Percorrer por autor "Ferreres, Frederico"
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- Analysis and quantification of flavonoidic compounds from Portuguese olive (Olea europeae L.) leaf cultivarsPublication . Meirinhos, Julieta; Silva, Branca M.; Valentão, Patrícia; Seabra, Rosa M.; Pereira, J.A.; Dias, Alberto; Andrade, Paula B.; Ferreres, FredericoTwenty three samples of 18 Portuguese olive leaf cultivars were analysed by a reversed-phase HPLC/DAD procedure and eight flavonoidic compounds were identified and quantified (luteolin 7,40-O-diglucoside, luteolin 7-O-glucoside, rutin, apigenin 7-O-rutinoside, luteolin 40-O-glucoside, luteolin, apigenin and diosmetin). Luteolin 7,40-O-diglucoside and luteolin 40-O-glucoside were identified by HPLC/DAD/MS/MS – ESI. The studied olive leaf samples showed a common phenolic pattern, in which luteolin 40-O-glucoside was almost always the major compound
- Analysis of phenolic compounds from hazelnut (Corylus avellana L.) leavesPublication . Amaral, Joana S.; Ferreres, Frederico; Santos, Alberto; Pinheiro, Cristina; Andrade, Paula B.; Seabra, Rosa M.Hazelnut leaf has been used in folk medicine in varicose veins and haemorrhoidal symptomatology for its vasoconstrictor and antihaemorrhagic properties. Slight antidysenteric, antifungal and healing properties have also been described
- Antioxidative properties of tronchuda cabbage (Brassica oleracea L. var. costata DC) external leaves against DPPH, superoxide radical, hydroxyl radical and hypochlorous acidPublication . Vrchovska, Vendula; Sousa, Carla; Valentão, Patrícia; Ferreres, Frederico; Pereira, J.A.; Seabra, Rosa M.; Andrade, Paula B.The ability of the aqueous extract of tronchuda cabbage (Brassica oleracea L. var. costata DC) external leaves to act as a scavenger of DPPH- and reactive oxygen species (superoxide radical, hydroxyl radical and hypochlorous acid) was investigated. A phytochemical study was also undertaken, and thirteen phenolic compounds and five organic acids were identified and quantified. Tronchuda cabbage extracts exhibited antioxidant capacity in a concentration-dependent manner in all assays, although some pro-oxidant effect was also noticed. The samples with higher phenolic and organic acid contents displayed the major antioxidant potentials.
- Chemical assessment and in vitro antioxidant capacity of Ficus carica latexPublication . Oliveira, Andreia P.; Silva, Luís R.; Ferreres, Frederico; Pinho, P. Guedes de; Valentão, Patrícia; Silva, Branca M.; Pereira, J.A.; Andrade, Paula B.Ficus species possess latex-like material within their vasculatures, affording protection and selfhealing from physical attacks. In this work, metabolite profiling was performed on Ficus carica latex. Volatiles profile was determined by HS-SPME/GC-IT-MS, with 34 compounds being identified, distributed by distinct chemical classes: 5 aldehydes, 7 alcohols, 1 ketone, 9 monoterpenes, 9 sesquiterpenes and 3 other compounds. Sesquiterpenes constituted the most abundant class in latex (ca. 91% of total identified compounds). Organic acids composition was also characterized, by HPLC-UV, and oxalic, citric, malic, quinic, shikimic and fumaric acids were determined. Malic and shikimic acids were present in higher amounts (ca. 26%, each). The antioxidant potential of this material was checked by distinct in vitro chemical assays. A concentration-dependent activity was noticed against DPPH, nitric oxide and superoxide radicals. Additionally, acetylcholinesterase inhibitory capacity was evaluated, but a weak effect was found.
- Chemical composition and antioxidant activity of tronchuda cabbage internal leavesPublication . Ferreres, Frederico; Sousa, Carla; Vrchovska, Vendula; Valentão, Patrícia; Pereira, J.A.; Seabra, Rosa M.; Andrade, Paula B.A phytochemical study was undertaken on the internal leaves of tronchuda cabbage (Brassica oleracea L. var. costata DC). Seventeen phenolic compounds were characterized and quantified by reversed-phase HPLCDAD-ESI-MSn and HPLC/DAD, respectively: quercetin 3-O-sophoroside-7-O-glucoside, 3-p-coumaroylquinic acid, kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-(caffeoyl)-sophoroside-7-O-glucoside, sinapoyl glucoside acid, kaempferol 3-O-(sinapoyl)-sophoroside-7-Oglucoside, kaempferol 3-O-(feruloyl)-sophoroside-7-Oglucoside, kaempferol 3-O-(p-coumaroyl)-sophoroside- 7-O-glucoside, 4-p-coumaroylquinic acid, sinapic acid, kaempferol 3-O-sophoroside, 3 isomeric forms of 1,2- disinapoylgentiobiose, 1-sinapoyl-2-feruloylgentiobiose, 1,2,2-trisinapoylgentiobiose and 1,2'-disinapoyl-2-feruloylgentiobiose. Seven organic acids (aconitic, citric, ascorbic, malic, quinic, shikimic and fumaric acids) were also identified and quantified. The hot water extract of tronchuda cabbage internal leaves was investigated for its capacity to act as a scavenger of DPPH- radical and reactive oxygen species (superoxide radical, hydroxyl radical and hypochlorous acid), exhibiting antioxidant capacity in a concentration dependent manner against all radicals.
- Composição química e actividade antioxidante das folhas internas da couve tronchudaPublication . Pereira, J.A.; Sousa, Carla; Ferreres, Frederico; Valentão, Patrícia; Seabra, Rosa M.; Andrade, Paula B.A couve tronchuda (Brassica oleracea L. var. costata DC) é uma das couves mais consumidas pelos portugueses, especialmente durante o Inverno, apresentando as folhas (internas e externas) diferenças organolépticas marcadas. No presente trabalho procedeu-se à caracterização química das folhas internas de couve tronchuda, através da identificação e quantificação dos compostos fenólicos e dos ácidos orgânicos que as compõem e avaliou-se o seu potencial antioxidante. Foram identificados e quantificados, por HPLC-DAD-ESI-MS e HPLC/DAD, respectivamente, 17 compostos fenólicos: quercetina 3-O-soforósido-7-O-glucósido, ácido 3-p-cumaroilquínico, campferol 3-O-soforósido-7-O-glucósido, campferol 3-O-(cafeoil)-soforósido-7-O-glucósido, ácido sinapoilglucósido, campferol 3-O-(sinapoil)-soforósido-7-O-glucósido, campferol 3-O-(feruloil)-soforósido-7-O-glucósido, campferol 3-O-(p-cumaroil)-soforósido-7-O-glucósido, ácido 4-p-cumaroilquínico, ácido sinápico, campferol 3-O-soforósido, 3 isómeros de 1,2-di-sinapoilgentiobiose, 1-sinapoil-2-feruloilgentiobiose, 1,2,2-tri-sinapoilgentiobiose e 1,2’-di-sinapoil-2-feruloilgentiobiose. Foram também identificados e quantificados, por HPLC/UV, sete ácidos orgânicos (ácidos aconítico, cítrico, ascórbico, málico, quínico, chiquímico e fumárico). A actividade antioxidante do extracto aquoso foi aferida pela capacidade para interceptar o radical DPPH e espécies reactivas de oxigénio (radicais superóxido e hidroxilo e ácido hipocloroso), tendo revelado grande efeito protector.
- Flavonóides em folhas de cultivares portuguesas de oliveira.Publication . Meirinhos, Julieta; Silva, Branca M.; Valentão, Patrícia; Seabra, Rosa M.; Pereira, J.A.; Dias, Alberto; Andrade, Paula B.; Ferreres, Frederico
- Free water-soluble phenolics profiling in barley (Hordeum vulgare L.)Publication . Ferreres, Frederico; Kršková, Zuzana; Gonçalves, Rui; Valentão, Patrícia; Pereira, J.A.; Dušek, Jaroslav; Martin, Jan; Andrade, Paula B.The phenolic profile of barley (Hordeum vulgare L.) leaves, seeds, awns, and stems, collected in two different locations from Portugal, was determined by a high-performance liquid chromatography/ diode array detector (HPLC/DAD). A total of 28 compounds were identified and quantified, which included 4 phenolic acids, 6 C-glycosylflavones, and 18 O-glycosyl-C-glycosyl flavones, with some of them acylated. Distinct profiles were noticed among the analyzed materials. The greatest diversity of compounds was found in barley leaves (26 flavonoids and 2 phenolic acid derivatives), which also exhibited the highest concentration of phenolics. Isoorientin-7-O-glucoside (lutonarin) was the major compound in leaves, while, in general, the pair isovitexin-7-O-rutinoside plus isoscoparin-7-O-glucoside were the main phenolics in the other materials. Thus, barley leaves may constitute an important dietary source of protective compounds, which could be used, for example, to take profit from the wastes resulting from alcoholic drink obtainment.
- Hazel (Corylus avellana L.) leaves as source of antimicrobial and antioxidative compoundsPublication . Oliveira, Ivo; Sousa, Anabela; Valentão, Patrícia; Andrade, Paula B.; Ferreira, Isabel C.F.R.; Ferreres, Frederico; Bento, Albino; Seabra, Rosa M.; Estevinho, Leticia M.; Pereira, J.A.Aqueous extracts of leaves of different hazel (Corylus avellana L.) cultivars (Cv. M. Bollwiller, Fertille de Coutard and Daviana), were analysed by reversed-phase HPLC/DAD for the definition of their phenolic composition. Antioxidant potential was assessed by the reducing power assay, and the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and b-carotene linoleate model system. Their antimicrobial capacity was also tested against Gram positive (Bacillus cereus, Bacillus subtilis, Staphylococcus aureus) and Gram negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae) and fungi (Candida albicans, Cryptococcus neoformans). Eight phenolic compounds were identified: 3-, 4- and 5-caffeoylquinic acids, caffeoyltartaric acid, p-coumaroyltartaric acid, myricetin-rhamnoside, quercetin 3-rhamnoside and kaempferol 3-rhamnoside. A p-coumaric acid, three myricetin and one quercetin derivatives were also detected. The hazel leaves extract presented high antioxidant activity in a concentration-dependent way, in general with similar behaviour of all cultivars. Gram positive bacteria revealed to be very sensitive to hazel leaf extract (MIC 0.1 mg/ml for B. cereus and S. aureus and 1 mg/ml for B. subtilis). However, Gram negative and the fungi displayed much lower sensitivity, being P. aeruginosa and C. albicans resistant at 100 mg/ml. Cv. M. Bollwiller exhibited the most potent antimicrobial activity.
- HPLC-DAD-MS/MS-ESI screening of phenolic compounds in Pieris brassicae L. reared on Brassica rapa var. rapa L..Publication . Ferreres, Frederico; Valentão, Patrícia; Pereira, J.A.; Bento, Albino; Noites, Alexandra; Seabra, Rosa M.; Andrade, Paula B.The phenolic profiles of cabbage white butterfly (Pieris brassicae L.; Lepidoptera: Pieridae) at different development stages (larvae, exuviae, and butterfly), its excrements, and its host plant Brassica rapa var. rapa L. were determined by high performance liquid chromatography- diode-array detector-mass spectrometry/mass spectrometry-electrospray ionization (HPLC-DAD-MS/MS-ESI). Twenty-five acylated and nonacylated flavonoid glycosides and ferulic and sinapic acids were identified in host plant, from which only 12 compounds were found in the excrements. In addition, the excrements showed the presence of sulfate flavonoids and other flavonoid glycosides that were not detected in the leaves. In the larvae kept without food for 12 h, only 3 compounds common to the plant material and 2 others, also present in the excrements, were characterized. The results indicate that deacylation, deglycosylation, and sulfating steps are involved in the metabolic process of P. brassicae and that its excrements may constitute a promising source of bioactive compounds, which could be used to take profit of this common pest of Brassica cultures.