Browsing by Author "Pintado, M. E."
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- Acceptance of exotic beverages with health benefits in Europe: a crosscountry comparison of hibiscus productsPublication . Monteiro, M. J. P.; Costa, A. I. A.; Fliedel, G.; Cisse, M.; Tomlins, K.; Pintado, M. E.
- Acidifying and aromatic properties of enterococcus strains in ovine and bovine milksPublication . Pimentel, L. L.; Soares, J. C.; Pintado, M. E.; Pintado, Ana I. E.; Gomes, Ana M. P.; Ferreira, A. C.; Malcata, F. X.
- Advances on pilot plant and cooking lab facilities for training and educationPublication . Silva, Cristina L. M.; Guimarães, Marta; Hogg, C.; Pintado, M. E.
- Advances on pilot plant and cooking lab facilities for training and educationPublication . Silva, Cristina L. M.; Guimarães, Marta; Hogg, C.; Pintado, M. E.
- As alterações da pintura mural a fresco no Norte de PortugalPublication . Marco, Alexandra; Vieira, Eduarda; Caetano, Joaquim I.; Pintado, M. E.; Moreira, Patrícia R.Apesar de grande parte do estudo da pintura mural a fresco estar por efectuar, esta expressão artística desenvolveu-se em Portugal com intensa actividade entre os séculos XV e XVI. No Norte de Portugal, devido a uma maior escassez da matéria-prima cal, a pintura apresenta frequentemente apenas uma camada de reboco, extremamente delgada, por oposição à usual utilização de duas camadas. O suporte destas pinturas foi quase exclusivamente o granito, uma rocha com boas propriedades fisico-químicas para a execução de revestimentos de cal e tipologias decorativas associadas. A degradação das pinturas murais, além da acção humana, está relacionada com a alta porosidade do substrato, sua natureza carbonatada, a presença de água nas paredes e as condições ambientais. A conjugação destes agentes é responsável pela perda significativa de área pictórica e das manchas negras inestéticas por biocolonização. No Norte de Portugal vários frescos dos séculos XV-XVI evidenciam esta alteração que mancha tanto os suportes como as pinturas – alteração de grande impacto estético que domina a atenção dos conservadores-restauradores na metodologia das intervenções. Apesar do substrato dos frescos ser principalmente inorgânico, o depósito de partículas atmosféricas e a absorção de água por capilaridade, pode promover o desenvolvimento de fungos, que segregam metabolitos como ácidos orgânicos. Diversos fungos também produzem pigmentos que variam em função da espécie, dos constituintes da pintura mural, dos factores ambientais, entre outros. O tratamento com biocidas é eficaz na erradicação dos organismos, mas não na remoção da pigmentação resultante do seu crescimento. Para assegurar intervenções éticas e sustentáveis, é fundamental conhecer tanto a natureza e comportamento dos materiais, como o seu estado de conservação actual e a identificação dos agentes e factores de degradação. Este trabalho pretende apresentar um estado da arte para este tema, incluindo os métodos mais comuns de abordagem em Conservação e Restauro para este problema.
- Anthocyanin extraction from plant tissues: a reviewPublication . Silva, S.; Costa, E. M.; Calhau, C.; Morais, R. M.; Pintado, M. E.Anthocyanins have gathered the attention of the scientific community mostly due to their vast range of possible applications. They have been the center point of the research in many different fields, among which is food development, where their innate coloring, antioxidant capacity, and biological potential open interesting venues to the development of new food additives and functional foodstuffs. As the range of application grows, so does the necessity to obtain these compounds, and since they are naturally occurring, the most common way to obtain anthocyanins is to extract them from different plant sources, such as fruits and flowers. Several efforts have been made to develop methods that allow for better extraction yields and higher purification rates therefore this review aims to compile the information regarding extraction and purification procedures in a comprehensive manner.
- Anti-biofilm potential of phenolic acids: the influence of environmental pH and intrinsic physico-chemical propertiesPublication . Silva, Sara; Costa, Eduardo M.; Horta, Bruno; Calhau, Conceição; Morais, R. M. S. C.; Pintado, M. E.Phenolic acids are a particular group of small phenolic compounds which have exhibited some anti-biofilm activity, although the link between their activity and their intrinsic pH is not clear. Therefore, the present work examined the anti-biofilm activity (inhibition of biomass and metabolic activity) of phenolic acids in relation to the environmental pH, as well as other physico-chemical properties. The results indicate that, while Escherichia coli was not inhibited by the phenolic acids, both methicillin resistant Staphylococcus aureus and methicillin resistant Staphylococcus epidermidis were susceptible to the action of all phenolic acids, with the pH playing a relevant role in the activity: a neutral pH favored MRSE inhibition, while acidic conditions favored MRSA inhibition. Some links between molecular polarity and size were associated only with their potential as metabolic inhibitors, with the overall interactions hinting at a membrane-based mechanism for MRSA and a cytoplasmic effect for MRSE.
- Anti-proliferative, anti-inflammatory, anti-ulcerogenic and wound healing properties of chitosanPublication . Tavaria, Freni; Jorge, Michelle P.; Lúcia T.G. Ruiz, Ana; Pintado, M. E.; Carvalho, João E.In this study, anti-inflammatory, wound healing and anti-ulcerogenic properties of chitosan were evaluated ‘in vivo’ using wistar rats and swiss adult mice and the anti-proliferative activity was tested ‘in vitro’. The tested chitosans displayed no anti-proliferative or anti-inflammatory properties. The cytotoxic activity of chitosan was found to be non-existent towards eight tumoral cell lines and no significant differences were found in the ear edema (anti-inflammatory model) induced by croton oil and chitosan groups. However, chitosan showed good anti-ulcerative and wound healing abilities. Low molecular weight (LMW) chitosan effectively reduced ulcerative wounds induced by ethanol, while high molecular weight (HMW) chitosan helped retain the stomachal folds rendering a gastro protective effect. These results suggest that chitosan can potentially be used in the treatment of peptic ulcers. HMW chitosan also potentiated the healing process both in normal and diabetic rats, probably without induction of fibroblast growth but via collagen synthesis
- Antibiofilm properties of quercus ilex acorn extracts against MRSA and MSSAPublication . Silva, Sara; Costa, Eduardo; Costa, Maria do Rosário; Pereira, Miguel; Coelho, Marta; Pintado, M. E.Biofilms are complex structures that grant microorganisms some survival advantages namely nutrient availability and antimicrobial resistance. As such, the need to find new antimicrobial compounds that are active against these structures is in great demand. Phenolic compounds are described as capable of interfering with the cellular membrane and interact with both intracellular and extracellular proteins, thus they may present an alternative to traditional biofilm control. Acorns have been reported as a rich source of phenolic compounds, particularly tannins, and thus are likely to exhibit some of the properties that are associated with these compounds, namely antimicrobial properties. As such, the present work aimed to assess the antibiofilm properties of hydroethanolic, phenolic rich, acorn extracts against two Staphylococcus aureus strains, one sensitive (MSSA) and one resistant (MRSA) to methicillin. To do so, both microorganisms were exposed to two different sub-MIC concentrations of extracts produced using acorn shells (fresh and roasted) and cotyledons (fresh or roasted). The amount of biofilm produced in the presence of the extracts, after 48 h, was then determined using the microtiter - crystal violet based assay. The results obtained showed that MRSA was the most sensitive strain, with biomass inhibition percentages ranging from 60 to 70%, while for MSSA all inhibition percentages ranged between 29 to 57%. No significant differences between shell and cotyledon were found when considering the results obtained for MRSA. The same was not observed for MSSA where biomass production was significantly higher for roasted cotyledon (2.5 to 20.6%). For this microorganism, it was interesting to note that lower concentrations of the extracts appeared to possess a higher antibiofilm activity (0.7 times more active for fresh or roasted shell extract and 0.6 times more active for fresh cotyledon extracts). Overall, these results indicate that Quercus ilex acorns possess the potential to be an effective means of biofilm control though further studies are still required to fully ascertain their true potential.
- Antimicrobial and antioxidant activity of different extracts of Mentha cervina from PortugalPublication . Rocha, J.; Carvalho, S. M. P.; Politi, M.; Castro, Paula M. L.; Pintado, M. E.