Journal of the Brazilian Chemical Society This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Bioactive Bioflavonoids from Platonia insignis (Bacuri) Residues as Added Value Compounds
Platonia insignis fruit, popularly known as bacuri, is traditionally used in folk medicine for its anti-inflammatory and antioxidant properties. Therefore, this study determined the chemical composition and biological activities of the bacuri ’ s shell and seeds extracts, considered residues from its consumption and industrial uses. Four biflavonoids (GB-2a, GB-1a, morelloflavone, and volkensiflavone) were identified in the extracts by high-performance liquid chromatography-diode array detection (HPLC-DAD), liquid chromatography tandem mass spectrometry (LC-MS/MS), and liquid chromatography-solid phase extraction-nuclear...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

Device for Streptavidin Detection Using LSPR and Electrochemical Transductions on the same Platform
Research in biosensing currently occupies an important role among biomolecular detection techniques, especially with respect to medical diagnoses. Is this sense, the development of biosensors based on the localized surface plasmon resonance (an optical transducer) or electrochemical transductions have been highlighted. However, optical and electrochemical detection working together enable more versatile detections in biosensing. Thus, we propose a dual sensor, which incorporates these two mechanisms on the same platform. The sensor shared the same transducer that was based on a glass-indium thin oxide (ITO) surface covered...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

Identification of Potential Human Protein Targets for Soybean Isoflavones
Soy isoflavones have been reported as endocrine disruptors due to their ability to modulate the activity of estrogen receptors (ERs) in mammals; however, its ability to modulate other metabolic pathways is not entirely clear, which makes it necessary to identify new pharmacological targets that interact with these compounds present in soybean. In this work, a virtual screening was executed to identify potential targets of nine soy isoflavones, employing human proteins target from PharmMapper. The best 25 fit scores were selected and prepared for AutoDock Vina docking protocols. The results suggest that equol, daidzein and ...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

Synthetic Studies toward (−)-Cleistenolide: Highly Stereoselective Synthesis of New γ-Lactone Subunits
This study describes the stereoselective synthesis of two new γ -lactones in 6 and 3 steps and 19 and 32% yield, respectively, directed toward the total synthesis of the natural product ( − )-cleistenolide. The starting material was an enantiomerically pure diacetonide diol, derived from d-mannitol with the required stereocenters for ( − )-cleistenolide synthesis. γ -Lactone syntheses were based on highly selective protection and deprotection of hydroxyls from d-mannitol. The formation of γ -lactone rings was the culmination of this approach, made possible by a Horner-Wadsworth-Emmons Z-olefination between diacetal ...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

The Stabilization of Asphaltenes in Different Crude Fractions: A Molecular Approach
The conditions of petroleum extraction may allow asphaltenes to precipitate, causing deposition that clogs wells, pipes and equipment, consequently reducing productivity. In this work, the solubility parameters and precipitation onset of polar fractions of heavy crudes from Brazilian fields were estimated using a simplified system of n-heptane/toluene mixtures. Asphaltenes were extracted by two different methods with regard to pressure and temperature. The samples were physically and chemically characterized, and both density (1053-1159 kg m-3) and molecular weight (1176-5316 g mol-1) were estimated based on the density of...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

Study of the CuII Affinity by Three Chelating Agents of Biological Interest: TPEN, TRIEN and Et2DTC
Copper is an important micronutrient, and it is present in some protein structures, as well as participate in several important biological processes. Due to its importance, some ligands are used and studied like carriers of copper in the biological systems. This work has investigated the affinity of CuII by three ligands of biological interest: N, N, N, N ’ -tetrakis (2-pyridilmethyl) ethylenediamine (TPEN), triethylenetetramine (TRIEN), and diethyldithiocarbamate (Et2DTC), used for this purpose. The studies were performed by evaluating the CuII d-d band when complexed with these three ligands. The CuII d-d band in aqueo...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

Validation of an UHPLC-MS/MS Method for the Determination of Malachite Green, Leucomalachite Green, Crystal Violet, and Leucocrystal Violet in Shrimp, Fish, and Salmon Muscle Using a Modified QuEChERS Approach
A quantitative and confirmatory method for detecting the presence of triphenylmethane dyes in shrimp muscle using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) and a quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction approach was validated. The method exhibited linearity and selectivity and the coefficient of determination (R2) was higher than 0.95 for all studied analytes. Limits of detection (LODs) varied from 0.32 to 0.44 µg kg-1 and the limit of quantification (LOQ) was determined to be 0.5 µg kg-1 for all studied analytes. The trueness, precision, decision limi...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

Synthesis, in silico Study and Antileishmanial Evaluation of New Selenides Derived from 7-Chloro-quinoline and N-Phenylacetamides
This study describes a virtual screening performed for two series of selenides (28 compounds), derived from N-phenylacetamides chlorides and 7-chloro-quinoline, to determine their potential for leishmanicidal activity against Leishmania amazonensis and Leishmania donovani. Seven compounds were predicted as potential leishmanicides; therefore, they were synthesized from elemental selenium, as a precursor for the production of NaHSe, and subsequent reactions with 4,7-dichloro-quinoline and N-phenylacetamides chlorides were performed. The compounds were characterized by infrared (IR), 1H and 13C nuclear magnetic resonance (NM...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

Microwave-Assisted Acid Digestion: Evaluation of Reaction Vessel Design and Performance
Nowadays, microwave-assisted procedures using closed vessels with thermal, chemical, and mechanical resistance are the state-of-the-art for efficient digestion of samples. Safety issues related to sample reactivity should be considered and analytical throughput is also a critical parameter. The choice of a specific vessel for a target application is not trivial and simple experiments are presented here for rice flour and bovine liver samples to illustrate effects of vessel design on digestion performance. Despite using the same heating program, the residual carbon contents varied from 22 to 67% to bovine liver digests and ...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

Structural Study of Wheat Gliadin in Different Solvents by Spectroscopic Techniques
Physicochemical properties of gliadin in different solvents (dimethyl sulfoxide (DMSO), H2O, and aqueous ethanol) and pH (9.8, 6.8, and 1.2) were investigated using dynamic light scattering (DLS), zeta potential (ZP), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Gliadin-DMSO and gliadin-deionized water (H2O) (pH 9.8) showed a lower size distribution, whereas samples solubilized in 60% aqueous ethanol presented a lower size distribution only at pH 1.2. ZP analysis showed that gliadin-H2O (pH 9.8) was the most stable evaluated system. ZP results of gliadin-DMSO indicated an unstable sy...
Source: Journal of the Brazilian Chemical Society - March 29, 2021 Category: Chemistry Source Type: research

Metal Distribution in the Environmental Compartments of Manguaba Lagoon (Alagoas State, Brazil)
The metal concentrations in water, sediments and mollusks (Tagelus plebeius) of the Manguaba Lagoon and the influence of humic substances from water and sediments in the distribution of these metals were investigated in this work. The mean metal concentrations in water were: Mg (89.0 ± 0.11), Ca (32.0 ± 0.10), Fe (0.97 ± 0.02), Mn (0.52 ± 0.01), Zn (0.33 ± 0.10) and Pb (0.22 ± 0.02) mg L-1. The Pb concentrations were above the Brazilian legislation limit. All sediment data were below maximum limit established by the National Council for the Environment (CONAMA, Brazil) of the Ministry of the Environment, and the conc...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

PhotoMetrix UVC: A New Smartphone-Based Device for Digital Image Colorimetric Analysis Using PLS Regression
A novel free PhotoMetrix UVC is proposed for both the operation of a universal serial bus video camera (UVC) and multivariate image analysis, allowing a full solution for point-of-use analysis. A UVC was placed in an open-source 3D-printed chamber illuminated by a white light-emitting diode (LED) with controlled intensity of light. The digital images captured were converted into red, green, and blue (RGB) histograms, and regression models were used within the app. As a proof-of-concept, four adulterants in raw milk samples were determined. The coefficient of determination (R2Cal) for all models was higher than 0.99, and no...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Perovskite-Type Oxides La0.6M0.4Ni0.6Cu0.4O3 (M = Ag, Ba, Ce) towards the Oxygen Reduction Reaction (ORR) in Alkaline Medium: Structural Aspects and Electrocatalytic Activity
In this work, La0.6M0.4Ni0.6Cu0.4O3 (M = Ag, Ba, and Ce, denoted as LANC, LBNC, and LCNC, respectively) electrocatalysts were synthesized by the Pechini method at 1023 K for two hours in air. Rietveld refinement allowed the identification of the crystallographic phases present in all oxides. The electrocatalytic performance of these oxides towards the oxygen reduction reaction (ORR) was examined in alkaline medium by rotating disk electrode (RDE) technique and scanning electrochemical microscopy (SECM) in the redox competition mode. The results indicate that the best performance was found with the LANC electrocatalyst prep...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Inhibition of Acetylcholinesterase by Coumarin-Linked Amino Acids Synthetized via Triazole Associated with Molecule Partition Coefficient
A previous study for the identification of acetylcholinesterase (AChE) inhibitors demonstrated that the hybrid between tyrosol, the 1,2,3-triazole nucleus, and the coumarin group, namely 7-({1-[2-(4-hydroxyphenyl)ethyl]-1H-1,2,3-triazol-4-yl}methoxy)-4-methyl-2H-chromen-2-one (10), has a high enzyme inhibitory activity. Here, we synthesized analogues of 10 via triazole with pharmacophoric groups represented by tyrosine, phenylalanine, tryptophan, and glycine in addition to evaluating the impact of coumarin-linked amino acids on AChE inhibition. We obtained eight triazoles, six of which are undescribed. In general, the pres...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Compatibility by a Nonisothermal Kinetic Study of Azathioprine Associated with Usual Excipients in the Product Quality Review Process
Azathioprine is an immunosuppressive drug for several inflammatory disorders. Due to its clinical relevance, to explore the solid-state properties for excipient compatibility in the product quality review process is essential. Fourier transform infrared spectroscopy, powder X-ray diffraction and thermal analysis (thermogravimetry/derivative thermogravimetry (TG/DTG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC)) were applied. The compatibility studies evidenced that starch pregelatinized, colloidal silicon dioxide, and talc are fully compatible with azathioprine. However, stearic acid, m...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research