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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.
11

Estudo do mecanismo de ação antirradicalar de betalaínas / Study of the mechanism of antiradical action of betalains

Karina Kinuyo Nakashima 21 December 2015 (has links)
Foi preparada uma série de quatro betalaínas com o objetivo de determinar o efeito da metilação do nitrogênio imínico e da presença de uma hidroxila fenólica na posição 3 do anel aromático sobre a estabilidade e propriedades antirradicalares, fotofísicas e redox desta classe de pigmentos vegetais. O estudo destes compostos, chamados de m-betalainofenol, N-metil-m-betalainofenol, fenilbetalaína e N-metil-fenilbetalaína, revelou que os derivados metilados apresentam um deslocamento hipsocrômico sutil dos máximos de absorção e fluorescência em relação aos compostos não metilados. Os deslocamentos de Stokes são maiores em cerca de 4 kJ mol-1 para os derivados metilados e os rendimentos quânticos de fluorescência cerca de três vezes menores. A hidrólise destas betalaínas foi investigada na faixa de pH entre 3 e 7. Todas as betalaínas são mais persistentes em pH = 6 e a metilação da porção imínica aumenta significativamente a estabilidade da betalaína em meio aquoso. A presença da porção fenólica, em comparação a um grupo fenila, não afeta as propriedades fotofísicas dos compostos e tem um efeito menos pronunciado do que o da metilação sobre a estabilidade destes em meio aquoso. O comportamento eletroquímico dos compostos foi estudado por voltametria cíclica, nas mesmas condições de pH. A N-metilação foi novamente mais significativa do que a hidroxilação, provocando aumento de até 200 mV no potencial de pico anódico. O aumento do pH diminuiu o potencial de pico anódico dos quatro compostos, com uma razão entre prótons e elétrons igual a 1 para a maioria dos picos. A capacidade antirradicalar foi quantificada pelo ensaio colorimétrico TEAC baseado na redução de ABTS•+. Os dois derivados N-metilados apresentaram, em média, o mesmo valor de TEAC, apesar de um ser fenólico e o outro não. Já entre os não metilados, que têm TEAC de 2 a 3 unidades inferior à dos outros, a presença do fenol provoca elevação da capacidade antirradicalar. Os resultados sugerem a participação dos elétrons do anel 1,2,3,4-tetraidropiridínico, acoplados ao próton do nitrogênio imínico na ação antirradicalar de betalaínas. / A series of four artificial betalains was prepared in order to determine the effect of imine nitrogen methylation and phenyl hydroxylation (position 3) over stability and antiradical, photophysical and redox properties of this class of natural pigments. The study of m-betalainophenol, N-methyl-m-betalainophenol, phenylbetalain and N-methylbetalain, revealed that the methylated compounds present a small hypsochromic shift of both absorption and fluorescence maxima when compared to the others. The Stokes shifts are around 4 kJ mol-1 higher for methylated betalains, whereas the quantum yields are approximately three times lower. Their hydrolysis was investigated between pH 3 and 7. All compounds are more persistent in pH = 6, and imine methylation increases the overall stability in aqueous medium. The presence of a phenol group, in comparison with a phenyl substituent, has a minor effect on the photophysical properties of betalains and has a less pronounced effect over stability than that of methylation. The electrochemical behavior was studied by cyclic voltammetry, in the same pH range, and is also more significantly affected by methylation, rather than by hydroxylation. Methylation increases anodic peak potential up to 200 mV, and the potential is also much higher in more acidic media for all compounds. The number of protons involved in the electrochemical oxidation is the same as the number of electrons for most peaks The antiradical capacity was quantified using the TEAC assay, and ABTS•+ as radical. The methylated betalains presented, in average, the same TEAC value, although only one of them is phenolic. Among the non methylated, which are 2 to 3 units more efficient than the others, the phenolic one has a greater TEAC. These results suggest a participation of the 1,2,3,4-tetraidropiridinic ring electrons in the oxidation by ABTS•+, coupled to the imine nitrogen proton.
12

Oxidação quimiluminescente do luminol em meios micelares: desenvolvimento de uma ensaio para determinação da capacidade anti-radicalar / Chemiluminescent oxidation of luminol in micellar media: development of an anti-radical capacity assay

Cerize da Silva Santos 16 October 2008 (has links)
Neste trabalho foi desenvolvida uma metodologia para a determinação da capacidade anti-radicalar de substâncias hidrofílicas e lipofílicas baseada na quimiluminescência do luminol em meio micelar. A reação de luminol, hemina e peróxido de hidrogênio foi estudada na presença de tensoativos carregados (CTAB/CTAC e SDS). Variou-se independentemente a concentração de cada reagente de forma a avaliar seu papel sobre a intensidade inicial de emissão (I0), que é proporcional à velocidade inicial da reação. Em solução aquosa de SDS, a I0 apresentou correlação linear com a concentração de H2O2 entre 5,0 10-6 e 6,0 10-5 mol/L e com a concentração de hemina no intervalo de 8,0 10-9 a 4,0 10-7 mol/L. O aumento da concentração de luminol no intervalo de 5,0 10-7 a 1,0 10-3 provocou aumento na I0 até 5,0 10-5 mol/L, permanecendo constante para concentrações maiores. Na presença de CTAB, o valor de I0 variou linearmente com a concentração de H2O2 no intervalo estudado (2,0 10-5 a 6,7 10-4 mol/L). A I0 aumentou com o aumento da concentração da hemina entre 8,0 10-8 e 8,0 10-6 mol/L. A variação da concentração de luminol de 5,0 10-7 a 5,0 10-5 também provocou aumento na I0, a qual ficou constante para concentrações maiores. Para este tensoativo foram realizadas também medidas de cmc nas condições de reação (tampão fosfato pH 11,6 e µ = 0,1), obtendo-se um valor de 2 10-4 mol/L, cinco vezes menor do que a cmc em água. As mudanças espectrais de hemina e luminol em diferentes concentrações de CTAB foram avaliadas, obtendo-se evidências da interação destes reagentes com o tensoativo. Destes estudos, foi possível compreender melhor o comportamento do sistema e foram encontradas condições nas quais se obtêm decaimento lento da intensidade de emissão e I0 alto. Estas condições são ideais para a realização de um ensaio de determinação da capacidade anti-radicalar. O efeito do antioxidante trolox, utilizado como padrão, foi avaliado nestas condições nos sistemas baseados nos três tensoativos. Em todos os casos, observou-se correlação linear entre a concentração de trolox e a área suprimida na cinética de emissão, a qual é proporcional ao número de radicais seqüestrados pelo antioxidante. Os limites de detecção para trolox ficaram abaixo de 1,0 10-7 mol/L, e a faixa de linearidade é de no mínimo uma ordem de grandeza (não foram testadas concentrações superiores a 2,0 10-6 mol/L). No meio de reação com CTAB foram determinadas as capacidades anti-radicalares (n) dos seguintes antioxidantes: vitamina E (n=3,5 ± 0,1), rutina (n=4,0 ± 0,2), quercetina (n=3,8 ± 0,4) e ácido úrico (n=1,3 ± 0,1). Os valores de n determinados com este método foram muito similares com aqueles medidos utilizando-se o ensaio com o radical estável DPPH. Portanto, o ensaio desenvolvido com luminol em meio micelar se mostrou adequado para testar tanto substâncias hidrossolúveis como lipossolúveis. Foram testadas condições para a realização de ensaios consecutivos com injeções repetidas de várias alíquotas de antioxidante na presença de CTAB. Os valores encontrados com o ensaio realizado desta forma foram iguais aos obtidos com o ensaio onde as injeções são feitas individualmente. Este método permite automação e resulta na economia de reagentes e redução do tempo de ensaio / In this work, a methodology to evaluate the anti-radical capacity of hydrophilic and lipophilic compounds based on luminol chemiluminescence in micellar media was developed. The reaction of luminol, hemin and hydrogen peroxide was studied in the presence of charged surfactants (CTAB/CTAC and SDS). The concentration of each reagent was independently varied in order to evaluate its influence on the initial emission intensity (I0), which is proportional to the initial reaction rate. In aqueous SDS solution, I0 showed a linear correlation with the H2O2 concentration between 5,0 10-6 and 6,0 10-5 mol/L, and with the hemin concentration between 8,0 10-9 and 4,0 10-7 mol/L. An increase in the luminol concentration between 5,0 10-7 and 1,0 10-3 mol/L led to an increase in I0 up to 5,0 10-5 mol/L, higher luminol concentrations do not further increased I0. In the presence of CTAB, I0 increased linearly with the H2O2 concentration in the interval studied (2,0 10-5 to 6,7 10-4 mol/L). An increase in I0 was also observed on increasing the hemin concentration from 8,0 10-8 to 8,0 10-6 mol/L. An increase of the luminol concentration from 5,0 10-7 to 5,0 10-5 increased the observed I0, which did not change for higher luminol concentrations. The cmc of CTAB was measured in the reaction conditions (phosphate buffer pH 11,6 and µ= 0,1), and the value determined, 2 10-4 mol/L, was five times lower than the cmc in water. The absorption spectra of hemin and luminol in different CTAB concentrations showed significant variation with the surfactant concentration, indicating an interaction between these reagents and the surfactant. With these studies it was possible to understand well the behavior of the system and to establish experimental conditions which lead to kinetic curves with a slow emission intensity decay and relatively high I0, ideal conditions for the performance of the anti-radical capacity assay. The effect of trolox, the antioxidant used as reference, was evaluated in this conditions in the systems based on the three surfactants. In all the cases a linear correlation between the trolox concentration and the suppressed area in the emission kinetics was observed. This area is proportional to the number of radicals trapped by the antioxidant. Detection limits for trolox were below 1,0 10-7 mol/L, and the linear range was at least one order of magnitude (concentrations higher than 2,0 10-6 mol/L were not evaluated). The antioxidant capacity (n) was determined in the reaction medium containing CTAB for vitamin E (n= 3,5 ± 0,1), rutin (n=4,0 ± 0,2), quercetin (n=3,8 ± 0,4) and uric acid (n=1,3 ± 0,1). The n values determined by this method were very similar to those measured with the DPPH assay. Hence, the assay developed with luminol in micelar media was adequate to evaluate the anti-radical capacity of hidrosoluble as well as liposoluble compounds. The assay conditions established in the presence of CTAB allowed the consecutive injection of antioxidant samples during the same kinetic run. The values determined in this consecutive injection assay proved to be very similar to those obtained in the assay where injections were made individually. This method allows automation, economy of reagents and reduction of assay time
13

Oxidação quimiluminescente do luminol em meios micelares: desenvolvimento de uma ensaio para determinação da capacidade anti-radicalar / Chemiluminescent oxidation of luminol in micellar media: development of an anti-radical capacity assay

Santos, Cerize da Silva 16 October 2008 (has links)
Neste trabalho foi desenvolvida uma metodologia para a determinação da capacidade anti-radicalar de substâncias hidrofílicas e lipofílicas baseada na quimiluminescência do luminol em meio micelar. A reação de luminol, hemina e peróxido de hidrogênio foi estudada na presença de tensoativos carregados (CTAB/CTAC e SDS). Variou-se independentemente a concentração de cada reagente de forma a avaliar seu papel sobre a intensidade inicial de emissão (I0), que é proporcional à velocidade inicial da reação. Em solução aquosa de SDS, a I0 apresentou correlação linear com a concentração de H2O2 entre 5,0 10-6 e 6,0 10-5 mol/L e com a concentração de hemina no intervalo de 8,0 10-9 a 4,0 10-7 mol/L. O aumento da concentração de luminol no intervalo de 5,0 10-7 a 1,0 10-3 provocou aumento na I0 até 5,0 10-5 mol/L, permanecendo constante para concentrações maiores. Na presença de CTAB, o valor de I0 variou linearmente com a concentração de H2O2 no intervalo estudado (2,0 10-5 a 6,7 10-4 mol/L). A I0 aumentou com o aumento da concentração da hemina entre 8,0 10-8 e 8,0 10-6 mol/L. A variação da concentração de luminol de 5,0 10-7 a 5,0 10-5 também provocou aumento na I0, a qual ficou constante para concentrações maiores. Para este tensoativo foram realizadas também medidas de cmc nas condições de reação (tampão fosfato pH 11,6 e µ = 0,1), obtendo-se um valor de 2 10-4 mol/L, cinco vezes menor do que a cmc em água. As mudanças espectrais de hemina e luminol em diferentes concentrações de CTAB foram avaliadas, obtendo-se evidências da interação destes reagentes com o tensoativo. Destes estudos, foi possível compreender melhor o comportamento do sistema e foram encontradas condições nas quais se obtêm decaimento lento da intensidade de emissão e I0 alto. Estas condições são ideais para a realização de um ensaio de determinação da capacidade anti-radicalar. O efeito do antioxidante trolox, utilizado como padrão, foi avaliado nestas condições nos sistemas baseados nos três tensoativos. Em todos os casos, observou-se correlação linear entre a concentração de trolox e a área suprimida na cinética de emissão, a qual é proporcional ao número de radicais seqüestrados pelo antioxidante. Os limites de detecção para trolox ficaram abaixo de 1,0 10-7 mol/L, e a faixa de linearidade é de no mínimo uma ordem de grandeza (não foram testadas concentrações superiores a 2,0 10-6 mol/L). No meio de reação com CTAB foram determinadas as capacidades anti-radicalares (n) dos seguintes antioxidantes: vitamina E (n=3,5 ± 0,1), rutina (n=4,0 ± 0,2), quercetina (n=3,8 ± 0,4) e ácido úrico (n=1,3 ± 0,1). Os valores de n determinados com este método foram muito similares com aqueles medidos utilizando-se o ensaio com o radical estável DPPH. Portanto, o ensaio desenvolvido com luminol em meio micelar se mostrou adequado para testar tanto substâncias hidrossolúveis como lipossolúveis. Foram testadas condições para a realização de ensaios consecutivos com injeções repetidas de várias alíquotas de antioxidante na presença de CTAB. Os valores encontrados com o ensaio realizado desta forma foram iguais aos obtidos com o ensaio onde as injeções são feitas individualmente. Este método permite automação e resulta na economia de reagentes e redução do tempo de ensaio / In this work, a methodology to evaluate the anti-radical capacity of hydrophilic and lipophilic compounds based on luminol chemiluminescence in micellar media was developed. The reaction of luminol, hemin and hydrogen peroxide was studied in the presence of charged surfactants (CTAB/CTAC and SDS). The concentration of each reagent was independently varied in order to evaluate its influence on the initial emission intensity (I0), which is proportional to the initial reaction rate. In aqueous SDS solution, I0 showed a linear correlation with the H2O2 concentration between 5,0 10-6 and 6,0 10-5 mol/L, and with the hemin concentration between 8,0 10-9 and 4,0 10-7 mol/L. An increase in the luminol concentration between 5,0 10-7 and 1,0 10-3 mol/L led to an increase in I0 up to 5,0 10-5 mol/L, higher luminol concentrations do not further increased I0. In the presence of CTAB, I0 increased linearly with the H2O2 concentration in the interval studied (2,0 10-5 to 6,7 10-4 mol/L). An increase in I0 was also observed on increasing the hemin concentration from 8,0 10-8 to 8,0 10-6 mol/L. An increase of the luminol concentration from 5,0 10-7 to 5,0 10-5 increased the observed I0, which did not change for higher luminol concentrations. The cmc of CTAB was measured in the reaction conditions (phosphate buffer pH 11,6 and µ= 0,1), and the value determined, 2 10-4 mol/L, was five times lower than the cmc in water. The absorption spectra of hemin and luminol in different CTAB concentrations showed significant variation with the surfactant concentration, indicating an interaction between these reagents and the surfactant. With these studies it was possible to understand well the behavior of the system and to establish experimental conditions which lead to kinetic curves with a slow emission intensity decay and relatively high I0, ideal conditions for the performance of the anti-radical capacity assay. The effect of trolox, the antioxidant used as reference, was evaluated in this conditions in the systems based on the three surfactants. In all the cases a linear correlation between the trolox concentration and the suppressed area in the emission kinetics was observed. This area is proportional to the number of radicals trapped by the antioxidant. Detection limits for trolox were below 1,0 10-7 mol/L, and the linear range was at least one order of magnitude (concentrations higher than 2,0 10-6 mol/L were not evaluated). The antioxidant capacity (n) was determined in the reaction medium containing CTAB for vitamin E (n= 3,5 ± 0,1), rutin (n=4,0 ± 0,2), quercetin (n=3,8 ± 0,4) and uric acid (n=1,3 ± 0,1). The n values determined by this method were very similar to those measured with the DPPH assay. Hence, the assay developed with luminol in micelar media was adequate to evaluate the anti-radical capacity of hidrosoluble as well as liposoluble compounds. The assay conditions established in the presence of CTAB allowed the consecutive injection of antioxidant samples during the same kinetic run. The values determined in this consecutive injection assay proved to be very similar to those obtained in the assay where injections were made individually. This method allows automation, economy of reagents and reduction of assay time
14

Propolio neetanolinio ekstrakto technologijos parinkimas ir veikliųjų medžiagų analizė / The selection of propolis non ethanolic extract technology and analysis of active substances

Jasaitytė, Jolanta 18 June 2014 (has links)
Tyrimo tikslas - parinkti neetanolinio propolio ekstrakto technologiją ir atlikti veikliųjų medžiagų analizę. Uždaviniai: nustatyti propolio koncentracijos, ekstrakcijos tirpiklių bei jų koncentracijų, ekstrakcijos laiko, temperatūros, ekstrakcijos metodo įtakas fenolinių junginių išsiskyrimui. Nustatyti propolio ekstrakto antiradikalinį aktyvumą ir flavonoidų kiekį bei efektyviosios skysčių chromatografijos metodu nustatyti propolio ekstrakte esančius cheminius junginius ir jų antiradikalinį aktyvumą. Metodika. Bendras fenolinių junginių kiekis, buvo nustatytas naudojant farmakopėjinį Folino Ciocalteu metodą pagal galo rūgšties ekvivalentą. Flavonoidų kiekis nustatytas naudojant spektrofotometrinį metodą pagal rutino ekvivalentą. Antioksidacinis aktyvumas spektrofotometriškai buvo nustatomas naudojant DPPH radikalą. Efektyviosios skysčių chromatografijos su elektrocheminiu detektoriumi būdu buvo identifikuoti fenoliniai junginiai ir nustatytas jų antiradikalinis aktyvumas. Rezultatai. Didinant propolio koncentraciją, naudojant tirpiklius didėja bendras fenolinių junginių kiekis (p<0,05). Technologiniai procesai t.y. ekstrakcijos trukmė, temperatūros padidinimas daro reikšmingą įtaką fenolinių junginių išsiskyrimui (p<0,05). Didžiausias bendras fenolinių junginių kiekis 35,60 mg/ml buvo gautas naudojant ultragarsu skatinamą ekstrakciją 10 min esant 70 ⁰C temperatūrai, ekstrakcijos tirpikliu naudojant 30 proc. makrogolio ir vandens mišinį. Šiame ekstrakte nustatytas 88,76±1... [toliau žr. visą tekstą] / The aim of survey - to select the technology of nonethanolic propolis extract and analyse the active substances. Tasks: To examine the influence of concentration, solvent and its concentration, extraction time, temperature, the extraction method on release of total phenolic compounds. Determine the radical scavenging activity and flavonoid content of propolis extract and using high performance liquid chromatography method identify active substances and its antiradical activity. Methods: Total phenolic compounds were determined by using pharmacopoeial Folin Ciocalteu method expressed in gallic acid equivalents. Flavonoids were determined using a spectrophotometric method in rutin equivalent. Radical scavenging activity was determined by spectrophotometry using DPPH radical. High performance liquid chromatography with electrochemical detection were used to identify phenolic compounds and its radical scavenging activity. Results: Increasing of propolis concentration made a significance impact on the amount of total phenolic content (p<0,05). Extraction time, increase of temperature made a significance impact on increase of the amount of total phenolic content (p<0,05). The highest amount of total phenolic compounds 35,60 mg/ml were obtained using ultrasonic induced extraction for 10 minutes at 70 ⁰ C temperature and using 30 % macrogol – water solution as solvent. The radical scavenging capacity of this extract was 88,76 ± 1,27% and amount of flavonoids were 3,89 ± 0,43 mg/ml... [to full text]
15

Potencial antioxidante de resíduo agroindustrial de goiaba

NASCIMENTO, Rosilda Josefa do 25 February 2010 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-07-27T15:12:30Z No. of bitstreams: 1 Rosilda Josefa do Nascimento.pdf: 820295 bytes, checksum: 67cf98bba801b8144e3c20d0ea20b4ba (MD5) / Made available in DSpace on 2016-07-27T15:12:30Z (GMT). No. of bitstreams: 1 Rosilda Josefa do Nascimento.pdf: 820295 bytes, checksum: 67cf98bba801b8144e3c20d0ea20b4ba (MD5) Previous issue date: 2010-02-25 / Considering the high production of agri-industrial waste and the possibility of this material have bioactive phytochemicals, this work aimed to evaluate the antioxidant potential of the guava waste (seed) from an industry of frozen fruit pulps. Hydroacetone, hydroethanolic, hydromethanolic and aqueous extracts, obtained by sequential extraction procedure, were submitted to the determination of total phenolic and antioxidant activity in β-carotene/linoleic acid co-oxidation system and by ferric thiocyanate method and screened for their free [DPPH• (1,1-diphenyl-2-picrilhidrazil) and ABTS•+ (2,2'-azino-bis-(3- etilbenzotiazolina 6-sulfonic acid)] scavenging activity. The hydroacetone and hydromethanolic extracts exhibited the highest content of total phenolics (5317.27 and 2176.46 ag catechin equivalent mL-1, respectively), while the aqueous and hydroethanolic extracts were excluded from antioxidant analysis. Hydroacetone extract exhibited high percentage of the inhibition of oxidation (81.95%) in β-carotene/linoleic acid co-oxidation system; high percentage of the inhibition of linoleic acid peroxidation (74.32% and 80.13%at concentrations 140 and 240mg/L, respectively), good DPPH• scavenging activity (scavenging percentage >60%; low value of EC50 and TEC50, middle value of AE), and good ABTS•+ scavenging activity (875.79mM TEAC.g-1). The hydromethanolic extract exhibited low percentage of the inhibition of oxidation (38.92%) in β-carotene/linoleic acid co-oxidation system, inhibition of linoleic acid peroxidation of the 50.50% and 73.70% (at concentrations 140 and 240mg/L, respectively), DPPH• scavenging activity (scavenging percentage < 30%, high EC50 and TEC50, and low value of AE), and bad ABTS• + scavenging activity (57.16 mM TEAC.g -1). Combining of the hydroacetone extract with BHT at different concentrations, the scavenging activity and inhibition of oxidation, in β-carotene/linoleic acid co-oxidation system were similar to that BHT alone, which demonstrated synergism between them. Hydroacetone extract from guava waste (seeds) has a significant potential antioxidant since it has shown better performance in scavenging DPPH • and ABTS• + radical, important antioxidant activity in lipid emulsion system, and synergism with BHT. Thus, the agri-industrial waste from guava can be considered as alternative of natural antioxidants. / Diante da elevada produção de resíduo agroindustrial e da possibilidade deste material conter fitoquímicos bioativos, este trabalho objetivou avaliar o potencial antioxidante de resíduo de goiaba (semente) proveniente de uma indústria de polpas de frutas congeladas. Extratos hidroacetônico, hidrometanólico, hidroetanólico e aquoso, obtidos por extração sequencial, foram utilizados para quantificar o teor de fenólicos totais e determinar a atividade antioxidante em sistema da co-oxidação β-caroteno/ácido linoléico e pelo método tiocianato férrico e a capacidade de seqüestrar radicais livres [DPPH• (1,1- difenil-2-picrilhidrazil) e ABTS•+ (2,2’-azino-bis-(3-etilbenzotiazolina-6-ácido sulfônico]. Os extratos hidroacetônico e hidrometanólico exibiram os maiores teores de fenólicos totais (5.317,27 e 2.176,46ag em equivalente de catequina mL-1, respectivamente), sendo, portanto, o aquoso e hidroetanólico excluídos da avaliação do potencial antioxidante. O extrato hidroacetônico exibiu elevado percentual de inibição da oxidação (81,95%) no ensaio da co-oxidação do β-caroteno/ acido linoléico; elevado percentual de inibição da peroxidação do ácido linoléico (74,32% e 80,13%, respectivamente, nas concentraçõesde 140 e 240mg/L); boa capacidade de sequestrar o radical DPPH (percentual de sequestro >60%, baixo valor de EC50 e de TEC50, e médio EA); e o radical ABTS•+ (875,79 mM TEAC.g-1). O extrato hidrometanólico exibiu baixo percentual de inibição da oxidação (38,92%) no ensaio da co-oxidação do β-caroteno/ acido linoléico; inibição da peroxidação do ácido linoléico de 50,50% e 73,70% (nas concentrações de 140 e 240mg/L, respectivamente); e fraca capacidade de sequestrar o radical DPPH (percentual de sequestro < 30%, alto valor de EC50 e de TEC50, e baixo EA) e o radical ABTS•+(57,16 mM TEAC.g-1). Ao associar o extrato hidroacetônico com o BHT, em diferentes concentrações, o percentual de sequestro do DPPH e de inibição da oxidação, em sistema da co-oxidação β-caroteno/ácido linoléico foi semelhante ao do BHT isolado, demonstrando haver sinergismo entre eles. O extrato hidroacetônico do resíduo agroindustrial de goiaba apresenta um expressivo potencial anti-radical, uma vez que demonstrou eficiência na captura dos radicais DPPH• e ABTS•+, relevante ação antioxidante em meio lipídico, além de sinergismo com o BHT. Desta forma, o resíduo agroindustrial de goiaba surge como alternativa de antioxidante natural.
16

Etudes phytochimique et biologique de plantes soudanaises : Hydnora johannis Beccari (Hydnoraceae) et Citrullus lanatus (Thunb.) Matsum. et Nakai var. citroides (Bailey) Mansf. (Cucurbitaceae) / Phytochemical and Biological Study of Sudanese Plants : Hydnora johannis Becc. (Hydnoraceae) and Citrullus lanatus (Thunb.) Matsum. et Nakai var. citroides (Bailey) Mansf. (Cucurbitaceae)

Yagi, Sakina 01 July 2011 (has links)
Différents extraits ont été préparés à partir de racines de H. johannis et différents tests biologiques ont été appliqués en vue de rechercher différentes activités. L'extrait aqueux s'est montré particulièrement actif sur Enterococcus fecalis, Staphylococcus aureus et Bacillus. Les extraits aqueux dépourvus de tanins et les tanins isolés ne présentent pas d'activité antibactérienne. L'effet synergétique des composés serait donc responsable de l'activité antibactérienne de la plante. Une activité antifongique sur Microsporum canis, une propriété antiradicalaire et une activité antiglycation ont été constatées avec les deux extraits. Une étude toxicologique de la poudre de plante et de l'extrait éthanolique sur des rats révèle une toxicité au niveau du foie et de la rate. Cinq composés ont été isolés puis identifiés. Il s'agit de 3',4',5-Trihydroxy-6,7-diméthoxyflavone ; 3,5-Dihydroxy-4,7-diméthoxy dihydroflavonol, Catéchine, Vanilline et l'acide Protocatechuic. Du stigmastérol, de l'acide oléique, de l'acide myristique et de l'acide palmitique ont été également identifiés. Le travail sur C. lanatus var. citroides a montré que l'extrait méthanolique (70%) des pulpes de fruits possède une activité contre B. subtilis, S. aureus et E. coli. Les extraits butanolique et à l'acétate d'éthyle ne sont pas toxiques contre les larves de crevettes. L'extrait butanolique possède une propriété significative antiradicalaire. Deux composés ont été isolés et identifiés. Ce sont la Cucurbitacine E 2-O-[bêta]-glucopyranoside et la Cucurbitacine L 2-O-[bêta]-glucopyranoside. Ces composés montrent une activité antibacterienne contre E. coli. La Cucurbitacine L 2-O-[bêta]-glucopyranoside possède une activité antibactérienne contre P. aeruginosa et une propriété modérée anti-radicaux libres / Different extracts were prepared from the roots of H. johannis and different biological tests were performed. Water extract exhibited significant activity against Enterococcus fecalis, Staphylococcus aureus and Bacillus. Water extract devoid from tannin or the tannin fraction did not show any antibacterial activity reflecting the synergistic property of active compounds. Both extracts showed antifungal, antiradical capacity as well as antiglycation activity. Toxicological study of the powder and ethanol extract on rats showed toxicity to the liver and kidney tissues. Five compounds were isolated namely; 3,4,5- Trihydroxy- 6,7-dimethoxy flavone ; 3,5-Dihydroxy- 4,7- dimethoxy dihydroflavonol, Catechin, Vanillin and Protocatechuic acid. Stigmasterol, Oleic acid, Myristic acid and Palmitic acid were also identified. A study on the fruit pulps of C. lanatus var. citroides revealed that the methanolic extract displayed an antibacterial activity against B. subtilis, S. aureus and E. coli. The butanolic extract showed antiradical capacity and was not toxic to brine shrimps larvae. Two compounds were isolated namely; Cucurbitacine E 2-O-[bêta]-glucopyranoside and Cucurbitacine L 2-O- [bêta] -glucopyranoside. Both compounds showed antibacterial activity against E.coli whereas, Cucurbitacine L 2-O-[bêta]-glucopyranoside showed antibacterial activity against P. aeruginosa as well as antiradical activity
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Uticaj fizičko-hemijskih karakteristika semena uljane tikve (Cucurbita pepo L.) na kvalitet i nutritivna svojstva hladno presovanog ulja / INFLUENCE OF PHYSICO-CHEMICAL CHARACTERISTICS OF PUMKIN SEED (Cucurbita pepo L.) ON THE QUALITY AND NUTRITIVE VALUE OF COLD PRESSED OIL

Rabrenović Biljana 09 February 2012 (has links)
<p style="text-align: justify; ">Hladno presovano ulje semena uljane tikve je&nbsp;proizvod specifičan za Srbiju, za razliku od zemalja u regionu koje imaju dugu tradiciju proizvodnje&nbsp;devičanskog tikvinog ulja.&nbsp;Tokom postupka hladnog presovanja sirovogosu&scaron;enog&nbsp;semena uljane tikve na pužnoj presi&nbsp;temperatura izdvojenog ulja ne prelazi 50 <sup>o</sup>C, &scaron;to se&nbsp;odražava na fizičko-hemijske, nutritivne i senzorne&nbsp;karakteristike kao i na oksidativnu stabilnost i&nbsp;antioksidativni potencijal ovog ulja.&nbsp;U cilju &scaron;to bolje karakterizacije ovog proizvoda na&nbsp;na&scaron;em trži&scaron;tu, ispitan je kvalitet hladno presovanog&nbsp;tikvinog ulja poreklom iz semena vi&scaron;e različitih&nbsp;slobodnooplodnih sorti i F1 hibrida, golosemenih i&nbsp;uljanih tikvi sa ljuskom, koje uspevaju u na&scaron;oj&nbsp;zemlji.&nbsp;Hladno presovano ulje semena tikve odlikuju&nbsp;specifične senzorne karakteristike: pored izuzetno&nbsp;blage arome, mirisa na sirovo seme tikve i ukusa&nbsp;koji podseća na meso tikve, ovo ulje se posebno&nbsp;izdvaja po boji koja je kod ispitivanog ulja bila&nbsp;svetlo-smedja do crvenkasta. Prema senzornim&nbsp;karakteristikama (naročito boji) izdvojili su se uzorci ulja poreklom iz semena austrijskih hibrida. Na&nbsp;osnovu sastava masnih kiselina ovo ulje pripada olinsko-linolnom tipu, &scaron;to ga svrstava u nutritivno&nbsp;veoma vredna biljna ulja, čemu doprinosi i visok&nbsp;sadržaj gama-tokoferola, koji je dominantan u&nbsp;tikvinom ulju. Određivanje sastava i sadržaja sterola je posebno bilo značajno kada je u pitanju hladno&nbsp;presovano tikvino ulje s obzirom da nema&nbsp;literaturnih podataka na tu temu. U ispitivanim&nbsp;uzorcima su bili dominantni delta-7 steroli, a određen je i izuzetno visok sadržaj skvalena, koji&nbsp;ima veoma važnu biolo&scaron;ku funkciju. Ispitivano ulje je posedovalo dobar antiradikalski potencijal, koji je&nbsp;bio u snažnoj linearnoj zavisnosti sa sadržajem fenolnih materija. Ulje dobijeno ekstrakcijom iz&nbsp;pogače, koja je zaostala nakon hladnog presovanja&nbsp;semena, posedovalo je veći antiradikalski potencijal&nbsp;u odnosu na hladno presovano &scaron;to je rezultat&nbsp;sadržaja fenolnih materija u većem procentu i ne&scaron;to&nbsp;nižeg sadržaja tokoferola u odnosu na hladno<br />presovano ulje.</p> / <p> Cold-pressed pumpkin oil is a product specific<br /> to Serbia, given that other countries in the<br /> region traditionally produce virgin pumpkin oil.<br /> In the process of cold pressing raw-dried<br /> pumpkin seeds by screw press, the<br /> temperature of extracted oil does not exceed<br /> 50oC, which affects physical, chemical,<br /> nutritional and sensory characteristics of this<br /> oil, as well as its oxidative stability and<br /> antiradical capacity.<br /> For the purpose of more precise<br /> characterization of this product in the domestic<br /> market, the quality of cold pressed oil from<br /> seeds of many free breeding varieties and F1<br /> hybrids &ndash; of both naked and husk seed<br /> pumpkins being grown in our country &ndash; was<br /> examined.<br /> Specific sensorial properties: light brown to<br /> reddish color, mild aroma, a smell similar to<br /> that of raw pumpkin seeds and a taste<br /> resembling that of pumpkin pulp are<br /> characteristic for this oil. As for sensory<br /> characteristics, the samples of oil from<br /> Austrian hybrid seeds, stood out. On the basis<br /> of fatty acid content, this oil belongs to the<br /> oleic-linoleic type, meaning it is a highly<br /> nutritional vegetable oil, which is also due to<br /> high levels of dominant gamma-tocopherol. Determination of the types and content of</p> <p> sterols was particularly important, given that<br /> there are no data specific to cold-pressed<br /> pumpkin oil in the literature. Delta-7 sterols are<br /> the most dominant sterols in examined oil<br /> samples and also very high content of<br /> squalene was found, which a compound with<br /> an important biological function is. The oil has<br /> an excellent antiradical capacity, showing a<br /> strong linear correlation with the amounts of<br /> phenolic compounds. Oil extracted from the<br /> cake, left over after the cold pressing of<br /> pumpkin seeds, had greater antiradical<br /> capacity than the samples of cold pressed oil,<br /> due to higher percentage of phenolic<br /> compounds and a slightly lower content of<br /> tocopherols compared to cold pressed oil.</p>
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Funkcionalne i antioksidativne osobine tropa cvekle (Beta vulgaris) / Functional and antioxidant characteristics of beetroot pomace (Beta vulgaris)

Vulić Jelena 04 September 2012 (has links)
<p>Etanolni ekstrakti tropa odabranih sorti cvekle (Detroit, Cardeal-F1, Egipatska, Bikor i Kestrel) preči&scaron;ćeni su primenom ekstrakcije na čvrstoj fazi (SPE). Sadržaj ukupnih<br />fenolnih jedinjenja, flavonoida i betalaina u preči&scaron;ćenim ekstraktima određeni su spektrofotometrijskim metodama. HPLC analizom utvrđen je kvalitativni i kvantitativni sastav fenolnih jedinjenja i betalaina ekstrakata tropa odabranih sorti cvekle. ESR spektroskopijom ispitana je antiradikalska aktivnost ekstrakata topa cvekle na stabilne DPPH i reaktivne superoksid anjon i hidroksil radikale.<br />Spektrofotometrijski je određena antioksidativna aktivnost na DPPH radikale i redukciona sposobnost po Oyaizu u ekstraktima odabranih sorti cvekle. Ispitana je in vitro<br />antiproliferativna aktivnost frakcija ekstrakata, njihovim delovanjem na rast tri histolo&scaron;ki različite humane ćelijske linije: MCF-7 (adenokarcinom dojke), HeLa (epitelni karcinom cerviksa)i MRC-5 (fetalni fibroblastni karcinom pluća). U zavr&scaron;noj fazi rada određena je antimikrobna aktivnost ekstrakata tropa odabranih sorti cvekle.</p> / <p> Beetroot (Detroit, Cardeal-F1, Egipatska, Bikor i Kestrel)<br /> pomace ethanol extracts were purified using solid phase<br /> extraction (SPE). Contents of total phenols, flavonoids and<br /> betalains in purified extracts were determined by spectrophotometric<br /> methods. HPLC analysis were used for quantitative<br /> and qualitative characterization of phenolic compounds<br /> and betalains in investigated extracts. ESR spectroscopy<br /> was used for investigation of antiradical activity of<br /> beetroot pomace extracts on stable DPPH and reactive<br /> superoxide anion and hydroxyl radicals. Antioxidant activity<br /> was determined spectrophotometrically on DPPH radicals<br /> and reducing power according to Oyaizu in the beetroot pomace<br /> extracts. Antiproliferative activity of investigated extracts<br /> was determined in vitro, testing their influence on the<br /> growth of three histologically different human cell lines:<br /> MCF-7 (breast adenocarcinoma), HeLa (cervix epithelioid<br /> carcinoma) and MRC-5 (fetal lung). Also, antimicrobial activity<br /> of beetroot pomace extracts was determined.</p>
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Antiradikalska i antiproliferativna aktivnost ekstrakata odabranih biljaka iz familija rosaceae i ericaceae / Antiradical and antiproliferative activity of selected plantextracts from Rosaceae and Ericaceae family

Tumbas Vesna 14 June 2010 (has links)
<p>Acetonski ekstrakti bobičastog voća iz familija Ericaceae<br />(borovnica,<em> Vaccinium myrtillus</em> L., i brusnica, <em>Vaccinium<br />macrocarpon</em> L.) i Rosaceae (&scaron;ipak, <em>Rosa canina</em> L., i glog,<br /><em>Crataegus oxyacantha</em> L.) preči&scaron;ćeni su i frakcionisani<br />primenom ekstrakcije na čvrstoj fazi (SPE). Sadržaj ukupnih<br />polifenolnih jedinjenja, flavonoida i antocijana u preči&scaron;ćenim<br />ekstraktima određeni su spektrofotometrijskim metodama.<br />HPLC analizom utvrđen je kvalitativni i kvantitativni<br />sastav frakcija ekstrakata ispitivanih bobica. ESR spektroskopijom<br />ispitana je antiradikalska aktivnost frakcija ekstrakata<br />bobica na stabilne DPPH<sup>●</sup> i reaktivne superoksid anjon i<br />hidroksil radikale. ESR spektroskopijom ispitano je i<br />prisustvo slobodnih radikala antioksidanata nastalih tokom<br />reakcije frakcija ekstrakata bobica sa superoksid anjon<br />radikalima. U zavr&scaron;noj fazi rada ispitana je<em> in vitro</em><br />antiproliferativna aktivnost frakcija ekstrakata bobica, njihovim<br />delovanjem na rast tri histolo&scaron;ki različite humane ćelijske<br />linije: HeLa (epitelni karcinom cerviksa), HT-29 (adenokarcinom<br />debelog creva) i MCF-7 (adenokarcinom dojke).</p> / <p>Acetone extracts of berries form Ericaceae (bilberry, <em>Vaccinium<br />myrtillus</em> L., and cranberry, <em>Vaccinium macrocarpon</em><br />L.) and Rosaceae (rose hip, <em>Rosa canina</em> L., and hawthorn,<br /><em>Crataegus oxyacantha </em>L.) families were purified and fractionated<br />using solid phase extraction (SPE). Contents of total<br />polyphenols, flavonoids and anthocyanins in purified extracts<br />were determined by spectrophotometric methods.<br />HPLC analysis were used for quantitative and qualitative<br />characterization of investigated berry extracts fractions. ESR<br />spectroscopy was used for investigation of antiradical activity<br />of berry extracts fractions on stable DPPH<sup>●</sup> and<br />reactive superoxide anion and hydroxyl radicals. The<br />presence of antioxidant free radicals formed during reaction<br />of investigated berry extracts fractions with superoxide<br />anion radicals was also investigated by ESR. Antiprolixferative<br />activity of investigated berry extracts fractions was<br />determined<em> in vitro</em>, testing their influence on the growth of<br />three histologically different human cell lines: HeLa (cervix<br />epithelioid carcinoma), HT-29 (colon adenocarcinoma) i<br />MCF-7 (breast adenocarcinoma).</p>
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Oligomérisation enzymatique de flavonoïdes et évaluation des activités biologiques des oligomères synthétisés / Enzymatic oligomerization of flavonoids and evaluation of the biological activities of synthesized oligomers

Ben Rhouma-Martin, Ghada 11 February 2013 (has links)
L'oligomérisation enzymatique de la rutine et esculine a donné lieu à cinq fractions d'oligomères de masse moléculaire moyenne entre 2127,42 et 8331,85 g/mol pour la rutine et 688,12 et 6973 g/mol pour l'esculine. L'analyse de ces fractions par FTIR montre que les fractions d'oligorutines sont obtenues à travers des liaisons C-C, C-O et C=O. Les fractions d'oligoesculines sont obtenues à travers des liaisons C-C. Une meilleure solubilité des oligorutines et des oligoesculines dans l'eau et une plus faible solubilité de ces oligomères dans l'éthanol comparé à leurs monomères a été mis en évidence. Une diminution de l'activité antiradicalaire vis-à-vis de DPPH., ABTS+. et OH. proportionnelle à la masse moléculaire moyenne des fractions d'oligorutines a été observé, contrairement aux fractions d'oligoesculines qui montrent un important pouvoir chélateur de ces mêmes radicaux comparé à leurs monomère. Une augmentation du pouvoir chélateur de fer, inhibiteur de la xanthine oxydase, réducteur du cuivre (CUPRAC), de l'activité antigénotoxique, ainsi que de l'activité stimulatrice de la prolifération des splénocytes, et des lymphocytes (B et T) proportionnelle au degré d'oligomérisation des oligomères étudiées a été noté. L'effet des fractions d'oligorutines et oligoesculines étudiées sur les macrophages en suivant la production de monoxyde d'azote (NO) montre un pouvoir anti-inflammatoire comparé à leurs monomères. L'étude de l'activité lysosomale induite par les fractions d'oligorutine révèle un pouvoir immunostimulateur proportionnelle à la masse moléculaire moyenne des oligorutines, et inversement proportionnelle à celle-ci pour les oligoesculines / Rutin and esculin have been polymerized by laccase. Five fractions with between 2127.42 and 8331.85 g/mol for oligorutins, and between 688.12 and 6973 g/mol for oligoesculins, were obtained. Fourier transformed infrared analysis showed that oligorutins were formed through C-C, C-O and C=O linkages, while oligoesculins were obtained through C-C linkages. Oligorutins and oligoesculins show a higher solubility in water and a lower solubility in ethanol compared to their monomers. The oligomerization of rutin decrease its antiradical capacity, while oligoesculin fractions demonstrated a high antiradical activity compared to monomeric esculin. Oligomer fractions showed a better iron chelating power, xanthine oxidase inhibition, copper reducing power (CUPRAC), antigenotoxic activity, and splenocytes stimulator activity compared to their monomers. Oligorutin and oligoesculin exhibited an important anti-inflammatory capacity through the nitric oxide inhibition. Moreover, oligorutin fractions demonstrated an immunostimulatory effect proportional to their degree of oligomerization, while oligoesculin fractions showed an immunostimulatory effect inversely proportional to their degree of oligomerization

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