Ricardo José Alves
Universidade Federal de Minas Gerais
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Featured researches published by Ricardo José Alves.
Phytochemistry | 1990
Jost Rěgo de sousa; Grácia Divina de Fátima Silva; Jose´L. Pedersoli; Ricardo José Alves
Abstract The bark wood of Austroplenckia populnea afforded, in addition to 3-hydroxy-2-oxofriedelan- 3-ene-20α-methylcar☐ylate, methyl populnonate, 3-hydroxy-2-oxofriedelan-3-ene-20α-car☐ylic acid, populnonic acid, epikatonic acid, dispermoquinone, β-sitosterol, β-sitostenone and dulcitol, two new pentacyclic triterpenes: 3-oxoolean-12-ene-20α-car☐ylic acid and 3β-hydroxy-2- oxofriedelan-20α-car☐ylic acid. The structures of these have been established from spectral studies and structural correlations, and single-crystal X-ray analysis of 3β-hydroxy-2-oxofriedelan- 20α-car☐ylic acid.
ChemMedChem | 2010
João P. Ribeiro; Sabine André; F. Javier Cañada; Hans-Joachim Gabius; Anna Paola Butera; Ricardo José Alves; Jesús Jiménez-Barbero
The growing awareness of the sugar code—i.e. the biological functionality of glycans—is leading to increased interest in lectins as drug targets. The aim of this study was to establish a strategic combination of screening procedures with increased biorelevance. As a model, we used a potent plant toxin (viscumin) and lactosides synthetically modified at the C6/C6′ positions and the reducing end aglycan. Changes in the saturation transfer difference (STD) in NMR spectroscopy, applied in inhibition assays, yielded evidence for ligand activity and affinity differences. Inhibitory potency was confirmed by the blocking of lectin binding to a glycoprotein‐bearing matrix. In cell‐based assays, iodo/azido‐substituted lactose derivatives were comparatively active. Interestingly, cell‐type dependence was observed, indicating the potential of synthetic carbohydrate derivative to interact with lectins in a cell‐type (glycan profile)‐specific manner. These results are relevent to research into human lectins, glycosciences, and beyond.
Bioorganic & Medicinal Chemistry Letters | 2010
André Luís Branco de Barros; Valbert Nascimento Cardoso; Luciene das Graças Mota; Ricardo José Alves
Three carbohydrate derivatives, MAG(3)-Gl, MAG(3)-Ga, MAG(3)-NG, were synthesized and radiolabeled in high yields. These substances were injected in health Swiss mice and their biodistribution were evaluated. Among them, (99m)Tc-MAG(3)-Ga displayed higher accumulation in hepatic tissue, due to the presence of specific receptors in the liver for this carbohydrate. Thus, the use of (99m)Tc-MAG(3)-Ga to assess hepatic function can be considered.
Bioorganic & Medicinal Chemistry Letters | 2010
André Luís Branco de Barros; Valbert Nascimento Cardoso; Luciene das Graças Mota; Elaine Amaral Leite; Mônica Cristina de Oliveira; Ricardo José Alves
A d-glucose-MAG(3) derivative was successfully synthesized and radiolabeled in high labeling yield. Biodistribution studies and scintigraphic images in Ehrlich tumor-bearing mice were performed. This compound showed high accumulation in tumor tissue with high tumor-to-muscle ratio. Thus, d-glucose-MAG(3) could be considered as agent for tumor diagnosis.
Antimicrobial Agents and Chemotherapy | 2015
Nayara Cristina Fonseca; Luana Faria da Cruz; Filipe Silva Villela; Glaécia Aparecida do Nascimento Pereira; Jair L. Siqueira-Neto; Danielle Kellar; Brian M. Suzuki; Debalina Ray; Thiago Belarmino de Souza; Ricardo José Alves; Policarpo Ademar Sales Junior; Alvaro José Romanha; Silvane M.F. Murta; James H. McKerrow; Conor R. Caffrey; Renata Barbosa de Oliveira; Rafaela Salgado Ferreira
ABSTRACT The pressing need for better drugs against Chagas disease, African sleeping sickness, and schistosomiasis motivates the search for inhibitors of cruzain, rhodesain, and Schistosoma mansoni CB1 (SmCB1), the major cysteine proteases from Trypanosoma cruzi, Trypanosoma brucei, and S. mansoni, respectively. Thiosemicarbazones and heterocyclic analogues have been shown to be both antitrypanocidal and inhibitory against parasite cysteine proteases. A series of compounds was synthesized and evaluated against cruzain, rhodesain, and SmCB1 through biochemical assays to determine their potency and structure-activity relationships (SAR). This approach led to the discovery of 6 rhodesain, 4 cruzain, and 5 SmCB1 inhibitors with 50% inhibitory concentrations (IC50s) of ≤10 μM. Among the compounds tested, the thiosemicarbazone derivative of peracetylated galactoside (compound 4i) was discovered to be a potent rhodesain inhibitor (IC50 = 1.2 ± 1.0 μM). The impact of a range of modifications was determined; removal of thiosemicarbazone or its replacement by semicarbazone resulted in virtually inactive compounds, and modifications in the sugar also diminished potency. Compounds were also evaluated in vitro against the parasites T. cruzi, T. brucei, and S. mansoni, revealing active compounds among this series.
Bioorganic & Medicinal Chemistry Letters | 2009
André Luís Branco de Barros; Valbert Nascimento Cardoso; Luciene das Graças Mota; Elaine Amaral Leite; Mônica Cristina de Oliveira; Ricardo José Alves
A d-glucose-MAG(3) derivative was successfully synthesized and radiolabeled in high labeling yield. Biodistribution studies in Ehrlich tumor-bearing mice were performed. This compound showed high accumulation in tumor tissue with high tumor-to-muscle ratio and moderate tumor-to-blood ratio. Thus, d-glucose-MAG(3) is a potential agent for tumor diagnosis.
Parasitology Research | 2007
Haendel G. N. O. Busatti; Andrea Vieira; Hugo E. Silva; Elaine M. Souza-Fagundes; Olindo Assis Martins-Filho; Ricardo José Alves; Maria Aparecida Gomes
We comparatively evaluate the effect of metronidazole (MTZ) and its five analogues on trophozoites of Giardia lamblia axenically growing. The compounds MTZ-Ms, MTZ-I, MTZ-Br, MTZ-N3, and MTZ-NH3Cl were obtained by molecular modification of the side chain of MTZ. Four of them presented higher giardicidal activity when compared with MTZ. Among them, MTZ-Br and MTZ-I were the most active, without cytotoxic effects against mitogen-activated human peripheral blood mononuclear cells (PBMC). The alteration of MTZ side chain constitutes a fruitful field to develop new drugs for the treatment not only of giardiasis but also of other diseases and signalize that metronidazole analogues are promising candidates as giardicidal and should be further evaluated.
Química Nova | 2002
Renata Barbosa de Oliveira; Ricardo José Alves
A problem often encountered in cancer therapy is the presence of tumor cell subpopulation that are resistant to treatment. Solid tumors frequently contain hypoxic cells that are resistant to killing by ionizing radiation and also by many chemotherapeutic agents. However, these hypoxic cells can be exploited for therapy by non-toxic hypoxic-activated prodrugs. Bioreductive drugs require metabolic reduction to generate cytotoxic metabolites. This process is facilitated by appropriate reductases and the lower oxygen conditions present in solid tumors. The unique presence of hypoxic cells in human tumors provides an important target for selective cancer therapy.
Memorias Do Instituto Oswaldo Cruz | 2003
Renata Barbosa de Oliveira; Ana Paula F. Passos; Rosana O. Alves; Alvaro J. Romanha; Maria Auxiliadora Fontes Prado; José Dias de Souza Filho; Ricardo José Alves
Fourteen compounds were evaluated for their activity against Trypanosoma cruzi blood stream forms at the concentration of 500 g/ml. Six compounds were active and re-tested at lower concentrations.
RSC Advances | 2015
Guilherme A. M. Jardim; Wallace J. Reis; Matheus Ribeiro; Flaviano Melo Ottoni; Ricardo José Alves; Thaissa L. Silva; Marília Oliveira Fonseca Goulart; Antonio L. Braga; Rubem F. S. Menna-Barreto; Kelly Salomão; Solange L. de Castro; Eufrânio N. da Silva Júnior
In our continued search for novel trypanocidal compounds, arylamine, chalcone, triazolic, triazole– carbohydrate and chalcogenium derivatives containing a naphthoquinone scaffold were prepared; in addition to electrochemical studies, these compounds were evaluated against the infective bloodstream form of Trypanosoma cruzi, the etiological agent of Chagas disease. Among the thirty-eight compounds herein evaluated, six were found to be more potent against trypomastigotes than the standard drug benznidazole, with IC50/24 h values between 52.9 and 89.5 mM.