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.

Background: In the U.S., Hispanics have among the highest rates of overweight and obesity when compared to other racial/ethnic groups placing them at a greater risk for obesity-related disease. Identifying intervention strategies to reduce caloric intake and/or improve cardiometabolic health in Hispanics is critical to reducing morbidity and mortality among this large and growing population. Evidence exists to support diet-specific behavioral interventions, including beverage modifications, in reducing obesity-related health risks. However, the acceptability and feasibility of a beverage intervention in obese Hispanic adults has not been robustly evaluated. Methods: The objective of this pilot study is to assess the feasibility and acceptability of a randomized, controlled beverage intervention in 50 obese Hispanic adults ages 18-64 over 8-weeks. Eligible participants were obese (30-50.0 kg/m(2)), between the ages 18-64, self-identified as Hispanic, and were able to speak, read, and write in either English and/or Spanish. Study recruitment was completed August 2017. Upon the completion of baseline assessments, participants will be randomized to either Mediterranean lemonade, Green Tea, or flavored water control. After completing a 2-week washout period, participants will be asked to consume 32 oz. per day of study beverage for 6-weeks while avoiding all other sources of tea, lemonade, citrus, juice, and other sweetened beverages; water is permissible. Primary outcomes will be recruitment, retention, and acceptability of the intervention strategies. Our study will also evaluate participant-reported tolerance and as an exploratory aim, assess safety/toxicity-related to renal and/or liver function. Fasting blood samples will be collected at baseline and 8-weeks to assess the primary efficacy outcomes: total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL). Secondary outcomes include fasting glucose, hemoglobin A1c (HbA1c), and high-sensitivity C-reactive protein (hs-CRP). Discussion: This pilot study will provide important feasibility, safety, and early efficacy data necessary to design a larger, adequately-powered randomized controlled trial.

A concerning situation has developed over the past few years where several tea estates had to close down due to high labour costs and low profitability. Solutions are desperately required to save these estates from further regression and to prevent others from joining their ranks. One solution is to redirect the tea factories from the current production of black tea to producing a value added commodity such as a high quality green tea extract with an increased market value. The aim of this study was to find an economically viable PPO inactivation method that can be implemented in existing tea factories for the production of high quality instant green tea. Further enhancement of quality may then be achieved by high throughput cultivar screening where those with a higher natural catechin to caffeine content will be favourable. Six different PPO inactivation methods (steaming, blanching, fluid bed drying, panfrying, grilling over direct heat and grilling over indirect heat) were explored. Four independent experiments were performed in duplicate with these six methods using fresh tea leaves donated by a tea estate in Tzaneen, South Africa. All samples were dried in a fluid bed drier and milled after PPO inactivation. Biochemical analysis of specific quality parameters followed where extractions from these green tea leaf samples were tested for theaflavin content, caffeine content, flavan-3-ol content, total free amino acid content, colour and taste. The six PPO inactivation methods were compared by data evaluation of the individual quality parameters where certain quality parameters carried a higher weight than others. For the purpose of this project, the catechin to caffeine ratio was the most important quality determinant to yield a high value IGT. Also, to prove effectiveness of the PPO inactivation method, low TF content was compulsory. All PPO inactivation methods explored proved successful in rapidly inactivating PPO enzyme. As hypothesised, a significant difference in biochemical composition is brought about between green teas produced by employing different PPO inactivation methods. Blanching was found to be the most efficient PPO inactivation method as well as the method resulting in the highest catechin to caffeine ratio (16.67:1 for 4 min blanch vs. 5.72:1 for 17 min FBD as determined by HPLC analysis). A freeze dried extract from a 1.5 minute blanched sample (IGT) was compared with foreign IGTs originating from Sri-Lanka, Kenya, China and India by HPLC analysis. A more than two fold greater catechin to caffeine ratio was obtained for the sample originating from the blanching method (9.08:1 vs. 2.81-5.02:1). A high quality, naturally low caffeine, instant green tea can therefore be produced by utilizing the blanching method of PPO inactivation. To allow for inter and intra cultivar screening, tentative identification of novel catechins (digallated catechins) and their HPLC retention times was done using HPLC-ESI-MS/MS. Potential HPLC retention times for EC-digallate were detected at tR 62.0 ± 0.2, 70.7 ± 0.1 and 76.7 ± 0.2 minutes while tR 64.6 ± 0.1 and 65.8 ± 0.1 minutes were detected for EGC-digallate. With this information at hand, cultivars of a higher quality, hence increased economical potential, can be identified upon confirmation by NMR. HPLC-ESI-MS/MS screening coupled with NMR confirmation is to be continued to detect several other novel flavan-3-ols that could not be detected in the 4 IGTs of different origin used in this study. This study gives an overview of the biochemical differences between green tea leaves prepared using six different PPO inactivation methods. The aim of this study was met by identification of the significant increase in quality brought about by PPO inactivation using the blanching method, which is also economical for use in Africa. Blanching of tea leaves caused a significant decrease in caffeine. Therefore, the 1st hypothesis, stating that the six polyphenol oxidase inactivation methods investigated will produce instant green teas with different catechin to caffeine ratios, is accepted. Also, a means to perform large scale screening of individual tea trees in Africa for their novel flavan-3-ol content was provided by tentative identification of these novel catechins by LC-MS. Thus, the 2nd hypothesis, stating that application of LC-MS will aid in the identification of HPLC retention times of compounds (novel catechins) from a crude extract, is also accepted. / Dissertation (MSc)--University of Pretoria, 2009. / Biochemistry / unrestricted

Philosophiae Doctor - PhD / The testes play a central role in the male reproductive system, as they represent the sites of male sex steroidogenesis and of spermatogenesis. Leydig cells, located at the testicular interstitium, produce predominantly testosterone upon stimulation with either chorionic gonadotropin (CG) or luteinising hormone by a series of enzymatic modifications of cholesterol. Sertoli cells respond to testosterone and follicle stimulating hormone to secrete inhibin and facilitate spermatogenesis by additional activities like maintaining Sertoli cell barrier (SCB) integrity and lactate secretion. Ultimately the Leydig cells, Sertoli cells etc. all work together to confer male fertility. However, infertility occurs globally; leading to the pursuit of treatment, including herbal medicines.

Fresh pork sausages were prepared from prerigor meat with synthetic antioxidants and combinations of Rosemary (R: 1500, 2000, 2500 ppm) and Green tea (G: 100, 200, 300 ppm) extracts. Experimental controls contained synthetic antioxidants only. A randomized complete block design with a factorial arrangement involving ten treatment combinations, three frozen storage periods (0.5, 3, 6 mos) and four retail display times (0, 7, 14, 21 d) was utilized. Secondary lipid oxidation products were reduced (P < 0.05) in treatments with higher amounts of R compared with the control across all frozen storage periods. Higher concentrations of both plant extracts led to increased (P < 0.05)CIE a* (redness) andCIE b* (yellowness) and decreased (P < 0.05) CIE L* (lightness) up to 6 mos of storage. Higher concentrations of R enhanced chroma and delayed discoloration throughout 14 d of retail display after 3 and 6 mos of storage. Combinations of R2500+G100 inhibited (P < 0.05) microbial growth compared with the control throughout retail display. Higher levels of R and G showed higher (P < 0.05) concentrations of spice-derived terpenes alpha-pinene, camphene, and isopulegol up to 3 mos of storage. Incorporation of R resulted in lower (P < 0.05) concentrations of lipid or microbial degradation products 2,4-decadienal, 2-butanone, and methanethiol following 3 mos of storage. Higher levels of G showed lower (P < 0.05) concentrations for 3-methyl-1-butanol and methyl isovalerate after 6 mos of storage. Natural plant extract addition led to higher (P < 0.05) consumer acceptability scores and were liked by >80% of the respondents across all frozen storage periods. The control displayed spoilage and detectable rancidity by day 7 following 6 mos of storage. Pork, nutmeg, ginger, and spice complex aromas were higher (P < 0.05) in sausages with increased concentrations of R following 0.5 and 3 mos of storage. Caramelized aroma followed a similar trend for treatments with a higher G content. Ginger, copper-herbal, rancid, offlavor and off-odor descriptors which were lower (P < 0.05) in sausages containing increased G concentrations. The use of R2500+G300 improved quality over time when the product was stored frozen for 6 mos.

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In both Type 1 diabetes (T1D) and Type 2 diabetes (T2D), inadequate beta-cell mass and beta-cell dysfunction lead to impaired insulin secretion, and ultimately worsen glycemic control. Green tea has drawn wide attention due to its possible health-promoting properties, including enhancement of beta-cell function. We assessed the acute and relative long-term effects of epigallocatechin gallate (EGCG) on insulin secretion and synthesis from clonal beta-cells (INS1E cells), rat islets, and human islets, using 0.1, 1, or 5 µM. We determined if EGCG decreased blood glucose in healthy rats acutely, using 50 or 150 mg/kg body weight (BW), and after 12 days of supplementation in drinking water, using 0.1% and 0.5%. In the in vitro studies, EGCG significantly potentiated glucose-stimulated insulin secretion (GSIS) in rat islets (at 0.1, 1, and 5 µM) and human islets (at 1 µM), and elevated insulin content within INS1E cells (at 0.1, 1, and 5 µm) and human islets (at 1 µM), (P<0.05). Nutritional supplementation of EGCG (0.5% in drinking water) for 12 days in healthy rats significantly increased insulin synthesis, compared to that of controls, from 0.2 ± 0.02 to 1.4 ± 0.2 ng/mg protein, without alteration of insulin secretion in isolated islets (P<0.05). These findings demonstrate that EGCG may play a role in the regulation of pancreatic beta-cell function, thereby contributing to an anti-diabetic effect of this agent. / Master of Science

Doctor of Philosophy / Department of Human Nutrition / Delores H. Chambers / A green tea descriptive sensory lexicon was developed by a highly trained panel, which identified, defined, and referenced 31 flavor attributes of green tea. The attributes were categorized as “green” (asparagus, beany, Brussels sprout, celery, parsley, spinach, green beans, and green herb-like), “brown” (ashy/sooty, brown spice, burnt/scorched, nutty, and tobacco), “fruity/floral” (fruity, floral/perfumy, citrus, and fermented), “mouthfeel” (astringent and tooth-etching), “basic tastes” (overall sweet and bitter), and other attributes (almond, animalic, grain, musty/new leather, mint, seaweed, and straw-like). Using the green tea lexicon, the flavor differences that exist among a wide range of green teas (n=138) produced in various countries were determined. Roast-processed teas were mostly responsible for brown-related flavors and steam-processed teas were mostly responsible for green-related flavors. Aroma analyses of green tea showed that the concentration of volatile compounds were much lower than stated in the literature. Brown, brown-related attributes, bitterness, and astringency became stronger and green and green-related attributes become weaker as the brewing time lengthened (1, 2, 5, and 20 min) and the water temperature increased (50, 70, 95°C). The flavor characteristics of roast-processed, steam processed, or roast-steam-processed Korean green teas differed only in their characterizing green flavors. The flavor and aroma of green teas change after sequential brewings. Green teas in leaf form can be brewed four times: the first two brews providing stronger flavor and aroma characteristics whereas the third and fourth brews will provide milder flavor and aroma characteristics. The flavor and aroma change in green teas that are stored over two years were observed at 3, 6, 12, 18, and 24 months after their original packaging dates. Green tea changes minimally during the first year of storage and only slightly more during the first two years of storage. Consumer studies and descriptive evaluations were conducted to understand what green tea flavor characteristics influence US consumers' liking. Twelve green tea samples were evaluated by three consumer groups from Korea, Thailand, and the United States. The current research suggests that familiarity plays a role in tea acceptance. However, various flavor profiles may be acceptable to consumers who are familiar with other flavors of green tea.

published_or_final_version / Physics / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Pharmacology / Master / Master of Philosophy