published_or_final_version / Public Health / Master / Master of Public Health

Flavonoids are a long and well known class of natural products. Their potential health benefits can be attributed to their antioxidant activity, and modulation of cell signaling pathways. Green tea one of the most widely consumed beverages, consist of flavonoids such as catechins and tannins. Epigallocatechin gallate (EGCG) the major catechin of green tea exhibits multiple health benefits due to its antioxidant nature. The radical scavenging activity of EGCG is attributed to its structure. Therefore, a study on molecular features of EGCG would provide valuable information on structural modifications, which may change the physiochemical properties such as bioavailability and solubility. Although flavonoids are abundant and commercially available they are difficult to purify and crystallize. In this respect, crystallizing EGCG was challenging. By exploring different techniques EGCG was crystallized. Here in this study one new form of EGCG and two solvates, acetonitrile and nitrobenzene, have been synthesized and structurally characterized by differential scanning calorimetry (DSC), infrared (IR) and powder X-ray diffraction (PXRD). The crystal structures were solved by single-crystal X-ray diffraction and a detailed description of synthesis and about the supramolecular synthons that exist in these crystal forms are given.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Additional advisors: Ada Elgavish, Vithal Ghanta, Hui-Chen Hsu, Thane Wibbels. Description based on contents viewed June 11, 2008; title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 91-101). Also available on the World Wide Web.

Thesis (M.Med.Sc.)--University of Hong Kong, 2003. / Includes bibliographical references (leaves 46-57). Also available in print.

Made available in DSpace on 2014-08-13T14:50:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-02-28Bitstream added on 2014-08-13T18:00:41Z : No. of bitstreams: 1 000756556.pdf: 305164 bytes, checksum: cf88d3a7c62cbaafd803cd3908ec908a (MD5) / Um dos mecanismos que explica como o infarto agudo do miocárdio (IAM) evolui para insuficiência cardíaca é denominado de remodelação ventricular. Dentre as inúmeras alterações bioquímicas associadas ao processo destaca-se o estresse oxidativo. O consumo habitual do chá verde (CV) é associado a benefícios à saúde, devido às suas propriedades, antioxidante, antiiflamatória, antiapoptótica, antiproliferativa, antimutagênica. Estas são atribuídas às catequinas, seu composto bioativo. Portanto, é possível que o extrato de chá verde atenue alguns parâmetros envolvidos na remodelação cardíaca. O objetivo do trabalho foi avaliar se o extrato de chá verde atenua a remodelação cardíaca após o infarto agudo do miocárdio. Para tanto foram utilizados ratos Wistar machos divididos em quatro grupos: controle padrão (CP) (28-sham); extrato do CV (CV) (32-sham e extrato de chá verde); infarto padrão (IP) (25-animais infartados controles); infarto e extrato do CV (ICV) (26- animais infartados e extrato do CV). Ecocardiografia inicial foi realizada após cinco dias ao IAM. A partir de uma divisão homogênea dos animais, considerando o tamanho do infarto maior a 35%, iniciou-se o tratamento. Ao final de três meses estes animais foram estudados por meio de ecocardiografia, morfometria, dosagens bioquímicas de enzimas do estresse oxidativo, metabolismo energético, perfil lipídico sérico, inibidor tecidual de metaloprotease (TIMP-1) e zimografia para atividade das metaloproteases (MMP-2 e MMP-9). Nos resultados, observou-se aumento do diâmetro diastólico do ventrículo esquerdo pelo peso corporal, diâmetro sistólico do ventrículo esquerdo pelo peso corporal e diâmetro do átrio esquerdo pelo peso corporal nos grupos com IAM, mas houve atenuação nos ICV. O tempo de desaceleração da onda E foi reduzido no IP, o que não foi observado no ICV, tendo valor similar ao CV. O extrato de CV também normalizou as atividades ... / One mechanism that explains how acute myocardial infarction develops into heart failure is called ventricular remodeling. Among the many biochemical changes associated with the process stands oxidative stress. The regular consumption of green tea (GT) is associated with health benefits due to its properties such as antioxidant, anti-inflammatory, antiapoptotic, antiproliferative, antimutagenic. These are attributed to catechins, its bioactive compound. Therefore, it is possible that GT extract mitigate some parameters involved in cardiac remodeling. The objective of this study was to assess whether the green tea extract attenuates cardiac remodeling after acute myocardial infarction. For both, male Wistar rats were allocated in 4 groups: control (C-28 sham); green tea extract (GT-32 sham and GT); infarction group (MI-25 infarcted animals controls); infarction and green tea extract (IGT-26 infarcted animals and GT). To start the treatment an initial echocardiography was performed five days after the myocardial infarction, from a homogeneous division of the animals, considering the size of the infarction greater than 35%. At the end of three months these animals were studied by echocardiography, morphometry, biochemical enzyme of the oxidative stress, energy metabolism, lipid profile, tissue inhibitor of metalloproteinase (TIMP-1) and zymography for activity of metalloproteinases (MMP-2 and MMP-9). The results showed an increase in left ventricular diastolic diameter by body weight, left ventricular systolic diameter by body weight and left atrial diameter by body weight in groups with MI, but there was attenuation in IGT. The deceleration time of the E wave was reduced in MI, which was not observed in IGT, with a value similar to GT group. GT extract also normalized the activities of antioxidant enzymes superoxide dismutase and catalase in the IGT group, when compared to MI. Regarding energy metabolism, the IGT group showed increased ...

Thesis submitted in fulfillment of the requirements for the degree Master of Technology: Biomedical Technology In the Faculty of Health and Wellness Sciences At the Cape Peninsula University of Technology, 2012 / Human and experimental animal studies have shown that biomarkers of oxidative damage are elevated in subjects with certain diseases or risk factors. Consequently, it is hypothesized that oxidative stress plays an important role in the pathogenesis of these diseases and that dietary intake of, or supplementation with antioxidants may be protective or be useful therapeutic targets. This study was designed to investigate the modulatory effect of Camellia sinensis (Chinese green tea), Aspalathus linearis (rooibos herbal tea) and the two commercial supplements on the antioxidant status of the liver and kidney of tert-butyl hydroperoxide (t-BHP)-induced oxidative stress male Wistar rats. Rooibos and green tea are beverages well-known for their antioxidant content. Based on the specific beverage consumed, sixty male Wistar rats were randomly assigned into six groups, i.e. fermented rooibos (FRT), unfermented rooibos (URT), Chinese green tea (CGT), rooibos supplement (RTS), Chinese green tea supplement (GTS) and control (CTL). The animals had free access to the respective beverages and standard diet for 10 weeks, while oxidative stress was induced during the last 2 weeks via intraperitoneal injection of 30 μM of t-BHP per 100 g body weight. Among all the beverage and/or supplement preparations, the commercial rooibos supplement had the highest total polyphenol content and antioxidant activity while fermented rooibos, as previously shown, had a lower antioxidant content and potency when compared to its unfermented counterpart. The ability of these beverages and/or supplements to modulate the antioxidant status in tissues was organ specific and varied according to the assessment method. When considering the liver, the intake of unfermented rooibos, Chinese green tea and the commercial rooibos supplement significantly (P<0.05) restored the t-BHP-induced reduction and increased the antioxidant status with regards to oxygen radical absorbance capacity and trolox equivalent antioxidant capacity (TEAC) levels. All the beverages and/or supplements also significantly (P<0.05) enhanced the renal antioxidant capacity as assessed by the TEAC assay. In what may be an indication of decreased oxidative stress, all the beverages were associated with a general decline in activities of the antioxidant enzymes which reached significant levels in renal superoxidase dismutase activity. Generally, the beverages did not impact significantly on lipid peroxidation (LPO) although there were differing trends in the two LPO markers assessed. While thiobarbituric acid reactive substances levels showed a declining trend in both tissues, the conjugated dienes were generally elevated. In conclusion, this study confirms Camellia sinensis and Aspalathus linearis as well as their two supplements as good sources of dietary antioxidants and results demonstrated that rooibos and green tea improved the liver and kidney antioxidant capacity of oxidative stress-induced rats. Their impact on antioxidant status in rats was shown to vary between organs and according to the method of assessment. Hence multi-method, multi-organ assessment may be a more informative approach in in vivo antioxidant studies.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / As doenças cardiovasculares são a principal causa de morte nos países ocidentais. Alguns estudos sugerem que o chá verde tem efeito benéfico sobre diferentes fatores de risco cardiovascular. No entanto, outros estudos não mostraram essa associação. Objetiva avaliar em mulheres pré-hipertensas obesas o efeito do consumo de chá verde sobre: a pressão arterial, a função endotelial, o perfil metabólico, a atividade inflamatória e a adiposidade corporal. Estudos clínico, randomizado, cruzado, duplo-cego e placebo-controlado. Durante 4 semanas as mulheres foram orientadas a ingerir 3 cápsulas de extrato de chá verde por dia (500mg extrato chá verde/cápsula) passando por 2 semanas de washout e posteriormente ingeriam por mais 4 semanas o placebo. As mulheres que iniciaram o estudo tomando placebo posteriormente utilizaram o chá verde. Ou seja, todas as pacientes receberam chá verde e placebo por um mesmo período. No início e final de cada tratamento foram analisadas as variáveis. Foram avaliadas 20 mulheres pré-hipertensas, obesidade grau I e II, idade entre 25 e 59 anos. O local do estudo foi o Laboratório da Disciplina de Fisiopatologia Clínica e Experimental Clinex. Universidade do Estado do Rio de Janeiro. As variáveis estudadas foram a pressão arterial, índice de hipertemia reativa (avaliada com Endo-PAT2000), proteína C reativa, interleucina-6, fator de necrose tumoral-&#945;, molécula de adesão intercelular e molécula de adesão vascular celular, inibidor de ativador do plasminogênio, fator de crescimento endotelial vascular, E-selectina, adiponectina, colesterol total, LDL-colesterol, HDL-colesterol, triglicérides, glicemia, insulina, HOMA, índice de massa corporal, circunferência de cintura, circunferência de quadril, relação cintura quadril e percentual de gordura corporal. Como resultados, na avaliação da pressão arterial pela monitorização ambulatorial da pressão arterial, observou-se redução significativa da pressão arterial sistólica de 24 horas (pré 130,31,7 mmHg vs. pós 127,02,0 mmHg; p= 0,02), pressão arterial sistólica diurna (pré 134,01,7 mmHg vs. pós 130,72,0 mmHg; p= 0,04) e pressão arterial sistólica noturna (pré 122,21,8 mmHg vs. pós 118,42,2 mmHg; p= 0,02), após o consumo do chá verde, em comparação ao uso do placebo. Após o consumo do chá verde foi observado aumento, embora estatisticamente não significativo, no índice de hiperemia reativa (pré 1,980,10 vs. pós 2,220,14), além de redução expressiva na concentração da molécula de adesão intercelular (pré 91,88,0 ng/ml vs. pós 85,85,6 ng/ml) e do fator de crescimento endotelial vascular (pré 195,846,2 pg/ml vs. pós 158,638,7 pg/ml), porém sem significância estatística. As demais variáveis avaliadas não se modificaram de forma significativa após o consumo do chá verde, em comparação ao placebo. Foi observada forte correlação entre redução de pressão arterial sistólica e diastólica de 24hs, avaliada pela monitorização ambulatorial da pressão arterial, e o aumento do índice de hipertemia reativa (r= -0,47; r= -0,50, respectivamente). Os resultados do presente estudo sugerem que o chá verde tem efeito benéfico sobre a pressão arterial e possivelmente sobre a função endotelial. / Cardiovascular diseases are the leading cause of mortality in Western countries. Some studies have suggested that green tea has beneficial effects on different cardiovascular risk factors. However, others have failed to show such an association. Objective to evaluate the effects of green tea on blood pressure, endothelial function, metabolic profile, inflammatory activity and body adiposity in obese pre-hypertensive women. Study clinical, randomized, crossover, double-blinded, placebo-controlled. During 4 weeks women were instructed to ingest 3 capsules of green tea extract per day (500mg green tea extract/capsule), after 2 weeks of washout and then ingested placebo for 4 weeks. The women who began the study with placebo later have used green tea. That is, all patients received placebo and green tea for the same period. At the beginning and end of each treatment the variables were analyzed. Study of 20 women with pre-hypertension, obesity grade I and II, aged between 25 and 59 years. Study site in Laboratory of the Discipline of Clinical and Experimental Pathophysiological Clinex. Rio de Janeiro State University. Variables studied was blood pressure, reactive hyperemia index (evaluated with Endo-PAT2000), C-reactive protein, interleukin 6, tumor necrosis factor alpha, vascular cell adhesion molecule, intercellular adhesion molecule, plasminogen activator inhibitor-1, vascular endothelial growth factor, E-selectin, adiponectin, total cholesterol, low density lipoprotein-cholesterol, high density lipoprotein-cholesterol, triglycerides, blood glucose, insulin, HOMA, body mass index, waist circumference, hip circumference, waist-to-hip ratio and body fat. As results, in the assessment of blood pressure by ambulatory blood pressure monitoring was observed significant reduction in 24 hours systolic blood pressure (pre 130.31.7 mmHg vs. post 127.02.0 mmHg; p= 0.02), daytime systolic blood pressure (pre 134.01.7 mmHg vs. post 130.72.0 mmHg; p= 0.04) and nighttime systolic blood pressure (pre 122.21.8 mmHg vs. post 118.42.2 mmHg; p= 0.02), after consumption of green tea compared with placebo. After consumption of green tea, there was an increase, although not statistically significant, in reactive hyperemia index (pre 1.980.10 vs. post 2.220.14), besides expressive reduction in the concentration of intercellular adhesion molecule (pre 91.88.0 ng/ml vs. post 85.85.6 ng/ml) and vascular endothelial growth factor (pre 195.846.2 pg/ml vs. post 158.638.7 pg/ml), however without statistical significance. The other variables evaluated did not change significantly after consumption of green tea. A strong correlation was observed between reduction in 24 hours systolic blood pressure and 24 hours diastolic blood pressure, assessed by ambulatory blood pressure monitoring, and the increase of reactive hyperthermia index (r= -0.47; r= -0.50, respectively). The results of this study suggest that green tea has a beneficial effect on blood pressure and possibly on endothelial function.