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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Nanoencapsulation of Tea Catechins in Casein Micelles: Effects on Processing and Biological Functionalities

Haratifar, Sanaz 25 November 2012 (has links)
This thesis focuses on the interactions between milk proteins (caseins) and tea catechins and the consequences of the interactions on the renneting properties and digestion of casein micelles as well as on the biological functionality of the mixture, as measured using intestinal cell models. The binding of epigallocatechin-gallate (EGCG) to casein micelles was quantified using HPLC and fluorescence quenching, and it was shown that a substantial amount of EGCG can be incorporated in the casein micelles. At concentrations < 2.5 mg/ml milk, most of the EGCG added to milk was associated with the caseins. The formation of EGCG-casein micelles complexes not only delayed the gelling point of milk, but they also affected the structure formation of the gels. EGCG is known to have antiproliferative activity on colon cancer cells. Although nanoencapsulation of EGCG in casein micelles may have some advantages, such as protecting this bioactive compound from degradation, it may also affect the bioavailability of EGCG. To test this hypothesis, the effect of nanoencapsulation of EGCG in casein micelles on the biological functionality of EGCG was tested by evaluating the cytotoxity and proliferation behaviour of HT-29 colon cancer cells. It was demonstrated that nanoencapsulation did not affect the bioefficacy of EGCG. Similar experiments were also carried out on rat colonic cells, a normal line and its cancerous tranformed line. For this study, nanoencapulated EGCG was subjected to in vitro digbefore absorption. The results showed that EGCG-casein binding did not affect the digestion of the milk proteins. In this case, the bioefficacy of EGCG was not diminished as well. In addition, studies on normal cell lines demonstrated the specific effect of EGCG on cancer cells, favoring normal cell survival whether EGCG was isolated or complexed with milk. These experiments bring further evidence that milk can be employed as an appropriate platform for the delivery of bioactive compounds.
2

Inhibition of phytopathogenic fungi on selected vegetable crops by catechins, caffeine, theanine and extracts of Camellia sinensis (L.) O. Kuntze

Wilmot, Michelle 30 July 2008 (has links)
The aim of our study was to determine whether Polyphenon G (PPG, a concentrated Camellia sinensis extract) and the individual compounds in PPG had activity against phytopathogenic fungi in vitro and in vivo. The present study reports on the sensitivity of twenty different phytopathogenic fungal species to extracts from black-, green- and rooibos tea extracts, concentrated green tea extract (Polyphenon G), caffeine, theanine, epigallocatechin gallate (EGCg), epicatechin gallate (ECg), epigallocatechin (EGC), and epicatechin (EC), and Polyphenon G combined with caffeine. The inhibition of fungal growth by the compounds was as follows (in decreasing order): caffeine > EGCg ECg > EGC EC > Polyphenon G > green tea extracts black tea extracts > rooibos tea extracts theanine. In some cases the Polyphenon G and caffeine combination reduced the IC50 values for both the compounds, indicating a synergistic effect. Phytophthora nicotianae and P. capsici were most sensitive to all the compounds, while Rhizopus stolonifer and Penicillium expansum were least sensitive. PPG and caffeine was subsequently tested individually and in combination in a greenhouse trial against seven pathogens on four crops. The combinations of Polyphenon G and caffeine gave the best overall results and effectively controlled Fusarium solani on cucumber, P. capsici and Sclerotium rolfsii on tomato, Sclerotinia sclerotiorum and Pythium F-group on lettuce. PPG individually significantly inhibited the growth of Sphaerotheca fuliginea of zucchini squash plants. In efforts to determine the mode of action of PPG, caffeine and the combination thereof, methods used in our study included determining total phenolic content by means of the Folin-Ciocalteu reagent, thin layer chromatography (TLC) bioautography to identify possible anti-microbial compounds and high performance liquid chromatography (HPLC) for identifying induced compounds based on standards included in the analysis. Results showed that ferulic, salicylic and caffeic acids increased in uninfected lettuce plants treated with a combination of PPG and caffeine. These results indicate that either the phenolic compounds in the treatments were accumulated in the roots or that the treatments induced de novo synthesis in the plants to increase the production of phenolic compounds or that the treatments caused induction of resistance in the plant. The results of the current study demonstrate the potential for tea (C. sinensis) extracts to be developed as effective crop protection agents against a range of plant diseases on a variety of crops. / Dissertation (MSc)--University of Pretoria, 2008. / Microbiology and Plant Pathology / unrestricted
3

Effects of water chemistry and panning on flavor volatiles and catechins in teas (Camellia sinensis)

Sheibani, Ershad 03 December 2014 (has links)
In the first experiment, effects of brewing time, chlorine, chloramine, iron, copper, pH and water hardness were investigated for their effects on extraction of epigallocatechine gallate (EGCG) and caffeine in green tea and oolong tea aqueous infusions. The extraction of EGCG and caffeine were lower when green tea was brewed in hard water compared to distilled water. Brewing green tea and Oolong tea in tap water resulted in higher extraction of caffeine but had no effect on EGCG compared to distilled water. The extraction of EGCG and caffeine were significantly increased (P<0.05) when green tea and Oolong tea were brewed in the chlorinated water at 4.0 mg free chlorine per liter. The purpose of the second experiment was to optimize SDE conditions (solvent and time) and to compare SDE with SPME for the isolation of flavor compounds in Jin Xuan oolong tea using Gas Chromatography- Mass Spectrometry (GC-MS) and Gas Chromatography- Olfactrometry (GC-O). The concentration of volatile compounds isolated with diethyl ether was higher (P<0.05) than for dichloromethane and concentration was higher at 40 min (P<0.05) than 20 or 60 minutes. For SDE, 128 volatiles were identified using GC-MS and 45 aroma active compounds using GC-O. The number of volatiles identified using GC-MS was lower in SPME than SDE. For SPME, 59 volatiles and 41 aroma active compounds were identified. The composition of the volatiles isolated by the two methods differed considerably but provided complementary information. The goal of the third experiment was to determine effects of panning on flavor volatile compositions of oolong using GC-MS and GC-O. Simultaneous Distillation and Extraction (SDE) and Solid Phase Microextraction (SPME) techniques were applied for extraction of volatiles in panned and unpanned teas. A total of 190 volatiles were identified from SDE and SPME extractions using GC-MS and GC-O. Trans-nerolidol, 2- hexenal, benzaldehyde, indole, gernaiol, and benzenacetaldehyde contents were significantly decreased (P<0.05) by panning; however, panning increased (P<0.05) contents of linalool oxide, cis jasmone, methyl salicylate in oolong tea. Overall, panning significantly changes the volatile compositions of the tea and created new aroma active compounds. / Ph. D.
4

Avaliação de parâmetros oxidativos e inflamatórios em neutrófilos de ratos obesos suplementados com extrato de chá verde. / Evaluation of oxidative and inflammatory parameters in neutrophils from obese rats supplemented with green tea extract.

Albuquerque, Karen Fernanda Felix da Silva de 29 April 2014 (has links)
Este estudo tem como objetivo principal avaliar os efeitos da suplementação crônica com extrato de chá verde sobre os indicadores inflamatórios e da função de neutrófilos de ratos obesos. Ratos machos Wistar (Rattus norvegicus) foram tratados com extrato de chá verde via intragástrica, durante 12 semanas (5 dias/semana; 500mg/kg) e a obesidade foi induzida por dieta de cafeteria (8 semanas). Os neutrófilos foram obtidos da cavidade peritonial pela injeção de glicogênio de ostra (1% em PBS) 4h antes do procedimento de eutanásia por decapitação. Os resultados obtidos demonstram que a obesidade causa uma redução nas funções efetoras de neutrófilos o que pode pode aumentar a suceptibilidade à infecções, e o tratamento com extrato de chá verde melhora as funções dessas células. Dessa forma, este trabalho contribui para a elucidação das alterações decorrentes da obesidade no sistema imune e as ações benéficas do extrato de chá verde nesta condição. / This study aims to evaluate the effects of chronic supplementation with green tea extract on inflammatory markers and neutrophil function of rats with obesity induced by cafeteria diet intake. For this study, male Wistar rats (Rattus norvegicus) were treated with green tea extract intragastric for 12 weeks (5 days/week; 500mg/kg) and obesity induced by cafeteria diet (8 weeks). Neutrophils were obtained from peritoneal cavity by injection of oyster glycogen (1% in PBS) 4 h before euthanasia by decapitation procedure. The results obtained demonstrate that the obesity causes a reduction in neutrophil effector functions which may increase susceptibility to infections, and the treatment with green tea extract seems to improve the functions of these cells in obese mice. This work contributes for the elucidation of the changes arising from obesity in the immune system and the beneficial actions of the green tea extract in this condition.
5

Investigação do potencial termogênico e metabólico da planta Camellia sinensis em camundongos obesos - repercussão sistêmica do fenótipo bege. / Investigation of the thermogenic and metabolic potential of the Camellia sinensis plant in obese mice - systemic repercussion of the beige phenotype.

Bolin, Anaysa Paola 28 March 2018 (has links)
O desenvolvimento de adipócitos termogênicos/bege no tecido adiposo branco (TAB) pode reduzir os efeitos adversos da obesidade e melhorar a saúde metabólica. Certos agentes farmacológicos e nutricionais podem promover esses efeitos ativando fatores de transcrição ou vias regulatórias, promovendo o browning do TAB. Como suplemento nutricional ou dietético, os compostos presentes no chá verde (CV) têm demonstrado fortes correlações entre o metabolismo energético e a perda de peso corporal (PC), no entanto, sua potencial contribuição para o desenvolvimento de células termogênicas/bege foram fracamente investigadas. O objetivo principal deste estudo foi avaliar a relação entre as alterações metabólicas induzidas por uma dieta obesogênica e a indução de células termogênicas/bege em camundongos obesos tratados com CV. Além disso, foi avaliado o efeito de uma mistura contendo as principais catequinas do CV (EGCG (2 <font face = \"symbol\">mM), EGC (1 <font face = \"symbol\">mM), ECG (0,6 <font face = \"symbol\">mM) e EC (0,4 <font face = \"symbol\">mM)) (Sigma) em uma concentração final de 4 <font face = \"symbol\">mM e o extrato de CV a 0,19% na indução de fenótipo bege in vitro (pré-adipócitos 3T3-F442A). Nós demonstramos que os camundongos induzidos à obesidade (dieta de cafeteria/16 semanas) e tratados com CV (500 mg/kg de PC) durante 12 semanas mostraram uma redução significativa nos indicadores de obesidade, ganho de peso, depósitos de gordura, hiperlipidemia e incremento nos níveis plasmáticos de adiponectina sem alteração na ingestão alimentar. A taxa metabólica basal foi aumentada, assim como, os genes envolvidos na oxidação de AG, termogênese e marcadores de células bege no TA subcutâneo de animais obesos tratados com CV. O CV também diminuiu a inflamação e o estresse de retículo endoplasmático induzido pela dieta e a resistência à insulina (RI). Nós também sugerimos pela primeira vez que o tratamento com CV induz um ciclo fútil que envolve a de novo lipogênese para ativação da via termogênica in vivo e in vitro. A mistura de catequinas e o extrato de CV demonstraram redução significativa no acúmulo de lipídios, além de induzir a expressão de marcadores termogênicos relacionados à oxidação de AG e ativação mitocondrial, bem como o consumo de oxigênio. O efeito termogênico do CV e do mix de catequinas ocorre de maneira autônoma e dependente da modulação temporal de fatores adipogênicos como o PPAR<font face = \"symbol\">g. Nosso estudo identificou que as alterações metabólicas promovidas pela ingestão de CV induzem o gasto energético e comprometem o destino final da célula adiposa, ainda em etapas iniciais do processo de adipogênese, com modulações que envolvem a via do PPAR<font face = \"symbol\">g, associado à ativação de um ciclo fútil e indução do fenótipo bege. Essas alterações culminam em uma estratégia terapêutica eficiente de combate à obesidade e suas co-morbidades. / The development of thermogenic/beige adipocytes in white adipose tissue (WAT) might reduce the adverse effects of obesity and could help to improve metabolic health. Certain pharmacological and nutritional agents can promote those effects by activating transcription factors or regulatory signaling pathways furthering WAT browning. As a nutritional or dietary supplement, compounds present in green tea (GT) has demonstrated remarkable correlations between energy metabolism and body weight (BW) loss, however, their potential contributions to the development of thermogenic/beige cells have been scarcely investigated. The aims of this study were to evaluate the relationship between metabolic alterations induced by an obesogenic diet and the induction of thermogenic/beige cells in GT-treated obese mice. We also evaluated the effect of a mix containing the main catechins found in GT (EGCG (2<font face = \"symbol\">mM), EGC (1<font face = \"symbol\">mM), ECG (0.6<font face = \"symbol\">mM) and EC (0.4<font face = \"symbol\">mM)) (Sigma) in a final concentration of 4<font face = \"symbol\">mM and a GT extract at 0.19%.in the induction of beige phenotype in vitro (3T3-F442A preadipocytes). Here, we show that obese-induced mice (cafeteria diet/16 weeks) that were treated with GT (500 mg/kg of BW) for 12 weeks showed a significant reduction in indicators of obesity such as BW gain, fat depots, hyperlipidemia and an increment in plasma adiponectin levels without alteration in food intake. The basal metabolic rate was increased as well as genes involved in FA oxidation, thermogenesis and beige cells markers in the subcutaneous AT of obese animals treated with GT. GT also decreased inflammation and endoplasmic reticulum stress induced by the diet and relief insulin resistance (IR). We also find that our treatment was able to induce a futile cycle through de novo lipogenesis to activate the thermogenic pathway in vivo and in vitro. The mix of catechins or the GT showed significant reduction of lipid accumulation and upregulated the expression of thermogenic markers related to FA oxidation and mitochondrial activation, as well as, oxygen consumption. The effects of GT and the mix of catechins occur in an autonomous manner and seems to be dependent on initial mechanism in adipogenesis through PPAR<font face = \"symbol\">g participation. Our study identified that the metabolic alterations caused by GT ingestion induce energetic expenditure and compromise the final commitment of adipose cell, still in the initial stages of the adipogenesis process, with modulations involving the PPAR<font face = \"symbol\">g pathway, associated to the activation of the futile cycle and induction of beige phenotype. These alterations culminate in an effective therapeutic strategy to combat obesity and its comorbidities.
6

Hepatocyte Cytotoxicity Induced by Hydroperoxide (Oxidative Stress Model) or Dicarbonyls (Carbonylation Model): Prevention by Bioactive Nut Extracts or Catechins

Banach, Monica Sofia 16 December 2009 (has links)
Carbonyl and oxidative stress augment the development of diabetic complications. We evaluated the cytoprotectiveness of walnut and hazelnut extracts and catechins for decreasing cytotoxicity, lipid peroxidation, reactive oxygen species (ROS) formation, and protein carbonylation in cell death models of carbonyl and oxidative stress. Polar extracts (methanol or water) showed better cytoprotection than the non-polar (ethyl acetate) nut extracts against hydroperoxide-induced hepatocyte cell death and oxidative stress markers. Catechin flavonoids found in plants, including walnuts and hazelnuts, prevented serum albumin carbonylation in a carbonyl stress model (using glyoxal or methylglyoxal). Hepatocyte protein carbonylation and cell death were prevented and UV spectra data suggested a catechin:methylglyoxal adduct was formed. We conclude that (a) bioactive nut constituents in polar extracts were more protective than non-polar extracts against oxidative stress, and (b) catechins were effective under physiological temperature and pH, at preventing dicarbonyl induced cytotoxicity likely by trapping dicarbonyls or reversing early stage carbonylation.
7

Hepatocyte Cytotoxicity Induced by Hydroperoxide (Oxidative Stress Model) or Dicarbonyls (Carbonylation Model): Prevention by Bioactive Nut Extracts or Catechins

Banach, Monica Sofia 16 December 2009 (has links)
Carbonyl and oxidative stress augment the development of diabetic complications. We evaluated the cytoprotectiveness of walnut and hazelnut extracts and catechins for decreasing cytotoxicity, lipid peroxidation, reactive oxygen species (ROS) formation, and protein carbonylation in cell death models of carbonyl and oxidative stress. Polar extracts (methanol or water) showed better cytoprotection than the non-polar (ethyl acetate) nut extracts against hydroperoxide-induced hepatocyte cell death and oxidative stress markers. Catechin flavonoids found in plants, including walnuts and hazelnuts, prevented serum albumin carbonylation in a carbonyl stress model (using glyoxal or methylglyoxal). Hepatocyte protein carbonylation and cell death were prevented and UV spectra data suggested a catechin:methylglyoxal adduct was formed. We conclude that (a) bioactive nut constituents in polar extracts were more protective than non-polar extracts against oxidative stress, and (b) catechins were effective under physiological temperature and pH, at preventing dicarbonyl induced cytotoxicity likely by trapping dicarbonyls or reversing early stage carbonylation.
8

Comportamento ingestivo e social de novilhas leiteiras suplementadas com extrato de chá verde (Camellia sinensis L.) / Feeding and social behavior of dairy heifers supplemented with green tea extract (Camellia sinensis L.)

Santos, Carolina da Silva dos January 2015 (has links)
A criação de novilhas pode utilizar aditivos fitogênicos, como o extrato de chá-verde (Camellia sinensis L.) para melhorar aspectos ligados à sanidade e eficiência digestiva. Todavia existem poucas informações sobre os seus efeitos no comportamento animal. O experimento foi conduzido com o objetivo de avaliar os efeitos da inclusão de diferentes doses do extrato herbal de chá-verde no comportamento social e ingestivo de novilhas leiteiras. Foram utilizadas 35 novilhas não prenhes e com idades entre 14 e 15 meses. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro tratamentos e medidas repetidas no tempo. O comportamento foi avaliado nos períodos diário (24 horas) e diurno (11 às 20:30 horas), e foi observado visualmente de forma individual em intervalos de 10 minutos. As variáveis estudadas foram: tempo em decúbito direito, tempo em decúbito esquerdo, tempo deitada total, tempo em estação, tempo em ócio, tempo ruminando, tempo pastejando, e a frequência com que os animais caminhavam, corriam, ingeriam água, ingeriam sal, interagiam e tinham comportamento de dominância/dominada entre eles. Os atributos comportamentais contínuos foram avaliados quanto ao efeito das doses de extrato de chá verde, segundo a análise de regressão e análise de variância, testando os efeitos de dia de avaliação, doses e sua interação, e os atributos comportamentais eventuais foram analisados usando regressão logística. Em relação ao comportamento diário (24h), a inclusão do extrato de chá verde na dieta aumentou linearmente o tempo deitada em decúbito direito e reduziu o tempo em pastejo. Os demais atributos não tiveram diferenças significativas. Em relação ao comportamento diurno, a inclusão do extrato de chá verde na dieta de novilhas influenciou o tempo deitada em decúbito direito, as que receberam 3g apresentaram maiores tempos em decúbito direito comparados com aquelas que receberam 2g. A chance de ocorrência de interações entre os animais diminuiu em 30% a cada grama de extrato de chá verde fornecida no alimento. Nos demais atributos não houve diferenças significativas. O extrato de chá verde altera em parte o comportamento ingestivo, diminuindo as atividades de pastejo, enquanto aumenta o tempo de permanência deitada em decúbito direito e diminui as interações sociais entre os animais. / In the production of dairy heifers, phytogenic additives, such as green tea extract (Camellia sinensis L.) might be used to improve aspects of health and digestive efficiency. There is limited information of the effects on performance and animal behavior. This trial was conducted to evaluate the effects of the inclusion of green tea herbal extract in the diet on the ingestive and social behavior of dairy heifers. Thirty-five non-pregnant heifers, aged between 14 and 15 months, were used. The experimental design was completely randomized, with four treatments and repeated measures. The behavior was visually observed individually and focal at 10 minute intervals. The variables studied were: time spent in right decubitus, in left decubitus, lying, standing, resting, ruminating, grazing, and the frequency animals walked, ran, drank water, ate salt, interacted and had dominance/submission behavior. Continuous behavioral attributes were evaluated for the effect of green tea extract doses, according to regression analysis and analysis of variance, testing the effects of valuation date, doses and their interaction, and discrete or categorical behavioral attributes were analyzed using logistic regression. Regarding the daily behavior (24 hours), the inclusion of green tea extract in the diet linearly increased the time lying on right decubitus and reduced grazing time. The other attributes did not differ significantly. Regarding the diurnal behavior, green tea extract in heifers’ diet influenced the lying time on right decubitus, those receiving 3g spent more time in right decubitus than those receiving 2g. The chance of occurrence of interactions between animals decreased by 30% every 1g of green tea extract of grass added into the diet. No differences were detected for other attributes. Green tea extract alters partially feeding behavior, reducing grazing activities, while it increases the time lying in right decubitus and reduces social interactions among animals.
9

Papel Protetor dos Chás Provenientes da Camellia Sinensis sobre Atividade da Enzima Δ-ALA-d de Tecido Ovariano Inibida pelo Cádmio / Protective Role of the Camellia Sinensis Teas on Ovarian Δ-ALA-D Enzyme Activity Inhibited by Cadmium

Soares, Melina Bucco 22 February 2014 (has links)
Submitted by Sandro Camargo (sandro.camargo@unipampa.edu.br) on 2015-03-08T23:12:00Z No. of bitstreams: 1 126110006.pdf: 1402473 bytes, checksum: aed1fe94c57f7ab83538a36308f58174 (MD5) / Made available in DSpace on 2015-03-08T23:12:00Z (GMT). No. of bitstreams: 1 126110006.pdf: 1402473 bytes, checksum: aed1fe94c57f7ab83538a36308f58174 (MD5) Previous issue date: 2014-02-22 / A δ-Aminolevulinato desidratase (δ-ALA-D) é uma enzima tiólica que catalisa uma das reações iniciais da biossíntese do heme. Essa enzima é considerada um marcador proteico de intoxicação com metais. O cádmio é um dos poluentes tóxicos, amplamente distribuído no meio ambiente, sendo que a exposição humana resulta principalmente da fumaça do cigarro, da poluição do ar e do consumo de alimentos e água contaminados pelo metal. O cádmio apresenta uma baixa taxa de excreção no organismo e um elevado tempo de meia- vida biológico e por esta razão, se acumula no sangue, rins e fígado, bem como nos órgãos reprodutivos, incluindo o ovário. A patogênese do dano ovariano e a redução da viabilidade folicular após exposição ao cádmio tem sido associada a danos oxidativos. Assim, compostos antioxidantes poderiam ser uma terapia alternativa frente a toxicidade do cádmio. O presente estudo avalia o efeito protetor da Camellia sinensis (chás verde, branco e vermelho) sobre a inibição da atividade da δ-ALA-D ovariana induzida pelo cádmio in vitro (ovário bovino) e ex vivo (ovário de camundonga). O efeito do cloreto de cádmio (IC 50 , 20μM), das infusões de chás (0,07 – 10 mg/mL) e das catequinas isoladamente –epicatequina (EC), epigalocatequina (EGC), epicatequina galato (ECG), epigalocatequina galato (EGCG) - foram avaliadas sobre a atividade da δ-ALA-D de ovário bovino (in vitro). Além disso, a composição das infusões de chá foi avaliada por HPLC (Cromatografia Líquida de Alta Eficiência) em um ensaio quantitativo de catequinas, alcalóides purina e ácido gálico, bem como o conteúdo de polifenóis totais. Os chás verde e branco nas maiores concentrações estudadas restauraram a atividade da δ-ALA-D inibida pelo cádmio enquanto o chá vermelho não apresentou efeito in vitro. O chá verde apresenta maior quantidadede conteúdo fenólico (757,24 μg EAG/mL) bem como de catequinas (EGCG = 205,64 μg/mL, EC = 84,59 μg/mL, EGC = 75,53 μg/mL, ECG = 64,73 μg/mL) comparado com o chá branco (499,37 μg EAG/mL) (EGCG = 105,57 μg/mL, EC = 54,73 μg/mL, EGC = 81,96 μg/mL, ECG = 34,25 μg/mL) e com o chá vermelho (272,39 μg EAG/mL) (só foi detectado ECG= 1,36 μg/mL). Nenhuma das catequinas testadas isoladamente foi eficaz em restaurar a atividade da enzima inibida pelo cádmio. Para os experimentos ex vivo, camundongas receberam uma única administração nas doses de 2,5 mg/kg e 5 mg/kg de CdCl 2 por via intraperitoneal e chá verde (250 mg/kg) administrado via oral. Verificou-se que a exposição aguda ao cádmio nas doses de 2,5 e 5 mg/Kg inibiu (cerca de 26% e 33%, respectivamente) a atividade da enzima δ-ALA-D de ovário de camundongas e o chá verde foi capaz de restaurar essa inibição. O maior efeito do chá verde observado in vitro, bem como o papel protetor apresentado no estudo ex vivo, poderia ser atribuído ao maior teor de fenóis, mas não de catequinas. Na verdade, as catequinas não foram capazes de restaurar a atividade da enzima inibida por cádmio, demonstrando que estes compostos não são os principais componentes responsáveis pelo efeito benéfico do chá verde observada neste estudo. Esse estudo demonstrou a eficácia do chá verde em restaurar a atividade da δ-ALA-D inibida pelo cádmio em tecido ovariano. / δ-aminolevulinate dehydratase (δ-ALA-D) is a thiol enzyme that catalyzes one of the initial reactions of heme biosynthesis. This enzyme is considered a marker protein for metal poisoning. Cadmium is a toxic pollutant, widely distributed in the environment, and human exposure results mainly from cigarette smoke, air pollution and consumption of food and water contaminated by the metal. Cadmium has a low excretion rate of the organism and high biological ha lf- life and for this reason it accumulates in the blood, kidney and liver as well as on reproductive organs including the ovaries. The pathogenesis of ovarian follicular damage and reduction of viability after exposure to cadmium has been associated with o xidative damage. Thus, antioxidant compounds may be an alternative therapy against cadmium toxicity. The present study evaluates the protective effect of Camellia sinensis (green, white and red teas) on the inhibition of ovarian δ-ALA-D activity induced by cadmium in vitro and ex vivo. The effect of cadmium chloride (IC 50 20μM), tea infusions (0.07 to 10 mg/ml) and individual catechins – epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), epigallocatechin gallate (EGCG) - were evaluated on bovine ovaries δ-ALA-D activity (in vitro). Furthermore, the composition of tea infusions was measured on a HPLC quantitative assay of catechins, gallic acid and purine alkaloids, and the content of total polyphenols was measured by Folin–Ciocalteu method. The green and white teas, at the highest concentrations studied, restored the δ-ALA-D activity inhibited by cadmium while red tea had no effect in vitro. Green tea has higher amount of phenolic content ( 757.24 mg GAE/mL ) and catechins (EGCG = 205.64 μg/mL; EC = 84.59 μg/mL; EGC = 75.53 μg/mL; ECG = 64.73 μg/mL) compared with white tea ( 499.37 mg GAE/mL ) (EGCG = 105.57 μg/mL; EC = 54.73 μg/mL; EGC = 81.96 μg/mL; ECG = 34.25 μg/mL) and red tea (272.39 mg GAE/mL) ( only detected ECG = 1.36 μg/mL). None of the tested catechins alone was effective in restoring the enzyme activity inhibited by cadmium. For the ex vivo experiments, mice received a single administration of CdCl 2 , at doses of 2.5 mg/kg and 5 mg/kg intraperitoneally, and green tea (250 mg/kg) administered orally. We found that acute exposure to cadmium at doses of 2.5 and 5 mg/kg inhibited (about 26% and 33%, respectively) δ-ALA-D activity of mice ovaries, and green tea was able to restore this inhibition. The greater effect observed in vitro by green tea as well as the protective role presented at the ex vivo study, could be attributed to the higher phenols content, but not catechins. In fact, the catechins were not able to restore the enzyme activity inhibited by cadmium, demonstrating that these compounds are not the key components responsible for the beneficial effect of green tea observed in this study. This study demonstrated the effectiveness of green tea in restoring the δ-ALA-D activity inhibited by cadmium in ovarian tissue.
10

Comportamento ingestivo e social de novilhas leiteiras suplementadas com extrato de chá verde (Camellia sinensis L.) / Feeding and social behavior of dairy heifers supplemented with green tea extract (Camellia sinensis L.)

Santos, Carolina da Silva dos January 2015 (has links)
A criação de novilhas pode utilizar aditivos fitogênicos, como o extrato de chá-verde (Camellia sinensis L.) para melhorar aspectos ligados à sanidade e eficiência digestiva. Todavia existem poucas informações sobre os seus efeitos no comportamento animal. O experimento foi conduzido com o objetivo de avaliar os efeitos da inclusão de diferentes doses do extrato herbal de chá-verde no comportamento social e ingestivo de novilhas leiteiras. Foram utilizadas 35 novilhas não prenhes e com idades entre 14 e 15 meses. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro tratamentos e medidas repetidas no tempo. O comportamento foi avaliado nos períodos diário (24 horas) e diurno (11 às 20:30 horas), e foi observado visualmente de forma individual em intervalos de 10 minutos. As variáveis estudadas foram: tempo em decúbito direito, tempo em decúbito esquerdo, tempo deitada total, tempo em estação, tempo em ócio, tempo ruminando, tempo pastejando, e a frequência com que os animais caminhavam, corriam, ingeriam água, ingeriam sal, interagiam e tinham comportamento de dominância/dominada entre eles. Os atributos comportamentais contínuos foram avaliados quanto ao efeito das doses de extrato de chá verde, segundo a análise de regressão e análise de variância, testando os efeitos de dia de avaliação, doses e sua interação, e os atributos comportamentais eventuais foram analisados usando regressão logística. Em relação ao comportamento diário (24h), a inclusão do extrato de chá verde na dieta aumentou linearmente o tempo deitada em decúbito direito e reduziu o tempo em pastejo. Os demais atributos não tiveram diferenças significativas. Em relação ao comportamento diurno, a inclusão do extrato de chá verde na dieta de novilhas influenciou o tempo deitada em decúbito direito, as que receberam 3g apresentaram maiores tempos em decúbito direito comparados com aquelas que receberam 2g. A chance de ocorrência de interações entre os animais diminuiu em 30% a cada grama de extrato de chá verde fornecida no alimento. Nos demais atributos não houve diferenças significativas. O extrato de chá verde altera em parte o comportamento ingestivo, diminuindo as atividades de pastejo, enquanto aumenta o tempo de permanência deitada em decúbito direito e diminui as interações sociais entre os animais. / In the production of dairy heifers, phytogenic additives, such as green tea extract (Camellia sinensis L.) might be used to improve aspects of health and digestive efficiency. There is limited information of the effects on performance and animal behavior. This trial was conducted to evaluate the effects of the inclusion of green tea herbal extract in the diet on the ingestive and social behavior of dairy heifers. Thirty-five non-pregnant heifers, aged between 14 and 15 months, were used. The experimental design was completely randomized, with four treatments and repeated measures. The behavior was visually observed individually and focal at 10 minute intervals. The variables studied were: time spent in right decubitus, in left decubitus, lying, standing, resting, ruminating, grazing, and the frequency animals walked, ran, drank water, ate salt, interacted and had dominance/submission behavior. Continuous behavioral attributes were evaluated for the effect of green tea extract doses, according to regression analysis and analysis of variance, testing the effects of valuation date, doses and their interaction, and discrete or categorical behavioral attributes were analyzed using logistic regression. Regarding the daily behavior (24 hours), the inclusion of green tea extract in the diet linearly increased the time lying on right decubitus and reduced grazing time. The other attributes did not differ significantly. Regarding the diurnal behavior, green tea extract in heifers’ diet influenced the lying time on right decubitus, those receiving 3g spent more time in right decubitus than those receiving 2g. The chance of occurrence of interactions between animals decreased by 30% every 1g of green tea extract of grass added into the diet. No differences were detected for other attributes. Green tea extract alters partially feeding behavior, reducing grazing activities, while it increases the time lying in right decubitus and reduces social interactions among animals.

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