Resumo em Inglês:

In spite of selenide semiconductors having a wide application area, TlCu2 Se2 (TCSe) is poorly studied and its synthesis by non-vacuum or thermic methodology in film form is non-existent. Generally, the main problems of applying these TCSe compounds are related to complicated single phase growth, and the great time consuming and non-scalable fabrication method. In this work, the facile, fast, scalable and new electrochemical deposition of this material was proposed as a workaround for these main problems and obtaining single phase thin film. Thus, the electrodeposited Tlx Cu3 - x Se2 films were characterized by scanning electron microscopy, X-ray diffraction (with Rietveld refinement) and energy dispersive X-ray spectroscopy. They showed interesting variation of composition (x =1.1, 1.2, and 1.25) and morphology as function of the electrodeposition potential, electrolytic bath temperature and thermal treatment.

Resumo em Inglês:

Vegetable oils have properties that are beneficial to the human skin, and so, they are being used increasingly as ingredients of many cosmetic preparations; however, they are targets of adulteration. This study will evaluate the authenticity of Brazilian cosmetics based on vegetable oils (sesame, peanut, sunflower, and almonds) to determine the composition of fatty acids by gas chromatography with flame ionization detection (GC-FID) and the percentage of fatty acids in conjunction with chemometric treatments (principal component analysis), and lipid profiles using direct infusion electrospray ionization mass spectrometry (ESI-MS). The results obtained were compared with the respective pure vegetable oils. Of the seven brands analyzed, three were revealed as authentic, three were found to be adulterated with the addition of large amounts of soybean oil, and one showed no vegetable oils. These results demonstrate the relevance of quality control for cosmetics based on vegetable oils, which are more susceptible to adulteration owing to their higher cost when compared with vegetable oils such as soybean.

Resumo em Inglês:

This work presents a voltammetric method for Zn2+ determination in antiseptic dusting powder and multivitamin commercial samples, combining an alkaline extraction using NaOH aqueous solution with a carbon paste electrode chemically modified with Bi anchored on Amberlite® IR120 ion exchange resin (CPEAmb/Bi). The best conditions for electrode preparation were: 10% (m/m) of Amberlite® IR 120; 30 s Bi3+ accumulation time (open circuit) in 0.5 mmol L-1 Bi3+ solution prepared in 0.1 mol L-1 acetate buffer (pH = 5.5). The analytical curve for Zn2+ using the CPEAmb/Bi presented linear range from 0.05 to 8.2 µmol L-1 and the limit of detection was 10 nmol L-1. The voltammetric method was simple, fast, efficient and low-cost for the Zn2+ determination in antiseptic dusting powder and multivitamin samples.

Resumo em Inglês:

This study aimed to optimize the acid hydrolysis of glycosylated flavonols, to apply the optimum conditions for hydrolyzing Inga edulis extract (IEE), rich in glycosylated flavonols, and evaluating its impact on the antioxidant capacity. To evaluate the influence of three independent variables on the aglycone obtained after the reaction, the response surface methodology was applied using myricetin-3-O-rhamnoside (M3R) as a pure compound. The phenolic compound profile and antioxidant capacity were determined by high-performance liquid chromatography (HPLC) and the Trolox-equivalent antioxidant capacity (TEAC) assay, respectively. The maximum content of the aglycone myricetin (81.15%) occurred with 2.5 M HCl at 75 ºC for 60 min. Under these conditions, the IEE produced the aglycones myricetin, quercetin and cyanidin. The TEAC values of the M3R samples and IEE before and after acid hydrolysis did not show significant differences (p > 0.05). These results suggest that the hydrolytic process is effective to produce aglycone flavonoids from leaf extracts of I. edulis, and probably for other plant extracts rich in M3R.

Resumo em Inglês:

We describe here the design and synthesis of novel pyrazolothienotriazine compounds based on diazotization followed by cycloaddition reactions of 4-amino-3-methyl-1-phenyl-1H-thieno[2,3-c]pyrazol-5-carbonitrile with sodium nitrite in the presence of concentrated HCl in acetic acid. The produced chloropyrazolothienotriazine underwent nucleophilic substitution reactions with various primary and secondary amines including sulfa drugs to afford the N-substituted aminopyrazolothienotriazines. Hydrazinolysis of the chlorotriazine with hydrazine hydrate afforded the hydrazinotriazine, which was used as a versatile precursor for synthesis of other compounds. The chemical structures of the newly synthesized compounds were confirmed on the basis of elemental and spectral analyses containing Fourier transform infrared spectroscopy (FTIR),1H and 13C nuclear magnetic resonance (NMR) and mass spectrometry. Some of the synthesized compounds showed high antibacterial and anti-fungal activities. Also, most of the tested compounds exhibited high anti-inflammatory activity compared with indomethacin using carrageenan induced rat paw edema assay.

Resumo em Inglês:

This paper reports the synthesis and characterization of ternary CdTe:Zn2+ quantum dots (QDs) passivated with reduced L-glutathione (GSH) dispersed in water. The synthesis was performed through a one-pot approach and their size-dependent optical properties were investigated through steady-state absorption and emission spectroscopies along with the evolving factor analysis/multivariate curve resolution alternating least squares (EFA/MCR-ALS) method. Our results show that the incorporation of Zn2+ ions in CdTe:Zn2+ QDs, during the synthesis time, decreases the CdTe:Zn2+ QDs predominant diameter in the ensemble and increases their size dispersion. In addition, fluorescence quantum yield measurements suggest a reduction in the number of surface defects in CdTe:Zn2+ QDs as compared with CdTe QDs, when both are produced from the same synthesis route.

Resumo em Inglês:

A thiourea derivative, N-[(phenylcarbonyl)carbamothioyl]benzamide, was synthesized and characterized by elemental analysis, thermal analysis, spectroscopic methods (Fourier transform infrared (FTIR), UV-Vis, Raman, matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF), tandem mass spectrometry (MS/MS) and nuclear magnetic resonance (NMR)) and quantum-chemical calculations. The synthetic route was simple and efficient, conducted just by one-step and no purification step was needed. The compound crystallizes in a non-centrosymmetric orthorhombic crystal system with a P21 21 21 space group, with a= 5.06220(10) Å, b= 11.8623(3) Å, c= 21.9682(8) Å. The molecular conformation of the solid is stabilized by the N-H···O intramolecular hydrogen bond, which was present in the X-ray structure and was also found in the optimized geometry. The theoretical analysis showed that this strong interaction remains even when molecules are solvated, i.e., the rotation barrier and the hydrogen bond strength are greater than the solvent stabilization energy. In addition to this hydrogen bond effect, the relative position of phenyl groups has a certain influence on the chemical behavior of this thiourea and probably for other phenylthioureas.

Resumo em Inglês:

Ephedrines are widely used in therapy. Because of their stimulant properties, these substances are relevant in different forensic fields. At present, the state of the art for ephedrines quantification relay based on a liquid chromatography mass spectrometry, mainly because of the dilute-and-shoot approach. Notwithstanding, several gas chromatography based methods have already been described, all of them include cleanup steps, with the potential disadvantage of incurring errors and increasing the workload. In this paper, a straightforward method for ephedrine quantification based on gas chromatographic mass spectrometry, without cleanup and based on Doehlert matrix optimization is presented. Only 10 µL of a urine sample is necessary and for N-methyl-N-(trimethylsilyl)trifluoroacetamide/N-methyl-bis-trifluoracetamide derivatives, the intermediate precision was 2.77% for ephedrine, 9.20% for cathine, 8.29% for norephedrine and 4.27% for pseudoephedrine. The limit of detection was 20 ng mL-1 for ephedrine, 30 ng mL-1 for cathine and 40 ng mL-1 for norephedrine and pseudoephedrine.

Resumo em Inglês:

Aqueous preparations of the grass Eleusine indica are used for treating malaria and lung infections. Despite its widespread occurrence and therapeutic potential, little is known about its chemical composition. This study reports a common chemical pattern for aqueous extracts of E. indica samples from four different localities, separated from each other by approximately 75 to 1340 km, in a wide variety of abiotic and biotic factors. High-performance liquid chromatography with diode array detection (HPLC-DAD), ultra-performance liquid chromatography with diode array detection and mass spectrometry (UPLC-DAD-MS/MS), and nuclear magnetic resonance (NMR) were the analytical techniques applied to characterize substances from E. indica, from each locality. Principal component analysis (PCA) confirmed that E. indica specimens came from four different localities. However, all of the four populations showed a common peaks pattern. This is the first chemical profile report of E. indica. Moreover, p-coumaric acid and isoschaftoside were characterized for the first time in this species.

Resumo em Inglês:

Effluents from pulp mills have a high organic load and can still contain high organic bio-recalcitrant material that is harmful to the aquatic environment, even after undergoing biological treatment in effluent treatment plants. This study presents a novel treatment method tested on effluents (prior to and after biotreatment) from a Brazilian kraft pulp mill, based on hydroxyl radical production and hydrogen peroxide obtained by plasma generated by high-voltage electrolysis. These species present significant oxidation potential that could enable the complete breakdown of the organic matter. From the application of plasma to treat pulp mill effluent for a 7-hour period, it was obtained a chemical oxygen demand (COD) removal between 88.2 and 99.7%, total organic carbon (TOC) removal of 90.3 to 95.6%, and a color removal of 95.0 to 98.0%. The final pH of the treated effluent was 11.6 to 11.9. The results obtained in this study showed that the high-tension plasma treatment, applied on effluent from kraft pulp mills before and after biological treatment, can be an attractive alternative.

Resumo em Inglês:

In this work, two β-enaminoesters, EN1 and EN2, were synthesized, characterized and their anticorrosion effects on American Iron and Steel Institute (AISI) 1020 carbon steel in 0.5 mol L-1 HCl were investigated using gravimetric and electrochemical methods. The results revealed that both compounds inhibit corrosion. Good correlations were observed between results obtained for gravimetric and electrochemical methods. EN1 exhibited highest efficiency of 98% after 24 h of immersion in HCl solution. The adsorption of compounds on steel surface followed the modified Langmuir adsorption isotherm. Surface morphology of carbon steel was examined using scanning electron microscopy showing that the metal surface was protected by EN1 as inhibitor of corrosion.

Resumo em Inglês:

Chagas disease is a tropical parasitic disease that is caused by Trypanosoma cruzi and causes 12,000 deaths per year, mainly in Latin America. The available drugs for treating have severe limitations, including poor efficacy and high toxicity. One way to overcome these limitations is targeting priority molecules with computational tools to direct in vitro assays against validated targets. Farnesyl pyrophosphate synthase (E.C. 2.5.1.10) is an enzyme that participates in the initial stage of sterol biosynthesis, and its inhibition causes damage to membrane integrity, leading to parasite death. With the aim to identify potential inhibitors against this target from T. cruzi, hierarchical virtual screening approaches were performed through a combination of ligand-based pharmacophore models and molecular docking. First, pharmacophore model filtering resulted in 15,154 molecules that had the minimum structural requirements for inhibition (QFIT > 0). These molecules were subsequently submitted to molecular docking routine, which resulted in 11,762 molecules (Grid Score between -232.74 to -0.96 kcal mol-1). The top 30 ranked molecules in these approaches were grouped in self-organizing maps. These analyses showed four promising compounds from natural products that mimic the major interactions present in the substrate/inhibitor, which indicates that these molecules can be assayed by in vitro experiments.

Resumo em Inglês:

A series of twenty-one L-tyrosine derivatives with modifications in the halogenation pattern of the aromatic ring and different degree of methylations on the amine and phenolic hydroxyl groups were synthesized. The structures of all the intermediates and target compounds were confirmed unambiguous by spectroscopy analysis. Additionally, all compounds were evaluated against Plasmodium falciparum and Leishmania panamensis parasites between 20-702 µg mL-1. The cytotoxic evaluation was done to determine the selectivity index for each compound. Six compounds had the lower EC50 (effective concentration 50) against L. panamensis. One of these compounds was the most active with an EC50 at 24.13 µg mL-1 (76.07 µM). All derivatives showed no significant activity against P. falciparum and no compound has in vitro antifungal activity at 500 µg mL-1.

Resumo em Inglês:

Uranium and radium are present in soil, rocks, water and building materials, therefore the presence of 222Rn in the air is natural, and its concentration is determined mainly by physical factors such as soil cover, altitude, porosity and soil particle size, and meteorological conditions. In rooms with poor ventilation,222Rn can accumulate to high concentrations, which increases the risk of developing lung cancer due to continuous exposure to this gas. In this work,222Rn was monitored, with the aid of a real-time radon monitor, RAD7, in offices and rooms at Hospital Universitário Antônio Pedro in order to evaluate the levels of 222Rn to which people are exposed. In general, the values measured in this work are similar to values observed in other studies around the world. The obtained 222Rn level of 40 Bq m-3 is close to the world average of 37 Bq m-3 defined by the United States Environmental Protection Agency (US EPA).

Resumo em Inglês:

Solid residues generated by the petroleum industry are often classified as hazardous, in part due to the lack of adequate analytical methods for their characterization, given their gluey and highly viscous nature. In this study, an alternative to the method described by the United States Environmental Protection Agency (US EPA) method 1311, replacing the zero headspace extraction (ZHE) approach with solid-phase microextraction followed by analysis via gas chromatography-mass spectrometry was developed, for the determination of aromatic chlorinated and non-chlorinated volatile organic compounds. The method was validated according to national and international regulations, with a working range of 2.00 to 90.00 µg L-1 and limit of detection varying from 0.12 to 0.41 µg L-1. Spiked matrices were analyzed and recovery values ranged from 79.7 to 98.4%. The analysis of real samples revealed levels below limit of quantification for chlorobenzene derivatives (2.00 µg L-1) and for the non-chlorinated aromatic compounds < 19.85 µg L-1, proving to be a viable alternative to overcome the difficulties encountered with filtration techniques.

Resumo em Inglês:

The use of insects to identify drugs in a cadaver has often been explored in the field of entomotoxicology. There are accurate methods; however, they require a high cost and are very time-consuming. The objective of this study was to develop two methods based on differential pulse voltammetry (DPV) and fluorescence excitation-emission matrix (EEM) spectroscopy to classify necrophagous larvae (Chrysomya megacephala, C. albiceps, Lucilia sp. and Cochliomyia macellaria) containing flunitrazepam. The voltammograms of larval extract samples were analyzed by principal component analysis (PCA), successive projection algorithm (SPA) and genetic algorithm (GA): linear and quadratic discriminant analysis (LDA and QDA). The EEM fluorescence data from larval extract samples were analyzed by 2D and parallel factor analysis (PARAFAC) with LDA. These results suggest that DPV and EEM combined with chemometrics can be used as tools for the classification of flunitrazepam in fly larvae presenting innovative applications.

Resumo em Inglês:

Biodiesel demand is increasing all over the world and the inhibition of microbial growth during the storage of this biofuel is extremely important. There are few studies involving the evaluation of biocides specifically for biodiesel. In the present work, we synthesized and evaluated a set of biocide candidates from chemical transformations in triacylglycerides. Samples of pure biodiesel with the products were evaluated against microorganisms which have been isolated from biodiesel/diesel blends (fungi A. niger, A. fumigatus, C. albicans and S. cerevisiae; and bacteria B. subtilis and Acinetobacter sp.). None of the products inhibited the growth of bacteria. Four nitrated derivatives presented fungicidal activity. The nitrated derivatives were also evaluated as cetane number improvers for B7 biodiesel/diesel blend. The nitrates of soybean methoxylated ethylene glycol esters increased the cetane number by more than three points. Despite showing modest biocide activity, the results can guide the planning of new products from triacylglycerides.

Resumo em Inglês:

Cat and dog feed production has increased worldwide, and much emphasis has been placed on the importance of determining the mineral composition of pet foods. In this work, the concentrations of Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Sr, V and Zn in dry feed for cats and dogs employing inductively coupled plasma-optical emission spectrometry (ICP OES) were determined and evaluated according to regulatory agencies. Forty-one dry feed samples (24 dog feed and 17 cat feed) were analyzed. The obtained concentrations ranged from 2.3 mg kg-1 (Ba) to 2.8 g kg-1 (Ca) in cat feeds, and from 3.8 mg kg-1 (Cu) to 3.4 g kg-1 (Ca) in dog feeds. The concentrations of P are in accordance with the Brazilian legislation, and Mn and Zn contents met the American legislation. The concentration values of Cu, K and Mg presented in some samples were below the limits established by American regulatory agency. Based on multivariate data analysis evaluated from flavors of the products and brands, it was concluded that the feed samples were uniform since there was no trend to group formation and classification according to their mineral composition, except one dog feed brand, which had a significant content of Al and Cu.

Resumo em Inglês:

Fusarium oxysporum is usually found in foods such as corn, wheat, soybeans and barley, and can cause economic losses and risks to health in humans and animals due to the production of mycotoxins. The conventional microbiological test for fungal identification is based on morphological characteristics, requires specialists, and it is very time-consuming as it is necessary to carry out a culture of the fungus for two weeks before microorganism identification. Nowadays, researchers have made efforts to develop alternative analytical methods with advantages such as shorter time of analysis and better accuracy and reproducibility when compared to microbiological methods. In this way, in the present work, a qualitative analytical method to detect the secondary metabolites of Fusarium oxysporum in culture media by gas chromatography coupled to mass spectrometry (GC-MS) was developed with the intention of relating the presence of these chemical compounds to contamination by the fungus. The method comprised liquid-liquid or liquid-solid extractions with ethyl acetate from liquid and solid culture media, respectively, followed by GC-MS analysis, which was able to identify the presence of fusaric acid, 13-socosenamide, 5-(4-hydroxybutyl)-2-pyridinecarboxylic acid and toxin HT-2. The presence of these compounds was confirmed by high-performance liquid chromatography coupled to mass spectrometry quadrupole time of flight (HPLC-MS/QTOF).

Resumo em Inglês:

A novel, fast, low-cost and scalable methodology to prepare stable magnetoliposomes (MGLs), without the use of organic solvents, is described. The concept of the work is based on the dual use of soy lecithin associated to a new liposome preparation methodology. Soy lecithin was used to coat the nanoparticles of magnetite (Fe3 O4 @lecithin) and for encapsulation of Fe3 O4 @lecithin (Lip-Fe3 O4 @lecithin). Liposomes with size less than 160 nm, polydispersity index of 0.25 and zeta potential of -41 mV, were prepared with the use of autoclave and sonication. The liposomal formulations containing magnetite and stigmasterol (Lip-Fe3 O4 @lecithin, Lip-Stigma and Lip-Stigma-Fe3 O4 @lecithin) were shown to be promising for the application as antibacterial. The liposomal formulation and magnetite were characterized by the following techniques: conventional and high-resolution transmission electron microscopy (TEM/HRTEM), energy-filtered transmission electron microscopy (EFTEM), proton nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), dynamic light scattering (DLS) and zeta potential. The Lip-Fe3 O4 @lecithin had a minimum inhibitory concentration (MIC) of 8.4 µg mL-1 in the presence of 200 Oe magnetic field against S. aureus.

Resumo em Inglês:

A novel one-pot sequence (in 2 or 3 steps) was developed for the synthesis of the tetrahydroquinoline alkaloids (±)-galipinine, (±)-cuspareine, (±)-galipeine and (±)-angustureine, and the derivative (±)-11-methoxy-5,6,6a,7,8,13-hexahydro-13a-aza-benzo[5,6]cyclohepta [1,2-a]naphthalene-12-ol from their respective Wittig adducts in moderate and high yields. The solvolytic N-methylation reaction was shown to be catalyzed by Pt0, generated in situ by reduction of PtO2. The evaluation of biofilm inhibition and antibacterial activity of the compounds against Staphylococcus aureus strains isolated from cows with mastitis revealed that the alkaloid derivative is a promising candidate for an antibiotic drug.

Resumo em Inglês:

In this work a series of 28 novel pyrazolo[3,4-d]pyridazin-7-ones were synthesized and tested against Leishmania amazonensis (strain WHOM/BR/75/JOSEFA) in promastigote and axenic amastigote forms. Five compounds were active against both cellular forms with IC50 (inhibitory concentration growth of 50%) values of 20.2, 11.7, 16.2, 29.5 and 40.3 µM for promastigote and 17.4, 25.2, 3.84, 21.8 and 22.7 µM for axenic amastigote. All compounds were studied by the Lipinski rule, cytotoxicity both in silico and in vitro to fibroblast line (L929) and macrophages (J774A1), and the most active compound showed a selectivity index of 59.9.