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Search Results: 1 - 10 of 240332 matches for " Raquel C;Costa-Lotufo "
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The Contribution of Natural Products as Source of New Anticancer Drugs: Studies Carried Out at the National Experimental Oncology Laboratory from the Federal University of Ceará [A Contribui o dos Produtos Naturais como Fonte de Novos Fármacos Anticancer: Estudos no Laboratório Nacional de Oncologia Experimental da Universidade Federal do Ceará]
Letícia V. Costa-Lotufo,Raquel C. Montenegro,Ana Paula N. N. Alves,Socorro V. F. Madeira
Revista Virtual de Química , 2010,
Abstract: The history of anticancer chemotherapy is closely related to that of natural products, as over 60% of currently used drugs in cancer therapy are natural products or inspired by a natural compound. Despite the introduction of new drugs in the therapeutic arsenal of anticancer medicines, many tumors do not properly respond to treatment. Natural resources comprise the most promising possibilities of finding new and efficient molecules with impact in the therapy of resistant diseases. The National Experimental Oncology Laboratory began a research program aiming at the evaluation of new natural or synthetic anticancer molecules through an experimental approach involving in vitro and in vivo models. In the period between 2000 and 2007, 5166 samples were screened, and three molecules, piplartine, biflorine and pisosterol, were selected for further studies.
Bioprospecting for bioactives from seaweeds: potential, obstacles and alternatives
Pereira, Renato C.;Costa-Lotufo, Leticia V.;
Revista Brasileira de Farmacognosia , 2012, DOI: 10.1590/S0102-695X2012005000077
Abstract: seaweeds are potential sources of high biotechnological interest due to production of a great diversity of compounds exhibiting a broad spectrum of biological activities. on the other hand, there is an urgent need for management options for a sustainable approach to the use of marine organisms as a source of bioactive compounds. this review discusses the bioprospection for bioactive seaweed compounds as pharmaceuticals and antifouling agents, encompassing their potential and possible obstacles and alternatives. in spite of their potential, research on pharmaceuticals and antifouling agents from seaweeds includes mainly the search for molecules that exhibit these biological activities, but lacks of consideration of fundamental and limiting aspects such as the development of alternatives to sustainable supply. however, for the complete development of pharmaceuticals and antifouling compounds in brazil, marine bioprospection should be more comprehensive, associating the search for molecules with an analysis of their supply. in this way, it is possible to promote sustainable development and conservation of biodiversity, as well as to assert the economic development of brazil.
Bioprospecting for bioactives from seaweeds: potential, obstacles and alternatives
Renato C. Pereira,Leticia V. Costa-Lotufo
Revista Brasileira de Farmacognosia , 2012,
Abstract: Seaweeds are potential sources of high biotechnological interest due to production of a great diversity of compounds exhibiting a broad spectrum of biological activities. On the other hand, there is an urgent need for management options for a sustainable approach to the use of marine organisms as a source of bioactive compounds. This review discusses the bioprospection for bioactive seaweed compounds as pharmaceuticals and antifouling agents, encompassing their potential and possible obstacles and alternatives. In spite of their potential, research on pharmaceuticals and antifouling agents from seaweeds includes mainly the search for molecules that exhibit these biological activities, but lacks of consideration of fundamental and limiting aspects such as the development of alternatives to sustainable supply. However, for the complete development of pharmaceuticals and antifouling compounds in Brazil, marine bioprospection should be more comprehensive, associating the search for molecules with an analysis of their supply. In this way, it is possible to promote sustainable development and conservation of biodiversity, as well as to assert the economic development of Brazil.
Biological activity of neosergeolide and isobrucein B (and two semi-synthetic derivatives) isolated from the Amazonian medicinal plant Picrolemma sprucei (Simaroubaceae)
Silva, Ellen CC;Cavalcanti, Bruno C;Amorim, Rodrigo CN;Lucena, Jorcilene F;Quadros, Dulcimar S;Tadei, Wanderli P;Montenegro, Raquel C;Costa-Lotufo, Letícia V;Pessoa, Cláudia;Moraes, Manoel O;Nunomura, Rita CS;Nunomura, Sergio M;Melo, Marcia RS;Andrade-Neto, Valter F de;Silva, Luiz Francisco R;Vieira, Pedro Paulo R;Pohlit, Adrian M;
Memórias do Instituto Oswaldo Cruz , 2009, DOI: 10.1590/S0074-02762009000100008
Abstract: in the present study, in vitro techniques were used to investigate a range of biological activities of known natural quassinoids isobrucein b (1) and neosergeolide (2), known semi-synthetic derivative 1,12-diacetylisobrucein b (3), and a new semi-synthetic derivative, 12-acetylneosergeolide (4). these compounds were evaluated for general toxicity toward the brine shrimp species artemia franciscana, cytotoxicity toward human tumour cells, larvicidal activity toward the dengue fever mosquito vector aedes aegypti, haemolytic activity in mouse erythrocytes and antimalarial activity against the human malaria parasite plasmodium falciparum. compounds 1 and 2 exhibited the greatest cytotoxicity against all the tumor cells tested (ic50 = 5-27 μg/l) and against multidrug-resistant p. falciparum k1 strain (ic50 = 1.0-4.0 g/l) and 3 was only cytotoxic toward the leukaemia hl-60 strain (ic50 = 11.8 μg/l). quassinoids 1 and 2 (lc50 = 3.2-4.4 mg/l) displayed greater lethality than derivative 4 (lc50 = 75.0 mg/l) toward a. aegypti larvae, while derivative 3 was inactive. these results suggest a novel application for these natural quassinoids as larvicides. the toxicity toward a. franciscana could be correlated with the activity in several biological models, a finding that is in agreement with the literature. importantly, none of the studied compounds exhibited in vitro haemolytic activity, suggesting specificity of the observed cytotoxic effects. this study reveals the biological potential of quassinoids 1 and 2 and to a lesser extent their semi-synthetic derivatives for their in vitro antimalarial and cytotoxic activities.
Cytotoxic, trypanocidal activities and physicochemical parameters of nor-2-lapachone-based 1,2,3-triazoles
Silva Júnior, Eufranio N. da;Moura, Maria Aline B. F. de;Pinto, Antonio V.;Pinto, Maria do Carmo F. R.;Souza, Maria Cecília B. V. de;Araújo, Ana J.;Pessoa, Claudia;Costa-Lotufo, Letícia V.;Montenegro, Raquel C.;Moraes, Manoel Odorico de;Ferreira, Vitor F.;Goulart, Marilia O. F.;
Journal of the Brazilian Chemical Society , 2009, DOI: 10.1590/S0103-50532009000400007
Abstract: the cytotoxicities of five nor-2-lapachone-based 1,2,3-triazoles and the precursor azidonaphthoquinone were assayed against six neoplasic cancer cell lines: sf-295 (central nervous system), hct-8 (colon), mdamb-435 (melanoma), hl-60 (leukaemia), pc-3 (prostate) and b-16 (murine melanoma). ic50 values ranging from 0.43 to 9.48 μm were obtained. 3-(4-(1-hydroxycyclohexyl)-1h-1,2,3-triazol-1yl)-2,2-dimethylnaphtho[1,2-b]furan-4,5-dione proved highly cytotoxic to mdamb-435, with ic50 even lower than the one from doxorubicin (positive control). in an attempt to correlate physicochemical parameters (reduction potentials and calculated log p) with cytotoxic activity, electrochemical studies were conducted in acetate buffer, ph 4.5, using a vitreous carbon electrode and calculated log p values were obtained. despite the absence of a structural conjugative interaction between the two systems (quinone and triazole), the heterocyclic group was found to influence the voltammetric behaviour, as indicated by anodic shifts in the reduction potentials. no correlation was found between epic and cytotoxicity. in contrast, a comparison of epic with previously reported trypanocidal activities reconfirmed the trend for higher activity coupled with better quinone electrophilicity (> epic).a leading term in the correlation of cytoxicity, despite the absence of a linear correlation, was the calculated log p: the lower the lipophilicity, the lower the cytoxicity (> ic50).
Sample optimization for rapid identification of nucleosides and bases from ascidian extracts using ESI-MS/MS
Takeara, Renata;Jimenez, Paula C.;Costa-Lotufo, Letícia V.;Lopes, Jo?o L. C.;Lopes, Norberto P.;
Journal of the Brazilian Chemical Society , 2007, DOI: 10.1590/S0103-50532007000500027
Abstract: electrospray ionization tandem mass spectrometry (esi-ms/ms) method was developed for identification of nucleosides and bases in extracts of ascidians. for this study a systematic sample preparation associated with the fragmentation pattern of a series of nucleosides and bases using esi-ms/ms was done. these approaches constitute powerful analytical tools for rapid screening and structural assignment of nucleosides and bases in ascidian extracts.
Evaluation of the cholinomimetic actions of trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana (Gastropoda, Opisthobranchia)
Kerchove, C.M.;Markus, R.P.;Freitas, J.C.;Costa-Lotufo, L.V.;
Brazilian Journal of Medical and Biological Research , 2002, DOI: 10.1590/S0100-879X2002000400013
Abstract: trimethylsulfonium, a compound present in the midgut gland of the sea hare aplysia brasiliana, negatively modulates vagal response, indicating a probable ability to inhibit cholinergic responses. in the present study, the pharmacological profile of trimethylsulfonium was characterized on muscarinic and nicotinic acetylcholine receptors. in rat jejunum the contractile response induced by trimethylsulfonium (pd2 = 2.46 ± 0.12 and maximal response = 2.14 ± 0.32 g) was not antagonized competitively by atropine. the maximal response (emax) to trimethylsulfonium was diminished in the presence of increasing doses of atropine (p<0.05), suggesting that trimethylsulfonium-induced contraction was not related to muscarinic stimulation, but might be caused by acetylcholine release due to presynaptic stimulation. trimethylsulfonium displaced [3h]-quinuclidinyl benzilate from rat cortex membranes with a low affinity (ki = 0.5 mm). furthermore, it caused contraction of frog rectus abdominis muscles (pd2 = 2.70 ± 0.06 and emax = 4.16 ± 0.9 g), which was competitively antagonized by d-tubocurarine (1, 3 or 10 μm) with a pa2 of 5.79, suggesting a positive interaction with nicotinic receptors. in fact, trimethylsulfonium displaced [3h]-nicotine from rat diaphragm muscle membranes with a ki of 27.1 μm. these results suggest that trimethylsulfonium acts as an agonist on nicotinic receptors, and thus contracts frog skeletal rectus abdominis muscle and rat jejunum smooth muscle via stimulation of postjunctional and neuronal prejunctional nicotinic cholinoreceptors, respectively.
Evaluation of the cholinomimetic actions of trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana (Gastropoda, Opisthobranchia)
Kerchove C.M.,Markus R.P.,Freitas J.C.,Costa-Lotufo L.V.
Brazilian Journal of Medical and Biological Research , 2002,
Abstract: Trimethylsulfonium, a compound present in the midgut gland of the sea hare Aplysia brasiliana, negatively modulates vagal response, indicating a probable ability to inhibit cholinergic responses. In the present study, the pharmacological profile of trimethylsulfonium was characterized on muscarinic and nicotinic acetylcholine receptors. In rat jejunum the contractile response induced by trimethylsulfonium (pD2 = 2.46 ± 0.12 and maximal response = 2.14 ± 0.32 g) was not antagonized competitively by atropine. The maximal response (Emax) to trimethylsulfonium was diminished in the presence of increasing doses of atropine (P<0.05), suggesting that trimethylsulfonium-induced contraction was not related to muscarinic stimulation, but might be caused by acetylcholine release due to presynaptic stimulation. Trimethylsulfonium displaced [3H]-quinuclidinyl benzilate from rat cortex membranes with a low affinity (Ki = 0.5 mM). Furthermore, it caused contraction of frog rectus abdominis muscles (pD2 = 2.70 ± 0.06 and Emax = 4.16 ± 0.9 g), which was competitively antagonized by d-tubocurarine (1, 3 or 10 μM) with a pA2 of 5.79, suggesting a positive interaction with nicotinic receptors. In fact, trimethylsulfonium displaced [3H]-nicotine from rat diaphragm muscle membranes with a Ki of 27.1 μM. These results suggest that trimethylsulfonium acts as an agonist on nicotinic receptors, and thus contracts frog skeletal rectus abdominis muscle and rat jejunum smooth muscle via stimulation of postjunctional and neuronal prejunctional nicotinic cholinoreceptors, respectively.
Synthesis and Biological Evaluation of Rigid Polycyclic Derivatives of the Diels-Alder Adduct Tricyclo[6.2.1.02,7]undeca-4,9-dien-3,6-dione
Felicia Megumi Ito,Jacqueline Marques Petroni,Dênis Pires De Lima,Adilson Beatriz,Maria Rita Marques,Manoel Odorico De Moraes,Letícia Veras Costa-Lotufo,Raquel Carvalho Montenegro,Hemerson Iury Ferreira Magalh?e,Cláudia Do ó Pessoa
Molecules , 2007, DOI: 10.3390/12020271
Abstract: art of our research program concentrates on the discovery of new bioactivecompounds prepared either by total synthesis or molecular transformation of compoundswith bioactivity profiles. In this work we have focused our interest on chemicaltransformations of the Diels-Alder adduct tricyclo[6.2.1.02,7]undeca-4,9-dien-3,6-dione inorder to obtain cage-like compounds and derivatives, followed by an evaluation of theirbiological activity.
Chemical constituents of Lecythis pisonis and cytotoxic activity
Oliveira, Jocélia P. C.;Ferreira, éverton L. F.;Chaves, Mariana H.;Milit?o, Gardenia C. G.;V. Júnior, Gerardo M.;Costa, Arenice de M.;Pessoa, Cláudia do ó;Moraes, Manoel O. de;Costa-Lotufo, Letícia V.;
Revista Brasileira de Farmacognosia , 2012, DOI: 10.1590/S0102-695X2012005000053
Abstract: the phytochemical investigation of the ethanol extract from leaves of lecythis pisonis cambess., lecythidaceae, resulted in the isolation of seven triterpenes: α- and β-amyrin, uvaol and erythrodiol, ursolic and oleanolic acids and 3β-friedelinol, as well as a mixture of sitosterol and stigmasterol steroids and a diterpene (e)-phytol. the structures of these compounds were identified by 1h and 13c nmr spectral analysis and compared with literature data. the mixture of triterpenes ursolic and oleanolic acids isolated from the active ethereal fraction showed moderate cytotoxic activity. this paper describes for the first time the phytochemical and cytotoxic study of lecythis pisonis' leaves.
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