Yazar "Ferreira D." seçeneğine göre listele

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    Antioxidant lignans from Larrea tridentata
    (2004) Abou-Gazar H.; Bedir E.; Takamatsu S.; Ferreira D.; Khan I.A.
    Three lignans, (7S,8S,7'S,8'S)-3,3',4'-trihydroxy- 4-methoxy-7,7'-epoxylignan and meso-(rel 7S,8S,7'S,8'S)-3,4, 3',4'-tetrahydroxy-7,7'-epoxylignan with significant antioxidant properties, and (E)-4,4'-dihydroxy-7,7'-dioxolign- 8(8')-ene, were isolated from the leaves of Larrea tridentata. The structures of the new compounds were determined primarily from 1D and 2D NMR analysis. Their antioxidant activities were evaluated on intracellular reactive oxygen species in HL-60 cells. Three lignans, (7S,8S,7'S,8'S)-3, 3',4'-trihydroxy-4-methoxy-7,7'-epoxylignan, meso-(rel 7S,8S,7'R,8'R)-3,4,3',4'-tetrahydroxy-7, 7'-epoxylignan, and (E)-4,4'-dihydroxy-7,7'-dioxolign- 8(8')-ene, together with 10 known compounds, were isolated from the leaves of Larrea tridentata. The structures of the new compounds were determined primarily from 1D and 2D NMR spectroscopic analysis. Their antioxidant activities against intracellular reactive oxygen species were evaluated in HL-60 cells. © 2004 Published by Elsevier Ltd.
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    Bioactive constituents from Turkish Pimpinella species
    (2005) Tabanca N.; Bedir E.; Ferreira D.; Slade D.; Wedge D.E.; Jacob M.R.; Khan S.I.; Kirimer N.; Can Baser K.H.; Khan I.A.
    A new 'phenylpropanoid', 4-(3-methyloxiran-2-yl)phenyl 2-methylbutanoate (1), a new trinorsesquiterpene, 4-(6-methylbicyclo[4.1.0]hept-2-en-7-yl)butan-2-one (2), and eight known compounds (3-10) were isolated from the essential oils of several Pimpinella species growing in Turkey. The structures of the new compounds were determined by 1D- and 2D-NMR analyses. The absolute configuration of 1 was established via comparison of its optical rotation with that of 'epoxypseudoisoeugenyl 2-methylbutyrate' (11), the absolute configuration of which was determined by chemical degradation and an appropriate Mosher ester formation. Direct bioautography revealed antifungal activity of 1 and 11 against Colletotrichum acutatum, C. fragariae, and C. gloesporioides. Subsequent evaluation of antifungal compounds in a 96-well microtiter assay showed that compounds 1 and 11 produced the most-significant growth inhibition in Phomopsis spp., Colletotrichum spp., and Botrytis cinerea. Compounds 1 and 6 displayed antimicrobial activities against Mycobacterium intracellulare, with IC50 values of 2.78 and 1.29 µM, respectively. © 2005 Verlag Helvetica Chimica Acta AG, Zürich.
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    Lotaustralin from Rhodiola rosea roots
    (2004) Akgul Y.; Ferreira D.; Abourashed E.A.; Khan I.A.
    Lotaustralin was isolated as a mixture of two diastereoisomeric forms from the methanol extract of Rhodiola rosea roots, together with the known compounds rosavin, rosarin, rosin, rosiridin, salidroside, and ß-sitosterol. The structure of lotaustralin was established by 1D and 2D-NMR spectroscopy, including 1H- 1H COSY, NOESY, HMQC, and HMBC, and FAB and HR MS. © 2004 Elsevier B.V. All rights reserved.