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MARE - Artigos com peer review

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Percorrer MARE - Artigos com peer review por Domínios Científicos e Tecnológicos (FOS) "Ciências Naturais"

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  • Asparagopsis armata and Sphaerococcus coronopifolius as a natural source of antimicrobial compounds
    Publication . Pinteus, Susete; Alves, Celso; Monteiro, Hugo; Ernesto Araújo; Horta, André; Pedrosa, Rui
    Methanol, n-hexane and dichloromethane extracts of twelve marine macro-algae (Rhodophyta, Chlorophyta and Heterokontophyta divisions) from Peniche coast (Portugal) were evaluated for their antibacterial and antifungal activity. The antibacterial activity was evaluated by disc diffusion method against Bacillus subtilis (gram positive bacteria) and Escherichia coli (gram negative bacteria). Saccharomyces cerevisiae was used as a model for the antifungal activity by evaluating the growth inhibitory activity of the extracts. The high antibacterial activity was obtained by the Asparagopsis armata methanolic extract (10 mm–0.1 mg/disc), followed by the Sphaerococcus coronopifoliusn-hexane extract (8 mm–0.1 mg/disc), and the Asparagopsis armata dichloromethane extract (12 mm–0.3 mg/disc) against Bacillus subtilis. There were no positive results against Escherichia coli. Sphaerococcus coronopifolius revealed high antifungal potential for n-hexane (IC50 = 40.2 µg/ml), dichloromethane (IC50 = 78.9 µg/ml) and methanolic (IC50 = 55.18 µg/ml) extracts against Saccharomyces cerevisiae growth. The antifungal potency of the Sphaerococcus coronopifolius extracts was similar with the standard amphotericin B. Asparagopsis armata and Sphaerococcus coronopifolius reveal to be interesting sources of natural compounds with antimicrobial properties. © 2015, Springer Science+Business Media Dordrecht.
    2015-01-15Artigo científico Acesso restrito Ver mais
  • Synthesis and anion binding properties of new dihomooxacalix[4]arene diurea and dithiourea receptors
    Publication . Marcos, Paula M.; Teixeira, Filipa A.; Segurado, Manuel A. P.; Ascenso, José R.; Bernardino, Raul J.; Brancatelli, Giovanna; Geremia, Silvano
    Functionalization of the lower rim of p-tert-butyldihomooxacalix[4]arene with two (thio)ureido moieties provided new diurea (n-propyl 5a, tert-butyl 5b and phenyl 5c) and dithiourea (phenyl 5d) derivatives, all in the cone conformation, as shown by NMR studies. The X-ray crystal structure of 5c is reported. The binding ability of these neutral receptors towards a large variety of anions was assessed by 1H NMR titrations. The structures and complexation energies of some complexes were also studied using DFT methods. The data showed that, in general, the association constants decrease with decrease of anion basicity and they are strongly dependent on the nature of the substituent at the urea moiety. Phenyl-(thio)urea derivatives 5c and 5d are the best anion receptors, showing the strongest complexation for F− (log Kass=2.70 and 2.75, respectively) and also for the oxoanions AcO−, BzO− and H2 PO4. These results were corroborated by DFT calculations.
    2014-09-16Artigo científico Acesso restrito Ver mais