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Biblioteca Digital do IPB (53.442 recursos)

A Biblioteca Digital do IPB, tem por objectivo divulgar e permitir o livre acesso à produção científica produzida pela comunidade académica, promovendo a integração, partilha e a visibilidade da informação científica e garantindo a preservação da memória intelectual do Instituto Politécnico de Bragança.

BB - Comunicações a Conferências

Mostrando recursos 1 - 15 de 15

  1. Analysis of phenolic compounds in flowers from wild medicinal plants from northeastern Portugal.

    Barros, Lillian; Dueñas, Montserrat; Carvalho, Ana Maria; Ferreira, Isabel C.F.R.; Santos-Buelga, Celestino
    This study aimed to analyse phenolic compounds in wild medicinal flowers of Crataegus monogyna, Cytisus multiflorus, Malva sylvestris and Sambucus nigra, by HPLC-DAD-ESI/MS. Flavonols and flavones were the main groups in almost all the studied samples. C. multiflorus sample gave the highest levels of flavonoids, being a chrysin derivative the most abundant flavone. C. monogyna revealed the highest concentration in phenolic acids that were not found in C. multiflorus; 5-O-caffeoylquinic acid was the most abundant phenolic acid found in the first species, being a procyanidin trimer also found. Kaempferol-3-O-rutinoside and quercetin-3-O-rutinoside were the main flavonols present in M. sylvestris and...

  2. Docking studies to evaluate mushrooms low molecular weight compounds as inhibitors of the anti-apoptotic protein BCL-2

    Froufe, Hugo J.C.; Abreu, Rui M.V.; Barros, Lillian; Ferreira, Isabel C.F.R.
    Several reports indicate that mushrooms have the ability to promote apoptosis in tumour cell lines, but the mechanism of action is not quite well understood. Inhibition of the interaction between Bcl-2 (anti-apoptotic protein) and pro-apoptotic proteins could be an important step that leads to apoptosis. Therefore, the discovery of compounds with the capacity to inhibit Bcl-2 is an ongoing research topic on cancer therapy. Herein, Autodock4 virtual screening was applied to a dataset of 40 low molecular weight compounds present in mushrooms, using 3D Bcl-2 protein structure (PDB:2XA0) as target. Results suggested that steroids mainly ergosta-4,6,8(14),22-tetraen-3-one, lucidenic lactone, cerevisterol, ganoderic...

  3. Analysis of phenolic, polysaccharidic and lipidic fractions of mushrooms from northeast Portugal

    Heleno, Sandrina A.; Barros, Lillian; Martins, Anabela; Queiroz, Maria João R.P.; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.
    Mushrooms consumption continues to increase due to their functional benefits and presence of bioactive compounds. Herein, phenolic, polysaccharidic and lipidic fractions of wild mushrooms from Northeast Portugal (Coprinopsis atramentaria, Lactarius bertillonii, Lactarius vellereus, Rhodotus palmatus and Xerocomus chrysenteron) were analysed. Protocatechuic, phydroxybenzoic, p-coumaric and cinnamic acids were found in the phenolic fraction; ramnose, xylose, fucose, arabinose, fructose, glucose, manose, mannitol, sucrose, maltose and trehalose were quantified in polysaccharidic fraction; linoleic and stearic (only in Lactarius sp.) acids, and β- and γ-tocopherols were the main compounds in the lipidic fraction.

  4. Effect of electron beam irradiation doses in antioxidant activity and phenolic content of Portuguese chestnuts

    Carocho, Márcio; Antonio, Amilcar L.; Barros, Lillian; Bento, Albino; Kałuska, Iwona; Ferreira, Isabel C.F.R.
    The objective of this study was to analyse the effect of electron beam irradiation (0.5, I and 3 kGy) on the antioxidant activity of Portuguese chestnuts (Castanea saliva Mill.) using different in vitro assays, such as the 2,2- diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power, inhibition of ~-carotene bleaching and inhibition of lipid peroxidation using thiobarbituric acid reactive species (TBARS). Total phenolics were determined by spectrophotometric assays. Irradiated samples seemed to preserve phenolics content and revealed higher antioxidant activity than the control sample. The most indicated dose to maintain antioxidants content, and to increase reducing power and lipid peroxidation inhibition was 1 kGy.

  5. Cistus ladanifer as a source of phenolic compounds with antifungal activity

    Barros, Lillian; Dueñas, Montserrat; Alves, Carlos Tiago; Silva, Sónia; Henriques, Mariana; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.
    A screening of the antifungal potential of phenolic extract of Cistus ladanifer from Northeast Portugal, against Candida species was performed. The extract was characterized by HPLC-DAD-ESI/MS. Phenolic acids and derivatives, ellagic acid derivatives and flavonoids, such as catechins, flavonols and flavones, were found in the sample. The most abundant group was ellagic acid derivatives in which punicalagin gallate, a derivative of punicalagin attached to gallic acid, was found in highest amount. These compounds could be related to the strong inhibition of C. albicans, C. glabrata and C. parapsilosis growth. Moreover, the best antifungal activity was against C. glabrata, where the...

  6. Mushroom extract increases p53 expression and causes cell cycle arrest and apoptosis in a breast cancer cell line

    Vaz, Josiana A.; Tavares, Catarina; Almeida, Gabriela M.; Martins, Anabela; Ferreira, Isabel C.F.R.; Vasconcelos, M. Helena
    Mushrooms are part of the sexual life cycle of particular fungi with specific metabolic pathways, and therefore may contain a largely unexploited source of powerful new pharmaceutical products with potential antitumor properties [1,2]. Furthermore, they may have potential as functional foods. Suillus collinitus is an edible mushroom found in European pine forests. The aim of this work was to study the cytotoxic potential of extracts from this mushroom in various cancer cell lines. Different extracts (methanolic, ethanolic and aqueous) were prepared and extractinduced cell growth inhibition was assessed with the sulforhodamine B assay in four human tumour cell lines (lung, breast, colon and gastric cancer). The methanolic extract...

  7. Effect of soil tillage on diversity and abundance of macrofungi associated with chestnut tree in the Northeast of Portugal

    Baptista, Paula; Martins, Anabela; Lino-Neto, Teresa; Tavares, Rui Manuel
    European chestnut trees (Castanea sativa Mill.) are of great economic importance for wood and fruit production in the northeast of Portugal. In order to maintain the soil free of weeds, farmers traditionally practice several superficial tillages along the year. Phytosanitary problems mainly related with increasing Phytophtora cinnamomi contamination of soils are progressively changing these practices.

  8. Free radical scavenging activity of different almond (Prunus dulcis) varieties

    Barreira, João C.M.; Ferreira, Isabel C.F.R.; Oliveira, M.B.P.P.; Pereira, J.A.
    Reactive oxygen species are known to be implicated in many cell disorders and in the development of many diseases including cardiovascular diseases atherosclerosis, cataracts, chronic inflammation or neurodegenerative diseases such as Alzheimer’s or Parkinson 's disease. Thus, synthetic antioxidants are widely used in the food industry, bur, because of their toxic and carcinogenic effects, their use is being restricted.

  9. Free radical scavenging activity and bioactive compounds of five Agaricus sp. edible mushrooms

    Barros, Lillian; Baptista, Paula; Correia, Daniela M.; Ferreira, Isabel C.F.R.
    Reactive oxygen and free radicals play an important role in cellular injury and the ageing process and also are considered to induce the lipid peroxidation that causes the deterioration of foods. Although organisms have endogenous antioxidant defenses produced during normal cell aerobic respiration against the reactive oxygen species, other antioxidants are taken from the diet, both from natural or synthetic origin.

  10. Lipid peroxidation inhibition, free radical scavenging activity and electrochemical behaviour of a dihydroxylated di(hetero)arylamine

    Ferreira, Isabel C.F.R.; Barros, Lillian; Falcão, Soraia; Vilas-Boas, Miguel; Queiroz, Maria João R.P.
    The skin provides the first line of defense against oxidative damage induced by environmental factors, having an elaborated antioxidant system designed to deal with free radicals and oxidative stress. However, under severe stress conditions this biological response is not sufficient, leading to oxidative damage and, in consequence, to skin disorders, immunosuppresion, premature skin aging and ultimately cancer.

  11. Electrochemical study of diarylamines in the benzo[b]thiophene series

    Ferreira, Isabel C.F.R.; Vilas-Boas, Miguel; Falcão, Soraia; Queiroz, Maria João R.P.
    The search for new molecules with antioxidant properties is a very active domain of research , since they can protect the human body from free radicals and retard the progress of many chronic diseases, such a. vascular diseases, some forms of cancer and oxidative stress responsible for D NA, protein and membrane damage.

  12. QSAR studies on di(hetero)arylamines derivatives of benzo[b]thiophenes as free radical scavengers

    Abreu, Rui M.V.; Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.
    Synthetic antioxidants are widely used in food industry y, but because of toxic and carcinogenic effects revealed by some compounds such as BHA and BHT, their use is being restricted. The pursuit for novel compounds with antioxidant properties gained higher significance, since these compounds may contribute for the prevention of diseases in which free radicals are implicated.

  13. Tocopherols composition of Portuguese wild mushrooms with antioxidant capacity

    Heleno, Sandrina A.; Barros, Lillian; Sousa, Maria João; Martins, Anabela; Ferreira, Isabel C.F.R.
    ln the last years nineteen different mushrooms species from Northeast Portugal, one of the European regions with higher , wild mushrooms diversity, were evaluated, by our team, for their antioxidant properties, in order to valorise them as a source of nutraceuticals [I]. Nevertheless, assuming that the proportion of used mushrooms among the undiscovered and unexamined ones is only 5%, there are thousands of species with possible benefit for mankind. Therefore, we intend to go on in the study of this matrix, documenting their nutraceutical potential and retaining the information for a better management and conservation of this natural resource and related habitats.

  14. Ceramic packaging for mineral waters: a preliminary study

    Pires, Susana; Pereira, Ermelinda; Lopes-da-Silva, M.F.
    The aim of this work is to present a preliminary study for the use of ceramic materials in packaging of natural mineral waters. Handmade ceramic bottles were produced from faience paste and tested for the influence of different glazing areas on the tightness of the ceramic bottles and in physic-chemical stability of bottled natural mineral water during storage (8 days, 15º C). Three ceramic bottles were totally glazed (TG) in both the inner and the outer surface, and other nine bottles were only partially glazed (PG) in the outer surface. Glass bottles were used as control (C). Results showed high...

  15. Basquets from Northeastern Portugal (Trás-os-Montes)

    Carvalho, Ana Maria

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