Browsing by Author "Ferreira, MJU"
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- A Diterpene with a Rearranged Jatrofane Skeleton and other Terpenes from Euphorbia portlandicaPublication . Madureira, AM; Ascenso, JR; Ferreira, MJU
- A New abietane quinoide diterpene and a new sesquiterpene-coumarin ether from Euphorbia portlandicaPublication . Madureira, AM; Abreu, P; Ferreira, MJU
- A New Lupane Triterpene from Euphorbia portlandicaPublication . Madureira, AM; Serrão, C; Duarte, MT; Piedade, MFM; Ascenso, J; Ferreira, MJU
- A new sesquiterpene-coumarin ether and a new abietane diterpene and their effects as inhibitors of p-glycoproteinPublication . Madureira, AM; Molnar, A; Abreu, PM; Molnar, J; Ferreira, MJUA new sesquiterpene-coumarin ether (5'beta,9'alpha,10'alpha)-7-O-(3alpha-methoxy-8'(12')-drimen-11'-yl) -scopoletin, designated driportlandin (1) and a new abietane quinoid diterpene 16-hydroxyabieta-8,12-diene-11,14-dione, named portlanquinol (2) together with lupeol, nepehinol, wrightial, formonetin and davidigenin were isolated and characterized from the Me2CO extract of whole dried plant of Euphorbia portlandica. The structures of the new compounds were elucidated from spectral data including 2D-NMR experiments of COSY, HMQC, HMBC and NOESY. When examined for their effects on the reversal of multidrug resistance (MDR) on mouse lymphoma cells, compound 1 proved to be more active than the positive control verapamil and compound 2 was found to be toxic. This is the first report on the isolation of a sesquiterpene-coumarin and a quinoid-type diterpenoid from Euphorbia.
- Antioxidant and antileishmanial activity of piceatannolPublication . Duarte, N; Figueira, ME; Mota-Filipe, H; Kayser, O; Abreu, PM; Castro, M; Ferreira, MJU
- Bioactive diterpenoids, a new jatrophane and two ent-abietanes, and other constituents from Euphorbia pubescensPublication . Valente, C; Pedro, M; Duarte, A; Nascimento, MSJ; Abreu, PM; Ferreira, MJUA new jatrophane diterpene, pubescenol (1), known ent-abietane lactones, helioscopinolide A (2) and B (3), and taraxerone, 24-methylenecycloartanol, and vanillin have been isolated from Euphorbia pubescens. Diterpenes 1-3 and previously described pubescene D (4) were shown to be moderate inhibitors of the growth of MCF-7, NCI-H460, and SF-268 human tumor cell lines, whereas compounds 2 and 3 also exhibited significant antibacterial activity against Staphylococcus aureus.
- Compostos Terpénicos Isolados de Euphorbia segetalisPublication . Madureira, AM; Valente, C; Palma, AC; Ascenso, JR; Ferreira, MJU
- Cycloartane triterpenes from Euphorbia tuckeyanaPublication . Ferreira, MJU; Pinto, FC; Ascenso, JRInvestigation of the acetone extract of the whole plant of Euphorbia tuckeyana afforded a new cycloartane-type triterpene named as cyclotucanol. Its structure was established as cycloartane-24-methylene-3beta,25-diol (1). The known cycloartane triterpenes cycloeucalenol (2), 3,8-hydroxy-cycloart-25-en-24-one (3), cycloart-25-ene-3beta,24-diol (4), 25,26,27-trisnor-3beta-hydroxycycloartan-24-al (5) and cycloart-23-ene-3beta,25-diol (6) were also isolated and identified.
- Effect of cycloartanes on reversal of multidrug resistance and apoptosis induction on mouse lymphoma cellsPublication . Madureira, AM; Spengler, G; Molnar, A; Varga, A; Molnar, J; Abreu, PM; Ferreira, MJUThe ability of fifteen cycloartanes, isolated from Euphorbia species, to reverse multidrug resistance (MDR) and apoptosis induction in L5178Y mouse lymphoma cells, including its multidrug-resistant subline, was studied by flow cytometry. Reversion of MDR was investigated using a standard functional assay with rhodamine 123 as a fluorescent substrate analogue. For the evaluation of apoptosis, the cells were stained with FITC-labeled annexin V and propidium iodide. The majority of the compounds were able to reverse MDR of the tested human MDR1 gene-transfected mouse lymphoma cells. Some of the compounds were able to induce moderate apoptosis in the PAR cell line, but this effect was less effective on multidrug-resistant cells. The results indicate that cycloartanes can be substrates of ABC transporters, which might compete with certain anticancer chemotherapeutics.
- Euphopubescenol and euphopubescene, two new jatrophane polyesters, and lathyrane-type diterpenes from Euphorbia pubescensPublication . Valente, C; Pedro, M; Ascenso, JR; Abreu, PM; Nascimento, MSJ; Ferreira, MJUThe structures of euphopubescenol and euphopubescene, two new macrocyclic jatrophane diterpene polyesters, isolated from the whole dried plant of Euphorbia pubescens, were established as 5alpha,8alpha,15beta-triacetoxy-3alpha-benzoyloxy-4alpha-hydroxy-9,14-dioxo-13betaH-jatropha-6(17),11E-diene (1) and 3beta,7beta,8beta,9alpha,14alpha,15beta-hexa-acetoxy-2betaH-jatropha-5E,11E-diene (2) by 1D- and 2D-NMR (COSY, HMQC, HMBC and NOESY), IR, EI-MS and EI-FTICR-MS. Two known lathyrane derivatives, jolkinol A (3) and jolkinol A (4), whose C-13-NMR spectra were assigned, were also isolated. Compounds 1-3 have been evaluated for their ability to inhibit the in vitro growth of three human tumour cell lines representing different tumour types, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and SF-268 (CNS cancer). They inhibited both MCF-7 and NCI-H460 cell lines, with GI(50) values ranging between 40.9 muM and 95.3 muM, but were found to be ineffective as growth inhibitors of the SF-268 cell line.
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