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 - Comunicações a Conferências / ConferenceItem

Mostrando recursos 1 - 20 de 40

  1. New syntheses of potential biologically active xanthones and benzoxanthones

    Rocha, Djenisa H. A.; Leal, Stephanie B.; Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.
    The synthesis of xanthones, adequately functionalized for a specific application, is a challenging task. In this presentation, will be disclosed our recent studies with this unique family of compounds, namely the one-pot photoinduced electrocyclisation of (E)-3-styrylflavones 1 and in situ oxidation of cycloadducts to give 5-phenyl-7H-benzo[c]xanthen-7-one derivatives 2,3a and aromatization studies of (E)-3-aryl-4-benzylidene-8-hydroxy-3,4-dihydro-1H-xanthene-1,9(2H)-diones 33b into 4-benzyl-1,8-dihydroxy-3-phenyl-9H-xanthen-9-one derivatives 4.

  2. Organic compounds isolated from Juniperus brevifolia bark

    Vieira, Amélia; Martins, Marcele; Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.
    In continuation of our study on the chemical characterization of endemic plants of the Azores archipelago, we have examined Juniperus brevifolia. Our interest in this plant was stimulated by the wide range of biological activities reported for other species of this genus and/or of their constituents. Previous work showed that leaves extracts, for instance dichloromethane extract and chloroform-soluble fraction of the acetone extract, showed high activity against HeLa and Hep-2 tumour cell lines. Chemical investigation of these extracts afforded more than thirty compounds, mainly abietane and pimarane derivatives, eight of them were new natural compounds and other exhibit interesting antitumor...

  3. New xanthenodione: synthesis and antioxidant activity evaluation

    Leal, Stephanie B.; Pinto, Diana C. G. A.; Seca, Ana M. L.; Silva, Artur M. S.; Cavaleiro, José A. S.
    Due to the continuing interest of the research group in the synthesis of novel oxygen heterocycles we have recently developed a unique synthetic route towards new xanthenodiones 5 (scheme 1).[6] The application of this methodology in the cyclization of chromone derivatives 4b,c bearing methoxyl groups not only promote the cyclization to xanthenedione derivatives but also promote the demethylation leading to the 4-(benzylidene)-8-hydroxy-3-phenyl-3,4-dihydro-1H-xanthene-1,9(2H)-diones 5b,c . This interesting result prompted us to investigate the antioxidant potential of 4-(benzylidene)-8-hydroxy-3-phenyl-3,4-dihydro-1H-xanthene-1,9(2H)-diones 5a-c .

  4. Some aromatic compounds from dichloromethane extract of Salicornia ramosissima.

    Isca, Vera M. S.; Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.; Silva, Helena
    Salicornia ramosissima J. Woods, is an annual halophyte, confined to saline habitats, widely distributed in the salt marsh of Ria de Aveiro (Portugal) and also present in many salt marshes of the Iberian Peninsula. Our interest in the phytochemical study of this specie, which belongs to the genus Salicornia and family Chenopodiaceae, is based on previous knowledge that plants of this genus presented compounds such as flavonoids, chromones and alkaloids which are well-recognized for their biological activities. Salicornia ramosissima was subject to some studies of growth conditions and salinity, but its phytochemical composition remains unknown. The analysis of the dichloromethane...

  5. Purification and structural characterization of compounds isolated from Cystoseira abies-marina

    Gouveia, Vera L. M.; Seca, Ana M. L.; Barreto, Maria do Carmo; Silva, Artur M. S.; Kijjoa, Anake
    6th Spanish-Portuguese-Japanese Organic Chemistry Symposium, Lisboa, de 18 a 20 de Julho de 2012 (Poster Communication).

  6. Synthesis and antioxidant activity of new xanthone-type compounds

    Leal, Stephanie B.; Pinto, Diana C. G. A.; Seca, Ana M. L.; Silva, Artur M. S.; Cavaleiro, José A. S.
    Owing to our continuing interest in the synthesis of novel oxygen heterocycles we have recently developed a unique synthetic procedure towards the synthesis of new xanthenodiones (2)[5] and extend the work to their aromatization into xanthones (3). Our aim was also to obtain new derivatives with potential biological activities, therefore their ability to scavenge the DPPH radical and to reduce iron(III) were also evaluated. In the present communication we will present and discussed our last results on the synthetic and potential application of xanthones (3).

  7. Compounds identified on hexane and dichloromethane extracts of Salicornia ramosissima

    Isca, Vera M. S.; Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.; Silva, Helena
    Salicornia ramosissima J. Woods (common purple glasswort) is an annual halophyte, widely distributed in the salt marsh of Ria de Aveiro (Portugal), that belongs to the Salicornia L. genus (Chenopodiaceae).[4] Although phytochemical studies genus on this genus report the presence of compounds which are well-recognized for their biological activities, such as flavonoids, chromones and alkaloids,[3] too little is known about secondary metabolites on purple glasswort. In our previous work we were able to isolate and identify ethyl o-hydroxycinnamate, (E)-fatty alcohol ferulic acid and scopoletin from the dichloromethane extract of S. ramosissima aerial parts. The structure and spectroscopic characterization of some...

  8. Chemical and biological studies from an Azorean macroalga: Ulva rigida

    Silva, Madalena; Vieira, Luís M. M.; Almeida, Ana Paula; Silva, Artur M. S.; Kijjoa, Anake; Seca, Ana M. L.; Barreto, Maria do Carmo
    3rd Portuguese Meeting on Medicinal Chemistry and 1st Portuguese-Spanish-Brazilian Meeting on Medicinal Chemistry, Aveiro, 28-30 Novembro 2012.

  9. Bioactive meroditerpenes from Cystoseira abies-marina, collected from the coast of S. Miguel island

    Gouveia, Vera L. M.; Seca, Ana M. L.; Barreto, Maria do Carmo; Silva, Artur M. S.; Kijjoa, Anake
    3rd Portuguese Meeting on Medicinal Chemistry and 1st Portuguese-Spanish-Brazilian Meeting on Medicinal Chemistry, Aveiro, 28-30 Novembro 2012.

  10. Protein-ligand docking study: diterpenes from Juniperus brevifolia as anticancer and antimicrobial agentes

    Sousa, Inês J.; Fernandes, Miguel X.; Seca, Ana M. L.
    From leaves of Juniperus brevifolia, an endemic conifer from Azores, were isolated and structurally characterized, several dehydroabietane and sandaracopimarane derivatives. Some of them (1-4), displayed antiproliferative activity against cancer cell lines (HeLa, A-549 and MCF-7) and bactericidal effect against Bacillus cereus at different concentrations tested. However, it is not known how these compounds interact with most often proteins involved in the antimicrobial and cytotoxic mechanisms. Protein-ligand docking is mainly used to predict (energy and conformation wise) how small molecules bind to a protein of known 3D structure and to predict possible molecular targets for a set of compounds. In this...

  11. Synthesis of new 1,8-dihydroxy-9h-xanthen-9-ones

    Leal, Stephanie B.; Seca, Ana M. L.; Pinto, Diana C. G. A.; Silva, Artur M. S.; Cavaleiro, José A. S.
    Xanthones have a rather restricted occurrence among higher plants, being found almost exclusively in Guttiferae and Gentianaceae. Xanthones are sometimes found as polyhydroxylated derivatives, exhibiting valuable biological activities [1], but more often bearing a variety of substituents. Xanthones are well known for their interesting phytochemical properties, which make them attractive to the pharmaceutical industry. Natural and synthetic derivatives have been described as exhibiting several important biological properties, such as anti-tumor [2], anti-inflammatory [3], antioxidant [4] and anticoagulant/antiplatelet activities [5]. Owing to our continuing interest in the synthesis of novel oxygen heterocycles we have recently developed an unique synthetic procedure towards...

  12. A new strategy for the synthesis of 3-cinnamoyl-2-styrylchromones and their transformation into new xanthenodiones derivatives

    Pinto, Diana C. G. A.; Seca, Ana M. L.; Leal, Stephanie B.; Silva, Artur M. S.; Cavaleiro, José A. S.
    Chromones are a class of oxygen heterocyclic compounds widely distributed in Nature. 2-Styrylchromones are, however, a small and rare naturally occurring chromones; only three derivatives have been isolated, two from the marine blue green algae Chrysophaeum taylori1 and one from the rhizomes of Imperata cylindrical. Even so, 2-styrylchromone derivatives are associated with noticeable biological activities. Our group has also been interested in the synthesis and biological evaluation of 3-aroylflavones and found that 3’,4’,5,7-tetrahydroxy-3-(3,4-dihydroxybenzoyl)flavone is a potential antioxidant agent. As part of our continuing work on the synthesis and antioxidant evaluations of polyhydroxy-2-styrylchromones,4 we set up a program aiming the synthesis...

  13. Quelidónia: um dom de Deus dos alquimistas

    Pavão, Maria Leonor
    […] a fim de verificar os efeitos antissépticos referidos, experimentou-se, in vitro, a acção do látex da planta sobre culturas de Staphylococcus desenvolvidas a partir de um inóculo de pús de uma pequena lesão cutânea sobre culturas puras de Bacillus subtilis. […].

  14. Prevalence of Heart Disease Risk Factors in the Azores

    Ferin, Rita; Schaefer, Ernst J.; Horvath, Katalin; Baptista, José; Pavão, Maria Leonor
    BACKGROUND and AIMS: In the Azores age adjusted death rates from coronary heart disease (CHD) are two-fold higher than in mainland Portugal. We determined the prevalence of standard and emerging CHD risk factors in 206 female and 146 male Azorean subjects (mean age 41 years).

  15. Descodificação da metáfora em Limite de Idade

    Pavão, Maria Leonor
    [...]. Fica pois, aqui, uma forma de homenagem simples ao poeta «pinsador», como se disse «paternalmente» chamado por Aurélio Quintanilha, o eminente geneticista português, a quem dedicou "Limite de Idade", e uma justificação, em jeito de apaziguamento dos meus receios, para o trabalho que se segue. [...].

  16. A alquimia de Nemésio

    Pavão, Maria Leonor
    […]. Da leitura e meditação de Limite de Idade, obra que o próprio autor designou como "delírios microfísicos e biopoéticos", surgem-me claramente como relevantes três observações ou motes de discussão que gostaria de partilhar convosco. […].

  17. Antioxidant markers and cardiovascular risk factors in Azorean subjects with coronary artery disease

    Ferin, Rita; Gomes, Carla; Castro, Ana Rita; Martins, Dinis; Santos, Víctor; Santos, Maria Cristina; Lopes, Paula Alexandra; Baptista, José; Viegas-Crespo, Ana Maria; Pavão, Maria Leonor
    To evaluate some blood antioxidant parameters in azorean subjects with coronary artery disease (CAD) previously submitted to percutaneous revascularization (PCI), by considering some cardiovascular risk factors.

  18. Blood trace element levels in patients with stabilized atherosclerosis

    Viegas-Crespo, Ana Maria; Napoleão, Patrícia; Lopes, Paula Alexandra; Santos, Maria Cristina; Pavão, Maria Leonor; Pinheiro, Teresa
    Cardiovascular diseases remain the leading cause of mortality in Western populations. Dislipidemia, hypertension, diabetes, obesity and tobacco consumption are the main risk factors for atherosclerosis and its thrombotic complications. However, these factors alone cannot account for all of the deaths caused by vascular pathologies. The possible interaction of some trace element levels with atherogenic diseases is not completely clarified. On the other hand, the intra and extracellular concentrations of elements playing an important function in the electrolytic equilibrium could partially be associated with cardiovascular dysfunctions and other associated pathologies. The aim of this study was to evaluate trace elements (Fe,...

  19. Blood antioxidant parameters and cardiovascular risk factors in subjects from the city of Ponta Delgada (Azores' Archipelago, Portugal)

    Pavão, Maria Leonor; Figueiredo, Teresa; Santos, Víctor; Lopes, Paula Alexandra; Ferin, Rita; Santos, Maria Cristina; Vicente, Luís; Viegas-Crespo, Ana Maria; Nève, Jean
    The purpose of this work was to evaluate serum selenium, copper and zinc concentrations, as well as the whole blood glutathione peroxidase and erythrocyte superoxide dismutase activities in subjects from the city of Ponta Delgada (S. Miguel Island, Azores’ Archipelago). The study of their relationship with generally accepted cardiovascular risk factors was also an objective. […].

  20. Serum selenium, copper and zinc concentrations in inhabitants of S. Miguel Island (Azores Archipelago)

    Viegas-Crespo, Ana Maria; Pavão, Maria Leonor; Santos, Maria Cristina; Santos, Víctor; Nève, Jean
    Selenium, copper and zinc are trace elements which, besides having other biological functions, are cofactors of enzymes involved in antioxidant systems. The aim of this study is to report the first data on serum selenium, copper and zinc concentrations in Portuguese subjects (W – Women, n = 149; M, Men, n = 92) living in urban, rural and fishing regions of S. Miguel Island. […].

Aviso de cookies: Usamos cookies propias y de terceros para mejorar nuestros servicios, para análisis estadístico y para mostrarle publicidad. Si continua navegando consideramos que acepta su uso en los términos establecidos en la Política de cookies.