Resumo em Inglês:

Ora-pro-nobis (Pereskia aculeata Mill) is an unconventional food plant (UFP) rich in proteins, vitamins, fibers, and antioxidants. In this study, ora-pro-nobis leaves were investigated as a proof of concept by near-infrared (NIR) spectroscopy concerning the storage time (from collection to 12 days), packaging system: styrofoam-based packaging covered with stretchable polychloride vinyl (PVC) film, and vacuum packaging (nylon/poly), temperature (at room temperature of 20 ºC, and in the refrigerator at 4 ºC), and sanitization condition (washed and without washing). Principal component analysis (PCA) was applied to augmented matrices, showing that unwashed leaves stored in the refrigerator with styrofoam-based packaging covered with PVC film were better preserved over time. Furthermore, it has been suggested that NIR absorptions are related to proteins, carbohydrates, lipids, vitamins, antioxidants, and water from ora-pro-nobis leaves and their physiological reactions over time. By combining NIR spectroscopy and chemometrics, a complete understanding of the shelf life of ora-pro-nobis leaves was achieved.

Resumo em Inglês:

Concrete slurry waste is a material removed from sedimentation tanks that receive water used to wash concrete mixer trucks and patios of concrete batching plants (CBP). The objectives of this study were to determine the chemical composition of this residue from three different producers, in three consecutive months and at different collection points using wavelength dispersive X-ray fluorescence, investigate the inconstancy of content through analysis of variance, compare the qualitative and quantitative results with the literature and discuss the possibility of inserting the material in the proposal of different authors. Twenty-two oxides and elements were identified; among them, five showed their incidence in a punctual way. The analysis of variance showed that there are significant differences in the concentration of components between batching plants, months and collection points. The comparison with the literature showed that CaO, Al2O3 and SiO2 are the majority, both in the samples under study and in the samples from different authors. However, the average amounts of CaO are higher in the waste sludge from the concrete batching plants in question and, consequently, if this material were reused in the same proposals as the authors, the products would possibly present different characteristics and performance.

Resumo em Inglês:

High water consumption during irrigation is one of the main problems in agriculture. The preparation of a material that prolongs the water retention capacity of the soil is important. This article aimed to prepare superabsorbent hydrogels by the complexation of chitosan (CHI), with high degree of deacetylation (DD), and carboxymethylcellulose (CMC), with high degree of substitution (SD). Different parameters (concentration and polymeric solutions addition order, polysaccharides’ ratio, pH) were studied. Morphology, thermal stability, chemical composition, mechanical strength, and swelling kinetics of hydrogels in water were evaluated. A hydrogel formation mechanism was discussed and proposed. Results showed that most samples prepared at acid pH disintegrated during swelling test. The morphology of the hydrogels varied with the pH. It was obtained superabsorbent hydrogels (swelling > 400%) based on CMC (SD = 2.23) and CHI (DD = 92%), at basic pH, with good compression strength, and applicable as soil conditioner. The best sample was the one prepared with CMC:CHI = 1:2, polymeric solutions 1.5% m/v and pH 8.

Resumo em Inglês:

Ursolic acid (UA) is being investigated due to its anti-inflammatory potential, and structural modifications can enhance its biological activities. The aim of this study was to evaluate the immunomodulatory effect of the ursolic acid derivatives (UAD) in macrophages and in the carrageenan-induced paw edema model. RAW264.7 cells were cultured in the presence or absence of UA or UAD (1-18). Nitric oxide (NO), nuclear factor kappa B (NF-κB), tumor necrosis factor (TNF), and cellular viability were measured. 30 min before the carrageenan-induced paw edema, the UAD1 and UAD2 (200 mg kg-1) were administered intraperitoneally. The results showed that UAD2-4, UAD7, UAD9-11 had half maximal inhibitory concentration (IC50) greater than 90 µM and were able to reduce NO, NF-κB and TNF production. Moreover, UAD1 and UAD2 reduced paw edema and IL-6 production. In conclusion, the results obtained demonstrated a variation in the response between the derivatives due to the chemical modifications, showing potential to reduce the inflammatory mediators, deserving further investigations.

Resumo em Inglês:

Thermo-responsive copolymers grafted with N-isopropylacrylamide (NIPAm) are excellent candidates for drug release. Dextran sulfate (DS) acts as a specific ligand in inflamed regions, turning it highly useful as a target for drug delivery. DS was associated with NIPAm to produce amphiphilic graft copolymers prepared via free radicals. The molar ratio of feed reagents NIPAm/DS varied from 1 (DS-g-PNIPAm) to 4 (DS-g-4PNIPAm). The synthesis was confirmed by spectroscopic techniques (Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR)). All copolymers showed self-organization capacity in an aqueous medium in temperatures higher than 34 °C, and sizes less than 300 nm. DS-g-3PNIPAm exhibited stability in water and in phosphate buffer at pH 7.4. Scanning electron microscopy confirmed their spherical shape. This copolymer showed specificity to leukemic cells, and normal cells’ proliferation. Methotrexate (MTX) is a very low water-soluble drug used for rheumatoid arthritis and cancer. Unfortunately, MTX have severe collateral effects. MTX-loaded nanoparticles can overcome such issues as well as enhance bioactivity and stability. The MTX was encapsulated and delivered from the DS-g-3PNIPAm with potential target delivery due to the presence of DS. Comparison with MTX encapsulated in other nanoparticles reveals that the DS-g-PNIPam presents the best performance among the thermo-responsive and the second among the target MTX nanocarriers.

Resumo em Inglês:

Cancer treatment represents one of the main scientific study targets today, mainly due to the pronounced side effects arising from chemotherapy. This study reports the synthesis, characterization, and anticancer activity of ten compounds from the Morita-Baylis-Hillman reaction. Ethylene glycol diacrylate was used as a double Michael acceptor in reactions with isatin derivatives to give homodimers of 3-hydroxyindolin-2-one core, recognized in the literature for its extensive pharmacological profile. The use of 1,4-diazabicyclo[2,2,2]octane (DABCO) as a catalyst and room temperature were the optimal conditions for the study reaction. The isolated yields were up to 63%, with most reaction times inferior to 24 h, some as fast as 15 min. The anticancer potential of the synthesized dimers was evaluated in vitro against three cancer strains, resulting in average inhibitory concentrations up to 0.72 µM. It was also found that the best performing homodimers are more active than their monomeric counterparts. Considering the promising selectivity indices observed, the preliminary results obtained here act as a basis for broader tests regarding the effectiveness of homodimeric adducts against cancer cells.

Resumo em Inglês:

Environmental pollution by contaminants of emerging concern, among these various pesticides, has been a concern of environmentalists and scientists around the world. Thus, efforts to mitigate the impacts of these substances have been carried out, and the use of advanced oxidation processes, such as photocatalysis, is an alternative. This work sought to synthesize a composite photocatalyst based on iron oxides and titanium dioxide to assess its applicability in degrading the herbicide bentazon (BTZ) by a lamp that simulates the solar spectrum (visible, ultraviolet A and ultraviolet B) and sunlight. Photocatalytic degradation reached 51% in 120 min with a rate constant k = 0.0058 min-1 when a UV-Vis lamp of 300 W was used. The applicability was demonstrated under sunlight radiation, reaching 38% degradation of a bentazon solution (4.1 × 10-4 mol L-1) after 320 min. TiO2 and Fe2O3 were synthesized similarly but showed no degradation under the same conditions. Thus, Fe2O3-TiO2 is an inexpensive and non-toxic material capable of efficiently conducting the photocatalytic degradation of organic compounds, such as the bentazon herbicide.

Resumo em Inglês:

The Brazilian Cerrado biome is considered one of the 25 hotspots worldwide that contain bioactive compounds due to its great biodiversity; however, the reduction of its native area over time due to the expansion of urbanization and agribusiness may have compromised knowledge of its biological variety. In this context, knowledge about Cerrado species can contribute to its biodiversity preservation. This study aims to describe the isolation, molecular architecture and theoretical calculations of the compound (3S,8S,9S,10R,13R,14S,17R)-17-[(2R,5R)-5 ethyl -6-methylheptan-2 yl]-10,13 dimethyl 2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro-1H cyclopenta[a]phenanthren-3 ol, extracted from the Brazilian Cerrado Miconia burchellii plant. The supramolecular arrangement was described by Hirshfeld surface analysis, demonstrating the intermolecular interactions in the crystalline packing. The structure-property relationship shows the electrostatic potential map analysis, which reveals that the oxygen region is susceptible to electrophilic attack, and the frontier molecular orbital confirmed the kinetic stability of this compound. This study represents another step forward in the knowledge of compounds with pharmacological and medicinal properties extracted from the Cerrado.

Resumo em Inglês:

Humans, animals and wildlife can suffer consequences due to exposure to toxic substances present in the environment, such as disinfection by-products, the halo benzoquinones, which are formed through reactions between chlorine and natural organic matter present in the water. In this paper, the interaction of 2,6-dichloro-3-methyl-1,4-benzoquinone with graphene layer was investigated by ab initio methods based on the density functional theory. The results show that 2,6-dichloro-3-methyl-1,4-benzoquinone adsorption changes the electronic properties of the nanostructure depending on molecule adsorption site. The calculated binding energies show that this molecule interacts with graphene through a chemical adsorption process when the 2,6-dichloro-3-methyl-1,4-benzoquinone molecule is parallel to the graphene layer. Our results are promising because they indicate the ability of graphene to serve as a filter for toxic substances present in the water.

Resumo em Inglês:

Pesticides present utmost importance in modern agriculture and are extensively used in countries with strong agricultural activity, such as Brazil. However, these substances are considered a significant part of environmental contamination by organic compounds. In the present work, Raman spectroscopy was employed in the vibrational characterization of the fungicide tebuconazole and surface-enhanced Raman scattering spectroscopy to the study of the adsorption of this compound on the surface of Ag nanoparticles. The proposed chemical interaction between tebuconazole and the metallic surface was inferred by relating experimental results and vibrational assignment supported by density functional theory calculations. The vibrational assignments of surface-enhanced Raman scattering spectra, by considering surface selection rules, suggest that the adsorption of the tebuconazole with Ag surface occurs by interactions of phenyl and triazole groups simultaneously. For the case of the interaction with the phenyl group, a modification of the charge distribution in the ring after adsorption was hypothesized, which was supported through the analysis of the frontier molecular orbitals of the Ag-tebuconazole complex calculated by density functional theory.

Resumo em Inglês:

Disposal of plastics into the environment has been one of the major problems for the environment. The accumulation of polystyrene (PS) occurs in an accelerated way and, therefore, its reuse is challenging. Polystyrene nanocomposites impregnated with Ag nanoparticles (PS/AgNP) are generated from polystyrene residues and can be applied in the catalytic and plasmonic photo-catalytic reduction of phenolic compounds such as p-nitrophenol (PNP) to p-aminophenol (PAP). The AgNP were synthesized by a reverse micelle method resulting in nanoparticles with sizes in a range of 31.1-34.0 nm. The organocolloid was characterized by UV Vis and dynamic light scattering (DLS), demonstrating the preparation of spherical nanoparticles. The preparation of the PS/AgNP, obtained using a thermally induced phase separation method (TIPS), was confirmed by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), laser-induced breakdown spectroscopy (LIBS), and Fourier transform visible infrared spectroscopy (FTIR). Nanocomposites showed impressive performance in the catalytic and plasmonic photocatalytic reduction under blue light irradiation, reaching up to 98% conversion, being a promising material for wastewater treatment as well as other various environmental issues. We used blue light to observe the plasmonic effect of silver nanoparticles, and no previous reports of this composite for PNP reduction using blue light photocatalysis were found.

Resumo em Inglês:

Rutin is found in several plant sources and has therapeutic effects with excellent healing potential. Its use is restricted due to its low aqueous solubility, requiring a carrier matrix that allows an adequate delivery system. Biopolymer matrices can release the active ingredient in a controlled manner, keeping it within the therapeutic range and minimizing side effects. This study used babassu mesocarp starch films prepared by different routes as Arrabidaea brachypoda DC Bureau (AB) leaf extract carrier matrices to produce a controlled release system. The films were produced by the casting method, and the AB extract was incorporated in the proportion of 0.5% m/m of dry starch. The presence of the extract in the matrix was identified with Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) data and functional analyses. The in vitro release of the AB extract was carried out in phosphate-buffered saline, pH 7.4, and adapted to the Korsmeyer-Peppas model, with coefficients of determination (R2) ≥ 0.9018. The release exponents (n) revealed that the release mechanism is diffusion controlled. Different kinetic constant values (k) indicated that the treatments employed allowed slower and more controlled release profiles, according to the route chosen for matrix preparation. Thus, the materials produced emerge as a new approach to releasing vegetable extracts.

Resumo em Inglês:

A new compound, (6R,7S,2E,4E)-6,7-dihydroxy-4,6-dimethylocta-2,4-dienoic acid (1), together with eight known compounds were isolated from the co-culture of Saccharicola sp. and Botryosphaeria parva, an endophytic fungi associated with Eugenia jambolana Lam. (Myrtaceae) plant species. The structures were elucidated by spectroscopic analysis of the one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and mass spectrometry (MS) data as well as by comparison with literature data. The bioactivity (antioxidant and antifungal) of the crude EtOAc was evaluated. All crude extracts presented antioxidant activity and only the crude extract from the co-culture was active on the fungus Cladosporium sphaerospermum. This investigation contributed to the knowledge about the metabolic production of two endophytic fungi Saccharicola sp. and Botryosphaeria parva in co-culture, once, until the present date, there are no studies in the literature that report the understanding of the chemical interaction of both grown in the same environment.

Resumo em Inglês:

Asymmetric addition of organozinc compounds to carbonyl groups is one of the most useful methods for the synthesis of alcohols with high enantioselectivity. There is a wide range of chiral catalysts, although their synthesis requires more than one step and not often readily available starting materials. In this work, chiral β-hydroxy oxazolines derived from (+)-camphor and (-)-fenchone were easily synthesized through a one-step method, with good yields. Both ligands were evaluated as catalysts for the stereoselective addition of diethylzinc to aromatic aldehydes. All ligands showed good catalytic activity, leading both to the preparation of the R enantiomer of chiral secondary alcohols. As ligand 2 provided slightly better enantioselectivities, it was used as chiral inductor for the addition of diethylzinc for a larger number of aldehydes, resulting in good to excellent yields (88-98%) and enantiomeric excess up to 96%.

Resumo em Inglês:

Cobalt electrowinning is an intensive energy-consuming process, and allied to the increasing demand for pure cobalt, has led to the need for optimization. Based on a statistical approach, the effects of additives, including sodium lauryl sulfate (SLS), boric acid (H3BO3), and cobalt chloride (CoCl2) on the current efficiency of electrowinning have been studied using the cyclic voltammetry (CV). CV tests indicated the concentration range of the more appropriate additives to be used in the factorial design study of electrowinning. Regarding the electrowinning tests, the addition of 0.05 g L-1 SLS, 10 g L-1 H3BO3, 50 g L-1 Na2SO4, and 1 g L-1 CoCl2 led to a current efficiency of 96% and energy consumption of 1.95 kWh kg-1, along with a smooth metallic deposit without evident pits and other defects. SLS in its higher concentration level led to the formation of compact structures, while the higher concentration level of H3BO3, lightens the deposits.