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81.
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Carlos Victor Montefusco-Pereira Maria José de Carvalho Ana Paula de Araújo Boleti Lorisa Simas Teixeira Humberto Reis Matos Emerson Silva Lima 《Applied biochemistry and biotechnology》2013,170(6):1367-1378
Diabetes mellitus is a metabolic disease characterized by abnormally high plasma glucose levels, leading to major complications, such as insulin resistance, obesity, hyperlipidemia, and hypertension, also with alterations in the immune and neuronal systems. Brazilian plants have been studied as important sources for new molecules with medicinal properties. The genus Passiflora known as “Maracujá” has been used as a traditional folk medicine for a long time, so an investigation was performed regarding an endemic kind of passion fruit (Passiflora nitida Kunth) from Amazonas, Brazil. Here, we aimed to determine its potential biological activity against metabolic syndrome, oxidative stress, pain, and inflammation. The hydroethanol leaf extract revealed an in vitro α-glucosidase inhibitory activity of 50 % inhibitory concentration (IC50)?=?6.78?±?0.31 μg/mL and an α-amylase inhibition of IC50?=?93.36?±?4.37. In vivo, experiments of different saccharide tolerance resulted in significant glycemia control and, with alloxan-diabetic mice, resulted in a decrease of total cholesterol, a hypoglycemic effect, and an antioxidant activity by thiobarbituric acid-reactive substances measurement. Also, it decreased the carrageenan-induced edema volume and the rate of writhing as a nociceptive response. These results indicate positive effects of P. nitida extract and its potential to inhibit metabolic syndrome. 相似文献
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84.
Determination of estrogens in environmental water samples using 1,3‐dipentylimidazolium hexafluorophosphate ionic liquid as extraction solvent in dispersive liquid–liquid microextraction 下载免费PDF全文
Bárbara Socas‐Rodríguez Javier Hernández‐Borges María Asensio‐Ramos Antonio V. Herrera‐Herrera Jose A. Palenzuela Miguel Ángel Rodríguez‐Delgado 《Electrophoresis》2014,35(17):2479-2487
In this work, the potential of a symmetric dialkyl‐substituted ionic liquid (IL), 1,3‐dipenthylimidazolium hexafluorophosphate ([PPIm][PF6]), as extraction solvent in dispersive liquid–liquid microextraction (DLLME) has been studied for the analysis of a group of three natural (estriol, 17β‐estradiol, and 17α‐estradiol) and four synthetic (17α‐ethynylestradiol, diethylstibestrol, dienestrol, and hexestrol) estrogenic compounds as well as one mycotoxin with estrogenic activity (zearalenone) in different types of water samples (Milli‐Q, mineral, and wastewater). Separation, determination, and quantification were developed by HPLC‐DAD and a fluorescence detector (FD) connected in series. Factors influencing the IL‐DLLME procedure (sample pH, amount of IL, type and volume of disperser solvent, ionic strength, and assistance of vortex agitation) were investigated and optimized by means of a step‐by‐step approach. Once the optimum extraction conditions were established (10 mL of water at pH 8, 60 mg of [PPIm][PF6], 500 μL of ACN as disperser solvent and vortex agitation for 1 min), the calibration curves of the whole method (IL‐DLLME‐HPLC‐DAD/FD) were obtained and precision and accuracy were evaluated. It was demonstrated that the developed methodology was repeatable, accurate, and selective with limits of detection in the 0.30–0.57 μg/L and 13.8–37.1 μg/L range for FD and DAD, respectively. Relative recovery values were higher than 85% for the different types of water samples and the Student's t test demonstrated that there were not significant differences between the added and the found concentration. 相似文献
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86.
A classical Lewis adduct derives from a covalent bond between a Lewis acid and a base. When the adduct formation is precluded by means of steric hindrance the association of the respective acid-base molecular system is defined as a frustrated Lewis pair (FLP). In this work, the archetypal FLP Mes3P/B(C6F5)3 was characterized for the first time by resonance Raman spectroscopy, and the results were supported by density functional theory (DFT) calculations. The charge transfer nature of the lowest energy electronic transition, from phosphine to borane, was confirmed by the selective enhancement of the Raman bands associated to the FLP chromophore at resonance condition. Herein, we demonstrate the use of resonance Raman spectroscopy as a distinguished technique to probe the weak interaction involved in FLP chemistry. 相似文献
87.
Leonardo Dalseno Antonino Júlia Rocha Gouveia Rogrio Ramos de Sousa Júnior Guilherme Elias Saltarelli Garcia Luara Carneiro Gobbo Lara Basílio Tavares Demetrio Jackson dos Santos 《Molecules (Basel, Switzerland)》2021,26(8)
Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers. 相似文献
88.
Moura Ramos Joaquim J. Diogo Hermínio P. 《Journal of Thermal Analysis and Calorimetry》2021,145(6):3077-3085
Journal of Thermal Analysis and Calorimetry - The thermal behavior of the two glass-forming drugs bifonazole and lamotrigine was studied by differential scanning calorimetry (DSC); we reported a... 相似文献
89.
NMR spin echo measurements of 13C in C60, 89Y in Y2O3, and 29Si in silicon are shown to defy conventional expectations when more than one pi pulse is used. Multiple pi-pulse echo trains may either freeze out or accelerate the decay of the signal, depending on the pi-pulse phase. Average Hamiltonian theory, combined with exact quantum calculations, reveals an intrinsic cause for these coherent phenomena: the dipolar coupling has a many-body effect during any real, finite pulse. 相似文献
90.
Godoi C. M. Santos M. C. L. Silva A. J. Tagomori T. L. Ramos A. S. de Souza R. F. B. Neto A. Oliveira 《Research on Chemical Intermediates》2021,47(2):743-757
Research on Chemical Intermediates - PdxCuy/C catalysts combinations were employed to CH4 partial oxidation in mild condition using a solid electrolyte reactor—alkaline fuel cell type. The... 相似文献