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Browsing by Author "Gaspar, Maria Nelma"

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  • Antimicrobial activity of Drosophyllum lusitanicum, an endemic Mediterranean insectivorous plant
    Publication . Gonçalves, Sandra; Quintas, Célia; Gaspar, Maria Nelma; Nogueira, José Manuel F.; Romano, Anabela
    The aim of this study was to evaluate the antimicrobial activity of Drosophyllum lusitanicum leaf extract against various yeasts and bacteria species, including both standard and clinically isolated strains. The extract exhibited strong antimicrobial activity against all the tested yeast strains with inhibition zones ranging 23.67–42.23mm and with minimum inhibitory concentration (MIC) values ranging 31–63 mgL 1. All the Gram-positive bacteria studied were inhibited by the extract, showing inhibition zones ranging 17.67–43.00mm and MIC values comprising between 15.6 and 250 mgL 1. In contrast, the growth of the tested Gram-negative bacteria was not significantly affected by the extract. Among the microorganisms tested, Staphylococcus epidermidis ATCC 12228 was the most sensitive, presenting the lowest MIC value (15.6 mgL 1), while Enterococcus faecalis ATCC 29212 was the most tolerant (250 mgL 1). The extract of D. lusitanicum was analysed by gas chromatography-mass spectrometry and the major constituent found was plumbagin.
    2009Journal article Restricted access Show more
  • Evaluation of the antioxidant and antimicrobial properties of in vitro cultured Drosera intermedia extracts
    Publication . Grevenstuk, Tomás; Gonçalves, Sandra; Almeida, Sara; Coelho, Natacha; Quintas, Célia; Gaspar, Maria Nelma; Romano, Anabela
    Evaluation of the antioxidant activity of the methanol, water and n-hexane extracts of Drosera intermedia, determined by the Folin-Ciocalteau (F-C), trolox equivalent antioxidant capacity (TEAC) and oxygen radical antioxidant capacity (ORAC) assays showed that the methanol extract had the highest antioxidant activity (F-C: 378.6 ± 31.5 μmolGAE/mgextract; TEAC: 332.2 ± 29.1 μmolTE/mgextract; ORAC: 64.7 ± 7.8 μmolTE/mgextract). Antimicrobial activity was tested against seven bacterial and eight yeast strains using the agar diffusion assay, followed by the determination of minimum inhibitory concentrations (MIC). All tested D. intermedia extracts demonstrated strong antimicrobial properties with a broad spectrum of activity. However, the n-hexane extract exhibited much greater activity than water and methanol extracts. The most susceptible microorganisms to the n-hexane extract were Staphylococcus epidermidis ATCC 12228 and Candida albicans YP0175, for which a MIC value of 13.0 μg/mL was scored.
    2009Journal article Restricted access Show more