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.

Assessment of Atmospheric PM10 Pollution Levels and Chemical Composition in Urban Areas near the 2016 Olympic Game Arenas
Coarse particulate matter (PM10) concentrations and chemical composition were monitored from 2014 to 2017 at three sampling sites in the Metropolitan Region of Rio de Janeiro, namely Botafogo, G ávea, and Gericinó. All sites are located close to the 2016 Olympic Game arenas. The average annual PM10 concentrations were above the limits recommended by the World Health Organization (WHO) at all sampling sites. Of all the analyzed water-soluble ions, the highest concentrations were obtained f or NO3-, SO42-, Cl- and Na+. Sulfate displayed a higher anthropic contribution (ca. 70%). Iron and copper were present in all samples,...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

3-Aminofurostane Alkaloids from Solanum paniculatum (“Jurubeba Verdadeira”) Roots
In this study, three principal alkaloids were isolated in mixture, and their structures were established by different spectroscopic methods, including 1D, 2D nuclear magnetic resonance (NMR) experiments, and the high-resolution electrospray ionization (HR-ESI)-MS analysis. The isolated alkaloids were used to explore fragmentation pathways. Compound identification was based on the exact mass and fragmentation behaviors. Two compounds were identified as new natural compounds as: (25R)-3 β -amino-furost-5-en-22 α ,26-diol O(26)- β -D-glucopyranoside (fatimagraine) and (25R)-3 β -amino-furost-22-en,26-ol O(26)- β -D-gluco...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Variability of the Volatile Organic Compounds of Achillea millefolium L. According to the Collection Time, Type of Polyethylene Packaging and Storage Period
The objective of this study was to distinguish the time for the collecting of Achillea millefolium L. leaves, which provides the highest yield and quality of the essential oil. Also, identify the type of polyethylene packaging and leaf storage period during the one-year period that would maintain the essential oil characteristics. Gas chromatography-mass spectrometry and chemometric studies were performed into two steps trial to detect changes in chemical profile induced by different conditions. First, an analysis of the leaf collection time was performed using chromatographic data from six different gathering times throug...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Regenerated Cellulose Membrane from Peanut Shell for Biodiesel Purification
Biodiesel purification by water washing has been proved to be an unattractive process from an economic and environmental point of view. In this work, we propose the use of regenerated cellulose membranes from peanut shell as an alternative in the biodiesel purification. The preparation of the membranes was optimized from a central composite design, resulting in dense and non-porous membranes. However, in contact with biodiesel, the membranes undergo expansion due to the retention of methanol, water, and glycerol molecules, allowing the permeation of fatty acid methyl esters. The filtered biodiesel presents quality paramete...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Combretastatin A-4: The Antitubulin Agent that Inspired the Design and Synthesis of Styrene and Spiroisatin Hybrids as Promising Cytotoxic, Antifungal and Antiviral Compounds
The design of a series of styrene and spiroisatin hybrids was based on the structure of combretastatin A-4 1. This library of 20 compounds were synthesized with the pharmacophoric units: 3,4,5-trimethoxy or/and 4-hydroxy-3-methoxy phenyl moities in their structure. Thereby, the libraries of β -nitrostyrenes 10a-10c, spiroisatin-dihydroquinolines 14a-14c, spiroisatin-thiazolidinones 17a-17c and spiroisatin-nitropyrrolizidines 20a-20k were evaluated for their in vitro cytotoxic, anti-proliferative, antifungal and antiviral activities. Biological results revealed that among these compounds, β -nitrostyrenes 10a-10c exhibite...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Chitosan and Agaricus brasiliensis Polysaccharides Films: A Preliminary Study
The known biotechnological properties of chitosan and the recent biological activities attributed to polysaccharides from Agaricus brasiliensis have been of interest to obtain films constituted by these two polymers. The glucans obtained from the mushroom inhibited about 96.5% of the ferrous ion, besides not promoting a significant increase of lactate dehydrogenase enzyme (LDH), which indicates that the polysaccharide is able to inhibit the production of radical species and also presents low cytotoxicity to the biological systems. The results of spectroscopy analyses in the infrared region (FTIR) and X-ray diffraction sugg...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Specific Disulfide Bond Formation Directed by Peptide Nucleic Acids
In this study, we successfully demonstrated a strategy for specific disulfide bond formation by hybridization of two complementary peptide nucleic acid strands. Peptides were linked to the pair of complementary peptide nucleic acids by native chemical ligation, respectively, and base pairing drove the two peptides into close proximity for interchain disulfide bond formation. Since peptide nucleic acids directed system is easier to manipulate than deoxyribonucleic acid system, this system will be more useful and have a broader application scope in the construction of complex biomolecular structures. (Source: Journal of the ...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Zn2Al Layered Double Hydroxides Intercalated with Nitrate and p-Aminobenzoate as Ultraviolet Protective Agents in Low-Density Polyethylene Nanocomposites and Natural Insulating Oils
Zn2Al-Cl and Zn2Al-NO3 layered double hydroxides (LDHs) were synthesized through the fixed pH co-precipitation method and used as precursor materials for the intercalation of p-aminobenzoate through anion exchange reactions. Since chloride in Zn2Al-Cl was only partially exchanged with p-aminobenzoate, the phases Zn2Al-NO3 and Zn2Al-N -AB (nitrate exchanged with p-aminobenzoate) were used in different percentages as functional fillers to produce nanocomposites of low-density polyethylene doped with maleic anhydride (LDPE). Analysis of thermal properties showed that the melting and recrystallization temperatures were slightl...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

An Alternative Spectrophotometric Determination of Carbaryl Insecticide Residues in Water Samples Using the Cerium-Catalyzed Belousov-Zhabotinsky Oscillating Reaction
An alternative approach for carbaryl determination based on the change in the oscillation period of the Belousov-Zhabotinsky (BZ) reaction under the addition of carbaryl is demonstrated. The oscillations were observed by spectrophotometric measurement at 320 nm, corresponding to the maximum absorption wavelength of cerium(IV) catalyst. The oscillation periods increase with the carbaryl concentrations, which can be discussed based on the Field-K örös-Noyes (FKN) mechanism. The increase of oscillation periods is proportional to the concentration of carbaryl in the range of 0.1-200 mg L-1 with the regression coefficient of ...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Synthesis, in silico Study and Antimicrobial Evaluation of New Diesters Derived from Phthaloylglycine
New diesters derived from phthaloylglycine (7a-7i) were synthesized and their structures characterized by infrared, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The compounds were evaluated in an in silico study, which demonstrated positive features indicating a possible drug candidate. The diesters showed antifungal activity ranging from moderate to strong against strains of Candida. Compounds 7a, 7b, 7c, 7e and 7i had a moderate minimum inhibitory concentration (MIC) of 1024 µg mL − 1 against all fungal strains, while 7h showed a very good MIC of 256 µg mL − 1 against Candida albicans, Candida parapsil...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Chemically-Activated Biochar from Ricinus communis L. Cake and Their Potential Applications for the Voltammetric Assessment of Some Relevant Environmental Pollutants
Biochar is a rich-carbon material highly functionalized, which allows the use as electrodes modifier for preconcentration and voltammetric determination of several species. This work describes a castor cake biochar production and chemical activation with different reaction conditions using HNO3 and/or H2O2. Biochar samples were characterized using scanning electron microscopy, energy dispersive spectroscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman and zeta potential. Carbon paste modified electrodes (CPME) have been constructed using different biochar samples to evaluate the adsorptive ca...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

In silico Risk Assessment Studies of New Psychoactive Substances Derived from Amphetamines and Cathinones
The amount and variety of new psychoactive substances (NPS) are expanding, and there are difficulties in assessing their risks. In this regard, in silico methods are potentially useful to predict NPS properties faster and at a lower cost. In this work a quantitative structure-activity relationship (QSAR) model was used to verify the risk of drugs derived from amphetamines and cathinones. A dataset of 26 derivatives with in vitro affinity for norepinephrine transporter (NET) was selected. To ensure reproducibility of the results, only geometric molecular descriptors (AM1 (Austin model 1) level) obtained from the platform Ch...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Methodology Development and Validation of Amphotericin B Stability by HPLC-DAD
The high worldwide consumption of antibiotics and their complex impurity profiles has drawn the attention of the scientific community to the development and validation of stability methods for these drugs. Amphotericin B is an antibiotic that is a natural fermentation product of bacterium Streptomyces nodosus, used as a broad-spectrum antifungal agent, and is highly unstable. For this reason, the objective of this work is the development and validation of an indicative method of stability by high performance liquid chromatography (HPLC) associated to diode array detector (DAD) for amphotericin B (AMB). To achieve this, the...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Optimization of Alkaline, Acidic, Ionic Liquid and Oxidative Pretreatments for Coconut Waste Conversion into Fermentable Sugars
Cocos nucifera L. is a palm tree of paramount importance in the food and chemistry industries, although over 50% of its biomass is discarded as waste. The aim of the study is to investigate different pretreatments in to coconut husks (CH), based on acid, alkaline, ionic liquid (IL), and peroxidative, in order to produce fermentable sugars. Severity factors were calculated for pretreatments; values ranged from 0.3 to 1.7 for peroxide, from 0.01 to 1.4 for alkaline, from 1.4 to 2.8 for acid and from 2.0 to 3.0 for ionic liquid. Pretreatments were optimized (time and temperature) to maximize the sugar yield and to remove the ...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research

Simple GFAAS Method for Determination of Pb, As, and Cd in Cannabidiol Extracts Used for Therapeutic Purposes
Cannabis sativa has many promising medicinal applications for the mitigation, or even cure, of chronic diseases. The high bioaccumulation potential of C. sativa enables its use for the phytoremediation and detoxification of soil, may increase the levels of inorganic elements in products such as cannabidiol (CBD) extracts being necessary the evaluation/monitoring of the level of inorganic components, mainly the toxic species in these formulations. An analytical method employing graphite furnace atomic absorption spectrometry (GFAAS) was developed for the quantification of Pb, As, and Cd in commercial CBD extracts and homema...
Source: Journal of the Brazilian Chemical Society - May 1, 2020 Category: Chemistry Source Type: research