Recursos de colección

Repositorio da Universidade dos Açores (8.657 recursos)

O Repositório Institucional da Universidade dos Açores desenvolvido no âmbito do projecto RCAAP.

DCTD - Artigos em Revistas Internacionais / Articles in International Journals

Mostrando recursos 1 - 17 de 17

  1. A new natural spiro heterocyclic compound and the cytotoxic activity of the secondary metabolites from Juniperus brevifolia leaves

    Moujir, Laila M.; Seca, Ana M. L.; Araujo, Liliana; Silva, Artur M. S.; Barreto, Maria do Carmo
    A new natural spiro compound 3,4-dehydrotheaspirone 1 and the known arctiol [1β,6α-dihydroxy-4(14)-eudesmene] 2 were isolated from Juniperus brevifolia. Arctiol is reported for the first time in the Juniperus genus. Their structures were established by 1D, and 2D NMR and MS spectra. Antimicrobial and cytotoxic activities of 1 and several secondary metabolites 3,4,5,6,7,8,9,10,11,12 previously isolated by our group from J. brevifolia were evaluated and some SAR has been established. The 18-hydroxydehydroabietane displayed great antiproliferative activity against cancer cell lines tested, namely HeLa, A-549 and MCF-7. Compound also presented a significant bactericidal effect against Bacillus cereus at different concentrations tested.

  2. A Novel Short-Step Synthesis of New Xanthenedione Derivatives from the Cyclization of 3-Cinnamoyl-2-styrylchromones

    Pinto, Diana C. G. A.; Seca, Ana M. L.; Leal, Stephanie B.; Silva, Artur M. S.; Cavaleiro, José A. S.
    Novel (E)-3-aryl-4-benzylidene-8-hydroxy-3,4-dihydro-1 H-xanthene-1,9(2H)-diones are prepared by the cyclization of (E,E)-3-cinnamoyl-5-hydroxy-2-styrylchromones efficiently catalyzed with boron tribromide. The (E,E)-3-cinnamoyl-5-hydroxy-2-styrylchromones are obtained from the Baker–Venkataraman rearrangement of (E,E)-2-acetyl-1,3-phenylene bis(3-phenylacrylate), which is greatly improved under microwave irradiation.

  3. Plasma aminothiol profile and some of its determinants in apparently Azorean subjects

    Lima, Ana; Ferin, Rita; Baptista, José; Pavão, Maria Leonor
    Copyright © 2014 Ana Lima et al. This is an open access article distributed under the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

  4. Trace element status (Se, Cu, Zn) and serum lipid profile in portuguese subjects of San Miguel Island from Azores' Archipelago

    Viegas-Crespo, Ana Maria; Pavão, Maria Leonor; Paulo, O.; Santos, Víctor; Santos, Maria Cristina
    Data on selenium, copper and zinc in serum of Portuguese inhabitants of the city of Ponta Delgada - Azores Archipelago are reported for the first time. The subjects are of both sexes, aged 20 to 60 years, and non-abusers of alcohol, tobacco or drugs. Serum concentrations of these elements are in the same range than those found for populations of Lisbon and of some other European countries. Differences between sexes are observed, with serum selenium and zinc levels being higher in males than in females, and the copper levels being higher in females as compared to males. These results can...

  5. Polymorphism of the APOE locus in the Azores Islands (Portugal)

    Bettencourt, Conceição; Montiel, Rafael; Santos, Cristina; Pavão, Maria Leonor; Viegas-Crespo, Ana Maria; Lopes, Paula Alexandra; Lima, Manuela
    Our aim in this study is to report on the polymorphism of the APOE gene in the Azores Islands (Portugal) to obtain a population baseline of the existing variation in this locus, known to be one of the genetic determinants of plasma lipid levels. One hundred twenty-six Azorean individuals were typed for the APOE polymorphism using standard PCR-RFLP. Allele frequencies obtained for APOE*2, APOE*3, and APOE*4 were 6.75%, 83.73%, and 9.52%, respectively. The APOE*3/*3 genotype presented the highest frequency (69.84%), and the APOE*4/*4 genotype had the lowest frequency (0.79%). Genotype frequencies were in conformity with Hardy-Weinberg expectations. The observed genotype...

  6. Diagnosis of Enzyme Inhibition Based on the Degree of Inhibition

    Antunes, Fernando; Marinho, Helena Susana; Barreto, Maria do Carmo; Pavão, Maria Leonor; Pinto, Ruy Eugénio
    In this work, a method for the diagnosis of kinetic inhibition, based on the dependence of the degree of inhibition (s) on the inhibitor concentration [1] and on the substrate concentration [S], is presented. Because the degree of inhibition is a ratio between rates, kinetic data are normalized by the introduction of an internal control-the rate of the uninhibited reaction. Therefore, the error associated with the kinetic measurements decreases and less experimental measurements are necessary to achieve the diagnosis. The process described, which uses graphical and/or non-linear fitting procedures, allows distinguishing between 20 different kinds of inhibition, including not only...

  7. Comparison of whole blood glutathione peroxidase activity, levels of serum selenium and lipid peroxidation in subjects from the fishing and rural communities of "Rabo de Peixe" Village, San Miguel Island, The Azores Archipelago, Portugal.

    Pavão, Maria Leonor; Cordeiro, Carla; Costa, Ângelo; Raposo, José Aires; Santos, Maria Cristina; Nève, Jean; Viegas-Crespo, Ana Maria
    The activity of glutathione peroxidase (GSH-Px), serum selenium (Se), and thiobarbituric acid reactive substances (TBARS) were measured in the whole blood of 148 healthy adults aged 20–60 yr from the fishing and rural communities of “Rabo de Peixe,” The Azores, Portugal. The subjects did not live in the same household and had different socioeconomic profiles and dietary habits. The serum lipid profile and selected life habits were also considered in this study. No significant differences in the activity of GSH-Px were found in the interpopulation or intrapopulation analyses, classified by age or lipid profile. An age-dependent GSH-Px increase was noted...

  8. Rapid, sensitive and simultaneous determination of ascorbic and uric acids in human plasma by ion-exclusion HPLC-UV

    Ferin, Rita; Pavão, Maria Leonor; Baptista, José
    Copyright © 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  9. Methodology for a rapid and simultaneous determination of total cysteine, homocysteine, cysteinylglycine and glutathione in plasma by isocratic RP-HPLC

    Ferin, Rita; Pavão, Maria Leonor; Baptista, José
    Alterations in the plasma aminothiols levels can be considered as important biomarkers for the diagnosis and screening of several human disorders, namely cardiovascular diseases. We aimed to optimize a rapid, sensitive and accurate RP-HPLC methodology with fluorescence detection, for the simultaneous determination of the total concentrations of cysteine, homocysteine, cysteinylglycine and glutathione in blood plasma, as well as its application to the evaluation of those thiols levels in plasma of a group of Azorean subjects. Aminothiols were reduced with tri-n-butylphosphine and derivatized with a thiol-specific fluorogenic reagent ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate. The thiols adducts were separated by an isocratic elution on a...

  10. Cross-sectional study of risk factors for atherosclerosis in the Azorean population

    Cymbron, Teresa; Raposo, Mafalda; Kazachkova, Nadia; Bettencourt, Conceição; Silva, Francisca; Santos, Cristina; Dahmani, Yahya; Lourenço, Paula C.; Ferin, Rita; Pavão, Maria Leonor; Lima, Manuela
    Copyright © 2011 Informa UK Ltd.

  11. Comparison of Apolipoprotein E polymorphism and other atherosclerotic risk factors in two Portuguese populations: the Influence of Insularity

    Lopes, Paula Alexandra; Gaspar, Gisela; Napoleão, Patrícia; Santos, Maria Cristina; Pavão, Maria Leonor; Viegas-Crespo, Ana Maria
    O principal objectivo deste estudo é o de pesquisar o efeito da insularidade nos polimorfismos da apolipoproteína (apo) E em indivíduos saudáveis do continente (Lisboa) e de Ponta Delgada (Ilha de S. Miguel, Arquipélago dos Açores). Adicionalmente, estudar a distribuição dos seus genótipos em doentes com aterosclerose da Ilha de S. Miguel. Em Lisboa, a distribuição dos genótipos da apo E foi a seguinte: e3/e3 > e3/e4 > e2/e3 > e4/e4, ao passo que em Ponta Delgada e independentemente da condição fisiológica foi: e3/e3 > e2/e3 > e3/e4. Distintas frequências genotípicas foram observadas entre homens e mulheres no grupo saudável...

  12. Systemic markers of the redox balance and Apolipoprotein E Polymorphism in Atherosclerosis: the Relevance for an Integrated Study

    Lopes, Paula Alexandra; Napoleão, Patrícia; Pinheiro, Teresa; Ceia, Fátima; Steghens, Jean-Paul; Pavão, Maria Leonor; Santos, Maria Cristina; Viegas-Crespo, Ana Maria
    Prospective studies have demonstrated that an imbalance between oxidative damage and antioxidative protection can play a role in the development and progression of atherosclerosis. Also, genotypes with the apolipoprotein E ζ4 allele have been associated with an increase risk for this pathology. Based on this knowledge, the aim of this study was to evaluate indicators of the redox balance, trace elements, and apolipoprotein E allelic profile in subjects from the Lisbon population with clinically stable atherosclerosis, at risk for atherosclerotic events, and in healthy subjects for comparison. The activities of superoxide dismutase in erythrocytes and glutathione peroxidase in whole blood,...

  13. Whole blood glutathione peroxidase and erythrocyte superoxide dismutase activities, serum trace elements (Se, Cu, Zn) and cardiovascular risk factors in subjects from the city of Ponta Delgada (Island of San Miguel, The Azores' Archipelago, Portugal)

    Pavão, Maria Leonor; Figueiredo, Teresa; Santos, Víctor; Lopes, Paula Alexandra; Ferin, Rita; Santos, Maria Cristina; Nève, Jean
    Activities of whole blood glutathione peroxidase (GSH-Px) and erythrocyte superoxide dismutase (SOD) and serum levels of selenium (Se), copper (Cu) and zinc (Zn) were measured in 118 apparently healthy subjects aged 20–60 years from the city of Ponta Delgada, Island of San Miguel, The Azores Archipelago, Portugal. Data were analysed by age/gender, lipid profile and blood pressure as cardiovascular risk factors searching for their relevance when assessing reference values for antioxidant biomarkers. GSH-Px was in the same range, but SOD was significantly lower than in other Portuguese populations. Neither activity differed with gender. GSH-Px activity increased with age, namely in...

  14. Trace element status (Se, Cu, Zn) in healthy portuguese subjects of Lisbon population-a reference study

    Lopes, Paula Alexandra; Santos, Maria Cristina; Vicente, Luís; Rodrigues, Maria Olívia; Pavão, Maria Leonor; Nève, Jean; Viegas-Crespo, Ana Maria
    Serum levels of selenium, copper, and zinc were systematically determined in healthy subjects of the Lisbon population. The sample consisted of 183 blood donors of both genders who were divided into two age groups: 20-44 and 45-70 yr of age; relationships with gender, age, the lipid profile, and tobacco consumption were investigated. In the female group, the intake of oral contraceptives and pregnancy were considered for the youngest women, and hormonal replacement therapy (HRT) was taken into account for the oldest ones. Serum concentrations of these elements were in the same range as those found for populations of other European...

  15. Di- and Sesquiterpenoids from Cystoseira Genus: structure, intra-molecular transformations and biological activity

    Gouveia, Vera L. M.; Seca, Ana M. L.; Barreto, Maria do Carmo; Pinto, Diana C. G. A.
    Natural products have been the single most productive source of leads for the development of drugs, because of the great variety of their chemical structures. Previous chemical investigation of members of the genus Cystoseira resulted in the discovery of various bioactive secondary metabolites. The secondary metabolites isolated and characterized are very interesting, both from the biological activity and structural complexity points of view, which make this genus an attractive target for further investigations. The present review covers the research progress on natural products isolated from this genus since January 1995 until now, concerning the isolation and structural elucidation of the...

  16. Cytotoxic meroterpenoids from the macroalga Cystoseira abies-marina

    Gouveia, Vera L. M.; Seca, Ana M. L.; Barreto, Maria do Carmo; Neto, Ana I.; Kijjoa, Anake; Silva, Artur M. S.
    Two new meronorsesquiterpenes (cystoazorones A and B) and two new meroditerpenes (cystoazorols A and B), along with benzoic acid were isolated from the brown macroalga Cystoseira abies-marina. The structures of the new compounds were established by 1D and 2D NMR as well as HRMS spectral analysis. The in vitro cytotoxicity and antioxidant activity of the isolated compounds were also evaluated. Cystoazorones A and B, and cystoazorol A exhibited in vitro growth inhibitory activity against HeLa cells. The HeLa cell line in log phase was found to be more sensitive to cystoazorol A than when it was in lag phase. Cystoazorol...

  17. Inhibition of mouse liver respiration by Chelidonium majus isoquinoline alkaloids

    Barreto, Maria do Carmo; Pinto, Ruy Eugénio; Arrabaça, João Daniel; Pavão, Maria Leonor
    The alkaloids from Chelidonium majus L. which had a significant inhibitory effect in mitochondrial respiration were those which contain a positive charge due to a quaternary nitrogen atom, i.e., chelerythrine, sanguinarine, berberine and coptisine, both with malate+glutamate or with succinate as substrates. When malate+glutamate was used as substrate, chelerythrine and berberine, which contain methoxy groups, were particularly more active, since they had a strong effect even at low concentrations. In submitochondrial particles, berberine and coptisine had a marked inhibitory effect on NADH dehydrogenase activity but practically no effect on succinate dehydrogenase activity, whereas chelerythrine and sanguinarine inhibited more strongly succinate...

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