Les modifications épigénétiques participent au contrôle de l'expression génique. Il a été montré que la méthylation des désoxycytidines (dC) de l'ADN joue un rôle clé dans la régulation épigénétique chez les mammifères. Cette modification correspond à la marque épigénétique la plus stable. Elle a lieu sur des résidus CpG regroupés en ilôts, essentiellement situés au niveau des séquences promotrices, des séquences répétées et des séquences encadrants les ilôtsCpG. L'hyperméthylation des promoteurs induit une inhibition de l'expression des gènes, tandis qu'une hypométhylation est associée à une expression. Les enzymes responsables de la méthylation de l'ADN sont les méthyltransférases d'ADN (DNMTs). Deux familles de DNMTscatalytiquement actives ont été identifiées: on distingue la DNMT1, principalement responsable de la maintenance de la méthylation de l'ADN lors de la réplication, et les DNMT3A et 3B, qui sont responsables d'une méthylation de l'ADN dite de novo. L'altération des profils de méthylation de l'ADN conduit à diverses maladies telles que le cancer. Les cellules cancéreuses présentent souvent un profil de méthylation de l'ADN différent des cellules saines, on observe en particulier une hyperméthylation spécifique des gènes dits suppresseurs de tumeur. Une restauration de leur expression par l'inhibition de la méthylation de l'ADN représente ainsi une stratégie thérapeutique attrayante. Plusieurs inhibiteurs de DNMTs ont été décrits et deux analogues de nucléosides sont approuvés par la FDA pour traiter certaines leucémies: la 5-azacytidine (VidazaTM) et la 5-azadeoxycytidine (Dacogene(r)). Notre laboratoire développe depuis plusieurs années de nouveaux inhibiteurs non nucléosidiques de DNMTs qui ciblent leur site catalytique. J'ai étudié ici les effets pharmacologiques de ces inhibiteurs catalytiques des DNMTs, en utilisant plusieurs lignées cellulaires cancéreuses (issues d'une leucémie, d'un lymphome et d'un cancer du côlon). J'ai utilisé pour cela différentes technologies permettant d'analyser la méthylation de l'ADN, l'accessibilité de la chromatine, les modifications des histones et l'expression des gènes. Ces nouvelles thérapies épigénétiques visent à la reprogrammation des cellules cancéreuses, c'est pourquoi j'ai exploré les modifications à long terme induites par ces nouveaux composés. Nous avons montré que ces composés sont des inhibiteurs puissants de DNMT3A et qu'ils sont capables d'induire l'expression d'un gène raporteur (la luciférase) sous le contrôle du promoteur CMV, par une déméthylation de ce promoteur et une ouverture de la chromatine. Enfin, ces nouveaux inhibiteurs de DNMTs déméthylent la région promotrice de gènes suppresseurs de tumeurs et induisent leur ré-expression. / Epigenetic modifications participate to the control of gene expression. Methylation of deoxycytidines (dC) in the DNA was shown to play a key role in epigenetic regulation in mammals. It is the most stable epigenetic mark and occurs at CpG sites, which are grouped in islands and essentially located in promoters, repeated sequences and CpG island shores. Hypermethylation of promoters induces gene silencing while hypomethylation is associated to gene expression. Enzymes responsible for DNA methylation are the DNA methyltransferases (DNMTs). Two families of catalyticallyactive DNMTs have been identified: DNMT1, mainly responsible for DNA methylation maintenance during replication; and DNMT3A and 3B that perform de novo DNA methylation and support maintenance. Alteration of DNA methylation patterns lead to various diseases such as cancer. Cancerous cells often present aberrant DNA methylation, in particular a specific hypermethylation of tumor suppressor genes is observed. Restoring their expression by inhibition of DNA methylation represents an attractive therapeutic strategy. Several DNMTs inhibitors have been described. Two nucleoside analogs are FDA approved to treat leukemia: 5-azacytidine (VidazaTM) and 5-azadeoxycytidine (Dacogene(r)). Our laboratory develops since several years new inhibitors of DNMT, non-nucleoside analogs, targeting the catalytic site. Here, I studied the pharmacological effects of these DNMTs catalytic inhibitors using several cancer cell lines (leukemia, lymphoma and colon cancer) and different technologies to follow DNA methylation, chromatin accessibility, histone modifications and gene expression. Since epigenetic therapies aim at the reprogramming of cancer cells, I explored the long-term modifications induced by the compounds. We show that these novel compounds are potent inhibitors of DNMT3A and able to induce the expression of a reporter gene (luciferase) under the control of a methylated CMV promoter by demethylation of the promoter and opening of the chromatin. Finally, these new DNMTs inhibitors demethylate the promoter region of tumor suppressor genes and induce their re-expression.

Liu, Xiaozhuo. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 156-169). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract in Chinese (摘要） --- p.iv / Acknowledgments --- p.vi / List of Abbreviations --- p.vii / Table of Contents --- p.xiv / Chapter Chapter One: --- General Introduction / Chapter 1.1 --- Hematopoiesis and Leukemia --- p.1 / Chapter 1.1.1 --- An Overview on Hematopoiesis --- p.1 / Chapter 1.1.2 --- Leukemia --- p.6 / Chapter 1.1.2.1 --- An Overview of Leukemia --- p.6 / Chapter 1.1.2.2 --- Classification and Epidemiology of Leukemia --- p.8 / Chapter 1.1.2.3 --- Conventional Approaches to Leukemia Therapy --- p.12 / Chapter 1.1.2.4 --- Novel Approaches to Leukemia Therapy --- p.15 / Chapter 1.2 --- Sophoraflavanone G: A Bioactive Compound Isolated from Kushen --- p.18 / Chapter 1.2.1 --- An Overview of Kushen: A Traditional Chinese Medicine --- p.19 / Chapter 1.2.2 --- An Overview of Lavandulyl Flavanones --- p.22 / Chapter 1.2.3 --- Historical Development and Occurrence of Sophoraflavanone G --- p.24 / Chapter 1.2.4 --- Biological Activities of Sophoraflavanone G --- p.25 / Chapter 1.2.4.1 --- Anti-microbial and Insecticidal Activities --- p.25 / Chapter 1.2.4.2 --- Anti-tumor Activities --- p.26 / Chapter 1.2.4.3 --- Pharmacodynamics of Sophoraflavanone G --- p.27 / Chapter 1.3 --- Objectives and Scopes of the Present Study --- p.30 / Chapter Chapter Two: --- Materials and Methods / Chapter 2.1 --- Materials --- p.32 / Chapter 2.1.1 --- Animals --- p.32 / Chapter 2.1.2 --- Cell lines --- p.32 / Chapter 2.1.3 --- "Cell Culture Medium, Buffers and Other Reagents" --- p.34 / Chapter 2.1.4 --- Reagents and Buffers for Flow Cytometry --- p.37 / Chapter 2.1.5 --- Reagents for DNA Extraction --- p.39 / Chapter 2.1.6 --- Reagents for Measuring Caspase Activity --- p.40 / Chapter 2.1.7 --- "Reagents, Buffers and Materials for Western Blotting" --- p.43 / Chapter 2.2 --- Methods --- p.48 / Chapter 2.2.1 --- Extraction and Isolation of Sophoraflavanone G from Kushen --- p.48 / Chapter 2.2.2 --- Culture of Tumor Cell Lines --- p.49 / Chapter 2.2.3 --- "Isolation, Preparation and Culturing of Human Peripheral Blood Leukocytes and Murine Bone Marrow Cells" --- p.50 / Chapter 2.2.4 --- Assays for Anti-proliferation and Cytotoxicity --- p.51 / Chapter 2.2.5 --- Determination of Anti-leukemic Activity In Vivo (In Vivo Tumorigenicity Assay) --- p.52 / Chapter 2.2.6 --- Cell Cycle Analysis by Flow Cytometry --- p.53 / Chapter 2.2.7 --- Measurement of Apoptosis-induced Activities --- p.54 / Chapter 2.2.8 --- Protein Expression Study --- p.59 / Chapter 2.2.9 --- Assessment of Differentiation-associated Characteristics --- p.64 / Chapter 2.2.10 --- Statistical Analysis --- p.65 / Chapter Chapter Three: --- Studies on the Anti-proliferative Effect of Sophoraflavanone G on Human Myeloid Leukemia Cells / Chapter 3.1 --- Introduction --- p.66 / Chapter 3.2 --- Results --- p.69 / Chapter 3.2.1 --- Structure Identification of Sophoraflavanone G Isolated from Sophora flavescens --- p.69 / Chapter 3.2.2 --- Anti-proliferative Activity of Sophoraflavanone G on Various Myeloid Leukemia Cell Lines --- p.72 / Chapter 3.2.3 --- Effect of Sophoraflavanone G on the Viability of the Human Promyelocytic Leukemia HL-60 Cells --- p.80 / Chapter 3.2.4 --- Cytotoxic Effect of Sophoraflavanone G on Primary Normal Cells In Vitro --- p.83 / Chapter 3.2.5 --- Kinetic and Reversibility Studies of the Anti-proliferative Effect of Sophoraflavanone G on the Human Promyelocytic Leukemia HL-60 Cells --- p.85 / Chapter 3.2.6 --- Effect of Sophoraflavanone G on the In Vivo Tumorigenicity of the HL-60 Cells --- p.88 / Chapter 3.2.7 --- Effect of Sophoraflavanone G on the Cell Cycle Profile of the HL-60 cells In Vitro --- p.90 / Chapter 3.2.8 --- Effect of Sophoraflavanone G on the Expression of Cell Cycle-regulatory Proteins in the HL-60 Cells --- p.93 / Chapter 3.2.9 --- Anti-proliferative Effect of Sophoraflavanone G on Multidrug-resistant (MDR) Leukemia Cell Line HL-60/MX2 Cells --- p.95 / Chapter 3.3 --- Discussion --- p.101 / Chapter Chapter Four: --- Studies on the Apoptosis- and Differentiation-inducing Activities of Sophoraflavanone G on Human Myeloid Leukemia Cells / Chapter 4.1 --- Introduction --- p.109 / Chapter 4.2 --- Results --- p.114 / Chapter 4.2.1 --- Induction of DNA Fragmentation in the Human Promyelocytic Leukemia HL-60 Cells by Sophoraflavanone G --- p.114 / Chapter 4.2.2 --- Induction of Phosphatidylserine Externalization in the Human Promyelocytic Leukemia HL-60 Cells by Sophoraflavanone G as Detected by Annexin V-GFP and PI Double Staining Method --- p.116 / Chapter 4.2.3 --- Effects of Sophoraflavanone G on the Caspase Activities in the Human Promyelocytic Leukemia HL-60 Cells --- p.119 / Chapter 4.2.4 --- Induction of Mitochondrial Membrane Depolarization in the Human Promyelocytic Leukemia HL-60 Cells by Sophoraflavanone G --- p.124 / Chapter 4.2.5 --- Involvement of Bcl-2 Family Members in Sophoraflavanone G-induced Apoptosis in the Human Promyelocytic Leukemia HL-60 Cells --- p.128 / Chapter 4.2.6 --- Effects of Sophoraflavanone G on the Induction of Reactive Oxygen Species in the Human Promyelocytic Leukemia HL-60 Cells --- p.131 / Chapter 4.2.7 --- Effect of Sophoraflavanone G on the Intracellular Ca2+ Level in the Human Promyelocytic Leukemia HL-60 Cells --- p.134 / Chapter 4.2.8 --- Morphological Studies on the Sophoraflavanone G-treated Human Promyelocytic Leukemia HL-60 Cells --- p.136 / Chapter 4.2.9 --- Effect of Sophoraflavanone G on the NBT Reducing Activity of the Human Promyelocytic Leukemia HL-60 Cells --- p.138 / Chapter 4.3 --- Discussion --- p.140 / Chapter Chapter Five: --- Conclusions and Future Perspectives --- p.148 / References --- p.156

126f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-03-22T15:11:05Z No. of bitstreams: 1 Tese_Lidércia.pdf: 1854558 bytes, checksum: 7d54dd03b3bb8154f1ce2f0564633c7d (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-04-19T13:36:52Z (GMT) No. of bitstreams: 1 Tese_Lidércia.pdf: 1854558 bytes, checksum: 7d54dd03b3bb8154f1ce2f0564633c7d (MD5) / Made available in DSpace on 2013-04-19T13:36:52Z (GMT). No. of bitstreams: 1 Tese_Lidércia.pdf: 1854558 bytes, checksum: 7d54dd03b3bb8154f1ce2f0564633c7d (MD5) Previous issue date: 2009 / CAPES / Este trabalho foi desenvolvido no âmbito do PRONEX – NQA e descreve o estudo através da técnica da Cromatografia Líquida de Alta Eficiência acoplada a detector de arranjo de diodos - CLAE-DAD nas análises de amostras de sucos de laranja obtidos por processos extrativos diversificados (espremidos a mão, extração em condições industriais com posterior comercialização em longo prazo e obtido através de máquinas tipo fresh-in-squeeze) para a identificação de flavonóides e psoraleno. Os diversos sucos foram submetidos às etapas de extração líquido-líquido e posterior análises por CLAE-DAD. Estes procedimentos permitiram identificar e quantificar algumas flavanonas e psoraleno presentes nos sucos cítricos. Dentre as flavanonas se determinou hesperidina, naringina, naringenina e poncirina. As faixas de concentrações destes compostos variaram de 17,8 - 245 mg 100 g-1 para hesperidina, 0,01 – 0,08 mg 100 g-1 para naringina, 0,05 – 0,170 mg 100 g-1 para naringenina e de 0,06 – 0,36 mg 100 g-1 para poncirina. Quanto ao psoraleno, em algumas amostras dos sucos, as concentrações estavam abaixo do limite de quantificação (< 0,02) e variou de < 0,02 – 0,05 mg 100 g-1. Estes resultados sugerem que o modo de obtenção dos sucos e os critérios de extração dos constituintes podem influenciar tanto nos teores dos flavonóides no suco como nas detecções de suas concentrações através da técnica aplicada. Para exames das informações geradas foram empregadas metodologias estatísticas multivariadas por meio de Análises de Componentes Principais (PCA) e Análise de Agrupamentos Hierárquicos (HCA) executando o estudo exploratório dos dados para avaliar tendências e discriminar amostras dos sucos de laranja quanto a sua origem, tipos de tratamentos de extração e características químicas para os teores de flavonóides e psoraleno. / Salvador

>Magister Scientiae - MSc / Flavonoids, one of the biggest classes of secondary metabolites, are found abundantly in nature in a broad range of fruits, vegetables and beverages such as tea, coffee, beer, wine and fruit drinks. Flavonoids have been reported to exert multiple biological functions as well as tremendous pharmacological activity, including anticancer activity, protection, antioxidant activity, cardiovascular protection, antibacterial, antifungal and antiviral activity. The antioxidant activity of flavones is reported to be associated with those bearing hydroxyl functions. In the present study, several reaction steps have been carried out to synthesize three sub classes of flavonoids namely; chalcones, dihydrochalcones and flavanones with various substituents attached. The first step involved protection of hydroxyl groups of acetophenone and benaldehyde as starting materials. Thereafter the Clasien Schmidt condensation reaction, under basic conditions, was performed to afford chalcone intermediates. Treatment of these chalcones with sodium acetate, under reflux, afforded flavanones as a single product in high yields. Thereafter all protecting groups where removed to yield the final products. All products and intermediates where purified by column chromatography and were characterized by Nuclear Magnetic Resonance Spectroscopy (NMR) (1H NMR and 13C NMR). An electrochemical analysis on all flavonoid compounds was performed by Cyclic Voltammetry (CV) and Square Wave Voltammetry (SWV) to give information on the accessible redox couples identified by their oxidation potentials. Oxidation potentials, which gave valuable information about reducing ability and hence the antioxidant activity, where used to compare all compounds. The antioxidant activity was observed to increase with the addition of hydroxyl groups on the B-ring. Compounds with a combination of hydroxyl groups on the A-ring and methoxy groups on the B-ring showed increased antioxidant activity when compared to those with only hydroxyl groups on the base structure. 2, 5, 4’-trihydroxy dihydrochalcone showed moderate antioxidant ability. However the 2, 5, 4’-trihydroxychalcone, containing the α, β unsaturated double bond, proved to have the greatest antioxidant ability.

Les maladies cardiovasculaires représentent l’une des principales causes de mortalitédans le monde et leur prévention constitue un enjeu majeur de santé publique. Les études épidémiologiques montrent que la consommation de fruits et légumes est associée à un moindre risque cardiovasculaire. Ces effets pourraient être expliqués par leur richesse en micronutriments et plus particulièrement en polyphénols. La consommation de flavanones, une classe de polyphénols présente spécifiquement et en grandes quantités dans les agrumes, a été inversement associée au risque d’accidents coronaires et d’accidents vasculaires cérébraux. Des données expérimentales obtenues in vivo et in vitro suggèrent que les flavanones (hespéridine ou naringine) possèdent des propriétés hypolipémiantes, hypotensives et anti-inflammatoires. Ces effets pourraient notamment être médiés par une modulation de l’expression de gènes par les flavanones. Cependant jusqu’à présent, l’action anti-athérogène des flavanones in vivo n’a été explorée qu’à des doses supra-nutritionnelles et les mécanismes responsables de ces effets sont encore largement méconnus. Par ailleurs, les données mécanistiques in vitro sont peu informatives, car obtenues avec des formes de flavanones non présentes dans l’organisme. Les objectifs de cette thèse ont donc été : (1) d’évaluer l’impact d’une consommation de flavanones (naringine et hespéridine) à dose nutritionnelle sur le développement de la lésion athéromateuse chez différents modèles murins d’hypercholestérolémie et d’appréhender les mécanismes moléculaires mis en jeu par une approche transcriptomique ; (2) de déterminer l’impact des métabolites circulants sur la fonction des cellules endothéliales et d’identifier les mécanismes moléculaires sous-jacents. In vivo, nous avons montré que seule la supplémentation en naringine (0,02%), la flavanone majoritaire du pamplemousse, réduisait la progression des lésions athéromateuses dans un modèle murin d’athérosclérose induite par l’alimentation (souris C57Bl/6J sous régime riche en graisse et en cholestérol). Cet effet était associé à une réduction des concentrations plasmatiques de non HDL-Chol et de biomarqueurs de la dysfonctionendothéliale, mais semblait indépendant d’une modulation du statut anti-oxydant. Une analyse transcriptomique pangénomique de l’aorte de ces animaux, a montré, que la supplémentation en naringine induisait une variation de l’expression de gènes impliqués dans des processus, tels que l’adhésion cellulaire ou l’organisation du cytosquelette, qui sont impliqués dans la migration trans-endothéliale des leucocytes. Ces résultats mettent en évidence de nouvelles cibles moléculaires d’action des flavanones qui ont été plus largement abordées in vitro. Les données obtenues in vitro montrent que l’exposition de cellules endothéliales(HUVEC) à des concentrations physiologiques de métabolites circulants de la naringénine(dérivés glucuronidés) ou de l’hespérétine (dérivés glucuronidés et sulfatés) diminue l’adhésion des monocytes (U937) aux cellules endothéliales, une étape clé de la migrationtrans-endothéliale. En accord avec ces résultats, une analyse TaqMan Low Density Array a montré que l’exposition des cellules endothéliales aux métabolites circulants de flavanones affectait l’expression de gènes impliqués dans l’inflammation, le chimiotactisme, l’adhésion ou encore la migration trans-endothéliale des leucocytes. Pris dans leur ensemble, les résultats de ce travail de thèse montrent que les effets antiathérogènesdes flavanones ne découlent pas exclusivement d’un effet hypolipémiant, mais aussi d’une action directe sur des étapes clés du développement de l’athérosclérose au niveau de l’endothélium, en particulier les processus d’adhésion et migration trans-endothéliale. / Cardiovascular disease is a major cause of mortality worldwide and its prevention is a major public health issue. Epidemiological studies have shown that fruit and vegetables consumption is associated with a lower cardiovascular risk. These effects could be explainedby their richness in micronutrients, especially polyphenols. Consumption of flavanones, a class of polyphenols present specifically and in large amounts in citrus fruits, was inversely associated with risk of coronary events and stroke. Experimental data obtained in vivo and invitro suggest that the flavanones (hesperidin or naringin) have lipid-lowering, hypotensive and anti-inflammatory properties. These effects could be mediated via modulation of gene expression by these bioactives. However, the anti-atherogenic effect of flavanones in vivo has been only explored at supra-nutritional doses and the mechanisms responsible for these effects are largely unknown. Furthermore, in vitro mechanistic data are questionable as they have been obtained using native forms of flavanones which are not present in the body.The objectives of this thesis were: (1) to assess the impact of consumption of flavanones (naringin and hesperidin) at nutritional doses on the development of atherosclerotic lesions indifferent mouse models of hypercholesterolemia and decipher molecular mechanisms brought into play, using a transcriptomic approach, (2) to determine the impact of physiological concentrations of plasma flavanone metabolites on endothelial cell function and theunderlying molecular mechanisms. In vivo, we showed that only naringin supplementation (0.02%), the major flavanonein grapefruit, reduced the progression of atherosclerotic lesions in a mouse model of dietinduced atherosclerosis (C57BL/6J mice fed an enriched diet in fat and cholesterol). Thiseffect was associated with a reduction in plasma non-HDL-Chol and biomarkers ofendothelial dysfunction, but appeared independent of a modulation of antioxidant status. Agenome-wide transcriptome analysis of the aorta of these animals showed that naringin supplementation modulated expression of genes involved in processes such as cell adhesion and cytoskeleton organization; these latter being involved in leukocytes trans-endothelialmigration. These results reveal new molecular targets of action of flavanones that have beenfurther studied in vitro.The in vitro data showed that exposure of endothelial cells (HUVEC) to physiological concentrations of circulating metabolites of naringenin (glucuronides) or hesperetin(glucuronides and sulfate) decreased the adhesion of monocytes (U937) to endothelial cells, a key step in the trans-endothelial migration. Consistent with these results, a TaqMan Low Density Array analysis showed that exposure of endothelial cells to these flavanone metabolites affected the expression of genes involved in inflammation, chemotaxis, adhesionas well as leukocytes trans-endothelial migration. Overall, the results of this work show that the anti-atherogenic effect of flavanones is not exclusively derived from lipid-lowering effect, but also due to a direct action on the endothelium by modulating key processes of atherosclerosis development, particularly adhesion and trans-endothelial migration.

Dans le but de rechercher de nouveaux inhibiteurs de l’ARN polymérase NS5 du virus de la dengue (DENV), un criblage a été mené sur 650 plantes néo-calédoniennes. A la suite de ce criblage, deux espèces (Cryptocarya chartacea Kostermans et Trigonostemon cherrieri Veillon) ont été sélectionnées. L’extrait AcOEt des écorces de Cryptocarya chartacea (Lauraceae) a montré une forte inhibition de la NS5 polymérase (99 % à 10 µg/ml). L’étude phytochimique de l’extrait a mis en évidence une série de nouvelles flavanones 6-mono et 6,8-dialkylées, nommées chartacéones. Celles-ci sont présentes sous forme de mélanges racémiques au sein de C. chartacea. La chartacéone A a été purifiée sur colonne chirale conduisant à l’isolement de quatre diastéréoisomères optiquement purs. Une étude configurationnelle basée sur le calcul théorique de spectres de dichroïsme circulaire a permis la détermination de leur configuration absolue. Les chartacéones inhibent de façon sélective la NS5 polymérase du DENV. L’étude des extraits AcOEt des écorces et du bois de Trigonostemon cherrieri (Euphorbiaceae) a mis en évidence une série de métabolites secondaires originaux de type Diterpènes Daphnane Orthoester (DDO) chlorés : les trigocherrines (non-macrocycliques) et les trigocherriolides (macrocycliques). Ces composés ont montré une inhibition de l’activité enzymatique de la NS5 polymérase du DENV et une activité antivirale sur le virus du chikungunya in cellulo. / In order to identify new inhibitors of the dengue virus (DENV) NS5 RNA polymerase, a screening was led on 650 new-caledonian plants. Two species, Cryptocarya chartacea Kostermans and Trigonostemon cherrieri Veillon were selected. The EtOAc bark extract of Cryptocarya chartacea (Lauraceae) showed a potent inhibition of the NS5 polymerase activity (99 % at 10 µg/ml). The phytochemical study of the extract led to the isolation of a series of new 6-mono and 6,8-dialkylated flavanones, called chartaceones. Chartaceones are present as racemic mixtures in the plant. Chartaceone A was purified on chiral column leading to the isolation of 4 optically pure diastereoisomers. A configurational study based on the theoretical calculation of circular dichroism spectra allowed the determination of their absolute configuration. Chartaceone are selective inhibitors of the DENV NS5 polymerase. The study of the EtOAc extract from the bark and wood of Trigonostemon cherrieri (Euphorbiaceae) led to the isolation of a series of unusual chlorinated daphnane diterpene orthoesters (DDO) : trigocherrins (non macrocylic) and trigocherriolides (macrocyclic). These compounds inhibit the DENV NS5 polymerase activity and present an antiviral activity on the chikungunya virus in cellulo.

As laranjas e seus derivados, principalmente os sucos, possuem compostos bioativos, tais como os flavonoides, entre eles as flavanonas hesperidina e narirutina, que podem estar relacionados à promoção e benefícios à saúde. A absorção e metabolização de flavonoides podem ser afetadas por diversos fatores como a microbiota e fatores antropométricos, o que pode afetar a sua bioatividade. Assim, o objetivo deste estudo foi comparar o metabolismo e excreção dos flavonoides entre indivíduos eutróficos e obesos após a ingestão de sucos de laranja pasteurizado obtidos das cvs. Pera e Moro. Em um estudo cross-over randomizado 20 voluntárias eutróficas e 10 voluntárias obesas, com idade entre 19 e 40 anos, consumiram em dose única 600 mL de cada suco, que contém as flavanonas narirutina e hesperidina, além das antocianinas no suco Moro. Os metabólitos de flavanonas e de antocianinas foram identificados e quantificados em urina coletada em diferentes períodos de tempo durante 24 horas. Não foi observada diferença significativa na permeabilidade intestinal entre os grupos. Foram detectados e identificados 8 metabólitos de fase II da hesperitina e naringenina, principalmente mono e diglicuronidados e sulfatos, além de três ácidos fenólicos catabólitos de flavanonas formados pela microbiota intestinal, entre elas o ácido hipúrico, ácido protocatecuico e ácido 3-(3-hidroxifenil)-3-hidroxipropiônico. Os ácidos fenólicos foram os metabólitos majoritários recuperados na urina, principalmente o ácido hipúrico. Ainda, os metabólitos de fase II apresentaram maior excreção entre o período de 4-8h e 8-12h (13 a 27% do total de metabólitos excretados). Não foi observada diferença significante (p<0,05) no total de metabólitos de naringenina e hesperitina excretados na urina durante o período de 24 h entre os dois grupos e para os sucos de laranja, nem para o total de metabólitos, provavelmente devido à grande variabilidade interindividual na excreção. Assim, não foi observada diferença entre a metabolização de flavanonas de laranja entre os eutróficos e obesos e nenhuma correlação com os parâmetros antropométricos avaliados. / Oranges and orange juices contain bioactive compounds, such as flavonoids, mainly the flavanones hesperidin and narirutin, which may be related to the promotion and health benefits. The absorption and metabolization of flavonoids can be affected by several factors such as the gut microbiota and anthropometric parameters, which may affect its bioactivity. Thus, the aim of this study was to compare the metabolism and excretion of flavonoids among eutrophic and obese people after ingestion of two pasteurized orange juice obtained from cvs. Pera and Moro. In a randomized cross-over study 20 eutrophic volunteers and 10 obese volunteers, aged 19-40 years, consumed a single dose of 600 mL of each juice. The metabolites of flavanones and anthocyanins were identified and quantified in urine collected at different time points for 24 hours. No significant difference in intestinal permeability was observed between groups. Eight Phase II metabolites of hesperitin and naringenin, mainly mono and diglycerides and sulfates, and three phenolic catabolites of flavanones formed by the gut microbiota were detected and identified, among them hippuric acid, protocatecuic acid and 3- (3-hydroxyphenyl) ) -3-hydroxypropionic acid. Phenolic acids were the major metabolites recovered in urine, mainly hippuric acid. Furthermore, phase II metabolites had greater excretion between the period of 4-8h and 8-12h (13-27% of total metabolites excreted). No significant difference (p <0.05) was observed in the total of naringenin and hesperitin metabolites excreted in the urine during the 24 h period between the two groups, probably due to interindividual variability in excretion. Thus, no difference was observed on metabolism of flavanones between the eutrophic and obese and no correlation was observed with the anthropometric parameters evaluated.

Made available in DSpace on 2014-06-11T19:31:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-13Bitstream added on 2014-06-13T20:21:47Z : No. of bitstreams: 1 duzzioni_ag_dr_arafcf.pdf: 388234 bytes, checksum: d7c91419dd815b4e0da6ee6928288eff (MD5) / Universidade Estadual Paulista (UNESP) / As frutas cítricas são muito consumidas e apreciadas por todo o mundo, não só devido ao seu paladar agradável como também ao seu valor nutricional. São fontes de constituintes bioativos que podem atuar como antioxidantes em defesa ao nosso organismo. Existem relatos principalmente sobre os fitoquímicos e o potencial antioxidante das laranjas, no entanto as tangerinas, que também apresentam estes constituintes e atividade antioxidante, ainda são pouco estudadas. O Brasil se destaca na produção e exportação do suco das laranjas, sendo o maior exportador mundial do suco da fruta, já a produção das tangerinas e limão tahiti vem crescendo a cada ano que passa. O ácido ascórbico, os compostos fenólicos totais e carotenóides são alguns dos componentes bioativos presentes nas frutas cítricas. Considerando a importância das frutas cítricas com relação aos seus benefícios para a saúde, os objetivos deste estudo foram analisar sete variedades de frutas cítricas quanto aos principais constituintes bioativos, a atividade antioxidante via radical livre DPPH• de dois diferentes extratos (sobrenadante e precipitado) do suco das frutas em três diferentes solventes (água, metanol e acetona) e a atividade antioxidante dos extratos de carotenóides totais e flavanonas isolados das frutas. A variedade limão tahiti apresentou o maior teor de ácido ascórbico e menor de fenólicos totais, já a variedade tangerina poncã conteve o maior teor de flavonóides totais e carotenóides totais. A atividade antioxidante foi maior no extrato aquoso do que nos extratos metanólico e cetônico. Das diferentes flavanonas analisadas (eriocitrina, naringina, neohesperidina, hesperidina e poncirina), somente a hesperidina esteve presente em todas as variedades, sendo que a variedade tangerina cravo foi a que apresentou o maior teor deste flavonóide... / The citrus fruits are consumed and enjoyed by the whole world, not only because of its pleasant taste but also by its nutritional value. They are sources of bioactive constituents that can act as antioxidants to defend our body. There are reports mainly on the phytochemical and antioxidant potential of oranges; however the tangerines, which also have these constituents and antioxidant activity, are still little studied. Brazil stands out in the production and exportation of the juice of oranges, the world's largest exporter of fruit juice, since the production of tangerine and Tahiti lemon is growing each year that passes. Some bioactive components present in citrus fruits are ascorbic acid, the total phenolic compounds, and carotenoids. Taking into account the benefits of citrus fruits to the human health, the objectives of this study were to analyze the main bioactive constituents, the antioxidant activity by DPPH• free radical of two different extracts (supernatant and precipitate) of fruit juice in three different solvents (water, methanol and acetone), and the antioxidant activity of extracts of total carotenoids and flavanones isolated from seven varieties of citrus fruits (pera orange, lima orange, valencia orange, ponkan tangerine, cravo tangerine, murcote tangor, and tahiti lemon). The tahiti lemon presented the highest content of ascorbic acid and the lowest content of total phenolic, since the variety ponkan tangerine contained the highest content of total flavonoids and total carotenoids. The antioxidant activity was higher in the aqueous extract than in the methanolic and cetones extracts. Analyzed the different flavanones (eriocitrin, naringin, neohesperidin, hesperidin, and poncirin), the only one presented in all varieties was the hesperidin, so that the cravo tangerine presented the highest content of this flavonoid. The antioxidant activity... (Complete abstract click electronic access below)

Yeung, Tak Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 181-197). / Abstracts in English and Chinese. / Abstract (English) --- p.i / Abstract (Chinese) --- p.iv / Acknowledgements --- p.vi / List of Publications --- p.vii / Presentation --- p.vii / List of Abbreviations --- p.viii / Abbreviations in Figures --- p.xiii / Abbreviations in Symbols --- p.xiv / List of Cell Lines Used in this Study --- p.xv / Table of Contents --- p.xvi / List of Figures --- p.xxv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Cellular Redox State and Cancer Biology --- p.1 / Chapter 1.2 --- Reactive Oxygen Species (ROS) --- p.1 / Chapter 1.3 --- Regulation of Cellular Redox State by Intrinsic and Extrinsic Antioxidant Systems --- p.5 / Chapter 1.3.1 --- Intrinsic Antioxidant System --- p.6 / Chapter 1.3.2 --- Extrinsic Antioxidant System --- p.8 / Chapter 1.4 --- Glutathione --- p.9 / Chapter 1.4.1 --- General Information of Glutathione --- p.9 / Chapter 1.4.2 --- Functions of Glutathione --- p.12 / Chapter 1.4.2.1 --- As an Antioxidant and Free Radical Scavenger --- p.12 / Chapter 1.4.2.2 --- As a Detoxifier --- p.13 / Chapter 1.4.2.3 --- As a Regulator of Cell Signaling --- p.14 / Chapter 1.4.3 --- Synthesis of Glutathione --- p.15 / Chapter 1.4.4 --- Catabolism of Glutathione --- p.15 / Chapter 1.4.5 --- Transport and Uptake of Glutathione --- p.16 / Chapter 1.4.6 --- Glutathione in Cancer Biology --- p.18 / Chapter 1.4.6.1 --- "Role of Glutathione in the Regulation of Carcinogenesis, Growth and Apoptosis of Cancer Cells" --- p.18 / Chapter 1.4.6.1.1 --- Role of Glutathione in Carcinogenesis --- p.18 / Chapter 1.4.6.1.2 --- Role of Glutathione in the Growth of Cancer Cells --- p.20 / Chapter 1.4.6.1.3 --- Role of Glutathione in Apoptosis of Cancer Cells --- p.21 / Chapter 1.4.6.2 --- Role of Glutathione in the Regulation of Metastasis --- p.23 / Chapter 1.4.6.3 --- Role of Glutathione in Cancer Resistance and Therapy --- p.24 / Chapter 1.4.6.3.1 --- Role of Glutathione in Cancer Resistance --- p.24 / Chapter 1.4.6.3.2 --- Role of Glutathione in Cancer Therapy --- p.24 / Chapter 1.5 --- Aims of the Present Study --- p.25 / Chapter Chapter 2 --- In Vitro Study of Bαicαlein and Baicalin on Glutathione Depletion --- p.28 / Chapter 2.1 --- Introduction --- p.28 / Chapter 2.1.1 --- Scutellaria bαicαlensis Georgi --- p.28 / Chapter 2.1.1.1 --- General Clinical Applications to Treat or Prevent Diseases --- p.28 / Chapter 2.1.1.2 --- As an Antioxidant and Free Radical Scavenger --- p.29 / Chapter 2.1.1.3 --- Long History for Treatment of Cancers with the Obscure Mechanism --- p.30 / Chapter 2.1.1.4 --- Major Components --- p.31 / Chapter 2.1.2 --- Baicalein and Baicalin --- p.32 / Chapter 2.1.2.1 --- General Clinical Applications to Treat or Prevent Diseases --- p.32 / Chapter 2.1.2.2 --- As an Antioxidant and Free Radical Scavenger --- p.33 / Chapter 2.1.3 --- Hypothesis: Baicalein and Baicalin Induce Cancer Cell Death Via Glutathione Depletion --- p.35 / Chapter 2.2 --- Materials and Methods --- p.36 / Chapter 2.2.1 --- Chemicals --- p.36 / Chapter 2.2.2 --- Buffers and Solutions --- p.36 / Chapter 2.2.3 --- Animals --- p.37 / Chapter 2.2.4 --- Preparation of Rat Brain Microsomes --- p.37 / Chapter 2.2.5 --- Glutathione Depletion Assay In Vitro and Thiol Depletion Assay in Rat Brain Microsomes --- p.38 / Chapter 2.2.6 --- Statistical Analysis --- p.39 / Chapter 2.3 --- Results --- p.40 / Chapter 2.3.1 --- Effects of Baicalein and Baicalin on Sulfhydryl Contents of Glutathione --- p.42 / Chapter 2.3.2 --- Effects of Baicalein and Baicalin on Sulfhydryl Contents of Rat Brain Microsomes --- p.42 / Chapter 2.4 --- Discussion --- p.44 / Chapter Chapter 3 --- Effects of Baicalein and Baicalin on Proliferation of Different Human Cancer and Normal Cells --- p.45 / Chapter 3.1 --- Introduction-Importance of Developing A Novel Compound Inducing Cancer Cells to Cell Death with the Least Side Effects on Normal Cells --- p.45 / Chapter 3.2 --- Materials and Methods --- p.46 / Chapter 3.2.1 --- Instruments --- p.46 / Chapter 3.2.2 --- Chemicals and Cell Culture Reagents --- p.46 / Chapter 3.2.3 --- Buffers --- p.46 / Chapter 3.2.4 --- Cell Lines --- p.47 / Chapter 3.2.5 --- Cell Culture --- p.48 / Chapter 3.2.6 --- Determination of Cell Proliferation by MTT Assay --- p.49 / Chapter 3.3 --- Results --- p.51 / Chapter 3.3.1 --- Anti-Proliferative Effects of Baicalein and Baicalin on Different Cancer Cell Lines --- p.51 / Chapter 3.3.2 --- Effects of Baicalein on Different Normal Cell Lines --- p.56 / Chapter 3.4 --- Discussion --- p.58 / Chapter 3.4.1 --- Anti-Proliferative Effects of Baicalein and Baicalin on Different Cancer Cell Lines --- p.58 / Chapter 3.4.2 --- Effects of Baicalein on Cell Proliferation on Different Human Normal Cell Lines --- p.60 / Chapter Chapter 4 --- Glutathione-Depleting Effects of Baicalein on Cell Proliferation of Different Cell Lines --- p.61 / Chapter 4.1 --- Introduction-Brain Tumors --- p.61 / Chapter 4.1.1 --- Types and Classifications of Brain Tumors --- p.61 / Chapter 4.1.2 --- "Incidence Time, Patient Survival Time and Rate for" --- p.65 / Chapter 4.1.3 --- Symptoms and Diagnostic Methods for Brain Tumors --- p.66 / Chapter 4.1.4 --- "Treatments, Side Effects and Difficulties of Treatments for Brain Tumors" --- p.67 / Chapter 4.1.5 --- Glutathione Levels in Brain Normal and Cancer Cells --- p.69 / Chapter 4.2 --- Materials and Methods --- p.70 / Chapter 4.2.1 --- Instruments --- p.70 / Chapter 4.2.2 --- Chemicals --- p.70 / Chapter 4.2.3 --- Buffers --- p.70 / Chapter 4.2.4 --- Determination of Cell Proliferation by MTT Assay --- p.70 / Chapter 4.2.5 --- Determination of Intracellular Glutathione Depletion by Fluorescent Dye CMAC --- p.71 / Chapter 4.2.6 --- Determination of Cellular Reduced Glutathione Levels by DTNB-Coupled Glutathione Reductase Recycling Assay --- p.73 / Chapter 4.3 --- Results --- p.75 / Chapter 4.3.1 --- Effects of Baicalein on Intracellular GSH Levels and Cell Proliferation for Different Cell Lines --- p.75 / Chapter 4.3.2 --- Basal Intracellular Glutathione in Different Cell Lines --- p.81 / Chapter 4.4 --- Discussion --- p.84 / Chapter 4.4.1 --- Intracellular Glutathione Depletion and Cell Death Induction Effects of Baicalein on Different Cell Lines --- p.84 / Chapter 4.4.2 --- Relationship between Basal Glutathione Levels and Drug Susceptibilities --- p.85 / Chapter Chapter 5 --- Effects of Baicalein on Apoptosis and Caspase Pathways --- p.88 / Chapter 5.1 --- Introduction-Modes of Cell Death --- p.88 / Chapter 5.1.1 --- Necrosis --- p.88 / Chapter 5.1.2 --- Apoptosis --- p.89 / Chapter 5.2 --- Materials and Methods --- p.92 / Chapter 5.2.1 --- Chemicals --- p.92 / Chapter 5.2.2 --- Buffers --- p.92 / Chapter 5.2.3 --- Determination of Change of Mitochondrial Membrane Potential by JC-1 --- p.93 / Chapter 5.2.4 --- Determination of Apoptosis by Annexin V-Propidium Iodide Staining --- p.94 / Chapter 5.2.5 --- Determination of Cell Cycle Arrest by Propidium Iodide Staining --- p.95 / Chapter 5.2.6 --- "Determination of Caspase-3, -8 and -9 Activities by Fluorescent-Labeled Peptides" --- p.96 / Chapter 5.2.7 --- Determination of DNA Fragmentation --- p.97 / Chapter 5.2.8 --- Terminal Deoxynucleotidyl Transferase Mediated dUTP End Labeling (TUNEL) Assay --- p.99 / Chapter 5.2.9 --- Flow Cytometry --- p.101 / Chapter 5.3 --- Results --- p.102 / Chapter 5.3.1 --- Effects of Baicalein on Mitochondrial Membrane Potential by JC-1 Staining --- p.102 / Chapter 5.3.2 --- Effects of Baicalein on Apoptosis and Necrosis by Annexin V-Propidium Iodide Staining --- p.104 / Chapter 5.3.3 --- Effects of Baicalein on Cell Cycle Arrest by Propidium Iodide Staining --- p.108 / Chapter 5.3.4 --- "Effects of Baicalein on Caspase-3, -8 and -9 Activities" --- p.110 / Chapter 5.3.5 --- Effeets of Baiealein on DNA Fragmentation --- p.115 / Chapter 5.3.6 --- Effects of Baicalein on TUNEL Assay --- p.117 / Chapter 5.4 --- Discussion --- p.120 / Chapter Chapter 6 --- Pro-Oxidant Role of Baicalein on Reactive Oxygen Species Generation --- p.122 / Chapter 6.1 --- Introduction --- p.122 / Chapter 6.2 --- Materials and Methods --- p.122 / Chapter 6.2.1 --- Chemicals --- p.122 / Chapter 6.2.2 --- Determination of Cellular Reactive Oxygen Species Generation by Fluorescent Dye cDCFDA --- p.123 / Chapter 6.2.3 --- Determination of Mitochondrial Reactive Oxygen Species Generation by Fluorescent Dye Rhl23 --- p.124 / Chapter 6.3 --- Results --- p.125 / Chapter 6.3.1 --- Effects of Baicalein on Cellular ROS Generation by Fluorescent Dye cDCFDA --- p.125 / Chapter 6.3.2 --- Effects of Baicalein on Mitochondrial ROS Generation by Fluorescent Dye Rhl23 --- p.129 / Chapter 6.4 --- Discussion --- p.132 / Chapter Chapter 7 --- The Anticancer Mechanistic Study of Baicalein --- p.133 / Chapter 7.1 --- Introduction --- p.133 / Chapter 7.2 --- Materials and Methods --- p.134 / Chapter 7.2.1 --- Chemicals --- p.134 / Chapter 7.2.2 --- Reversibility of Baicalein-Induced GSH Depletion and Cell Death by Different Antioxidant Treatments --- p.134 / Chapter 7.2.3 --- Reversibility of Baicalein-Induced Cellular ROS Generation --- p.136 / Chapter 7.2.4 --- Reversibility of Baicalein-Induced Apoptosis by Co-Treatment of Different Antioxidants and Caspase Inhibitors --- p.137 / Chapter 7.2.5 --- "Reversibility of Baicalein-Induced Caspase-3, -8 and -9 Activation by Co-Treatment of Different Antioxidants" --- p.138 / Chapter 7.3 --- Results --- p.139 / Chapter 7.3.1 --- Reversibility of Baicalein-Induced GSH Depletion and Cell Death by Different Antioxidant Treatments --- p.139 / Chapter 7.3.1.1 --- Pre-treatments --- p.139 / Chapter 7.3.1.2 --- Co-treatments --- p.141 / Chapter 7.3.1.3 --- Post-treatments --- p.144 / Chapter 7.3.2 --- Reversibility of Baicalein-Induced Cellular ROS Generation by Co-Treatment of Different Antioxidants --- p.147 / Chapter 7.3.3 --- Reversibility of Baicalein-Induced Apoptosis by Co-Treatment of Different Antioxidants and Caspase Inhibitors --- p.152 / Chapter 7.3.4 --- Reversibility of Baicalein-Induced Caspase-3 Activation by Co-Treatment of Different Antioxidants --- p.156 / Chapter 7.3.5 --- Reversibility of Baicalein-Induced Caspase-8 and -9 Activation by Co-Treatment of Different Antioxidants --- p.160 / Chapter 7.4 --- Discussion --- p.164 / Chapter 7.4.1 --- Reversibility of Baicalein-Induced GSH Depletion and Cell Death --- p.164 / Chapter 7.4.2 --- "Reversibility of Baicalein-Induced ROS Generation," --- p.167 / Chapter 7.5 --- Concluding Remarks --- p.168 / Chapter Chapter 8 --- General Discussion --- p.169 / Chapter 8.1 --- Drug Delivery to Brain --- p.169 / Chapter 8.2 --- Protective Roles of Baicalein on Brain Cells --- p.170 / Chapter 8.2.1 --- Actions Against Oxidative Stress --- p.170 / Chapter 8.2.2 --- Actions Against Other Neurotoxic Damages --- p.171 / Chapter 8.2.3 --- Actions Against Neuronal Diseases --- p.172 / Chapter 8.3 --- Anticancer Roles of Baicalein on Astrocytoma --- p.173 / Chapter 8.4 --- Implications on the Dual Roles of Baicalein: Antioxidant and Pro-oxidant --- p.175 / Chapter 8.5 --- Future Perspectives --- p.175 / Chapter 8.5.1 --- Effects of Baicalein on Antioxidant System --- p.175 / Chapter 8.5.2 --- Effects of Baicalein on GSH Synthesis --- p.176 / Chapter 8.5.3 --- In Vivo Studies on Cytotoxic Effects of Baicalein --- p.177 / Chapter 8.5.4 --- In Vivo Studies on Anti-Tumor Effects and In Vitro Studies on Anti-Metastasis Effects of Baicalein --- p.178 / Reference List --- p.181

Li, Wing Yan Kate. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 130-154). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.iii / Abstract (Chinese Version) --- p.vi / Table of Contents --- p.viii / List of Figures --- p.xiii / List of Abbreviations --- p.xv / Chapter Chapter 1 --- General Introduction / Chapter 1.1. --- Overview of cancer --- p.1 / Chapter 1.2. --- Apoptosis and cancer --- p.4 / Chapter 1.3. --- Roles and regulation of caspase-dependent apoptosis --- p.7 / Chapter 1.3.1. --- Extrinsic death receptor pathway --- p.8 / Chapter i. --- TNFR1 and TNFa --- p.13 / Chapter ii. --- CD95/Fas and CD95 Ligand/FasL --- p.14 / Chapter iii. --- "TRAIL-R1(DR4), TRAIL-R2 (DR5) and TRAIL" --- p.14 / Chapter 1.3.2. --- Intrinsic mitochondrial pathway --- p.16 / Chapter i. --- Bcl-2 family of proteins --- p.17 / Chapter ii. --- Reactive Oxygen Species (ROS) --- p.19 / Chapter 1.4. --- Phytochemicals from Traditional Chinese Medicine (TCM) as a source of new therapeutics --- p.22 / Chapter 1.5. --- Biological effects of baicalein --- p.25 / Chapter 1.5.1 --- Roles of baicalein as a lipoxygenase inhibitor --- p.28 / Chapter 1.5.2 --- Dual roles of baicalein as an antioxidant and prooxidant --- p.28 / Chapter 1.5.3 --- "Roles of baicalein as an anti-carcinogenic, anti-proliferative and anti-metastatic agent" --- p.29 / Chapter 1.6. --- Aims of current study --- p.30 / Chapter Chapter 2 --- Effects of Baicalein on Growth and Survival of Human Cancer Cells / Chapter 2.1 --- Introduction --- p.33 / Chapter 2.2 --- Materials and Methods / Chapter 2.2.1 --- Cell culture --- p.35 / Chapter 2.2.2 --- Measurement of growth and survival of various cell lines --- p.36 / Chapter 2.2.3 --- Statistical analysis --- p.37 / Chapter 2.3 --- Results / Chapter 2.3.1 --- Baicalein retards the growth and survival of human melanoma A375 and colorectal carcinoma Caco-2 --- p.37 / Chapter 2.3.2 --- Baicalein reduces the growth and survival of melanoma A375 but not in normal skin fibroblast Hs68 cells --- p.40 / Chapter 2.4 --- Discussion --- p.42 / Chapter Chapter 3 --- Effects of Baicalein on Cell Cycle and the Apoptosis in Human Melanoma A375 Cells / Chapter 3.1 --- Introduction --- p.44 / Chapter 3.2 --- Materials and Methods / Chapter 3.2.1 --- Determination of cell cycle changes and quantification of apoptosis --- p.51 / Chapter 3.2.2 --- Immunoblotting --- p.52 / Chapter 3.2.3 --- Inhibition of caspase-8 by caspase-8 inhibitor --- p.54 / Chapter 3.2.4 --- Fluorometric measurement of caspase-3 activity --- p.54 / Chapter 3.2.5 --- Statistical analysis --- p.55 / Chapter 3.3 --- Results / Chapter 3.3.1 --- Baicalein induces S-phase arrest in cell cycle and triggers apoptosis --- p.55 / Chapter 3.3.2 --- Baicalein induces proteolytic inactivation of PARP and activation of caspases --- p.59 / Chapter 3.3.3 --- Caspase-8 is the major initiator caspase eliciting the baicalein-induced apoptosis --- p.62 / Chapter 3.4 --- Discussion --- p.67 / Chapter Chapter 4 --- Effects of Baicalein on the Extrinsic Apoptotic Pathways in Human Melanoma A375 Cells / Chapter 4.1 --- Introduction --- p.72 / Chapter 4.2 --- Materials and Methods / Chapter 4.2.1 --- Immunoblotting --- p.75 / Chapter 4.2.2 --- Determination of sub-lethal dose of exogenous TRAIL --- p.76 / Chapter 4.2.3 --- Determination of the combinatory effect of exogenous TRAIL and baicalein --- p.76 / Chapter 4.2.4 --- Statistical analysis --- p.77 / Chapter 4.3 --- Results / Chapter 4.3.1 --- Baicalein upregulates the expressions of death receptor 4 (DR4) and death receptor 5 (DR5) --- p.77 / Chapter 4.3.2 --- Baicalein sensitizes the melanoma cells to sub-lethal dose of exogenous TRAIL --- p.80 / Chapter 4.4 --- Discussion --- p.84 / Chapter Chapter 5 --- Effects of Baicalein on the Extrinsic Apoptotic Pathways in Human Melanoma A375 Cells Cancer Cells / Chapter 5.1 --- Introduction --- p.88 / Chapter 5.2 --- Materials and Methods / Chapter 5.2.1 --- Analysis of mitochondrial membrane potential --- p.94 / Chapter 5.2.2 --- Fractionation of cell lysates into cytosolic and mitochondrial fractions for immunoblotting --- p.95 / Chapter 5.2.3 --- Immunoblotting --- p.95 / Chapter 5.2.4 --- Determination of cellular reactive oxygen species (ROS) production --- p.96 / Chapter 5.2.5 --- Verification of ROS generation via the addition of Trolox´ёØ --- p.96 / Chapter 5.2.6 --- Statistical analysis --- p.97 / Chapter 5.3 --- Results / Chapter 5.3.1 --- Baicalein induces mitochondrial membrane depolarization --- p.97 / Chapter 5.3.2 --- Cytochrome c is released in the baicalein-induced mitochondrial membrane depolarization --- p.100 / Chapter 5.3.3 --- Baicalein does not elicit the intrinsic apoptotic pathway via modulation of some better-characterized Bcl-2 family proteins in A375 cells --- p.102 / Chapter 5.3.4 --- Baicalein induces ROS production --- p.105 / Chapter 5.3.5 --- Baicalein induces mitochondrial permeabilization via ROS-mediated mechanisms --- p.108 / Chapter 5.4 --- Discussion --- p.112 / Chapter Chapter 6 --- General Discussion --- p.119 / References --- p.130