Coumarins are a large class of compounds that display a range of interesting biological properties, being considered privileged structures because of the ability of their 2H-chromen-2-one nuclei to bind to multiple pharmacological targets. We hypothesized that the linkage of a second pharmacophore nucleus to the 2H-chromen-2-one core, the 1,2,3-triazole moiety, would entail more selective and pharmacologically active coumarins. Therefore, we describe the synthesis of fourteen 4-methylcoumarins/1,4-substituted 1,2,3-triazole conjugates, which were predicted by in silico methods to inhibit acetylcholinesterase (AChE) and proved to be moderate in vitro inhibitors of this enzyme. Molecular docking simulations suggest that the most active of these compounds has a putative binding mode similar to donepezil, both occupying the peripheral anionic site of AChE, which is associated with the secondary noncholinergic functions of the enzyme. This highlights the potential of this series for further optimization in the search of new coumarins for the treatment of Alzheimer's disease.

Um método para quantificação simultânea de licopeno, β-caroteno, retinol e α-tocoferol por cromatografia líquida de alta eficiência (HPLC) com detecção no visível/fluorescente e eluição isocrática foi otimizado e validado. O método consiste de extração líquido-líquido rápida e simples e posterior quantificação do sobrenadante extraído por HPLC. Alíquotas de plasma foram estocadas a -20°C por três meses para estudo da estabilidade. Aplicação metodológica foi realizada em amostras fornecidas por pintores e indivíduos não expostos a tintas (n = 75). O ensaio foi linear para todas as vitaminas analisadas (r > 0,99). Precisões intradia e interdia apresentaram coeficiente de variação (CV) menor que 5%. Exatidões variaram de 0,29 a -5,80% e recuperações entre 92,73 e 101,97%. Amostras de plasma e sobrenadante extraído foram estáveis por até 60 dias a -20°C. Foi demonstrada uma diminuição significativa nas concentrações de licopeno, β-caroteno e retinol em indivíduos expostos quando comparados com os não-expostos (p < 0,05). O método é simples, reprodutível, preciso, exato e sensível, e pode ser utilizado na rotina de laboratórios clínicos.

A method for the simultaneous quantification of lycopene, β-carotene, retinol and α-tocopherol by high-performance liquid chromatography (HPLC) with Vis/fluorescence detection with isocratic elution was optimized and validated. The method consists of a rapid and simple liquid-liquid extraction procedure and a posterior quantification of extracted supernatants by HPLC. Aliquots of plasma were stored at -20°C for three months for stability study. The methodology was applied to samples from painters and individuals not exposed to paints (n = 75). The assay was linear for all vitamins (r > 0.99). Intra- and inter-run precisions were obtained with coefficient of variation smaller than 5%. The accuracies ranged from 0.29 to -5.80% and recoveries between 92.73 and 101.97%. Plasma samples and extracted supernatants were stable for 60 days at -20°C. A significant decrease of lycopene, β-carotene and retinol concentrations in plasma from exposed individuals compared to non-exposed individuals (p < 0.05) was observed. The method is simple, reproducible, precise, accurate and sensitive, and can be routinely utilized in clinical laboratories.

A contaminação de pacientes com insuficiência renal por espécies metálicas pode estar associada a presença destes na medicação empregada durante o tratamento. Dentre os possíveis contaminantes estão metais nefrotóxicos tais como alumínio, cromo e níquel. No presente trabalho, a presença de Al, Cr e Ni como contaminantes em formulações de eritropoetina (EPO) foi investigada através da otimização de métodos analíticos empregando a voltamétria adsortiva de redissolucao catódica (AdCSV) associada a foto-decomposição de amostras com radiação UV. A irradiação UV de amostras acidificadas de EPO pelo período de 2 a 3 horas na presença de H2O2 possibilitou a decomposição eficiente da amostra e a determinação dos contaminantes por AdCSV sem a interferência da matriz. O método otimizado foi aplicado na determinação dos metais em formulações comerciais de EPO utilizadas rotineiramente no tratamento da anemia em pacientes com insuficiência renal crônica. Os níveis de contaminação encontrados nas amostras estudadas variaram de 420,2 a 840,5 ng mL-1 (RSD 2-5%) para o Al, de 12,0 a 40,0 ng mL-1 (RSD 2-6%) para o Cr e de 4,1 a 8,2 ng mL-1 (RSD 3-8%) para o Ni. Os resultados obtidos por AdCSV foram comparáveis aos obtidos por espectrometria de absorção atômica com atomização em forno de grafite (GFAAS). A contaminação de formulações EPO com Al, Cr e Ni mostrou ser uma fonte de contaminação importante para pacientes anêmicos com insuficiencia renal crônica.

The contamination of renal failure patients by metals can be associated to the presence of toxic metals in the medication, since they can be absorbed by the organism. Among the possible contaminants, there are nephrotoxic metals such as aluminum, chromium and nickel. In the present work, the presence of Al, Cr and Ni as contaminants in erythropoietin formulations (EPO) was investigated by optimizing the adsorptive cathodic stripping voltammetric (AdCSV) method and the photo-decomposition of samples by UV irradiation. The UV irradiation of acidified EPO samples from 2 to 3 h in the presence of H2O2 allowed the efficient sample decomposition and the determination of the contaminants by AdCSV without matrix interferences. The method was applied for the determination of the metals in commercial EPO formulations used routinely in the treatment of anemia in patients undergoing chronic renal failure. The contamination levels determined in the samples ranged from 420.2 to 840.5 ng mL-1 (RSD 2-5%) for Al, 12.0 to 40.0 ng mL-1 (RSD 2-6%) for Cr and 4.1 to 8.2 ng mL-1 (RSD 3-8%). The results obtained by AdCSV were in good agreement with those obtained by the comparative GFAAS measurements. The contamination of EPO formulations with Al, Cr and Ni was shown to be a serious contamination source for anemic patients undergoing chronic renal failure.

This work describes the optimization of pretreatment steps for the destruction of organic matter in samples of waters and biological fluids, by using an UV irradiation system with a high power UV radiation source (400 W). The efficiency of the system constructed for the photo-decomposition of samples of model waters, natural waters and biological fluids was investigated by performing recovery experiments of the metallic species Zn(II), Cd(II), Pb(II), Cu(II), Al(III) and Fe(III). The use of UV irradiation allowed the liberation of metals bound to the organic matrix and the determination of the total content of elements in the samples.

Large differences in reduced glutathione (GSH) levels have been found in different investigations, also in healthy people. GSH oxidation in vitro has been associated with sample acidification in the presence of oxihemoglobin. In this work, the influence of different acids on GSH determination utilizing HPLC with UV detection was evaluated. The results showed that metaphosphoric acid and sulfosalicylic acid were inadequate for analysis, because metaphosphoric acid showed to be inefficient for deproteinization and with sulfosalicylic acid loss of GSH was observed. Trichloroacetic acid did not effect GSH quantification, since the deproteinized form was immediately derivatized with 5, 5´-dithio-bis (2-nitrobenzoic) acid. Methods with TCA deproteinization presented linear results from 0.5 to 3.0 mM. The correlation coefficient between aqueous curves and GSH spiked RBC exceeded 0.99. Precision calculations showed CV lower than 10% and bias within ± 10% for concentrations of 0.5; 1.5 and 3.0 mM GSH. The recovery was higher than 94%. Moreover, GSH blood concentrations were independent of hemoglobin concentrations.