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Registros recuperados: 26
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A new voltammetric tool for prppolis origin discrimination IPB - Escola Superior Agrária
Falcão, Soraia; Freire, C.; Vilas-Boas, Miguel.
The study of botanical extracts used in traditional medicinal have always captured researchers attention. Propolis (bee glue) is a sticky dark-colored material that honeybees collected from parts of plants, buds and exudates, mix it with wax and other secretions and use it as construction and defense material in the hive. Because its biological and pharmacological properties, is extensively used in foods and beverages with the purpose of maintain or improve human health.
Tipo: ConferenceObject
Ano: 2010 URL: http://hdl.handle.net/10198/5029
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Antioxidant activity of Agaricus sp mushrooms by chemical, biochemical and electrochemical assays IPB - Escola Superior Agrária
Barros, Lillian; Falcão, Soraia; Baptista, Paula; Freire, C.; Vilas-Boas, Miguel; Ferreira, Isabel C.F.R..
The antioxidant activity of five Agaricus sp. mushrooms was screened through chemical, biochemical and electrochemical techniques. The chemical assays allowed an evaluation of their reducing power and radical scavenging activity, while biochemical assays evaluated the lipid peroxidation inhibition capacity, using erythrocytes and brain cells as models; the electrochemical characterization of the mushrooms extracts were performed by cyclic voltammetry and differential pulse voltammetry. All the species proved to have antioxidant activity and particularly, by the electrochemical techniques, it has been shown that mushroom extracts revealed similar electrochemical responses, suggesting similar electroactive chemical composition, and oxidation potentials more...
Tipo: Article Palavras-chave: Agaricus sp mushrooms; Electrochemical assays; Lipid peroxidation inhibition.
Ano: 2008 URL: http://hdl.handle.net/10198/814
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Characterization of new phenolic derivatives in Portuguese propolis by electrospray mass spectroscopy IPB - Escola Superior Agrária
Falcão, Soraia; Vilas-Boas, Miguel; Freire, C.; Domingues, M.R.M.; Cardoso, Susana M..
This research outlines an extensive characterization of the phenolic composition of a propolis sample from the northeast of Porto gal. For that, ao ethanolic extract was prepared, fractionated by HPLC and the identification of the phenolic compounds was done by electro spray mass spectrometry in the negative mode. This technical approach allowed the identification of 37 phenolic compounds in the Portoguese propolis sample, including seven that were described for the first time. Two of these new compounds had [M-Hr ions at mlz 403, aod the others had [M-Hr ions at mlz 433, mlz 461, mlz 417, mlz 475, and mlz 565. In general, the molecular weight of these compounds was higher thao the common phenolic compounds of propolis aod their fragmentation pattern...
Tipo: ConferenceObject Palavras-chave: Propolis; Phenolic compounds; Mass spectrometry; Electrospray ionization.
Ano: 2009 URL: http://hdl.handle.net/10198/5265
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Characterization of new phenolic derivatives in Portuguese propolis by electrospray mass spectroscopy IPB - Escola Superior Agrária
Falcão, Soraia; Vilas-Boas, Miguel; Freire, C.; Domingues, M.R.M.; Cardoso, Susana M..
Propolis is a resinous substance collected by honeybees from tree buds, comprising plant exudates, secreted substances from bee metabolism, pollen and waxes. This product is widely used in traditional medicine [I] and it has recently gained popularity as a health food supplement. Currently, it is extensively used in foods and beverages, and it is claimed to improve health and prevent diseases such as inflammation, heart disease, diabetes and cancer.
Tipo: ConferenceObject
Ano: 2009 URL: http://hdl.handle.net/10198/5682
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Characterization of phenolic compounds of OMW: toxicity and degrability by yeasts IPB - Escola Superior Agrária
Gonçalves, Cristiana; Ferreira, João P.; Lopes, Marlene; Falcão, Soraia; Peres, António M.; Cardoso, Susana M.; Belo, Isabel.
The olive oil extraction, performed by the 3-phases process, results on a large amount of an effluent, usually known as Olive Mill Wastewater (OMW). It is mainly produced in the Mediterranean area, with the exception of Spain that is one of the major producers but mostly use the 2-phases process. OMW represents a major environmental problem due to its high organic content, being characterized by a strong acidic smell and an intensive brown to dark color due to the presence of biodegradable, recalcitrant and biostatic compounds. OMW phytotoxicity can be attributed to the phenolic compounds (Lanciotti et al, 2005). Owing to their instability, OMW phenols tend to polymerise during storage into condensed high-molecular-weight polymers that are difficult to...
Tipo: ConferenceObject Palavras-chave: Lipolytic yeasts; Phenol compounds; Lipase; OMW.
Ano: 2008 URL: http://hdl.handle.net/10198/5769
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Effect of microwave heating with different exposure times on physical and chemical parameters of olive oil IPB - Escola Superior Agrária
Malheiro, R.; Oliveira, I.; Vilas-Boas, Miguel; Falcão, Soraia; Bento, Albino; Pereira, J.A..
This study reflects the effect of different microwave heating times (1, 3, 5, 10 and 15 min) on physical and chemical characteristics of three Portuguese olive oils from three protected designation of origin (PDO), "Azeite de Tras-os-Montes PDO", "Azeites da Beira Interior PDO", and "Azeite de Moura PDO". The parameters evaluated were free acidity, peroxide value, specific extinction coefficients (K-232 and K-270), color and chlorophylls and carotenoids content. A differential pulse voltammeter was also used to monitor the changes in a-tocopherol content. The results showed that microwave heating produce losses in the quality of the different analysed olive oils. The heating time did not promote the occurrence of hydrolysis in the samples since no changes...
Tipo: Article Palavras-chave: Microwave heating; Olive oil; Quality parameters; Alpha-tocopherol.
Ano: 2009 URL: http://hdl.handle.net/10198/1240
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Electrochemical evaluation of the redox-properties of diarylamines in the 2,3-dimethylbenzo[b]thiophene series IPB - Escola Superior Agrária
Falcão, Soraia; Abreu, Rui M.V.; Ferreira, Isabel C.F.R.; Vilas-Boas, Miguel; Queiroz, Maria João R.P..
Tipo: ConferenceObject
Ano: 2008 URL: http://hdl.handle.net/10198/3531
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Electrochemical study of diarylamines in the benzo[b]thiophene series IPB - Escola Superior Agrária
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.
Tipo: ConferenceObject
Ano: 2007 URL: http://hdl.handle.net/10198/3710
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Evaluation of the antioxidant capacity of edible wild mushrooms by cyclic voltammetry IPB - Escola Superior Agrária
Falcão, Soraia; Barros, Lillian; Ferreira, Isabel C.F.R.; Freire, C.; Vilas-Boas, Miguel.
The problems of oxygen metabolism in humans constantly attract the attention. especially now that is obvious that the excess of oxygen and its reactive species cause radical-chain oxidation processes in cellular tissues, resulting in fast aging, cell destruction and incurable diseases. Cells are equipped with several defense systems which act through a variety of mechanisms, one of those is the protection through low-molecular weight antioxidants. like phenolic compounds
Tipo: ConferenceObject
Ano: 2008 URL: http://hdl.handle.net/10198/3553
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Insights in the antioxidant activity of diarylamines from the 2,3-dimethylbenzo[b]thiophene by the redox profile IPB - Escola Superior Agrária
Abreu, Rui M.V.; Falcão, Soraia; Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Vilas-Boas, Miguel.
Cyclic voltammetry was used to evaluate the antioxidant activity of 7-aryl or 7-heteroarylamino-2,3-dimethylbenzo[b]thiophenes previously synthesized by some of us, comparing their oxidation potentials with those of the well-known synthetic standards (BHA, BHT). Compounds with electron-donating groups on the arylamine moiety have lower Ep/2 than compounds with electron-withdrawing groups or electron-deficient rings (pyridines). The position of the methoxy group on the arylamine moiety also changes the oxidation potential: lower Ep/2 for the diarylamines with methoxy groups in the para position. Comparing the first peak potential with the ones of BHA and BHT, the diarylamine compounds show lower oxidation potential, and therefore higher reducing power. A...
Tipo: Article Palavras-chave: Benzo[b]thiophene; Diarylamines; Antioxidant properties; Electrochemical assays.
Ano: 2009 URL: http://hdl.handle.net/10198/2717
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Insights into olive mill wastewaters phenolic compounds IPB - Escola Superior Agrária
Cardoso, Susana M.; Falcão, Soraia; Peres, António M.; Pereira, Olívia; Domingues, M.R.M..
Olive mill wastewaters (OMW) have high contents of phenolic compounds, which possess a wide range of biological activities. Therefore, OMW are regarded as a potent source of biophenols for food and pharmaceutical industries. Important biophenols occurring in OMW include tyrosol, oleuropein and hydroxytyrosol, with the latter being commercially exploited as a novel ingredient with a broad use in dietary supplements, functional foods and natural cosmetics [1 ,2]. Nevertheless, the phenolic profile of OMW is extremely complex and many compounds remain unknown. The elucidation of new phenolic compounds in this matrix is an important task to encourage the search of more bioactive compounds. Indeed, hydroxytyrosyl acyclodihydroelenolate and p-coumaroyl-6' -...
Tipo: ConferenceObject
Ano: 2011 URL: http://hdl.handle.net/10198/6403
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Insigths in the phenolic composition of portuguese própolis IPB - Escola Superior Agrária
Falcão, Soraia; Cardoso, Susana M.; Domingues, M.R.M.; Vilas-Boas, Miguel.
The chemical composition of propolis is highly variable, depending strongly on thc plant sources available to the bees at different locations, the geographic and climatic characteristics of these locations, I n the temperate zone, propol is originates mostly Ii'om bud exudates of poplar trees (Populus spp .. section Aigciros), For this reason, European propolis contains the typical 'poplar bud' phenolics: flavonoid aglicones (flavones and flavanones), phenolic acids and their esters.
Tipo: ConferenceObject
Ano: 2009 URL: http://hdl.handle.net/10198/5026
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Is Portugal a country of propolis diversity? IPB - Escola Superior Agrária
Falcão, Soraia; Batista, V.; Cardoso, Susana M.; Domingues, M.R.M.; Vilas-Boas, Miguel.
Portugal geographical situation and therefore their floral diversity points towards the existence of typical propolis from temperate zones, where bud exudates of poplar trees (Populus species) are the main source of this honeybee product With the exception of Madeira and Azores Islands, where the floral diversity could present significant differ· ences, it would be expected to find a product rich in flavonoid aglycones (flavones and flavanones), phenolic acids and their esters, characteristic of European propolis, In order to clarify this issue, several propolis samples were collected along the country, including islands, and their colour, ashes, content of wax, phenols and flavonoids, as also their phenolic profile, were determined,
Tipo: ConferenceObject
Ano: 2010 URL: http://hdl.handle.net/10198/5027
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Lipid peroxidation inhibition, free radical scavenging activity and electrochemical behaviour of a dihydroxylated di(hetero)arylamine IPB - Escola Superior Agrária
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.
Tipo: ConferenceObject
Ano: 2007 URL: http://hdl.handle.net/10198/3715
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New biophenols in olive mill wastewaters IPB - Escola Superior Agrária
Cardoso, Susana M.; Falcão, Soraia; Peres, António M.; Domingues, M.R.M..
Olive mill wastewaters (OMW) have been attracting the attention of food and pharmaceutical industries, as it is a potential source of biophenols with a wide range of biological activities. This effluent produced in the olive oil industry contains approximately half of the total phenolic compounds of the olive fruit and it is currently exploited for industrial extraction of hydroxytyrosol [1]. Still, the phenolic composition of OMW is extremely complex, and many compounds are yet unidentified. In this context, the identification of unknown phenolic compounds can encourage the search of new bioactive compounds in OMW and contribute to further valorize this waste. In the present work, six new phenolic compounds were identified in Portuguese olive mill...
Tipo: ConferenceObject Palavras-chave: Phenolic compounds; Olive mill wastewaters; Oleuropein; Ligstroside.
Ano: 2010 URL: http://hdl.handle.net/10198/3772
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Northeast Portuguese propolis protects against neurotoxic events in cerebral cortical neurons IPB - Escola Superior Agrária
Cardoso, Susana M.; Ribeiro, M.; Ferreira, I.L.; Falcão, Soraia; Vilas-Boas, Miguel; Rego, A.C..
Propolis is a sticky substance that honeybees manufacture by mixing secreted substances from their metabolism with plant exudates, pollen and waxes. This product has been used in folk medicine for centuries. Currently, it is extensively used in foods and beverages and is claimed to improve human health. Propolis is known to have a wide range of biological properties, including anti-microbial, anti-inflammatory, anti-tumoral and antioxidative activities [1]. Indeed, oxidative stress and apoptosis has been implicated in both aging and several neurodegenerative disorders. The chemical composition of propolis is very complex, varies with geographic origin, depending on the local flora and typically contains resin composed of flavonoids and related phenolic...
Tipo: ConferenceObject
Ano: 2010 URL: http://hdl.handle.net/10198/5028
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O efeito do timol como acaricida alternativo na qualidade do mel em modo de preparação biológica IPB - Escola Superior Agrária
Falcão, Soraia; Garção, H.; Barros, Lillian; Álvares, R.; Vilas-Boas, Miguel.
Para a apicultura em modo de produção biológica, MPB, o uso de acaricidas é legalmente restringido aos óleos essenciais e a alguns ácidos orgânicos que se podem encontrar entre os vários constituintes do mel, pois não é permitido adicionar qualquer composto sintético à sua composição. As principais alternativas no controlo da varroa são o timol, o ácido oxálico e o ácido fórmico, substâncias regularmente usadas em todo o mundo com bons resultados.
Tipo: ConferenceObject
Ano: 2006 URL: http://hdl.handle.net/10198/5878
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Oleuropein/ligstroside isomers and their derivatives in Portuguese olive mill wastewaters IPB - Escola Superior Agrária
Cardoso, Susana M.; Falcão, Soraia; Peres, António M.; Domingues, M.R.M..
Olive mill wastewaters (OMW) are a potential source of biophenols, but they have a complex composition with many unknown phenolics. The analysis of purified methanol extracts from two Portuguese OMW by electrospray mass spectrometry in the negative mode showed [M-H]- ions at m/z 539 and m/z 523, corresponding respectively to oleuropein and ligstroside isomers which contain the glucose unit linked to its aromatic moiety. Also, the fragmentation pathway of the [M-H]- ions at m/z 863, 685 and 847 indicated the presence of a diglucoside derivative of the oleuropein isomer and of mono- and diglucosides of the ligstroside isomer, respectively. Moreover, the two OMW samples contained an elenoic derivative of the ion at m/z 685 and a degradation product (m/z 453)...
Tipo: Article Palavras-chave: Phenolic compounds; Biophenols; Olive mill wastewaters; Oleuropein; Ligstroside.
Ano: 2011 URL: http://hdl.handle.net/10198/6405
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Phenolic characterization of Northeast Portuguese propolis: usual and unusual compounds IPB - Escola Superior Agrária
Falcão, Soraia; Vilas-Boas, Miguel; Estevinho, Leticia M.; Barros, Cristina; Domingues, M.R.M.; Cardoso, Susana M..
In this study, an ethanolic extract from Portuguese propolis was prepared, fractionated by highperformance liquid chromatography, and the identification of the phenolic compounds was done by electrospray mass spectrometry in the negative mode. This technical approach allowed the identification of 37 phenolic compounds, which included not only the typical phenolic acids and flavonoids found in propolis from temperate zones but also several compounds in which its occurrence have never been referred to in the literature. Four of the novel phenolic compounds were methylated and/or esterified or hydroxylated derivatives of common poplar flavonoids, although six peculiar derivatives of pinocembrin/pinobanksin, containing a phenylpropanoic acid derivative moiety...
Tipo: Article Palavras-chave: Phenolic compounds; Flavonoids; Phenolic acids; Mass spectrometry; Electrospray ionization.
Ano: 2010 URL: http://hdl.handle.net/10198/3608
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Polymeric biophenols in olive mill wastewaters IPB - Escola Superior Agrária
Cardoso, Susana M.; Falcão, Soraia; Peres, António M.; Pereira, Olívia; Domingues, M.R.M..
Tipo: ConferenceObject
Ano: 2011 URL: http://hdl.handle.net/10198/6413
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