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Abreu R.M.V.,Instituto Polytechnic Of Bragana | Abreu R.M.V.,University of Trás os Montes e Alto Douro | Ferreira I.C.F.R.,Instituto Polytechnic Of Bragana | Calhelha R.C.,Instituto Polytechnic Of Bragana | And 6 more authors.
European Journal of Medicinal Chemistry | Year: 2011

Hepatocellular carcinoma (HCC) is a highly complex cancer, resistant to commonly used treatments and new therapeutic agents are urgently needed. A total of thirty-two thieno[3,2-b]pyridine derivatives of two series: methyl 3-amino-6-(hetero)arylthieno[3,2-b]pyridine-2-carboxylates (1a-1t) and methyl 3-amino-6-[(hetero)arylethynyl]thieno[3,2-b]pyridine-2-carboxylates (2a-2n), previously prepared by some of us, were evaluated as new potential anti-HCC agents by studying their in vitro cell growth inhibition on human HepG2 cells and hepatotoxicity using a porcine liver primary cell culture (PLP1). The presence of amino groups linked to a benzene moiety emerges as the key element for the anti-HCC activity. The methyl 3-amino-6-[(3-aminophenyl)ethynyl] thieno[3,2-b]pyridine-2-carboxylate (2f) is the most potent compound presenting GI50 values on HepG2 cells of 1.2 μM compared to 2.9 μM of the positive control ellipticine, with no observed hepatotoxicity (PLP1 GI 50 > 125 μM against 3.3 μM of ellipticine). Moreover this compound changes the cell cycle profile of the HepG2 cells, causing a decrease in the % of cells in the S phase and a cell cycle arrest in the G2/M phase. QSAR studies were also performed and the correlations obtained using molecular and 1D descriptors revealed the importance of the presence of amino groups and hydrogen bond donors for anti-HCC activity, and hydrogen bond acceptors for hepatotoxicity. The best correlations were obtained with 3D descriptors belonging to different subcategories for anti-HCC activity and hepatotoxicity, respectively. These results point to different molecular mechanisms of action of the compounds in anti-HCC activity and hepatotoxicity. This work presents some promising thieno[3,2-b]pyridine derivatives for potential use in the therapy of HCC. These compounds can also be used as scaffolds for further synthesis of more potent analogs. © 2011 Elsevier Masson SAS. All rights reserved.

Barros L.,Instituto Polytechnic Of Bragana | Duenas M.,Grupo de Investigacion en Polifenoles GIP USAL | Ferreira I.C.F.R.,Instituto Polytechnic Of Bragana | Maria Carvalho A.,Instituto Polytechnic Of Bragana | Santos-Buelga C.,Grupo de Investigacion en Polifenoles GIP USAL
Food Chemistry | Year: 2011

In some Mediterranean areas traditional wild greens are responsible for a significant percentage of total dietary antioxidant intakes. Asparagus acutifolius L. (wild asparagus), Bryonia dioica Jacq. (white bryony) and Tamus communis L. (black bryony) are important examples of those edible wild greens widely consumed. This study aimed to determine the phenolic profile and composition of edible vernal early shoots of those species. Wild asparagus and black bryony revealed glycosides of flavonols as the main phenolic compounds, while white bryony contained C-glycosylated flavones. Black bryony was the wild green that possessed the highest content of phenolic compounds (2200 mg/kg). Amongst the 11 flavonols found in this sample, kaempferol glycosides were the main compounds (1760 mg/kg). In the sample of wild asparagus, quercetin 3-O-rutinoside was the main flavonol found (263 mg/kg). Five flavones and one flavonol were found in the white bryony sample, apigenin 6-C-glucoside-7-O- glucoside being the major compound (1550 mg/kg). © 2011 Elsevier Ltd. All rights reserved.

Vaz J.A.,Instituto Polytechnic Of Bragana | Vaz J.A.,University of Porto | Barros L.,Instituto Polytechnic Of Bragana | Barros L.,Polytechnic Institute of Coimbra | And 6 more authors.
Food Chemistry | Year: 2011

Mushrooms have become attractive as functional foods and as a source of physiologically beneficial bioactive compounds. Herein, we describe and compare the chemical constituents (phenolic compounds, macronutrients, sugars, fatty acids, tocopherols and ascorbic acid) of four wild edible mushrooms widely appreciated in gastronomy: Armillaria mellea (Vahl) P. Kumm., Calocybe gambosa (Fr.) Donk, Clitocybe odora (Fr.) P. Kumm., Coprinus comatus (O.F. Müll.) Pers. Furthermore, the antioxidant activity of their water soluble polysaccharidic and ethanolic fractions was studied by three different in vitro assays. C. comatus revealed the highest concentrations of sugars (43.23/100 g dry weight), PUFA (77.46%), phenolic compounds (45.02 mg/kg), tocopherols (301.03 μg/100 g) and, among all of the fractions tested, its ethanolic fraction showed the highest antioxidant activity (EC50 < 2.6 mg/ml). C. odora revealed one of the highest ascorbic acid (172.65 mg/100 g) contents and its water soluble polysaccharidic fraction showed the best antioxidant properties (EC50 < 3.6 mg/ml) among the polysaccharidic fractions. The studied mushrooms species could potentially be used in well-balanced diets and as a source of bioactive compounds. © 2010 Elsevier Ltd. All rights reserved.

Barros L.,Instituto Polytechnic Of Bragana | Barros L.,University of Salamanca | Duenas M.,University of Salamanca | Dias M.I.,Instituto Polytechnic Of Bragana | And 3 more authors.
Food Chemistry | Year: 2012

Coriandrum sativum L. is a source of a variety of polyphenols and other phytochemicals, related to its high antioxidant activity and to its use for indigestion, rheumatism, and prevention of lipid peroxidation damage. Plant cell cultures are a means to study or to produce some active metabolites, such as polyphenols. This technique was applied to the investigation of coriander, and a detailed analysis of individual polyphenols in vivo and in vitro grown samples was performed. The in vivo vegetative parts showed quercetin derivatives as the main flavonoids and quercetin-3-O-rutinoside (3296 mg/kg dw) was the main polyphenol found in this part of coriander. The fruits revealed only phenolic acids and derivatives, caffeoyl N-tryptophan hexoside (45.33 mg/kg dw) being the most abundant phenolic derivative. In vitro samples also gave a high diversity of polyphenols, being C-glycosylated apigenin (2983 mg/kg dw) the main compound. Anthocyanins were only found in clone A, which was certainly related to its purple pigmentation, and peonidin-3-O-feruloylglucoside-5-O-glucoside was the major anthocyanin found (1.70 μg/kg dw). In vitro culture can be used to explore new industrial, pharmaceutical, and medicinal potentialities, such as the production of secondary metabolites like flavonoids. © 2011 Elsevier Ltd. All rights reserved.

Mesquita D.P.,IBB Institute for Biotechnology And Bioengineering | Dias O.,IBB Institute for Biotechnology And Bioengineering | Elias R.A.V.,Instituto Polytechnic Of Bragana | Amaral A.L.,IBB Institute for Biotechnology And Bioengineering | And 2 more authors.
Microscopy and Microanalysis | Year: 2010

The properties of activated sludge systems can be characterized using image analysis procedures. When these systems operate with high biomass content, accurate sludge characterization requires samples to be diluted. Selection of the best image acquisition magnification is directly related to the amount of biomass screened. The aim of the present study was to survey the effects of dilution and magnification on the assessment of aggregated and filamentous bacterial content and structure using image analysis procedures. Assessments of biomass content and structure were affected by dilutions. Therefore, the correct operating dilution requires careful consideration. Moreover, the acquisition methodology comprising a 100 × magnification allowed data on aggregated and filamentous biomass to be determined and smaller aggregates to be identified and characterized, without affecting the accuracy of lower magnifications regarding biomass representativeness. © Microscopy Society of America 2010.

Peres A.M.,Polytechnic Institute of Coimbra | Peres A.M.,Instituto Polytechnic Of Bragana | Dias L.G.,Instituto Polytechnic Of Bragana | Veloso A.C.A.,IBB Institute for Biotechnology And Bioengineering | And 4 more authors.
Talanta | Year: 2011

An all-solid-state potentiometric electronic tongue with 36 polymeric membranes has been used for the first time to detect gliadins, which are primarily responsible for gluten intolerance in people suffering from celiac disease. A linear discriminant model, based on the signals of 11 polymeric membranes, selected from the 36 above using a stepwise procedure, was used to semi-quantitatively classify samples of a "Gluten-free" foodstuff (baby milked flour), previously contaminated with known amounts of gliadins (<10, 20-50 or >50 mg/kg), as "Gluten-free", "Low-Gluten content" or "Gluten-containing". For this food matrix, the device had sensitivity towards gliadins of 1-2 mg/kg and overall sensitivity and specificity of 77% and 78%, respectively. Moreover, the device never identified an ethanolic extract containing gliadins as "Gluten-free". Finally, the system also allowed distinguishing "Gluten-free" and "Gluten-containing" foodstuffs (15 foods, including breads, flours, baby milked flours, cookies and breakfast cereals) with an overall sensitivity and specificity greater than 83%, using the signals of only 4 selected polymeric membranes (selected using a stepwise procedure). Since only one "Gluten-containing" foodstuff was misclassified as "Gluten-free", the device could be used as a preliminary tool for quality control of foods for celiac patients. © 2010 Elsevier B.V. All rights reserved.

Pereira O.R.,Polytechnic Institute of Coimbra | Silva A.M.S.,University of Aveiro | Domingues M.R.M.,University of Aveiro | Cardoso S.M.,Polytechnic Institute of Coimbra | Cardoso S.M.,Instituto Polytechnic Of Bragana
Food Chemistry | Year: 2012

The phenolic composition of the ethanolic extract obtained from the flowers of the medicinal plant Cytisus multiflorus has been elucidated by high performance liquid chromatography, electrospray mass spectrometry and nuclear magnetic resonance analysis. The extract was mainly composed of flavones, including the common chrysin, orientin, luteolin-5-O-glucoside, luteolin-7-O-glucoside, apigenin and apigenin-7-O-glucoside, which appeared as minor components. The major flavone in the extract was chrysin-7-O-β-d- glucopyranoside, and it also contained moderate amounts of a dihydroxyflavone isomer of chrysin, as well as of 2″-O-pentosyl-6-C-hexosyl-luteolin, 2″-O-pentosyl-8-C-hexosyl-luteolin and 6″-O-(3-hydroxy-3- methylglutaroyl)-2″-O-pentosyl-C-hexosyl-apigenin, which are not commonly found in the Fabaceae family. Other novel phenolic compounds found in the ethanolic extract of C. multiflorus comprised the flavones 2″-O-pentosyl- 6-C-hexosyl-apigenin, 2″-O-pentosyl-8-C-hexosyl-apigenin and 6″-O-(3-hydroxy-3-methylglutaroyl)-2″-O-pentosyl-C-hexosyl-luteolin. The assessment of the biological activities of the main compounds of this extract are now keen, in order to determine their relevance in the beneficial properties of the plant. © 2011 Elsevier Ltd. All rights reserved.

Barros L.,Instituto Polytechnic Of Bragana | Cabrita L.,Instituto Polytechnic Of Bragana | Boas M.V.,Instituto Polytechnic Of Bragana | Carvalho A.M.,Instituto Polytechnic Of Bragana | Ferreira I.C.F.R.,Instituto Polytechnic Of Bragana
Food Chemistry | Year: 2011

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, based on chemical, biochemical and electrochemical methods. F. ulmaria was found to be richest in antioxidant phytochemicals, such as phenolics (228 mg GAE/g DW), flavonoids (62 mg CE/g DW), ascorbic acid (2700 μg/g DW) and tocopherols (497 μg/g DW). The antioxidant activity was found to vary in the order: F. ulmaria > S. nigra > C. multiflorus, irrespective of the analysis method. Electrochemical methods have proven to be rapid and inexpensive techniques to characterise the antioxidant activity of plant extracts. © 2011 Elsevier Ltd. All rights reserved.

Pereira E.,Instituto Polytechnic Of Bragana | Pereira E.,Polytechnic Institute of Coimbra | Barros L.,Instituto Polytechnic Of Bragana | Barros L.,Polytechnic Institute of Coimbra | And 3 more authors.
Food Chemistry | Year: 2012

Mushrooms have been valued as highly tasty/nutritional foods and as a source of compounds with medicinal properties. The huge mushrooms reservoir of Northeast Portugal must be chemically and nutritionally characterized for the benefit of the local populations and for the genetic conservation of wild macrofungi. Herein, a chemical, nutritional and bioactive inventory of potentially interesting species (and not yet characterized in the literature) from different habitats (Castanea sativa, Pinus sp., Quercus sp., fields and mixed stands) was performed. Besides macronutrients with a well-balanced proportion, the studied wild mushrooms also have important micronutrients (vitamins) and non-nutrients (phenolics) with bioactive properties such as antioxidant potential. Furthermore, being a source of important antioxidants the wild species, mainly Suillus variegatus (Pinus sp. habitat), Boletus armeniacus (C. sativa habitat), Clavariadelphus pistillaris (Quercus sp. habitat), Agaricus lutosus (fields) and Bovista aestivalis (mixed stands), can be used in human diet as nutraceuticals and/or functional foods maintaining and promoting health, longevity and life quality. © 2011 Elsevier Ltd. All rights reserved.

Dias L.G.,Instituto Polytechnic Of Bragana | Peres A.M.,Instituto Polytechnic Of Bragana | Peres A.M.,Polytechnic Institute of Coimbra | Barcelos T.P.,Instituto Polytechnic Of Bragana | And 2 more authors.
Sensors and Actuators, B: Chemical | Year: 2011

A potentiometric electronic tongue with 36 cross-sensibility lipo/polymeric membranes was built and applied for semi-quantitative and quantitative analysis of non-alcoholic beverages. A total of 16 commercial fruit juices (e.g., orange, pineapple, mango and peach) from five different brands were studied. In the semi-quantitative approach, the signal profiles recorded by the device were used together with a stepwise linear discriminant analysis to differentiate four beverage groups with different fruit juice contents: >30%, 14-30%, 6-10% and <4%. The model, with two discriminant functions based on the signals of only four polymeric membranes, explained 99% of the total variability of experimental data and was able to classify the studied samples into the correct group with an overall sensibility and specificity of 100% for the original data, and greater than 93% for the cross-validation procedure. The signals were also used to obtain MLR and PLS calibration models to estimate and predict the concentrations of fructose and glucose in the soft drinks. The linear models established were based on the signals recorded by 16 polymeric membranes and were able to estimate and predict satisfactorily (cross-validation) the concentrations of the two sugars (R2 greater than 0.96 and 0.84, respectively). © 2010 Elsevier B.V. All rights reserved.

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