Separation of the toxic zierin from Zollernia ilicifolia by high speed countercurrent chromatography

Preliminary pharmacological assays of the 70% methanol extract from the leaves of the Brazilian medicinal plant Zollernia ilicifolia Vog. (Fabaceae) showed analgesic and antiulcerogenic effects. Previous analyses have shown that this extract contains, besides flavonoid glycosides and saponins, a toxic cyanogenic glycoside. Flavonoids and saponins are compounds reported in literature with antiulcerogenic activity. In this work, we developed a methodology to separate the cyanogenic glycoside from these compounds in order to obtain enough amount of material to perform pharmacological assays. The cyanogenic glycoside zierin (2S)-β-D-glucopyranosyloxy-(3-hydroxy-phenyl)- acetonitrile was separated from the other components by high speed countercurrent chromatography (HSCCC). The solvent system used was composed of chloroform-methanol-n-propanol-water (5:6:1:4, v/v/v/v). This technique led to the separation of zierin from the possible active compounds of Zollernia ilicifolia.

Persistence of epoxy-based sealer residues in dentin treated with different chemical removal protocols

The presence of residual endodontic sealer in the pulp chamber may cause discoloration of the dental crown and interfere with the adhesion of restorative materials. The aim of this study was to compare the efficacy of different solvents in removing residues of an epoxy resin-based sealer (AH Plus) from the dentin walls of the pulp chamber, by scanning electron microscopy (SEM). Forty-four bovine incisor dental crown fragments were treated with 17% EDTA and 2.5% NaOCl. Specimens received a coating of AH Plus and were left undisturbed for 5 min. Then, specimens were divided in four groups (n = 10) and cleaned with one of the following solutions: isopropyl alcohol, 95% ethanol, acetone solution, or amyl acetate solution. Negative controls (n = 2) did not receive AH Plus, while in positive controls (n = 2) the sealer was not removed. AH Plus removal was evaluated by SEM, and a score system was applied. Data were analyzed by Kruskal-Wallis and Dunn tests. None of the solutions tested was able to completely remove AH Plus from the dentin of the pulp chamber. Amyl acetate performed better than 95% ethanol and isopropyl alcohol (p < 0.05), but not better than acetone (p > 0.05) in removing the sealer from dentin. No significant differences were observed between acetone, 95% ethanol, and isopropyl alcohol (p > 0.05). It was concluded that amyl acetate and acetone may be good options for cleaning the pulp chamber after obturation with AH Plus. SCANNING 35:17-21, 2013. © 2012 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

Characterization of a tannase from Emericela nidulans immobilized on ionic and covalent supports for propyl gallate synthesis

The extracellular tannase from Emericela nidulans was immobilized on different ionic and covalent supports. The derivatives obtained using DEAE-Sepharose and Q-Sepharose were thermally stable from 60 to 75 °C, with a half life (t50) >24 h at 80 °C at pH 5. 0. The glyoxyl-agarose and amino-glyoxyl derivatives showed a thermal stability which was lower than that observed for ionic supports. However, when the stability to pH was considered, the derivatives obtained from covalent supports were more stable than those obtained from ionic supports. DEAE-Sepharose and Q-Sepharose derivatives as well as the free enzyme were stable in 30 and 50 % (v/v) 1-propanol. The CNBr-agarose derivative catalyzed complete tannic acid hydrolysis, whereas the Q-Sepharose derivative catalyzed the transesterification reaction to produce propyl gallate (88 % recovery), which is an important antioxidant. © 2012 Springer Science+Business Media Dordrecht.

Atividade de fosfomonohidrolases envolvidas com o crescimento e absorção da cauda de girinos de rã-touro (Lithobates catesbeianus)

Pós-graduação em Biotecnologia - IQ

Prospecção de bioprodutos de interesse industrial a partir da fermentação do glicerol por leveduras

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento de metodologia para determinação de álcoois superiores em álcool combustível, utilizando a técnica de cromatografia líquida de alta eficiência com detecção eletroquímica

Pós-graduação em Química - IQ

Desenvolvimento de um sensor de amálgama sólido para a determinação de enxofre em microemulsões de biodiesel

Pós-graduação em Química - IQ

Síntese, caracterização e investigação das atividades biológicas de complexos de cobre(II) contendo moléculas bioativas e ligantes nitrogenados

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de um magnetometro a precessão nuclear

O objetivo desta tese foi desenvolver um magnetômetro à precessão nuclear para prospecção geofísica e estações-base magnéticas. O magnetômetro à precessão nuclear mede a intensidade total do campo magnético. Seu funcionamento é baseado na ressonância magnética nuclear. A medida de campo é feita pela de terminação da freqüência de precessão de núcleos de hidrogênio – prótons - de líquidos não viscosos no campo magnético terrestre. O magnetômetro é constituído de duas partes: o sensor e o instrumento de medida. O sensor é uma bobina solenoidal, cujo núcleo é preenchido com o líquido. Três líquidos diferentes foram testados; água, propanol e um querosene sintético. Optou-se pelo uso do querosene porque oferece maior amplitude no sinal de precessão, dando, conseqüentemente, maior relação sinal/ ruído. O sistema de medida contém os circuitos de sintonia e amplificação do sinal e, os circuitos lógicos para a programação da operação e contagem da freqüência de precessão. Cada ciclo de medida tem duração de 3 segundos, sendo 2,3s para a polarização e 0,7s para a recepção do sinal. São possíveis dois modos de operação: manual, reciclando automaticamente e por controle remoto. O sinal de precessão é amplificado seletivamente em uma das 14 faixas de sintonia, que cobrem medidas entre 22000 e 95000 gammas. A freqüência de precessão é multiplicada por um fator de 64 e contada durante um tempo igual a 0,36699s, determinado com base na razão giromagnética do próton. O número de pulsos contados é numericamente igual ao valor do campo magnético em gammas. A resposta pode ser lida em mostradores digitais ou na saída BCD paralela quando operando por controle remoto. A precisão da medida é de 1 gamma. O instrumento foi testado no campo para avaliar a relação sinal/ruído, gradiente suportável e consumo de potência. Nos testes de aplicação do protótipo, foram obtidos dados de variação diurna e realizaram-se levantamentos magnético de reconhecimento e detalhe em um sítio arqueológico na Ilha de Marajó, Pará. As respostas dos testes foram comparados com dois magnetômetros comerciais - o GP-70, McPhar e o G-816, Geometrics e, ainda, com dados do Observatório Magnético de Tatuoca-Pa. Em todos os casos, a comparação dos dados mostrou bom desempenho do magnetômetro em teste.

Terpenos e lignanas de Aristolochiaceae

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de sensor baseado em eletrodo modificado com nanotubos de carbono contendo pentacianonitrosilferratos de metais para determinação de antioxidantes em microemulsão de biodiesel

Pós-graduação em Química - IQ

Critical Water Effect on the Plasmon Band and Visible Light Activity of Au/ZnO Nanocomposites

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Acid Lipase from Candida viswanathii: Production, Biochemical Properties, and Potential Application

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thermal and spectroscopic studies of the antioxidant food additive propyl gallate

Literature mentions propyl gallate (PG) as a non-toxic synthetic antioxidant that can be used as a food additive due to its high tolerance to heat. It is important to understand the thermal properties and to identify the decomposition products of this substance, since it has been reported to be thermally stable at temperatures as high as 300 °C. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry-photovisual (DSC-photovisual), coupled thermogravimetry-infrared spectroscopy (TG-FTIR) analyses and spectroscopic techniques were used to study the food additive PG. The TG-DTA curves, which were performed with the aid of DSC-photovisual, provided information concerning the thermal stability and decomposition profiles of the compound. From the TG-FTIR coupled techniques, it was possible to identify n-propanol as a possible volatile compound released during the thermal decomposition of the antioxidant. A complete spectroscopic characterization in the ultraviolet, visible, near and middle infrared regions was performed in order to understand the spectroscopic properties of PG.

Uma nova abordagem analítica sobre teores de 'Zn' por HR-CSAAS em plantas medicinais voltadas ao emagrecimento

The following research project deals with the development of new analytical procedures aimed at the identification and quantification of the element zinc in different fractions of vegetable drugs used for weight loss, using the high-resolution continuum source atomic absorption spectrometry in flame. The determination of the levels of zinc was made in an AnalytikJena ContrAA 300 spectrometer in the principal line of Zn at 213.857 nm and wavelength integrated absorbance equal to 3 pixels. Calibration curves were obtained with linear dynamic range from 0.10 to 1.00 mg L-1, correlation coefficient equal to 0.9991 and limit of detection equal to 0.020 mg L-1. The total Zn content in the samples obtained after microwave-assisted acid digestion system were: 28.06 mg kg-1 (Artichoke), 31.49 mg kg-1 (Chamomile), 77.16 mg kg-1 (Gorse), 105.38 mg kg-1 (Horsetail), 32.37 mg kg-1 (Fennel) and 5.00 mg kg-1 (Senna). The extraction in aqueous environment assisted by microwave radiation produced extracts containing: 5.40 mg kg-1 (Artichoke), 10.65 mg kg-1 (Chamomile), 14.83 mg kg-1 (Gorse), 18.90 mg kg-1 (Horsetail), 7.80 mg kg-1 (Fennel), 3.24 mg kg-1 (Senna), corresponding to 19%, 34%, 19%, 18%, 24% and 64% of their total content of Zn, respectively. The amounts of Zn in the extracted samples from some plants indicate that this metal was strongly bounded to the plant's matrix. The sequential extraction using solvents and mixtures with different polarities (n-hexane, ethyl acetate, propanol, methanol, ethanol-water 1:1 (v/v), water) aimed the separation of different Zn containing species and water was considered the most efficient extractor. The Zn contents extracted were: 14.82 mg kg-1 (Artichoke), 16.82 mg kg-1 (Chamomile), 34.09 mg kg-1 (Gorse), 4.75 mg kg-1 (Senna), corresponding to 53% in the first two samples, 44% and 95% for the last two, respectively. It was observed that Zn is found complexed under