University of Macau / Institute of Chinese Medical Sciences

Lee, Ngan Hon. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 120-133). / Abstracts in English and Chinese. / Acknowledgements --- p.IV / Abstract --- p.V / 論文摘要 --- p.VII / Table of Contents --- p.IX / List of Figures --- p.XI / List of Abbreviations --- p.XIII / Chapter 1 Introduction --- p.1 / Chapter 1.1 --- Hepatocellular carcinoma (HCC) --- p.1 / Chapter 1.1.1 --- Risk factors --- p.1 / Chapter 1.1.2 --- Molecular mechanism of HCC --- p.4 / Chapter 1.1.3 --- Treatment of HCC --- p.7 / Chapter 1.2 --- Gambogic acid (GA) - a compound derived from Tradition Chinese Medicine (TCM) --- p.9 / Chapter 1.2.1 --- Traditional Chinese Medicine (TCM) --- p.9 / Chapter 1.2.2 --- Gambogic acid --- p.13 / Chapter 1.3 --- Molecular mechanism of apoptosis --- p.18 / Chapter 1.3.1 --- Overview of apoptosis --- p.18 / Chapter 1.3.2 --- Caspases cascade --- p.18 / Chapter 1.3.3 --- Bcl-2 family --- p.20 / Chapter 1.3.4 --- Mitochondria in apoptosis --- p.23 / Chapter 1.4 --- Apoptosis as a strategy for cancer therapies --- p.26 / Chapter 1.5 --- Aims of study --- p.29 / Chapter Chapter 2 --- Materials and Methods --- p.30 / Chapter 2.1 --- Cell culture and treatment --- p.30 / Chapter 2.1.1 --- Cell lines used --- p.30 / Chapter 2.1.2 --- Gambogic acid (GA) --- p.31 / Chapter 2.1.3 --- Chemicals and reagents --- p.31 / Chapter 2.1.4 --- Preparation of solutions --- p.32 / Chapter 2.1.5 --- Procedures --- p.33 / Chapter 2.2 --- Apoptotic detection --- p.35 / Chapter 2.2.1 --- Chemicals and reagents --- p.35 / Chapter 2.2.2 --- Preparation of solutions --- p.35 / Chapter 2.2.3 --- Procedures --- p.37 / Chapter 2.3 --- Effects of GA on gene expression in HepG2 --- p.41 / Chapter 2.3.1 --- Chemicals and Reagents --- p.41 / Chapter 2.3.2 --- Preparation of solutions --- p.41 / Chapter 2.3.3 --- Procedures --- p.43 / Chapter 2.4 --- Protein expression in GA-induced apoptotic cells --- p.51 / Chapter 2.4.1 --- Chemicals and Reagents --- p.51 / Chapter 2.4.2 --- Preparation of solution --- p.51 / Chapter 2.4.3 --- Procedures --- p.54 / Chapter 2.5 --- Caspase cascade study in GA-induced apoptosis --- p.60 / Chapter 2.5.1 --- Chemicals and reagents --- p.60 / Chapter 2.5.2 --- Procedures --- p.60 / Chapter 2.6 --- Downregulation of mRNA using siRNA vector --- p.62 / Chapter 2.6.1 --- siRNA expression vector --- p.62 / Chapter 2.6.2 --- Chemicals and Reagents --- p.63 / Chapter 2.6.3 --- Preparation of solution --- p.63 / Chapter 2.6.4 --- Procedures --- p.64 / Chapter Chapter 3 --- Results --- p.71 / Chapter 3.1 --- GA induces apoptosis in hepatocellular cells --- p.71 / Chapter 3.2 --- Effects of gene expression in HCC --- p.80 / Chapter 3.3 --- Caspase cascade studies in GA-induced apoptosis --- p.83 / Chapter 3.4 --- Caspase 8 activation in GA-treated cells lead to Bid cleavage --- p.89 / Chapter 3.5 --- GA induces Bax conformational changes and cytochrome c release --- p.95 / Chapter 3.6 --- Levels of protein players involved in apoptosis and cell cycle --- p.101 / Chapter Chapter 4 --- Discussion --- p.106 / References --- p.120

Στην παρούσα διατριβή παρουσιάζεται η σύνθεση regio-εκλεκτικών υποκατεστημένων παραγώγων φθαλαζινών, με διαδικασίες οι οποίες χαρακτηρίζονται από απλές σχετικά συνθετικές πορείες ενώ ταυτόχρονα συνοδεύονται και από υψηλές αποδόσεις. Οι φθαλαζίνες και τα παράγωγα αυτών παρουσιάζουν συνθετικό αλλά και ευρύτερο φαρμακολογικό ενδιαφέρον. Επιπρόσθετα η σύνθεση υποκατεστημένων φθαλαζινών αποκτά μια επιπλέον σημασία αφού μέσω κατάλληλων τροποποιήσεων μπορεί τα ανωτέρω μόρια να οδηγήσουν στην παραλαβή μη φυσικών αρωματικών αμινοξέων. Η μεθοδολογία η οποία αναπτύχθηκε ως προς τη σύνθεση των φθαλαζινών περιλαμβάνει: (α) πρωτόκολλο άμεσου/εμμέσου παραγωγοποίησης της ξανθόνης προς την 2-βρωμο-ξανθεν-9-όνη αλλά και την 2,7-διβρωμο-ξανθεν-9-όνη. (β) πυρηνόφιλη διάνοιξη, (γ) οξειδωτικό μετασχηματισμό ακυλο-υδραζονών της ξανθόνης Παράλληλος στόχος της παρούσης εργασίας αποτελεί και η ανάπτυξη ενός αποτελεσματικού πρωτοκόλλου για τη σύνθεση υποκατεστημένων (στη θέση 3) 1,2 βενζοϊσοξαζολίων καθώς και των Ν-οξειδίων αυτών. Η ανάπτυξη 1,2 βενζοϊσοξαζολίων υποκατεστημένα στον C-3 με φαρμακοφόρες ομάδες παρουσιάζει έντονο ερευνητικό ενδιαφέρον κυρίως λόγω των εφαρμογών τους στη φαρμακευτική. Εν κατακλείδι από την παρούσα εργασία αναδεικνύεται η δυνατότητα του μορίου της ξανθόνης να αποτελέσει μια ιδιαιτέρως χρήσιμη συνθόνη η οποία μέσω κατάλληλων τροποποιήσεων δυνατόν να οδηγήσει στην παραλάβη βιοδραστικών μορίων. Κατά αντιστοιχία με τη σύνθεση των φθαλαζινών η σύνθεση των βενζοϊσοξαζολίων και τωβ Ν-οδειδίων αυτών, ξεκινά με την ίδια εφαρμογή του πρωτοκόλλου άμεσου/έμμεσου παραγωγοποιήσεως της ξανθόνης, Ακολουθεί διάνοιξη αυτού και μετατροπή της σχηματιζόμενης καρβοξυλομάδας σε οξίμη. Η διασικασία ολοκληρώνεται με διεργασίες κυκλοαφυδάτωσης. Για την παραλαβή των Ν-οξειδίων αυτών ως αντιδραστήριο χρησιμοποιείται ο φαινυλο-ιωδο-διακετόξυ εστέρας. / There are numerous naturally occurring xanthones. The xanthone core is present in a large family of natural products with a broad spectrum of biological and pharmacological activities. In the present work is evaluated the usefulness of substituted xanthones as synthones towards synthesis of regio substituded phthalazines, 1,2 benzisoxazoles and N-oxides of them. The above molecus are of considerable pharmacological significance and also very useful in synthesis. The synthesis of phthalazines is achieved with simple synthetic roots followed by high yields. The procedure includes: • Protocol of direct/indirect derivatisation of xanthone mainly towards 2-bromo-xanthe-9-on and 2,7-dibromo-xanth-9-on. • Nucleophilic ring opening • Oxidative transformation of acyl-hydrazones of xanthone A parallel aim of this work is the development of an efficient protocol towards synthesis of substituted in potition 3 1,2 benzisoxazoles and the corresponding N-oxides. Following a similar strategy with the one used in the synthesis of phthalazines, xanthone is being derivatized and after the ring’s opening is transformed to the corresponding oxime. Cyclization of oxime is achieved with dehydration procedures. Finally the N-oxides of benzisoxazoles are obtained using PIDA as oxidative agent.

Thesis (Msc Food Sc (Food Science))--Stellenbosch University, 2008. / Extraction efficiency of soluble solids (SS), total polyphenols (TP) and xanthones (AlCl3 assay) from dried, green Cyclopia subternata, as affected by mass-solvent ratio, extraction time and solvents, was investigated. In addition the effect of solvent composition on extraction of mangiferin and hesperidin was determined. Extraction of 5 g plant material as opposed to 0.5 and 1 g resulted in lower recoveries of SS, TP and xanthones (P<0.05). Extraction of SS and TP increased during the initial 20 min of contact time, where after it remained constant (P>0.05). Water, 33% acetonitrile, ethanol (50, 80 and 100%), methanol (50 and 100%) and 70% acetone were investigated as extraction solvents. Extraction for 30 min with 33% acetonitrile on a steam bath or 50% ethanol at 64°C on a water bath proved to be the most effective for extraction of SS, TP and xanthones, while 33% acetonitrile was most effective in extracting hesperidin from C. subternata. However, 70% acetone was most effective in extracting mangiferin. A poor correlation (r = 0.54) was observed for the total antioxidant activity (TAA) of C. subternata, as determined for water extracts and with the mangiferin content determined by HPLC. A moderate correlation (r = 0.85) was, however, obtained for TAA and TP content. The mangiferin content of green C. subternata can be determined using the aluminium chloride (AlCl3) colorimetric method. A moderate correlation (r = 0.87) was found for the xanthone content of the plant material determined using the AlCl3 colorimetric method and mangiferin content quantified by HPLC (y = 1.2x + 0.54) following extraction with hot water. For extraction using 33% acetonitrile a weaker correlation (r = 0.74; y = 1.3x + 0.87) was found between the xanthone and mangiferin contents. The xanthone content (determined by AlCl3) of the plant material as extracted by the two solvents, correlated well (r = 0.91). Good correlations were also obtained, when comparing extractions with water and 33% acetonitrile, for determination of the SS (0.94) and mangiferin contents (r = 0.97) of the plant material. Near infrared (NIR) spectroscopy was investigated as a rapid and more economical method for prediction of mangiferin and xanthone contents of dried, green C. subternata plant material. NIR spectroscopy calibration models can be used for screening purposes for the mangiferin and (SEP = 0.21 g.100 g-1; r = 0.82) and xanthone (SEP = 0.27 g.100 g-1; r = 0.81) contents. The effect of various pre-drying treatments and storage temperatures on the colour, soluble SS, TP, mangiferin and hesperidin contents of green C. subternata was investigated. By steaming green C. subternata directly after maceration, its colour retention can be improved. Good stability was shown for mangiferin and hesperidin during manufacture and storage of C. subternata.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Mangiferin, a glucosylxanthone from the fruiting tree Mangifera indica Linn. (Anacardiaceae), was evaluated for the first time in acute models of gastric injury. Mangiferin (3, 10 and 30 mg/kg, p.o.) significantly attenuated (p<0,001) the gastric damage induced by ethanol (30, 35 and 63% of reduction), acidified ethanol (27, 44 and 78% of inhibition), indomethacin (22, 23 and 57% of reduction) and compound 48/80. This xanthonoid (30 mg/kg) markedly attenuated (p<0,01) the depletion of gastric mucosal non-protein sulfhydryl and the increase of malonyldialdehyde levels ethanol associated. While pretreatment with TRPV1 antagonist capsazepine (5 mg/kg, i.p.) failed to block effectively (p>0,05) the gastroprotective effect of mangiferin (30 mg/kg) against ethanol damage. Furthermore, the mangiferin effect was significantly (p<0,01) reduced in mice pretreated with indomethacin, L-NAME and glibenclamide. Mangiferin (30 mg/kg) caused significant diminutions (p<0,001) in gastric secretory volume and total acidity and significantly enhanced (p<0,001) gastric emptying in rats. Taken together, the results of this study strongly indicate a cytoprotective role for mangiferin affording gastroprotection against gastric damage induced by various ulcerogens, which is possibly mediated, in part, by endogenous prostaglandins, nitric oxide release, K+ ATP channel opening and antioxidant action / Mangiferina, uma glicosilxantona isolada da Ãrvore frutÃfera Mangifera indica L. (Anacardiaceae), foi avaliada em modelos experimentais de lesÃo gÃstrica aguda. Mangiferina (3, 10 e 30 mg/kg, v.o.) atenuou significativamente (p<0,001) as lesÃes gÃstricas induzidas por etanol (30, 35 e 63% de reduÃÃo), etanol acidificado (27, 44 e 78% de inibiÃÃo), indometacina (22, 23 e 57% de reduÃÃo) e composto 48/80. Esta xantona (30 mg/kg) foi capaz de diminuir de forma significativa (p<0,01) a depleÃÃo dos grupos sulfidrilas nÃo-proteicos e o aumento nos nÃveis de malonildealdeÃdo, associados à administraÃÃo de etanol. O prÃ-tratamento com o antagonista dos receptoes TRPV1 capsazepina (5 mg/kg, i.p.) nÃo foi capaz de reverter (p>0,05) o efeito gastroprotetor da mangiferina (30 mg/kg) frente Ãs lesÃes induzidas por etanol. Adicionalmente, o efeito da mangiferina foi significativamente reduzido (p<0,01) em camundongos prÃ-tratados com indometacina, L-NAME e glibenclamida. Mangiferina (30 mg/kg) causou diminuiÃÃo significativa (p<0,001) do volume secretÃrio e da acidez total gÃstrica e aumentou significativamente (p<0,001) o esvazimento gÃstrico em ratos. Os resultados do presente estudo indicam uma aÃÃo citoprotetora da mangiferina conferindo efeito gastroprotetor contra injÃria gÃstrica induzida por diversos agentes, que pode ser atribuÃdo, ao menos em parte, Ãs prostaglandinas endÃgenas, liberaÃÃo de Ãxido nÃtrico, abertura de canais de potÃssio sensÃveis a ATP e aÃÃo antioxidante

As xantonas compreendem uma importante classe de heterocíclicos moleculares que possuem um esqueleto dibenzo-gama-pironas, podendo estes serem obtidos tanto por meios sintéticos quanto naturais. Estes constituintes têm sido freqüentemente isolados de plantas medicinais brasileiras e vêm recebendo atenção devido a seus aspectos fitoquímicos e suas propriedades biológicas. No entanto, poucos estudos são dedicados à abordagem estrutural mais aprofundada desses compostos no estado sólido, principalmente com relação a estudos cristalográficos. Uma justificativa para a escassez de trabalhos dessa natureza pode estar relacionada com a dificuldade de obtenção de cristais de qualidade. Com isso, a primeira etapa deste trabalho dedicou-se à obtenção de monocristais dos derivados xantônicos e, posteriormente, realizaram-se as medidas de difração de raios X por monocristal. Após a coleta de dados de difração de raios X, as estruturas cristalinas foram resolvidas e refinadas. Neste trabalho estudaram-se doze estruturas cristalinas de derivados xantônicos oxigenados, sendo que, uma das xantonas tetra-oxigenadas apresentou dois polimorfos. Portanto, onze constituintes quimicamente diferentes estão envolvidos (I-XI). Ressalta-se que das doze estruturas determinadas por difração de raios X apenas uma, III, trata-se de uma redeterminação, as demais foram estudadas pela primeira vez. Através da estrutura refinada estudou-se as geometrias moleculares de cada composto. Em relação aos aspectos intramoleculares, destacam-se as conformações dos anéis e substituintes, além dos efeitos causados pelos mesmos. Assim, observou-se que existe a tendência do sistema de anéis xantônicos apresentar uma conformação planar, e isso foi confirmado por cálculos de otimização de geometria. Na conformação molecular das xantonas 1-hidroxiladas, o efeito de ligação de hidrogênio assistida por ressonância (LHAR) foi exaustivamente estudado. As interações intermoleculares mostraram que a grande maioria das estruturas cristalinas são estabilizadas por ligações de hidrogênio fortes (OH...O) e fracas (CH...O). Além disso, as informações cristalográficas mostraram a existência de interações pi-pi, um importante contato hidrofóbico que contribui para manter o arranjo supramolecular. / Xanthones are a group of heterocyclic molecules having a dibenzo-gama-pyrone skeleton, and can be obtained as a synthetic or natural product. These compounds have often been afforded from Brazilian medicinal plants and have received special attention due to their phytochemical and biological properties. However, this compound class was seldom studied in the solid state, mainly with regard to the crystal structure. The lack of crystallographic studies can be explained due to the difficulties found in the production of single crystals. So, the goal of the first stage of this project was to obtain well shaped single crystals of the xanthones derivatives and then to perform X-ray diffraction measurements. After the data collection, the crystal structures were solved and refined. Here, twelve crystal structures of oxygenated xanthones derivatives were studied, in which one tetra-oxygenated xanthone presented two crystal forms. Hence, there are eleven chemically different constituents (I-XI) involved in the context of the xanthones. It is worth to emphasize that only the structure named III was a redetermination, being the others ones studied by X-ray diffraction for the first time. The molecular geometric parameters of each compound were provided by the refined structure. Despite the intramolecular aspects, the conformations of the rings and the substituents were highlighted, besides the effects caused by them. Usually, in the xanthone rings the preferred conformation is the planar, which was confirmed by theoretical calculations. The effect of the resonance assisted hydrogen bond (RAHB) on the molecular conformation was widely studied in the 1-hydroxylated xanthones derivatives. Finally, the intermolecular interactions and their meaning to the crystal structures stabilization were discussed, revealing that in almost all xanthones, the crystal packing are kept by strong (OH...O) and weak (CH...O) hydrogen bonds. In addition, the crystallographic analysis also pointed out to the presence of interactions pi-pi, an important hydrophobic contact for supramolecular assembly.

研究背景： / 肝癌是全球常見的惡性腫瘤之一，世界上每年大約有50萬死亡病例，並且呈逐年上升之勢， 是全球第3位的腫瘤死亡原因。慢性乙型和丙型肝炎病毒感染是肝癌的主要成因。肝癌惡性程度高、預後差，並且目前的治療手段非常有限，術後易復發和轉移，迄今尚無正式獲准有效治療藥物。現階段，治療肝癌的主要方法是手術切除，但是隨之引起的併發症以及較高的復發機率嚴重影響了治療的療效，大大降低肝癌病人的存活期。 / 研究目的： / 分析TDP對肝癌細胞和肝腫瘤旁細胞生長的影響；分析TDP抑癌的分子靶標蛋白及其分子機理；驗證TDP對肝癌動物模型的抑制效果。開發一種新型有效的肝癌治療藥物。 / 研究方法： / 首先用MTT法從102種來源於嶺南山竹子的純複合物中分離出了TDP,它是一種甾醇類化合物。採用MTT法檢測TDP對腫瘤細胞生長的影響；流式細胞實驗驗證TDP能否引起腫瘤細胞的凋亡；採用蛋白組學和質譜分析找出TDP抑癌的分子靶標；進一步的蛋白功能增加和缺失實驗證明Hsp27的功能和作用；生物資訊學驗證HSP27和TDP的作用結果；最後利用動物模型驗證TDP對肝腫瘤的治療效果。 / 結果： / TDP不但能效率極高的抑制肝癌細胞的生長而且可以大量誘發肝癌細胞的凋亡，而對正常的肝癌旁細胞沒有影響。二維電泳以及質譜分析TDP處理的肝癌細胞對比DMSO處理的肝癌細胞發現了具有不同表達水準的18種蛋白，Hsp27是其中一個在TDP誘導下調變化倍數較大並且與細胞凋亡有密切關係的蛋白，Hsp27的過表達以及Knock-down都充分驗證了TDP通過調節Hsp27的表達參與了依賴於caspase的線粒體凋亡途徑，在Western Blotting以及RT-PCR中得到了充分的驗證。生物資訊學預測TDP可以與Hsp27結合，實驗結果表明TDP可以誘導Hsp27的聚集並導致功能喪失。動物實驗腫瘤生長結果以及免疫組化結果證明，TDP可以在很大程度上對肝癌有抑製作用。 / 結論： / 本研究首次表明，TDP如果不是完全的,最起碼也是部分通過誘導依賴於caspase的線粒體凋亡的途徑來抑制肝癌細胞的增值和分化, 具有明顯的抗腫瘤的功效，特別是對Hsp27高表達的腫瘤細胞有比較明顯的作用，是一種值得繼續深入研究的有較高潛在價值的藥物。 / Background： / Hepatocellular carcinoma (HCC), the most common primary hepatic malignancy, is a global public health problem that accounts for approximately 500,000 deaths annually. Chronic hepatitis B and hepatitis C infections are the major risk factors for the development of HCC. Due to the high rate of these infections, the incidence of HCC remains alarmingly high globally. Although great advances have been made in HCC treatment, poor prognosis and high risk of recurrence have been major challenges to patients. Currently, surgical resection is the main treatment option for HCC patients; however, complications arising from surgery can threaten its therapeutic effect and patients’ survival. / Objectives： / To characterize the functions of 1,3,5-trihydroxy-13,13-dimethyl-2H-pyran [7,6-b]Xanthone (TDP) in cell proliferation of HepG2 cells; to discover the molecular target genes and elucidate the underlying molecular mechanism of TDP; to examine the in vivo function of TDP in a nude mouse tumor model of HCC. Finally, to investigate TDP’s potential as an anti-HCC drug candidate. / Methods and Results： / In this study, we discovered that TDP, isolated from the Chinese medicinal herb, Garcinia oblongifolia, strongly inhibited cell growth and induced caspase-dependent mitochondrial apoptosis in HCC, as evidenced from MTT assay and flow cytometry analysis. Two-dimensional gel electrophoresis and mass spectrometry-based comparative proteomics were applied to find the molecular targets of TDP in HCC cells, and eighteen proteins were identified with altered expression, with Hsp27 protein being one of the proteins most significantly down-regulated by TDP. Further Hsp27-siRNA knockdown and Lenti-Hsp27 overexpression studies found that Hsp27 was involved in TDP induced mitochondrial apoptosis, with bioinformatics predictions and biological results revealing that TDP might cause Hsp27 protein form dimer and consequent degradation via the ubiquitin-proteasome system. Finally, subcutaneously injecting cancer cells with Hsp27 expression vector into the dorsal flank of nude mice tumor model also demonstrated the suppressive effect of TDP on HCC. / Conclusions： / In summary, our study discovered that TDP, a natural xanthone, was a potent inhibitor of Hsp27 in HCC. TDP inhibited cell growth and induced apoptosis by inducing Hsp27 degradation, which stimulated mitochondrial cytochrome C release which resultantly activated caspase-3 and caspase-9. These data combined with the results of the animal model strongly supported TDP’s potential as a novel anti-cancer drug candidate, especially for cancers with an abnormally high expression of Hsp27. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Fu, Weiming. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 111-151). / Abstract also in Chinese. / Abstract (English) --- p.i / Abstract (Chinese) --- p.iiv / Acknowledgment --- p.vi / Publications --- p.viii / List of Contents --- p.ix / List of Tables --- p.xii / List of Figures --- p.xiii / List of Abbreviations --- p.xv / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- General Introduction --- p.1 / Chapter 1.1.1 --- Overview of HCC --- p.1 / Chapter 1.1.2 --- Epidemiology of HCC in China and Hong Kong --- p.3 / Chapter 1.2 --- Etiology of HCC --- p.7 / Chapter 1.2.1 --- Cirrhosis --- p.8 / Chapter 1.2.2 --- HBV infection --- p.9 / Chapter 1.2.3 --- HCV infection --- p.10 / Chapter 1.2.4 --- Viral Co-Infection --- p.11 / Chapter 1.2.5 --- Fatty Liver Disease and Cryptogenic Cirrhosis --- p.12 / Chapter 1.2.6 --- Alcohol --- p.13 / Chapter 1.2.7 --- Iron --- p.13 / Chapter 1.2.8 --- Aflatoxin --- p.14 / Chapter 1.2.9 --- Others --- p.14 / Chapter 1.3 --- Diagnosis of HCC --- p.14 / Chapter 1.4 --- Prognosis of HCC --- p.17 / Chapter 1.5 --- Treatment of HCC --- p.19 / Chapter 1.5.1. --- Early stage --- p.19 / Chapter 1.5.2. --- Intermediate and advanced stage --- p.24 / Chapter 1.5.3. --- Terminal stage --- p.28 / Chapter 1.6 --- Signaling pathways in HCC --- p.28 / Chapter 1.6.1 --- Proliferation signaling pathways --- p.29 / Chapter 1.6.2 --- Signaling pathways frequently dysregulated in HCC --- p.30 / Chapter 1.6.3 --- Pathways involved in liver development and cell differentiation --- p.34 / Chapter 1.6.4 --- Inflammation pathways involved in hepatocarcinogenesis --- p.35 / Chapter 1.6.5 --- Pathways involved in neoangiogenesis --- p.37 / Chapter 1.6.6 --- The P53 tumor suppressor --- p.38 / Chapter 1.6.7 --- Heat shock proteins in HCC --- p.39 / Chapter 1.7 --- The roles of microRNAs in liver cancer progression --- p.42 / Chapter 1.8 --- TCM in the treatment of HCC --- p.45 / Chapter 1.8.1 --- Introduction --- p.45 / Chapter 1.8.2 --- Garcinia --- p.49 / Chapter 1.9 --- Objectives of the study --- p.51 / Chapter Chapter 2 --- Materials and Methods --- p.52 / Chapter 2.1 --- Preparation of the pure compounds --- p.52 / Chapter 2.2 --- Liver cell lines and tissue culture --- p.52 / Chapter 2.3 --- Human tissue samples --- p.52 / Chapter 2.4 --- Cell viability assessment with MTT assay --- p.53 / Chapter 2.5 --- Apoptosis analysis --- p.53 / Chapter 2.6 --- Two-dimensional electrophoresis (2-DE), protein visualization and image analysis --- p.54 / Chapter 2.6.1 --- Materials --- p.54 / Chapter 2.6.2 --- Protein extraction --- p.54 / Chapter 2.6.3. --- 2-DE protein profiling --- p.55 / Chapter 2.6.4. --- Gel staining and image analysis --- p.55 / Chapter 2.6.5. --- In-gel protein digestion with trypsin --- p.56 / Chapter 2.6.6. --- MALDI-TOF mass spectrometric analysis --- p.56 / Chapter 2.6.7. --- Database search --- p.57 / Chapter 2.7.1 --- Sample preparation --- p.58 / Chapter 2.7.2 --- SDS-PAGE --- p.58 / Chapter 2.7.3 --- Protein transfer --- p.58 / Chapter 2.7.4 --- Blocking --- p.59 / Chapter 2.7.5 --- Incubation with primary and secondary antibodies --- p.59 / Chapter 2.7.6 --- Proteins Visualization --- p.59 / Chapter 2.8 --- Real-time PCR --- p.60 / Chapter 2.9 --- Vector construction and lentivirus production --- p.61 / Chapter 2.9.1 --- Lenti-vector construction for Hsp27 expression --- p.61 / Chapter 2.9.2 --- Lentivirus production --- p.62 / Chapter 2.9.3 --- Lentivirus infection --- p.63 / Chapter 2.10 --- SiRNAs transfection. --- p.63 / Chapter 2.11 --- Identification of potential protein targets for TDP --- p.64 / Chapter 2.12 --- In Vivo Tumorigenesis --- p.64 / Chapter 2.13 --- Assay of chaperone activity of Hsp27 using lysozyme as substrate --- p.65 / Chapter 2.14 --- Mitochondria and cytosolic proteins preparation --- p.66 / Chapter 2.15 --- Immunohistochemistry (IHC) --- p.67 / Chapter 2.15.1 --- Preparation of paraffin tissue sections --- p.67 / Chapter 2.15.2 --- Immunostaining --- p.67 / Chapter 2.16 --- Methodology of this study --- p.68 / Chapter 2.17 --- Statistical analysis --- p.68 / Chapter CHAPTER 3 --- Results --- p.69 / Chapter 3.1 --- Introduction --- p.69 / Chapter 3.2 --- TDP significantly suppressed cell growth and induced apoptosis in HCC cells. --- p.69 / Chapter 3.2.1 --- TDP was identified from 102 pure compounds by using MTT assay --- p.69 / Chapter 3.2.2 --- TDP significantly suppressed HCC cell growth --- p.73 / Chapter 3.2.3 --- TDP induced the apoptosis of HCC cells --- p.74 / Chapter 3.3 --- Study of the molecular mechanism of TDP on HCC --- p.76 / Chapter 3.3.1 --- The comparative proteomic profiling --- p.76 / Chapter 3.3.2 --- Hsp27 was one of the molecular targets of TDP in HepG2 cells. --- p.80 / Chapter 3.3.3 --- TDP induced apoptosis through the caspase-dependent mitochondrial pathway. --- p.82 / Chapter 3.3.4 --- Hsp27 involved in the mitochondrial apoptosis induced by TDP --- p.84 / Chapter 3.3.5 --- Enforced Hsp27 overexpression rescued the mitochondrial apoptosis induced by TDP in HepG2 cells --- p.87 / Chapter 3.3.6 --- The possible regulatory signaling by TDP --- p.91 / Chapter 3.4 --- TDP directly targeted Hsp27 and destroyed its chaperone action --- p.92 / Chapter 3.5 --- Degradation of Hsp27 aggregation stimulated by TDP was mediated by ubiquitin-proteasome system (UPS) pathway --- p.96 / Chapter 3.6 --- Nude mice model demonstrated the suppressive effect of TDP on HCC --- p.97 / Chapter Chapter 4 --- Discussion and Conclusions --- p.100 / Chapter 4.1 --- Discussion --- p.100 / Chapter 4.2 --- Conclusion --- p.110 / Reference --- p.111

As xantonas compreendem uma importante classe de heterocíclicos moleculares que possuem um esqueleto dibenzo-gama-pironas, podendo estes serem obtidos tanto por meios sintéticos quanto naturais. Estes constituintes têm sido freqüentemente isolados de plantas medicinais brasileiras e vêm recebendo atenção devido a seus aspectos fitoquímicos e suas propriedades biológicas. No entanto, poucos estudos são dedicados à abordagem estrutural mais aprofundada desses compostos no estado sólido, principalmente com relação a estudos cristalográficos. Uma justificativa para a escassez de trabalhos dessa natureza pode estar relacionada com a dificuldade de obtenção de cristais de qualidade. Com isso, a primeira etapa deste trabalho dedicou-se à obtenção de monocristais dos derivados xantônicos e, posteriormente, realizaram-se as medidas de difração de raios X por monocristal. Após a coleta de dados de difração de raios X, as estruturas cristalinas foram resolvidas e refinadas. Neste trabalho estudaram-se doze estruturas cristalinas de derivados xantônicos oxigenados, sendo que, uma das xantonas tetra-oxigenadas apresentou dois polimorfos. Portanto, onze constituintes quimicamente diferentes estão envolvidos (I-XI). Ressalta-se que das doze estruturas determinadas por difração de raios X apenas uma, III, trata-se de uma redeterminação, as demais foram estudadas pela primeira vez. Através da estrutura refinada estudou-se as geometrias moleculares de cada composto. Em relação aos aspectos intramoleculares, destacam-se as conformações dos anéis e substituintes, além dos efeitos causados pelos mesmos. Assim, observou-se que existe a tendência do sistema de anéis xantônicos apresentar uma conformação planar, e isso foi confirmado por cálculos de otimização de geometria. Na conformação molecular das xantonas 1-hidroxiladas, o efeito de ligação de hidrogênio assistida por ressonância (LHAR) foi exaustivamente estudado. As interações intermoleculares mostraram que a grande maioria das estruturas cristalinas são estabilizadas por ligações de hidrogênio fortes (OH...O) e fracas (CH...O). Além disso, as informações cristalográficas mostraram a existência de interações pi-pi, um importante contato hidrofóbico que contribui para manter o arranjo supramolecular. / Xanthones are a group of heterocyclic molecules having a dibenzo-gama-pyrone skeleton, and can be obtained as a synthetic or natural product. These compounds have often been afforded from Brazilian medicinal plants and have received special attention due to their phytochemical and biological properties. However, this compound class was seldom studied in the solid state, mainly with regard to the crystal structure. The lack of crystallographic studies can be explained due to the difficulties found in the production of single crystals. So, the goal of the first stage of this project was to obtain well shaped single crystals of the xanthones derivatives and then to perform X-ray diffraction measurements. After the data collection, the crystal structures were solved and refined. Here, twelve crystal structures of oxygenated xanthones derivatives were studied, in which one tetra-oxygenated xanthone presented two crystal forms. Hence, there are eleven chemically different constituents (I-XI) involved in the context of the xanthones. It is worth to emphasize that only the structure named III was a redetermination, being the others ones studied by X-ray diffraction for the first time. The molecular geometric parameters of each compound were provided by the refined structure. Despite the intramolecular aspects, the conformations of the rings and the substituents were highlighted, besides the effects caused by them. Usually, in the xanthone rings the preferred conformation is the planar, which was confirmed by theoretical calculations. The effect of the resonance assisted hydrogen bond (RAHB) on the molecular conformation was widely studied in the 1-hydroxylated xanthones derivatives. Finally, the intermolecular interactions and their meaning to the crystal structures stabilization were discussed, revealing that in almost all xanthones, the crystal packing are kept by strong (OH...O) and weak (CH...O) hydrogen bonds. In addition, the crystallographic analysis also pointed out to the presence of interactions pi-pi, an important hydrophobic contact for supramolecular assembly.

No / Three new xanthones, hypericorin C (1), hypericorin D (2) and 3,4-dihydroxy-5-methoxyxanthone (3), along with eight known compounds; 2,3-dimethoxyxanthone (4), 3,4-dihydroxy-2-methoxyxanthone (5), 3,5-dihydroxy-1-methoxyxanthone (6), 3-acetylbetulinic acid (7), 10H-1,3-dioxolo[4,5-b]xanthen-10-one (8), 3-hydroxy-2-methoxyxanthone (9), 3,4,5-trihydroxyxanthone (10) and betulinic acid (11) were isolated from the roots of Hypericum oblongifolium. The structures of the new compounds 1, 2 and 3 were deduced by spectroscopic techniques [ESI MS, (1)H NMR, (13)C NMR, and 2D NMR (HMQC, HMBC, COSY and NOESY)]. The entire series of compounds were evaluated for anti-ulcer activity.

La guttiférone A , appartenant à la famille des PPAPs ou Acyle Phloroglucinol Polycycliques Polyprénylées, est une molécule extraite à partir d’un arbre tropicale, le Symphonia globulifera. Cette matière première est abondante et peut être facilement obtenue. De plus, elle présente de nombreuses activités biologiques, lui conférant un potentiel pharmacologique très intéressant. Trois approches ont été effectuées durant ces travaux. La première fût l’utilisation de microorganismes pour effectuer des biotransformations. L’utilisation de levures a permis de synthétiser la 3,16-oxy-guttiférone A, forme xanthone de la guttiférone. Le second axe a été d’utiliser des outils chimiques pour obtenir des dérivés de la guttiférone A. Dans un premier temps, une vingtaine d’analogues éther et ester du catéchol a été synthétisée, certains de ces composés ont montré un meilleur indice de sélectivité sur les parasites. Une synthèse sélective de xanthone par une réaction de couplage phénolique oxydatif a également été étudiée. Nous avons pu obtenir par cette approche la 3,16-oxy-guttiférone A, la 1,16-oxy-guttiférone A et la 1,12-oxy-guttiférone A. Ces réactions ont aussi donné accès à des dérivés xanthone hydroxylée jamais décrits dans la littérature. Enfin, un travail préliminaire de phytochimie sur les graines et feuilles du Symphonia globulifera a été réalisé, permettant d’isoler des analogues de la guttiférone A, la guttiférone C et D, ainsi que d’autres molécules comme des bisflavonoides et des xanthones. / Guttiferone A, belonging to the PPAPs family (Polycyclic Polyprenylated Acylphloroglucinols), is extracted from a tropical tree called Symphonia globulifera. This raw material is abundant and can be easily obtained. In addition, it has many biological activities, giving it a very interesting pharmacological potential. Three approaches were used in this work. The first was the use of microorganisms to perform biotransformations. The use of yeast allow the synthesis of 3,16-oxy-guttiférone A, a xanthone derivative of guttiferone A. The second theme was the use of chemical tools for guttiferone A derivation. First, twenty ether and ester catechol analogs were synthesized, some of these compounds showed a better selectivity index of parasites. Selective synthesis of xanthone by phenolic oxidative coupling reaction was also studied. We obtained by this approach the 3.16-oxy-guttiferone A, 1,16-oxy-guttiferone A and 1,12-oxy-guttiferone A. These reactions have also provided some hydroxylated xanthone never described before in the literature. Finally, preliminary phytochemical work on seeds and leaves of Symphonia globulifera lead to the isolation of guttiférone A analogues such as guttiférone C and D, as well as other molecules such as bisflavonoides and xanthones.