published_or_final_version / Pharmacology / Master / Master of Philosophy

published_or_final_version / Pharmacology / Doctoral / Doctor of Philosophy

Antioxidant properties of green tea (GT) have been widely reported. The antioxidant capacity (AOC) of green tea was investigated to include the effect of infusion time over 24 hours. The AOC was measured by the FRAP, DPPH, TEAC, and CBA assays. It was proven according that after 2 hours of brewing, tea has higher AOC and Total phenolic content (TPC), these significantly decreases after 4 hours. GT has a high amount of polyphenols with potent AOC. However, interactions between polyphenols and food matrix may decrease their potential benefit. The objective of this experiment was to test the hypothesis that the addition of milk (full fat, semi-skimmed, and skimmed) may affect the phenolic content and AOC was measured. The results indicated the plain GT had highest activity; then tea with FFM had a significantly higher amount of AO than others. Plant extracts possess health promoting properties. The objective of this study was to determine the TPC and AOA of different concentrations of spice extracts (fennel, clove, cardamom, cinnamon, ginger, anise, and black pepper) with DPPH, TEAC and Rancimat methods. At low concentration, black pepper had a highest activity but at high concentration, ginger showed the highest activity among the extracts. The TPC for spice extract was greater for anise. Results provided evidence that the studied spices may be used as a natural AO. In recent decades, saliva has emerged as a new way to diagnose and investigate basic health problems. In this study, salivary TPC and AOC were measured after consumption a single cup of green tea with and without of milk. In a healthy adult crossover design. The salivary AOC and TPC were measured before and after consumption up to 3 hours. Results indicated that milk decreased AOC of GT when compared with the control water. The activity reached peak 1 hour after ingestion and then decreased returning to the baseline. Results confirmed that saliva could be used as an easier and safer alternative to blood to assess AOA in humans.

O diabetes é um problema de saúde que vem aumentando cada vez mais na população mundial. Suas principais causas estão relacionadas aos comportamentos da vida moderna, como a má alimentação e o sedentarismo. O tratamento extremo da doença é a aplicação de insulina exógena, mas atualmente, busca-se terapias alternativas, menos invasivas e dispendiosas, e mais práticas, como o uso do chá-verde, por seu possível efeito antihiperglicêmico. Neste estudo, o objetivo foi analisar os efeitos do chá em alguns parâmetros bioquímicos do sangue e histológicos dos tecidos dentários de ratos diabéticos. Foram utilizados 80 ratos Wistar, sendo que 40 constituíram o grupo experimental diabético e 40, o grupo controle. Estes grupos foram subdivididos em dois cada, os tratados com chá-verde e os que não receberam tratamento. Seguiu-se uma terceira subdivisão em grupos de 5 animais (n=5) de acordo com os períodos experimentais de 15 dias, 1, 2 e 3 meses. A indução do diabetes foi conseguida pela injeção de 50 mg/kg de estreptozotocina intra-peritoneal em animais com 2 meses de idade. Após 1 semana o diabetes foi diagnosticado por exames clínicos e glicemia maior do que 180 mg/dL. A partir daí, os animais tratados tiveram a ingestão hídrica substituída pela ingestão de chá-verde por 24 h ao dia. O chá-verde foi preparado com 7 g da folha desidratada / L água, em infusão por 10 min. Ao completarem-se os períodos experimentais, o sangue foi colhido, os animais foram mortos e suas mandíbulas extraídas e preparadas para a análise histológica. A avaliação histomorfométrica mostrou uma redução do volume de fibras entre os grupos de 3 meses em relação ao de 15 dias. As lesões cariosas foram verificadas e apresentaram-se nos períodos de 2 e 3 meses da doença, sendo que o chá-verde provavelmente inibiu em 50% as cáries nos animais diabéticos aos 2 meses experimentais. Os níveis glicêmicos sofreram um aumento significante entre os períodos de 15 dias a 1 mês da doença e, então, mantiveram-se constantes, sendo que o chá-verde parece ter apresentado efeito anti-hiperglicêmicos neste período. Os níveis de uréia aumentaram gradualmente nos animais diabéticos, mas diminuíram aos 3 meses da doença nos animais tratados (diabéticos e controle). Os níveis de albumina mostraram-se menores somente nos diabéticos tratados aos 3 meses. Os níveis de proteínas totais foram menores desde os quinze dias de diabetes nos animais sem chá em relação aos tratados. Os níveis de colesterol acompanharam a curva de crescimento da glicemia através do tempo nos diabéticos sem tratamento. Um achado curioso foi a menor média de colesterol, aos quinze dias, do grupo diabético tratado com chá-verde. Os níveis de triglicérides só foram afetados pela doença ao terceiro mês, quando o maior nível de triglicérides foi o do grupo diabético tratado. No primeiro mês do experimento, os animais diabéticos apresentaram níveis maiores de creatinina do que os do grupo controle, mas com o chá-verde este aumento foi significativamente menor. Com base nestes dados, podemos inferir que cháverde, ingerido regularmente por via-oral, pode controlar inicialmente o avanço da cárie dentária, da glicemia e outros compostos sangüíneos, mas com o passar do tempo esse efeito parece diminuir sobre alguns produtos enquanto aumentar sobre outros. / The diabetes is a increasing all around the world. The most probable causes are the problems related to the dietry and the lack of physical exercises. The best treatment known is the insulin, however, nowadays we have some efforts to discovery new types of treatment, chipper and more practical as the green tea. The green tea is wideness know like a anti-hyperglycemic agent. In our study, we aim to analyze the biochemical effects in the blood and the histology of the dental tissues in diabetic rats submitted to the therapy of green tea. For that we used 80 Wistar rats divided first in 2 groups, control and diabetic induced by streptozotocin. So on, the groups of 40 we divided again in 2 groups, each one recived water or green tea. Each 5 animals (n=5) of each group were killed according to the periods (15, 30, 60 and 90 days). The induction was achieved by the intraperitoneal injection of 50 mg/kg of weight body of streptozotocin. One week later the diabetes was diagnosed by clinical exams where the glycemic level reached 180 mg/dL. Then, the treatment started and the green tea groups had their liquid dietry of water substituted by green tea 24 h a day. The tea was prepared with 7 g/L of water in 10 min infusion. When the periods were completed the animals were killed and their maxillaries were removed and prepared for the histological analysis. The histomorphometrical evaluation showed a reduction in the fibers volume between the 15 and 90 days experimental periods. The caries injuries were presented in the periods of 60 and 90 days, but only in the diabetical group, and the green tea was able to prevent in 50% the number of caries in 60 days of treatment. The glycemic level was pretty higher in 30 days when compared to the 15 days, after that it didnt present any significant elevation. In this gap of time (15 to 30 days) the green tea showed anti-hyperglycemic and anticholesterol effects and also decreased the creatinina level in diabetics. The urea level increased through the time in the diabetic animals, but decreased after 90 days of green tea treatment. The albumin level responded in the same way. Based on this evaluations, we are able to infer that the green tea ingested via-oral is capable of control inicially the caries and some biochemical substancies in the blood. However, these effects seam to decrease over some levels and increased in others while the time goes on presenting cumulative effects.

Environmental contamination is a public health concern. In particular persistent organic pollutants like Polychlorinated Biphenyls (PCBs) have been associated with multiple chronic inflammatory diseases, including non-alcoholic fatty liver disease (NAFLD). NAFLD prevalence has steadily increased and is expected to continue to rise with an estimated 25% of the world’s population and 80-100 million people affected in the United States alone. Importantly, the liver is the primary site for endobiotic and xenobiotic metabolism, hence its proper function is critical for the body’s response to innate and extrinsic molecules. One way to combat the deleterious effects of PCB toxicity and fatty liver disease is by increasing consumption of beverages and foods that contain beneficial bioactive nutrients, like dietary polyphenols. However, the biological properties of these dietary compounds are subject to their bioavailability which is directly dependent on the activity of the liver. The first aim of this dissertation was to test the hypothesis that in the presence of a compromised liver, PCB-126 toxicity is altered. Indeed, hepatic and systemic PCB-126 toxicity was exacerbated in this severe liver injury mouse model with an observed increase in hepatic inflammation, systemic inflammation, and early markers of endothelial cell dysfunction. Interestingly, we also observed an increase in the novel gut-liver axis derived cardiovascular disease (CVD) marker trimethylamine-N-oxide (TMAO). Taken altogether, aim 1 proved that a compromised liver can alter PCB toxicity, with implications of the gut microbiota in disease pathology. In aim 2 we investigated whether GTE can protect against MCD-induced hepatic toxicity and development of NAFLD. Results indicated that MCD mice exhibited severe liver injury and gut dysbiosis and unexpectedly, GTE had no protective effects. Interestingly MCD mice displayed differential epigallocatechin-3-gallate (EGCG) metabolism at the hepatic and gut microbiota level, which may alter polyphenol bioavailability and therapeutic potential. Overall, the results provide insight into how a dysfunctional liver and gut dysbiosis can alter polyphenol metabolism, possibly reducing its therapeutic efficiency. In aim 3 we sought to determine potential protective effects of a prebiotic in this mouse model. MCD-fed mice were exposed to PCB-126 with or without inulin supplementation. Although findings from this study are preliminary, our evidence indicates that inulin restores body weight and body composition in this MCD+PCB mouse model and alters the expression of Cyp1a1 in PCB exposed mice, suggesting that inulin’s protective effects may be a result of its ability to interact with the AhR pathway. However further analysis will need to be done to examine the effects of inulin on hepatic, systemic, and gut microbiota endpoints. Overall the data contained in this dissertation suggests that in the presence of a compromised liver both pollutant toxicity and nutrient metabolism are altered, with implications of the gut-microbiota in disease risk. These findings suggest that individuals with end stage liver injury may be more susceptible to pollutant-induced toxicity and nutritional intervention may be unsuccessful at mitigating disease risk.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 102-115). Also available on the World Wide Web.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

The overall objective of this thesis was to test the hypothesis that maternal overnutrition has adverse effects on the expression of central metabolic regulators in offspring but could be offset by supplementing green tea extract (GTE) to the dams during gestation and/or lactation. This thesis focuses on two aspects of central metabolic regulation: the leptin signaling that links to appetite regulation and the sirtuin 1(SIRT1)/oxidative stress pathway that links to insulin sensitivity (IS). This study was initiated based on previous findings of this laboratory that via developmental programming energy intake of offspring born to dams given GTE during lactation was suppressed and that IS was improved in offspring of dams supplemented with GTE during gestation and/or lactation. The diets used included low fat (LF), high-fat (HF), and HF diet added with 0.75% or 1%GTE (GT1, GT2). In experiment 1, female rats were given the respective diet 8 weeks prior to mating till the end of lactation. Male offspring were weaned to the HF, GT1 or GT2 diet for 10 weeks forming the LF/HF, HF/HF, GT1/HF, GT2/HF, HF/GT1 and HF/GT2 groups. Maternal and postweaning GTE supplementation increased hypothalamic leptin receptor (OB-Rb) and signal transducer activator of transcription 3 (STAT3) mRNA suggestive of enhanced leptin signaling but pro-opiomelanocortin (POMC) mRNA expression, an appetite inhibitor was only elevated in the HF/GT1 group which was associated with reduction in food intake in this group. Central oxidative status was improved in GT1/HF and GT2/HF offspring through enhanced hypothalamic SIRT1 and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) expression compared with the HF/HF group. These improvements coincided with better IS in the HF offspring born of GTE supplemented dams. Experiment 2 was designed to determine the relative importance of gestation and lactation as the critical period for GTE supplementation. Female rats were assigned to LF, HF or GT1 diet 9 weeks prior to mating till the end of pregnancy. During lactation half of the HF and GT1 dams had the diet switched to GT1 and HF, respectively. Male offspring were fed the LF or HF diet until 22 weeks of age forming 10 offspring groups: LF/LF/LF, LF/LF/HF, HF/HF/LF, HF/HF/HF, HF/GT1/LF, HF/GT1/HF, GT1/HF/LF, GT1/HF/HF, GT1/GT1/LF, and GT1/GT1/HF. Consistent with a reduction in energy intake in offspring born to dams receiving GTE supplementation during lactation, there was an increase in melanocortin 4 receptor (MC4R) expression in the hypothalamus (P<0.05). Regardless of postweaning diet, offspring of dams given GTE during gestation and/or lactation had elevated hypothalamic PGC-1α and reduced protein phosphorylation of c-Jun N-terminal kinase-1 when compared with offspring of unsupplemented dams(P<0.05) which was associated with improved IS. Hence, leptin signaling and appetite regulators in the offspring were selectively affected by GTE supplementation during lactation whereas offspring exhibited improved ability to handle oxidative stress if dams received GTE supplementation during gestation and/or lactation. Collectively, these results support the notion that central mechanisms with roles in appetite control and oxidative status are susceptible to the programming phenomenon triggered by maternal nutritional status. / published_or_final_version / Biological Sciences / Master / Master of Philosophy

Risks of metabolic syndrome including cardiovascular disease and diabetes are significantly affected by maternal nutrition. This concept of developmental programming had been investigated in our laboratory and in an earlier study, it was established that maternal high-fat diet predisposed rat offspring to insulin resistance and higher triglyceride in serum, liver, skeletal muscle and adipose tissue. These abnormalities, however, were ameliorated by supplementing green tea extract to dam’s diet throughout gestation and lactation. The overall objective of this thesis was to examine lipid metabolism, oxidative stress and inflammatory responses in heart of offspring born to dams receiving high-fat diet with or without green tea supplementation during pregnancy and lactation. Female Sprague-Dawley rats were fed an obesogenic diet which was a high-fat diet (HF,30%), low-fat diet (LF,7%) or HF diet containing 0.75% green tea extract prior to conception and throughout gestation. During lactation, half of the dams had their diet switched from HF to GT and vice versa. Pups were weaned to the HF or LF diet, forming 10 offspring groups (gestation/lactation/postweaning): LF/LF/LF, LF/LF/HF, HF/HF/LF, HF/HF/HF, HF/GT/LF, HF/GT/HF, GT/GT/LF, GT/GT/HF, GT/HF/LF and GT/HF/HF. Except a larger fibrotic area, maternal HF diet did not affect lipid accumulation, oxidative status and inflammatory response in the heart of offspring. Analysis of variance revealed different, and even opposite, effects of GT supplementation during gestation and lactation. In offspring born to dams receiving GT supplementation during gestation, they had suppressed fatty acid oxidation (FAO) and higher triglyceride (TG) level in the heart. In contrast, when GT was supplemented to dams during lactation, offspring had elevated heart TG, cholesterol and free fatty acid levels but up-regulated FAO. Since FAO is associated with reactive oxygen species (ROS) production, modulation of FAO is believed to affect cellular stress responses in heart. Consistent with FAO, cardiac stress, apoptotic and inflammatory biomarkers including B-type natriuretic peptide (BNP), bcl 2 associated-x (bax) and interleukin-1β (IL1b) were down-regulated in offspring born to dams given GT during gestation, whereas GT supplementation during lactation increased the expression of pro-apoptotic markers: bax and caspase-3 (Cas3) concurrent with activation of antioxidant defense system: catalase, glutathione peroxidase (GPx) and glutathione S-transferase (GST) as adaptive mechanism against increased ROS. Uncoupling protein 2 (UCP 2) and subsequent higher bcl 2 /bax ratio has been reported to stimulate apoptosis. In agreement with this, mRNA expression of BNP, bax and Cas3 were found to correlate with that of UCP 2. This suggests UCP 2may play an important role in apoptosis under the impact of maternal GT supplementation. The present data suggest that the effect of maternal high-fat diet is organ specific causing apparently lesser damage to the heart. When GT is given in conjunction with a high-fat diet to dams during gestation, there is no clear cut advantage to the offspring. However, potential adverse effects could not be ruled out when GT is supplemented to dams during lactation possibly due to higher catechin exposure via milk. Future study should focus on establishing the benefits and safety use of GT during gestation. / published_or_final_version / Biological Sciences / Master / Master of Philosophy

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences