114 resultados para Hydrolyzable tannins
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Qualea grandiflora is one of the species widely used in folk medicine to treat gastric ulcers in Cerrado of the central region of Brazil. The hydroalcoholic extract of bark (HE) of Qualea grandiflora was investigated for their ability to prevent and heal lesions in the gastric mucosa. The oral administration of HE exhibited antiulcer activity decreasing the ulcerative index induced by HCl/ethanol solution, indomethacin/bethanechol and stress. In the Shay model, results showed that HE (p.o.) only reduced the severity of gastric lesions without effects on pH, gastric acidity or volume. When given by intraduodenal route, HE changed the pH, but did not modify the other parameters of the gastric juice. These data were in accordance with those obtained when HE was administered orally for 14 days after gastric ulcers were induced by acetic acid in rats. HE presented healing process in subacute gastric ulcer induced by acetic acid in rats. Moreover, histological examinations showed the simple columnar epithelium, lamina propria with simple branched tubular glandules with dilated lumen and large amounts of mucus secretion. Phytochemical investigation of HE led to the detection of terpenes, steroids, saponins, phenolic compounds and tannins in this extract, which may be involved in the observed activity. (c) 2005 Elsevier B.V.. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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An aqueous extract of Rhizophora mangle L. bark is used as raw material in pottery making in the State of Espirito Santo, Brazil. This extract presents large quantities of tannins, compounds possessing antioxidant properties. Tannin antioxidant activity, as a plant chemical defense mechanism in the process of stabilizing free radicals, has been an incentive to studies on anti-mutagenicity. The present work aimed to evaluate possible antimutagenic activity of a R. mangle aqueous extract, using the Allium cepa test-system and micronuclear (MN) assay with blockage of cytokinesis in Chinese hamster ovary cells (CHO-K1). The Allium cepa test-system indicated antimutagenic activity against the damage induced by the mutagenic agent methyl methanesulfonate. A reduction in both MN cell frequency and chromosome breaks occurred in both the pre and post-treatment protocols. The MN testing of CHO-K1 cells revealed anti-mutagenic activity of the R. mangle extract against methyl methanesulfonate and doxorubicin in pre, simultaneous and post-treatment protocols. These results suggest the presence of phyto-constituents in the extract presenting demutagenic and bio-antimutagenic activities. Since the chemical constitution of Rhizophora mangle species presents elevated tannin content, it is highly probable that these compounds are the antimutagenic promoters themselves.
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Fruit traits evolve in response to an evolutionary triad between plants, seed dispersers, and antagonists that consume fruits but do not disperse seeds. The defense trade-off hypothesis predicts that the composition of nutrients and of secondary compounds in fruit pulp is shaped by a trade-off between defense against antagonists and attraction to seed dispersers. The removal rate model of this hypothesis predicts a negative relationship between nutrients and secondary compounds, whereas the toxin-titration model predicts a positive relationship. To test these alternative models, we evaluated whether the contents of nutrients and secondary compounds can be used to predict fruit removal by mutualists and pathogens in 14 bird-dispersed plants on a subtropical island in São Paulo state, southeastern Brazil. We selected eight to ten individuals of each species and prevented fruit removal by covering four branches with a net and left fruits on four other branches available to both, vertebrate fruit consumers and pathogens. The persistence of ripe fruits was drastically different among species for bagged and open fruits, and all fruit species persisted longer when protected against seed dispersers. We found that those fruits that are quickly removed by vertebrates are nutrient-rich, but although the attack rate of pathogens is also high, these fruits have low contents of quantitative defenses such as tannins and phenols. Thus, we suggest that the fruit removal rate by seed dispersers is the primary factor selecting the levels of fruit defense. Likewise, nutrient-poor fruits have low removal of seed dispersers and low probability of attack by pathogens. These species retain ripe fruits in an intact condition for a prolonged period because they are highly defended by secondary compounds, which reduce overall attractiveness. However, this strategy might be advantageous for plants that depend on rare or unreliable dispersers.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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O pequi é um dos frutos mais abundantes no Cerrado, sendo sua polpa muito apreciada na culinária regional, porém, sua amêndoa (também comestível) é pouco aproveitada. O consumo da amêndoa crua pode acarretar em problemas digestivos, devido à possível presença de fatores antinutricionais, assim como a torra pode alterar, nutricionalmente, a amêndoa. Este trabalho objetivou verificar a composição centesimal, o perfil de ácidos graxos e os fatores antinutricionais, em amêndoas de pequi crua e torrada (a 270ºC, por 15 minutos), oriundas do Estado de Goiás e submetidas às análises de composição centesimal (umidade, proteínas, lipídeos, cinzas, carboidratos e valor energético), perfil de ácidos graxos e fatores antinutricionais (inibidores de tripsina, tanino e fitatos). A composição centesimal e os fatores antinutricionais, respectivamente para as amêndoas crua e torrada, apresentaram os seguintes teores: umidade: 25,40% e 1,70%; cinzas: 3,90% e 4,60%; proteínas: 13,40% e 14,70%; lipídeos: 24,70% e 25,70%; carboidratos: 32,50% e 53,30%; e valor energético: 406,20 kcal/100 g e 503,00 kcal/100 g, com ausência de inibidores de tripsina e taninos com 1,21% e 1,17% e fitatos com 2,64% e 1,86%. No perfil de ácidos graxos, respectivamente para as amêndoas crua e torrada, foram obtidos 86,90% e 84,61% de ácidos saturados e 10,57% e 10,40% de insaturados. A torra das amêndoas não influenciou, significativamente (p > 0,05), somente a variável proteína, interferindo, assim, nas características nutricionais e antinutricionais.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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As frações protéicas foram isoladas dos cotiledones e os taninos isolados e purificados da casca da lentilha. A fração globulina correspondeu a 42,7 % do nitrogenio total da farinha de lentilha representando a fração protéica majoritária. Comparativamente ao metanol e metanol-HCl 1% a mistura acetona:água (7:3) representou o melhor meio extrator para os taninos da casca. A fração globulina isolada, nativa e aquecida (99oC/15 min), e caseína foram hidrolisadas com tripsina e pepsina na ausência de taninos e na presença de relações tanino:proteína de 1:40, 1:20, 1:10, 1:5 e 1:2,5. A hidrólise tríptica e péptica das proteínas não-aquecidas foram reduzidas com o aumento da relação tanino-proteína. A caseína não aquecida mostrou ser mais susceptível à tripsina que à globulina, o oposto sendo observado com a pepsina. O aquecimento seguido de interação com os taninos e hidrólise teve um efeito mais pronunciado sobre a digestão com tripsina que com pepsina para ambas proteínas.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The amazonian climber Gnetum venosum contains, besides the stilbenes resveratrol and rapontigentin (3-methoxyresveratrol), oxidative stilbene oligomers such as the dimer gnetin C and the trimers gnetin E, gnetin J (3''-hydroxygnetin E) and gnetin K (3''-methoxygnetin E). Gnetins J and K are described for the first time. Oligomers of stilbenoids constitute a new class of condensed tannins.