Browsing by Author "Duarte, Noelia"
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- Antibacterial activity of ergosterol peroxide against Mycobacterium tuberculosisPublication . Duarte, Noelia; Ferreira, Maria-Jose U.; Martins, Marta; Viveiros, Miguel; Amaral, LeonardErgosterol peroxide, cycloart-23-en-3 beta,25-diol, vanillin and 4-hydroxybenzaldehyde have been isolated and characterized from a crude methanol extract of Euphorbia lagascae. Previous studies have shown contradictory results about the antibacterial activity of ergosterol peroxide against Mycobacterium tuberculosis. In order to clarify this question, the activity of this compound was tested against Mycobacterium tuberculosis H37Rv ATCC 27294 strain using two different systems: BACTEC 460TB (Bactec 460) and BACTEC MGIT 960 system (Bactec 960). The results obtained show that significant activity was demonstrable only with the Bactec 460 system. The lack of activity noted with the Bactec 960 system appears to be due to the much faster growth rate of the organism in the medium of this system as opposed to that of the Bactec 460 system. Ergosterol peroxide is also shown by the current study to be devoid of any activity against an antibiotic sensitive ATCC strain of Staphylococcus aureus.
- ANTICANCER PROPERTIES AND MDR MODULATORY EFFECT OF PLANT POLYPHENOLS AND THEIR INTERACTION WITH MEMBRANE COMPONENTSPublication . Michalak, Krystyna; Wesolowska, Olga; Wisniewski, Jerzy; Sroda, Kamila; Teisseyre, Andrzej; Kuzdzal, Michal; Strancar, Janez; Duarte, Noelia; Ferreira, Maria-Jose U.
- ANTICANCER PROPERTIES AND MULTIDRUG RESISTANCE MODULATORY EFFECT OF PLANT POLYPHENOLS AND THEIR INTERACTION WITH MEMBRANE COMPONENTSPublication . Michalak, Krystyna; Wesolowska, Olga; Wisniewski, Jerzy; Sroda, Kamila; Teisseyre, Andrzej; Kuzdzal, Michal; Strancar, Janez; Duarte, Noelia; Ferreira, Maria-Jose U.
- Antileishmanial activity of piceatannol isolated from Euphorbia lagascae seedsPublication . Duarte, Noelia; Kayser, Oliver; Abreu, Pedro; Ferreira, Maria-Jose U.In the search for biologically active compounds from Euphorbia lagascae Spreng, an herbaceous plant native to southeast of Iberic Peninsula, a stilbene, two coumarins and two 1-2-deoxyphorbol diterpene esters were isolated by chromatographic methods, from the methanol extracts of its defatted seeds. The structures of these compounds were elucidated by a combination of physical and spectral data (IR, MS and high-resolution H-1-NMR and C-13-NMR spectroscopy utilizing COSY, HMBC, HMQC and NOESY experiments). The stilbene, piceatannol, was screened for its antileishmanial activity against promastigotes as an extracellular form of Leishmania donovani, Leishmania infantum and Leishmania major, and amastigotes of Leishmania donovani as an intracellular form. Pentostan((R)) (sodium stibogluconate), the first line clinical drug, was used as a standard reference. Piceatannol was moderately active against the extracellular forms of the three tested Leishmania species, and more active than the reference compound against the intracellular form of Leishmania donovani. Copyright (c) 2007 John Wiley & Sons, Ltd.
- ANTINEOPLASIC ACTIVITY OF PHENOLIC COMPOUNDS AGAINST SENSITIVE AND RESISTANT HUMAN CANCER CELLSPublication . Duarte, Noelia; Lage, Hermann; Ferreira, Maria-Jose U.
- Antiplasmodial Activity of Lignans and Extracts from Pycnanthus angolensisPublication . Abrantes, Marta; Mill-Homens, Tania; Duarte, Noelia; Lopes, Dinora; Cravo, Pedro; Madureira, Maria do Ceu; Ferreira, Maria-Jose U.The dichloromethane, methanol and aqueous ethanol extracts of the stem bark of Pycnanthus angolensis were evaluated for their in vitro activity against the 3D7 Plasmodium falciparum strain. The CH2Cl2 extract was the most active showing an IC50 = 1.6 mu g/mL. From this extract, a new dibenzylbutane lignan, threo-4,4'-dihydroxy-3-methoxylignan (1) named pycnantolol, together with the known lignans (-)-dihydroguaiaretic acid (2), heliobuphthalmin (3), talaumidin (4), hinokinin (5), the labdane-type diterpene ozic acid (6), and the steroids stigmast-4-en-6 beta-ol-3-one (7), beta-sitosterol (8) and stigmasterol (9) were isolated. Their structures were established on the basis of physical and spectroscopic methods, including 2 D NMR experiments (COSY, HMQC, HMBC and NOESY). The antimalarial activity of compounds 1 - 7 was evaluated against 3D7 and Dd2 P. falciparum strains. Despite the significant activity displayed by the crude CH2Cl2 extract, the isolated compounds showed weaker antiplasmodial activity. The lowest IC50 value was obtained for talaumidin (4) (IC50 = 20.7 mu g/mL against the Dd2-chloroquine resistant P. falciparum strain).. - Science and Technology Foundation (FCT), Portugal. - The authors thank Prof. Jorge Paiva (Instituto Botanico, University of Coimbra) for identification of the plant. This work was supported by the Science and Technology Foundation (FCT), Portugal.
- Apoptosis induction and modulation of P-glycoprotein mediated multidrug resistance by new macrocyclic lathyrane-type diterpenoidsPublication . Duarte, Noelia; Varga, Andras; Cherepnev, Georg; Radics, Rita; Molnar, Joseph; Ferreira, Maria-Jose U.The macrocyclic lathyrane diterpenes, latilagascenes D-F (1-3) and jolkinol B (4), were isolated from the methanol extract of Euphorbia lagascae, and evaluated for multidrug resistance reversing activity on mouse lymphoma cells. All compounds displayed very strong activity compared with that of the positive control, verapamil. The structure-activity relationship is discussed. The evaluation of compounds 1 and 4, and of latigascenes A-C (5-7), isolated from the same species, as apoptosis-inducers was also carried out. Compound I was the most active. Furthermore, in the model of combination chemotherapy, the interaction between the doxorubicine and latilagascene B (6) was studied in vitro, on human MDR1 gene transfected mouse lymphoma cells, showing that the type of interaction was synergistic. Latilagascenes D-F (1-3) are new compounds whose structures were established on the basis of spectroscopic methods, including 2D NMR experiments (COSY, HMQC, HMBC and NOESY). (c) 2006 Elsevier Ltd. All rights reserved.
- Evaluation of Cucurbitane-type Triterpenoids from Momordica balsamina on P-Glycoprotein (ABCB1) by Flow Cytometry and Real-time FluorometryPublication . Spengler, Gabriella; Ramalhete, Catia; Martins, Marta; Martins, Ana; Serly, Julianna; Viveiros, Miguel; Molnar, Joseph; Duarte, Noelia; Mulhovo, Silva; Ferreira, Maria-Jose U.; Amaral, LeonardBackground: Cancer cells become refractory to chemotherapy as a consequence of their overexpressing ABC transporters that extrude not only the therapeutic agent but other unrelated compounds such as chemotoxins and biocides before they can reach their intended targets. A compound that can inhibit the activity of these transporters may find use as an adjunct to chemotherapy that had been rendered ineffective. Materials and Methods: Four curcubitane-type triterpenes isolated from Momordica balsamina Linn. (Cucurbitaceae), a plant from Mozambique were evaluated for their inhibition of the ABC transporter P-glycoprotein coded by the human ABCB1 gene transfected into mouse lymphoma cells. The evaluation was conducted by flow cytometry using rhodamine 123 and real-time fluorometry assessing accumulation of ethidium bromide (EB) on a real-time basis. Results: Among the compounds isolated, the most active was 7-methoxycucurbita-5,24-diene-3 beta,23(R)-diol, which inhibited the efflux of ethidium bromide (EB) and rhodamine 123 from the ABCB1-transfected mouse lymphoma cell. Conclusion: Real-time fluorometry replicated the flow cytometric results with significant advantages for the evaluation of efflux pump inhibitors. The substitution of side groups on the cucurbitane skeleton appears to be significant in the inhibition of ABCB1 activity.. - Fundacao para a Ciencia e a Tecnologia [FCT], Portugal [SFRH/BPD/34578/2007, SFRH/BD/22321/2005, SFRH/BD/19445/2004]; Luso-Hungarian Cooperation [FCT/DREBM 00542, OMFB-00389/2008, PT-13/2007]. - G. Spengler, C. Ramalhete and A. Martins were supported by grants SFRH/BPD/34578/2007, SFRH/BD/22321/2005 and SFRH/BD/19445/2004 (Fundacao para a Ciencia e a Tecnologia [FCT], Portugal), respectively and by Luso-Hungarian Cooperation FCT/DREBM 00542, OMFB-00389/2008, PT-13/2007.
- Inhibition of MRP1 transport activity by phenolic and terpenic compounds isolated from Euphorbia speciesPublication . Wesolowska, Olga; Wisniewski, Jerzy; Duarte, Noelia; Ferreira, Maria-Jose U.; Michalak, KrystynaBackground: A search for inhibitors of multidrug resistance (MDR)-associated protein 1 (MRP1) was performed among the compounds isolated from Euphorbia species, plants traditionally used in folk medicine. Materials and Methods: Fifteen compounds with terpenic or phenolic structures (macrocyclic and polycyclic diterpenes, coumarins, stilbenes and flavonoids) were isolated from the methanol extracts of Euphorbia lagascae and Euphorbia tuckeyana or obtained by derivatization. A functional test based on measuring the efflux of fluorescent MRP1 substrate (BCECF) from human erythrocytes was employed. Results: Effective MRP1 inhibitors were identified among the stilbenes (piceatannol and its derivatives) and the flavonoids (aromadendrin, naringenin and its derivatives). Conclusion: Euphorbia species constitute a promising source of multidrug resistance modulators.
- Interaction between doxorubicin and the resistance modifier stilbene on multidrug resistant mouse lymphoma and human breast cancer cellsPublication . Ferreira, Maria-Jose U.; Duarte, Noelia; Gyemant, Nora; Radics, Rita; Cherepnev, Georgy; Varga, Andras; Molnar, JosephThe hydroxystilbene trans-3,5,3,4-tetrahydroxystilbene (piceatannol) (1), isolated from the methanol extract of Euphorbia lagascae defatted seeds, was methylated to yield the derivatives trans-3,5,3,4'-tetramethoxystilbene (2), (trans-3,5-dihydroxy-3', 4'-dimethoxystilbene) (3) and trans-3,5,3'-trihydroxy4'-methoxystilbene (4). The structures of the compounds were assigned by spectroscopic methods (IR, H-1-NMR, C-13-NMR and MS). The ability of piceatannol (1) and the three methylated derivatives to modulate the transport activity of P-glycoprotein (P-gp) and apoptosis induction on the L5178 mouse lymphoma cell line containing the human MDR1 gene was studied by flow cytometry. The reversal of multidrug-resistance (MDR) was investigated by measuring the accumulation of rhodamine-123, a fluorescent substrate analog of doxorubicin, in cancer cells. Verapamil was applied as a positive control. For the evaluation of the compounds as apoptosis inducers, tumor cells were stained with FITC-labelled annexin-V and propidium iodide. The tetramethylated derivative (2) was found to be a powerful inhibitor of P-gp activity. Compounds I and 2 showed an increased apoptotic effect in the MDR subline, the most active being piceatannol (1). Furthermore, in the combination chemotherapy model, the interaction between doxorubicin and the resistance modifier 2 was studied in vitro. The results of checkerboard experiments indicated that the type of interaction was additive between doxorubicin and compound 2 on the human MDR1 gene-transfected mouse lymphoma cells. However, in the MCF7/dox human breast cancer cells, the interaction was non-additive. The degree of additive and non-additive interactions were close to the borderline of the FIX values corresponding to the two types of interactions.