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Búsqueda : ANTIOXIDANTES [Descritor de assunto]
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  1 / 4 ins  
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Id:8316
Autor:Montoro, P; Carbone, V; De Simone, F; Pizza, C; De Tommasi, N
Título:Studies on the constituents of Cyclanthera pedata fruits: isolation and structure elucidation of new flavonoid glycosides and their antioxidant activity^ien ..-
Fuente:Washington; American Chemical Society; 2001. 5156-60 p. ^bgraf, ^btab.
Resumen:The isolation of six flavon glycosides (1-6), among them four new natural compounds (1-4), from the CHCl(3)/MeOH extract of the fruits of Cyclanthera pedata is reported. All of the structures were elucidated by spectroscopic methods, including the concerted application of one-dimensional ((1)H, (1)H TOCSY, (13)C, and (13)C DEPT-NMR) and two-dimensional NMR techniques (DQF-COSY, HSQC, and HMBC). For all of the isolated compounds the antioxidant activity was determined by measuring the free radical scavenging activity, using the Trolox equivalent antioxidant capacity (TEAC) method, and the coupled oxidation of beta-carotene and linoleic acid. (AU)^ien.
Descriptores:Cucurbitaceae
Cucurbita
Flavonas
Antioxidantes
Límites:Humanos
Localización:PE14.1


  2 / 4 ins  
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Id:8302
Autor:Valentová, K; Sersen, F; Ulrichová, J
Título:Radical scavenging and anti-lipoperoxidative activities of Smallanthus sonchifolius leaf extracts^ien ..-
Fuente:Washington; American Chemical Society; 2005. 5577-5582 p. ^btab, ^bgraf.
Resumen:Radical scavenging and anti-lipoperoxidative effects of two organic fractions and two aqueous extracts from the leaves of a neglected Andean crop-yacon (Smallanthus sonchifolius Poepp. & Endl., Asteraceae) were determined using various in vitro models. The extracts' total phenolic content was 10.7-24.6 percent. They exhibited DPPH (IC50 16.14-33.39 microg/mL) and HO scavenging activities (4.49-6.51 mg/mL). The extracts did not scavenge phenylglyoxylic ketyl radicals, but they retarded their formation. In the xanthine/xanthine oxidase superoxide radical generating system, the extracts' activities were 26.10-37.67 superoxide dismutase equivalents/mg. As one of the extracts displayed xanthine oxidase inhibitory activity, the effect of the extracts on a nonenzymatically generated superoxide was determined (IC50 7.36-21.01 microg/mL). The extracts inhibited t-butyl hydroperoxide-induced lipoperoxidation of microsomal and mitochondrial membranes (IC50 22.15-465.3 microg/mL). These results make yacon leaves a good candidate for use as a food supplement in the prevention of chronic diseases involving oxidative stress. (AU)^ien.
Descriptores:Plantas Medicinales
Compuestos Fenólicos
Antioxidantes
Peroxidación de Lípido
Límites:Humanos
Localización:PE14.1


  3 / 4 ins  
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Id:8295
Autor:Valentova, K; Cvak, L; Muck, A; Ulrichova, J; Simanek, V
Título:Antioxidant activity of extracts from the leaves of Smallanthus sonchifolius^ien ..-
Fuente:Darmstadt; Springerlink; 2003. 61-66 p. ^btab, ^bgraf.
Resumen:BACKGROUND & AIMS: Yacon ( Smallanthus sonchifolius, Asteraceae) is a native Andean plant, cultivated for its tubers throughout South America. The leaves are used in folk medicine as a medicinal tea for hypoglycemia. This paper describes the antioxidant activity of various extracts from S. sonchifolius leaves for their content of phenolic components. METHODS: The dried leaves were extracted in several ways. Two fractions were selected for their high content of phenolic compounds and analyzed by RP-HPLC. The antioxidant activity of these fractions was tested in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and xanthine/XOD superoxide radical scavenging assays, as inhibition of lipoperoxidation of subcellular membranes and as protective activity against oxidative injury of rat hepatocytes in primary cultures. RESULTS AND CONCLUSIONS: The presence of protocatechuic (2.5 and 0.12 mg/g), chlorogenic (9.9 and 1.7 mg/g), caffeic (14.7 and 0.09 mg/g) and ferulic (traces) acids were determined in the two fractions. Both fractions showed potent antioxidant activity in DPPH (IC(50) = 16.1 +/- 3.4 and 24.3 +/- 2.7 mg/ml) and xanthine/XOD superoxide radical scavenging (42.0 +/- 20.3 and 34.3 +/- 11.4 SOD equivalents (U/mg)) tests, they inhibited the lipoperoxidation of rat liver subcellular membranes and they protected rat hepatocytes against oxidative injury. Our results may predetermine the use of S. sonchifolius leaves in human diet as a potential remedy in the prevention of chronic diseases caused by radicals, e. g., arteriosclerosis. (AU)^ien.
Descriptores:Plantas Medicinales
Antioxidantes
Límites:Masculino
Ratas
Localización:PE14.1


  4 / 4 ins  
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Id:3385
Autor:World Health Organization*.
Título:Evaluation of food additives: some enzymes, modified starches, and certain other substances, toxicological evaluations and specifications and a review of the technological efficacy of some antioxidants, fifteenth report of the Joint FAO/WHO Expert Committee on Food Additives ..-
Fuente:Ginebra; WHO; 1972. 41 p. . (WHO Technical Report Series, 488).
 (WHO Technical Report Series, 488).
Descriptores:Aditivos Alimentarios/normas
Aditivos Alimentarios/toxicidad
Antioxidantes/normas
Localización:PE14.4, CH-00013



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