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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.
191

Vienapiesčių gudobelių (Crataegus monogyna Jacq.) lapų ir vaisių antioksidantinio aktyvumo ir bioaktyvių junginių tyrimas / The Analysis of Leaves and Fruits Antioxidant Activity and Bioactive Compounds of Single Seed Hawthorn (Crataegus monogyna Jacq.)

Brazinskaitė, Simona 18 June 2014 (has links)
Tyrimo tikslas: įvertinti bioaktyvių junginių kiekybinės sudėties bei antioksidantinio aktyvumo įvairavimą vienapiestės gudobelės žaliavų mėginiuose, rinktuose skirtinguose Lietuvos vietovėse. Tyrimo uždaviniai: Įvertinti suminio flavonoidų kiekio ir suminio fenolinių junginių kiekio įvairavimą vienapiestės gudobelės vaisių ir lapų mėginiuose, rinktuose skirtingose Lietuvos vietovėse; įvertinti chlorogeno rūgšties ir flavonoidų (epikatechino, hiperozido, izokvercitrino, viteksino-2“-O-ramnozido, rutino) kiekinį pasiskirstymą C.monogyna žaliavose efektyviosios skysčių chromatografijos metodu; ištirti gudobelių vaisių ir lapų žaliavų antioksidantinį aktyvumą ir įvertinti jo įvairavimą naudojant DPPH ir ABTS metodus; pritaikyti klasterinę analizę vienapiesčių gudobelių vaisių ir lapų mėginių grupavimui, iškiriant reikšmingai besiskiriančias antioksidantiniu aktyvumu grupes. Tyrimo metodai: Flavonoidų kiekiui įvertinti naudoti spektrofotometriniai ir efektyviosios skysčių chromatografijos metodai, suminis fenolinių junginių kiekis įvertintas spekrofotometriškai. Antioksidantinis aktyvumas nustatytas spektrofotometriniu metodu, naudojant DPPH ir ABTS testus. Tyrimo objektas: Lietuvos skirtinguose regionuose rinktos Crataegus monogyna Jacq. vaisių ir lapų žaliavos. Tyrimo rezultatai: Flavonoidų kiekis lapų žaliavose įvairavo nuo 0,47 iki 2,34 proc., vaisių žaliavoje nuo 0,12 iki 0,91proc.. Suminis fenolinių junginių kiekis lapų mėginiuose nuo 5,68 iki 11,80 proc., vaisių... [toliau žr. visą tekstą] / The aim of the research: to evaluate the variety of quantitative composition of bioactive combination and antioxidant activity in the samples of C. monogyna selected in different parts of Lithuania. The objectives of the research: to evaluate the variety of total amount of flavonoids and total amount of phenolic combinations in the samples of C. monogyna leaves and fruit; to evaluate the quantitative distribution of of chlorogenic acid and flavonoids in C. monogyna raw materials by the method of effective chromatography of liquid; to analyse the antioxidant activity of hawthorn leaves and fruit and evaluate the variety of it using DPPH and ABTS methods; to apply cluster analysis of sample grouping of monopistil howthorn leaves and fruit marking out groups having definetely different level of antioxidant activity. The methods of the research: the methods of spectrophotometry and efective liquid chromatography were used to evaluate the amount of flavonoids and the total amount of phenolic combinations. The antioxidant activity was established using DPPH and ABTS tests. The object the research: Crataegus monogyna Jacq. raw material of leaves and fruit selected in different parts of Lithuania. The results of the research: the amount of flavonoids in leaves differed from 0,47 to 2,34%; in fruit it difffered from 0,12 to 0,91 %. Total amount of phenolic combinations in the samples of leaves differed from 5,68 to 11,80 percent; in raw material of fruit differed from 1,03 to 2,78%... [to full text]
192

Characterization and isomer differentiation of glycosides and oligosaccharides using chemical derivatization with quadrupole ion trap mass spectrometry

Pikulski, Michael, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
193

Bio-active compounds isolated from mistletoe (Scurulla oortiana (Korth.) Danser) parasitizing tea plant (Camellia sinensis L.) /

Kirana, Chandra. January 1996 (has links) (PDF)
Thesis (M. Ag. Sc.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1997. / Includes bibliographical references (leaves 87-96).
194

Effects of flavonoids on proliferation of breast cancer cells and vascular smooth muscle cells /

Liu, Po-shiu, Jackie. January 2007 (has links)
Thesis (M. Med. Sc.)--University of Hong Kong, 2007.
195

Structural characterization and enhanced detection of flavonoids by electrospray ionization mass spectrometry and molecular modeling

Zhang, Junmei, Brodbelt, Jennifer S., January 2004 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Jennifer S. Brodbelt. Vita. Includes bibliographical references. Also available from UMI.
196

Protective effects of icariin extracted from epimedii herba on fetal rat hippocampal neurons

Zou, Liangliang. January 2009 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 95-112). Also available in print.
197

In vitro digestion models for dietary phenolic compounds /

Aura, Anna-Marja. January 1900 (has links) (PDF)
Thesis (doctoral)--Helsinki University of Technology, 2005. / Includes bibliographical references. Also available on the World Wide Web. Myös verkkojulkaisuna.
198

Role of bioactive compounds in the regulation of insulin sensitivity

Purushotham, Aparna. January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Full text release at OhioLINK's ETD Center delayed at author's request
199

Compostos bioativos de chás: comparação das infusões a quente e a frio

Rodrigues, Vanessa de Carvalho 13 February 2015 (has links)
O chá é uma das bebidas mais consumidas em todo o mundo. Algumas funções biológicas dos chás têm sido relatadas, tais como antiinflamatória, antioxidante, antialérgica, e anti-obesidade. Estas atividades biológicas estão associadas, em parte, com a atividade antioxidante dos compostos químicos presentes nos chás, especialmente flavonoides e ácidos fenólicos. No entanto, os compostos fenólicos são primariamente responsáveis pelas propriedades benéficas do chá. Assim, a avaliação total e de quantificação individual de compostos fenólicos é essencial para correlacionar sua a atividade biológica. As amostras avaliadas foram chá verde, camomila, carqueja, boldo, branco, cidreira, preto e mate. Neste estudo os compostos fenólicos totais e flavonoides foram quantificados por espectrofotometria. A capacidade antioxidante dos extratos fenólicos foi avaliada pelos métodos DPPH e ABTS+. Compostos fenólicos foram identificados por cromatografia líquida de alta eficiência (CLAE). A atividade antimicrobiana foi determinada pela avaliação da concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM). A análise de componentes principais (ACP) e a análise hierárquica de agrupamentos (AHA) mostraram que não foi observada uma distinção clara entre os métodos de extração. Neste estudo, a extração à frio mostrou-se mais eficiente na extração de compostos bioativos. / Tea is one of the most consumed beverages in the world. Some biological functions of tea have been reported, such as anti-inflammatory, antioxidant, anti-allergic, and anti-obesity. These biological activities are associated, in part, to the antioxidant activity of chemical compounds present in tea, especially flavonoids and phenolic acids, however, the phenolic compounds are primarily responsible for the beneficial properties of tea. Thus, the total evaluation and quantification of individual phenolic compounds is essential to correlate its biological activity. The samples were evaluated green tea, chamomile, broom, Boldo, white, lemon, black and matte. In this study, flavonoids and phenolic compounds were quantified by spectrophotometry. The antioxidant capacity of phenolic extracts was evaluated by DPPH and ABTS•+ methods. Phenolic compounds were identified by high performance liquid chromatography (HPLC). Antimicrobial activity was determined by assessing the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed that it was not observed a clear distinction between the extraction methods. In this study, the cold extraction was more efficient in the extraction of bioactive compounds.
200

Estudo do potencial antimutagênico, mutagênico, estrogênico e antibacteriano de flavonoides

Resende, Flávia Aparecida [UNESP] 28 November 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-11-28Bitstream added on 2014-06-13T20:44:23Z : No. of bitstreams: 1 resende_fa_dr_arafcf.pdf: 1608524 bytes, checksum: b43a0ccb7787273f1e72021fb36546bf (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Os flavonoides exibem uma multiplicidade de atividades biológicas tanto in vivo como in vitro. No entanto, não existem dados suficientes para fornecer provas conclusivas sobre os efeitos benéficos da maioria das subclasses de flavonoides. Dessa maneira, neste estudo tornou-se relevante avaliar a mutagenicidade, antimutagenicidade, estrogenicidade e atividade antibacteriana dos flavonoides, com o objetivo de traçar o perfil relação estrutura-atividade, uma vez que a atividade biológica dos flavonoides depende da sua estrutura química. A mutagenicidade e antimutagenicidade foram avaliadas pelo teste de Ames, em cepas de Salmonella typhimurium TA98, TA100 e TA102, com e sem ativação metabólica. Para comparação do efeito protetor dos flavonoides foram utilizados 4-nitro-o-fenilenodiamina (NPD), azida sódica (AZS) e mitomicina C (MMC) como mutágenos de ação direta e benzo[a]pireno (B[a]P), aflatoxina B1 (AFB1) e 2-aminoantraceno (2-AA) como mutágenos de ação indireta. A atividade estrogênica foi avaliada por meio do ensaio com leveduras recombinantes (RYA - Recombinant Yeast Assay) e pelo ensaio de proliferação de células de câncer de mama humano (MCF-7⁄BUS) responsivas à estrógeno (E-screen). A determinação da atividade antibacteriana in vitro foi realizada neste estudo utilizando a técnica de diluição em microplacas, com as bactérias Staphylococcus aureus ATTC 25923 e Escherichia coli ATCC 25922. Os compostos avaliados foram: quercetina, kaempferol, luteolina, fisetina, crisina, galanina, flavona, 3-hidroxiflavona, 5- hidroxiflavona e 7-hidroxiflavona. No teste de Ames, a quercetina mostrou-se diretamente mutagênica na linhagem TA98 e antimutagênica... / The flavonoids exhibit a wide range of biological activities both in vivo and in vitro. However, there are insufficient data to provide conclusive evidence on the health effects of most flavonoid subclasses. Thus, is relevant to assess the mutagenicity, antimutagenicity, estrogenicity and antibacterial activity of flavonoids with the aim of tracing the structure-mutagenicity relationship profile, since the biological activity of flavonoids is governed by their chemical structure. The mutagenicity and antimutagenicity was assayed by the Ames test, with Salmonella typhimurium strains TA98, TA100 and TA102, carried out with and without metabolic activation. To compare the protective effect of flavonoids were used 4-nitro-o-phenylenediamine (NPD), sodium azide (AZS) and mitomycin C (MMC) as direct acting mutagens and benzo[a]pyrene (B[a]P), aflatoxin B1 (AFB1) e 2-aminoanthracene (2-AA) as indirect acting mutagens. The estrogenic activity was assayed by recombinant yeast assay (RYA) and by proliferation assay of cells of human breast cancer (MCF-7⁄ BUS) responsive to estrogen (E-screen). The determination of antibacterial activity in vitro was performed in this study by technique of dilution in microplates, with the bacteria Staphylococcus aureus ATTC 25923 and Escherichia coli ATCC 25922. The evaluated compounds were: quercetin, kaempferol, luteolin, fisetin, chrysin, galangin, flavones, 3-hydroxyflavone, 5- hydroxyflavone and 7- hydroxyflavone. In the Ames test, quercetin was directly mutagenic... (Complete abstract click electronic access below)

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