapter 4.4.2 --- Pharmacological action of marine algal extracts --- p.152 / Chapter CHAPTER 5 --- Conclusion --- p.160 / REFERENCES --- p.165 / RELATED PUBLICATIONS --- p.177
26

Hypotensive, antioxidative and antitumour substances in kelp, laminaria japonica. / CUHK electronic theses & dissertations collection

January 2004 (has links)
Fung Yin Lee, Annie. / "January 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 132-146). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
27

Effect of phytochemicals on estrogen biosynthesis in human breast cancer and placental cells. / CUHK electronic theses & dissertations collection

January 2005 (has links)
A breast cancer cell line stably transfected with the CYP19 gene had been employed for aromatase inhibition. Among the phytochemicals tested, the major dietary flavonoids, such as genistein and daidzein, produced very weak inhibition. On the other hand, the red clover isoflavone biochanin A, the hydroxychalcone butein and the red grape phytoalexin resveratrol were found to be effective aromatase inhibitors. Cell proliferation assay had shown that they could inhibit ER-positive cell proliferation induced by testosterone, and the inhibitory effect was specifically attributed to the reduction of estrogen synthesis. In another breast cancer cell line SK-BR-3, resveratrol, biochanin A and genistein inhibited CYP19 both in enzyme and promoter I.3/II transcriptional levels. The element responsible for the inhibition of aromatase by these phytoestrogens should fall within the region between -556 to -446 by upstream of exon II. / Breast cancer is one of the most common cancers affecting women. Estrogen plays an important role in breast cancer initiation and development. The majority of breast tumors are initially dependent upon estrogen to support their growth. Most breast cancers occur in the postmenopausal period. However, the intra-tumoral estradiol (E2) is maintained at a high level equivalent to the pre-menopausal status. High intra-tumoral E2 level in postmenopausal women is sustained by the biosynthesis of estrogens in the tumorous tissue. / Genistein and Biochanin A, ranged from 0.1 to 10 muM, might act as estrogen agonist and induced aromatase activity and promoter I.1 transactivation in ERalpha-transfected SK-BR-3 cells. (Abstract shortened by UMI.) / The aromatase enzyme, CYP19, belongs to a family of P450 enzyme. As a final rate-limiting step in estrogen biosynthesis, it catalyzes the conversion of C 19 steroids to estrogens. The expression of CYP19 is tissue-specific, and is regulated by alternate promoter usage. The use of aromatase inhibitors for breast cancer treatment has become a major therapeutic approach. / The consumption of some phytochemicals protects against breast cancer. Yet the mechanisms are far from clear. In my present study, various phytochemicals, including phytoestrogens, monoterpenes and carotenoids, were evaluated for their effect on aromatase. / Wang Yun. / "July 2005." / Adviser: Lai-Kwok Leung. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3716. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 145-169). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

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