Encontrados 14 documentos, a visualizar página 1 de 2
Chemical, biochemical and electrochemical assays to evaluate phytochemicals and...
Barros, Lillian; Cabrita, Luís; Vilas-Boas, Miguel; Carvalho, Ana Maria; Ferreira, Isabel C.F.R.Plants are a source of compounds that may be used as pharmacologically active products. Cytisus multiflorus, Filipendula ulmaria and Sambucus nigra have been used as important medicinal plants in the Iberian Peninsula for many years, and are claimed to have various health benefits. Herein, the phytochemical composition and antioxidant activity of the mentioned wild medicinal plants were evaluated in vitro, base...
Avaliação da actividade antioxidante de extractos de plantas medicinais e aromá...
Cabrita, Luís; Carvalho, Ana Maria; Vilas-Boas, Miguel; Ferreira, Isabel C.F.R.A actividade antioxidante de extractos metanólicos de plantas aromáticas e medicinais silvestres referidas em inventários etnobotânicos realizados na região de Trás-os-Montes foi avaliada in vitro através de técnicas electroquímicas, nomeadamente, por Voltametria Cíclica (CV) e por Voltametria Diferencial por Pulso (DPV). Utilizaram-se eléctrodos de carbono vítreo (diam = 3 mm) e NaClO4 como electrólito. Foram...
Análise e identificação das antocianinas de couve rôxa (Brassica spp.)
Lopes, Dulce; Jesus, Benvinda; Cabrita, LuísA couve rôxa é uma espécie comestível com uma composição em antocianinas rica e complexa. Sabe-se que contem antocianinas poliglicosiladas, aciladas com um ou mesmo dois grupos acilo aromáticos, nomeadamente com ácidos coumárico e caféico. Este padrão de acilação é particularmente interessante, porque confere estabilidade às antocianinas e aumenta o seu potencial de utilização em aplicações famacêuticas, alimen...
Análise e identificação das antocianins do mirtilo da Madeira (Vaccinium padifo...
Cabrita, Luís; Neves, Higuinaldo Chaves dasAnalisaram-se as antocianinas dos mirtilos da Madeira e dos Açores. Os pigmentos foram isolados por cromatografia líquida preparativa bi-dimensional (exclusão molecular vs fase reversa), e identificados por RMN (1H, CAPT, COSY, HSQC, HMBC). Em V. padifolium isolou-se e identificou-se a malvidina 3-rhamnósido, um pigmento muito raro, elevando para 26 o total de antocianinas já descritas nesta espécie (3 tri-glic...
Polyacylated anthocyanins from Hebe
Cabrita, Luís; Justesen, Ulla; Frøystein, Nils Åge; Andersen, Øyvind M.Four acylated anthocyanins were isolated from flowers of Hebe spp. On the basis of LC-MS (Liquid Chromatography - Mass Spectrometry) and NMR (Nuclear Magnetic Resonance) techniques, they were identified as (1) cyanidin 3-O-[2-O-(6-O-(E-caffeoyl)-beta-glucopyranosyl)-6-O-(E-p-coumaroyl)-beta-glucopyranoside]-5-O-beta-glucopyranoside, (2) cyanidin 3-O-[2-O-(6-O-(E-p-coumaroyl)-beta-glucopyranosyl)-6-O-(E-p-coumar...
Anthocyanin stability: a chemometrical approach
Cabrita, Luís; Fossen, Torgils; Flåten, Geir R.; Andersen, Øyvind M.The stability of cyanidin 3-glucoside towards five different factors (pH, anthocyanin concentration, sodium chloride concentration, ascorbic acid concentration, Oxygen) was studied during 60 days storage at room temperature using a 2^4-1 reduced factorial design. The influence of each individual parameter on anthocyanin stability was found to vary as a function of time. Sodium chloride and ascorbic acid were, r...
Anthocyanins from pomegranate (Punica granatum L.)
Cabrita, Luís; Neves, Higuinaldo Chaves dasThe anthocyanin contents in the fruits from three cultivars of Punica granatum L. (asseria, mollar and negral) was studied. Six anthocyanins were isolated from the red seeds of pomegranate fruits using a combination of Sephadex LH-20 column chromatography and reverse-phase semi-preparative HPLC. On the basis of chromatographic and spectroscopic techniques, they were identified as the 3-monoglucosides and 3,5-d...
Anthocyanin-rich extract decreases indices of lipid peroxidation and DNA damage...
Ramirez-Tortosa, Carmen; Cabrita, Luís; Andersen, Øyvind M.; Gardner, P.T.; Morrice, P.C.; Wood, S.G.; Duthie, S.J.; Collins, A.R.; Garry, G.G.Anthocyanins are secondary plant metabolites responsible for the blue, purple, and red color of many plant tissues. The phenolic structure of anthocyanins conveys marked antioxidant activity in model systems via donation of electrons or hydrogen atoms from hydroxyl moieties to free radicals. Dietary intakes of anthocyanins may exceed 200 mg/day, however, little is known about their antioxidant potency in vivo. ...
Anthocyanin trisaccharides in blue berries of Vaccinium padifolium
Cabrita, Luís; Frøystein, Nils Åge; Andersen, Øyvind M.Delphinidin 3-O-alfa-rhamnoside, malvidin 3-O-(6''-O-alfa-rhamnopyranosyl-beta-glucopyranoside) and the 3-O-(6''-O-alfa-rhamnopyranosyl-2''-O-beta-xylopyranosyl-beta-glucopyranosides) of cyanidin, petunidin and peonidin were isolated by various chromatographic techniques from the edible berries of Vaccinium padifolium. Their complete structures were elucidated mainly by one- and two-dimensional nuclear magnetic...
Colour and stability of the six common anthocyanidin 3-glucosides
Cabrita, Luís; Fossen, Torgils; Andersen, Øyvind M.This study on anthocyanin stability and colour variation (lambda max, absorptivity) in the pH range 1-12 during a period of 60 days storage at 10 and 23ºC, was conducted on the 3-glucosides of the six common anthocyanidins. It was mostly in the alkaline region that differences in colour and stability became significant. Although it has been generally accepted that anthocyanins are stable only at low pH values, ...
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