Resumo em Inglês:

Plectranthus amboinicus is an aromatic herb often used in traditional medicine due to its antimicrobial properties. Based on it, the present study aimed to assess the toxic, antioxidant and, antibacterial properties of P. amboinicus essential oil (EO) either separated or mixed into fish feed. The chemical composition of the EO was also investigated. All samples were prepared with over 50% of carvacrol. The results revealed that the EO is a weak antioxidant and highly toxic against Artemia salina, showing greater antibacterial activity than positive control of chloramphenicol and synergistic effects. The EO also presented high antimicrobial activity against Aeromonas hydrophila strains when free or feed-incorporated, thus being a promising product for the treatment of opportunistic infections in fish.

Resumo em Inglês:

We report an ab initio study on the kinetics and chemical dynamics of the CH4 + CH reaction using a coupled cluster based composite scheme that includes unrestricted coupled cluster singles and doubles with perturbative connected triples method, UCCSD(T), energies extrapolated to the complete basis set limit, in addition to core-valence, higher-order correlation, and relativistic corrections. With this protocol, the reaction enthalpies for the two main reaction channels, C2H4 + H and CH2 + CH3, are reproduced with an absolute deviation of 0.04 kcal mol–1 relative to experimental data. At the UCCSD(T)/complete basis set (CBS) level of theory, the formation of the C2H5 intermediate is barrierless, in contrast with the low submerged barrier (–1.87 kcal -mol–1 relative to the reactants) found at the UCCSD(T)/augmented correlation-consistent polarized double-zeta (aug-cc-pVDZ) level of theory. With the correlation-consistent polarized triple-zeta (cc-pVTZ) basis set, we describe structural variations for the reaction bottleneck along the reaction path, finding at least three canonical variational transition states for the temperature range from 20 to 800 K. The thermal rates were obtained via the canonical unified statistical theory (CUS), using the canonical variational transition state theory (VTST) for the inner-transition state and long-range transition state theory (LRTST) for the outer-transition state. Our calculations agree with literature measurements and show inverse Arrhenius behavior, as observed experimentally. At 298 K, the computed rate constant is 2.65 × 10–10 cm3 molecule–1 s–1 and reported experimental measurements range from 2.5 × 10–12 to 3.0 × 10–10 cm3 molecule–1 s–1. Our theoretical study represents an improvement on previous computational investigations and highlights that even relatively simple gas-phase reactions can require high levels of theory to be modeled accurately.

Resumo em Inglês:

Low-cost adsorbents promote the valorization of locally sourced waste materials and are still a significant challenge for removing toxic metal ions from industrial effluents. In this sense, Castor (Ricinus communis L.) stalks (CS) were activated with an alkaline solution and tested as an adsorbent to remove nickel, copper, cadmium, and lead ions. A 24-1 factorial design was carried out and showed a correlation and influence of the variables, such as pH, adsorbent mass, agitation rate, and initial concentration in the adsorption process. The adsorbents in their natural, activated, and saturated states were characterized. After activation, X-ray diffraction results revealed a change from cellulose I to cellulose II. The X-ray fluorescence showed that the ion exchange adsorption mechanism occurred. For the kinetic adsorption studies, the equilibrium time was reached up to 15 min. Different isotherm models described the adsorption process, with the Sips model providing the best fit to the experimental data. Five cycles of sorption/desorption using 0.1 mol L-1 HCl elution were carried out with a minimal loss in sorption capacity and physical degradation. Nickel and copper ions exhibited the lowest desorption rates. Due to their efficiency, CS can be a promising and low-cost alternative for removing metal ions.

Resumo em Inglês:

This study aimed to assess how a partial lockdown due to the coronavirus disease 2019 (COVID-19) pandemic affected air quality in four cities with dissimilar characteristics. In three cities, Araraquara (ARQ), Presidente Prudente (PPE), and Santos (STS), reductions in NO2 concentrations were observed due to social distancing. Conversely, in Santa Gertrudes (SGD), NO2 concentrations increased, indicating that a brief pause in ceramics industry activity was not sufficient to reduce NO2 emissions. A variable behavior was observed in O3 concentrations; in some cases, it followed the trends observed in previous years, but in others, an increase or decrease in concentrations was observed due to variations in concentrations of NO2 and volatile organic compounds and/or climatic conditions. Particulate matter (PM) concentrations decreased in SGD and STS due to social distancing, meteorological conditions, such as wind speed, and reductions in industrial and port activities. Nevertheless, in the cities of ARQ and PPE, particulate matter with aerodynamic diameter ≤ 10 µm (PM10) concentrations were elevated during the pandemic period, due to numerous biomass burning events in 2020. Thus, although vehicular and industrial emission control/reduction policies are effective in improving air quality, they may not be sufficient to achieve air quality standards if they are not combined with more restrictive measures to manage biomass burning.

Resumo em Inglês:

This work is based on the precursor compound cyproflanilide and designs a series of methoxy containing meta-diamine compounds. By replacing the fluorine atom on the phenyl ring in cyproflanilide with methoxy group, 17 derivatives (12a-12q) were obtained with yields ranging from 46 to 92%, which were characterized by high-resolution mass spectrometry, and nuclear magnetic resonance (1H and 13C) spectroscopy and infrared. The insecticidal activities were evaluated against the Plutella xylostella and Spodoptera frugiperda. Compound N-(3-((2-bromopropane-4-(perfluoropropan-2-yl))-6-(trifluoromethyl)phenyl)methoxyphenyl)-N-(cyclopropylmethyl)-6-fluoronicotinamide (12q) showed significant insecticidal activity against the Plutella xylostella with a mortality rate of 97.67% at a concentration of 1 mg L-1. It also exhibited moderate activity against the Spodoptera frugiperda at a concentration of 0.1 mg L-1, which can be used as a template for structure modification to obtain higher insecticidal activity.

Resumo em Inglês:

This work evaluated the multi-element concentration in grape must and soil samples employing inductively coupled plasma optical emission spectrometry (ICP OES), after microwave-assisted digestion. The study aimed to establish a profile of seven grape varieties produced in Petrolina, region Submedium São Francisco, Brazil. Principal component analysis (PCA) clearly showed a good separation of samples in terms of mineral constituents. Although some soil samples showed concentrations of Co, Cu and Ni higher than the prevention values (VP), no sample exceeded the values stipulated for an intervention in agricultural soils based on Resolution No. 420/2009 of the National Council for the Environment (CONAMA). So, the results obtained contribute to food mineral composition table, as it brings unprecedented information about the concentration of the elements in seven grape varieties, providing indicators of geographic location, and contributing to the preliminary construction of a geochemical base of the regional soil.

Resumo em Inglês:

The indiscriminate use of herbicides makes weeds resistant, increasing the demand for more efficient herbicides. Novel potential herbicides were prepared from sorbic acid, being 8 dienamides and 6 epoxides. Subsequently, phytotoxic activities of sorbic acid and 14 synthesized compounds were evaluated against sorghum, onion, cucumber, lettuce, and beggartick seeds. Furthermore, the protein target of the most active substance in plants was identified in silico. Among the tested compounds, (2E,4E)-N-(p-fluorophenyl)hexa-2,4-dienamide (2c), (2E,4E)-N -(o-naphthyl) hexa-2,4-dienamide (2d), (E)-N-methylphenyl-3-((2R,3R)-3-methyloxiran-2-yl)acrylamide (3b), (E)-N-bromophenyl-3-((2R,3R)-3-methyloxiran-2-yl)acrylamide (3e), and (E)-N-methoxyphenyl-3-((2R,3R)-3-methyloxiran-2-yl)acrylamide (3f) showed pronounced inhibitory activities, both of shoots and roots, making them candidates for promising herbicides. All compounds altered seed development, and compounds 2c, 2d, 3b, 3e, and 3f presented equal or superior results to the commercial control herbicide S-metolachlor. Docking studies suggest that enzyme mitogen-activated protein kinase can be the target of those compounds.

Resumo em Inglês:

Ezetimibe has significant lipid-lowering activity but presents low aqueous solubility. Co-crystallization techniques can be used to overcome this limitation. However, it is not yet clear whether the solubility of the cocrystal can be maintained after oral administration. In the present study, an ezetimi-imidazole cocrystal was synthetized by the reaction crystallization method, a promising strategy in cocrystal engineering. After conducting characterization tests, we determined the solubility and thermodynamic stability of the cocrystal. Also, the solubility advantage for both water and biorelevant fasted state simulated intestinal fluid (FaSSIF) was calculated. Dissolution was determined under supersaturated conditions, and the hypolipidemic activity of the cocrystal was assessed in vivo. The cocrystal exhibited high solubility and thermodynamic stability in FaSSIF. The solubility advantage was calculated as 22.4 in water and 11.8 in FaSSIF. The dissolution of the cocrystal resulted in supersaturation levels (σmax) of 1.3 in water and 3.3 in FaSSIF and the area under the curve (AUC) increased from 478.49 (ezetimibe) to 2963.62 µg min mL-1(cocrystal) in FaSSIF. The atherogenic index of the animals that received the cocrystal was similar to that of the control group. These results demonstrate that the inherent advantages of the co-crystallization process were maintained, enabling us to elucidate the behavior of the cocrystal.

Resumo em Inglês:

Herein, we report the preparation of a variety of dye-sensitized TiO2 and its application as a heterogeneous photocatalyst for the oxidative hydroxylation of boronic acids and esters to synthesize phenols. Several organic dyes, namely eosin Y, rose bengal, purpurin, alizarin blue, fluorescein and riboflavin were combined with TiO2. The nanohybrid TiO2-eosin Y showed the best results. Furthermore, we demonstrated a synergistic association between dyes and TiO2 that improves its photocatalytic properties. This methodology resulted compatible for aryl boronic acids with both electron-withdrawing and electron donor groups on the aromatic ring. Thus, the reactions were performed under heterogeneous photocatalytic conditions, employing visible light, saturated oxygen atmosphere, short reaction time, acetonitrile and water as environmentally friendly solvents, to produce the corresponding phenols in very good to excellent isolated yields. Finally, we proposed a mechanism where the selective excitation of EY associated with TiO2 using visible light and the formation of the superoxide anion play a main role in this reaction.

Resumo em Inglês:

Synthesized benzoxazepine derivatives have been characterized and evaluated using 1H, 13C nuclear magnetic resonance (NMR), DEPT 135 (distortionless enhancement by polarization transfer), and high resolution mass spectrometry (HRMS) to confirm the leading benzoxazepine chemical structures. X-ray crystal structure of compounds 10 and 13 (10,11-dimethyl-6,7-dihydrobenzo[f]benzo[4,5]imidazo[1,2-d][1,4]oxazepine and 8,9-dihydrobenzo [4,5]imidazo[1,2-d]naphtho[1,2-f][1,4]oxazepine) were obtained after successful diffraction of the compound crystals. The anti-microbial, anti-cancer and anti-inflammatory activities of the synthesized benzoxazepine derivatives were evaluated. The effect of benzoxazepine derivatives on cancer cell proliferation and microbial growth was studied. Our results revealed limited antimicrobial activity to the synthesized benzoxazepine derivatives with significant activities against certain bacterial pathogens for two compounds. The synthesized benzoxazepine derivatives displayed cytotoxicity against selected solid tumor cell lines with varying effects on the release of human interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) pro-inflammatory cytokines depending on the cancer cell type used. The results of the study suggest that the synthesized benzoxazepine derivatives show anti-cancer and anti-inflammatory agents, though with dependence on the type of cancer cell line.

Resumo em Inglês:

We report on the synthesis of zinc oxide (ZnO) nanostructures using a simple, green, water-based process, without the aid of any chemical precursor or external energy source. Zinc plates were immersed in deionized water and kept at ambient conditions in a dark cabinet for up to 21 days. After immersion, the reaction products were analyzed using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence spectroscopy and Raman spectroscopy. After short immersion times (1-3 days), ZnO agglomerates with a high concentration of oxygen defects were formed, which overlapped along the c axis to form ZnO nanoflowers. After long immersion times (21 days), ZnO microswords with smooth surfaces, well-defined tips, and less oxygen defects were formed. This low-cost, low-energy synthesis process is an attractive alternative to produce ZnO nanostructures with low impact on the environment.

Resumo em Inglês:

Enzymatic reactions have been widely applied to the design of various sensing systems. However, the detection sensitivity of partial systems is still low, possibly attributed to the large molecular size of the substrate. In this study, we propose a strategy toward sensitive enzyme analysis with monoaromatic substrate. That is, salicyl phosphate ester (SPE) as a fluorimetric probe is presented for evaluating the enzymatic activity of alkaline phosphatase (ALP). The sensing mechanism is that ALP catalyzes the dephosphorylation cleavage of SPE and generates salicylic acid with strong fluorescence by modulating intramolecular hydrogen bonding. Due to the specific phosphorylation-dephosphorylation chemistry, the SPE based probe shows high specificity toward ALP over other possible interferents. The SPE probe provides a limit of detection of 0.005 U L-1. In addition, the practical application of the SPE probe is supported by ALP determination in human serum.

Resumo em Inglês:

This work aims to optimize the process of extracting pigments from the peel of Amazonian fruits (bacupari, peach palm, and tucumã) using the enzyme pectinase. First, pigment extraction was carried out using different solvents (ethanol and acetone 80%, ethanol and acetone 50%, and water), temperatures (44, 40, 35, and 26 °C), and wavelengths (400, 450, and 490 nm). In the second stage, the best parameters found in the first stage were applied in a statistic with a response surface varying time (60, 120, and 180 min) and enzyme concentration (40, 80, and 120 U). The best results for extraction for bacupari and peach palm were acetone at 50% and 45 °C and ethanol at 50% and 35 °C for tucumã. In the second stage, the optimum point found was 1.5 h and 100 U concentration, and 2.5 h and 90 U concentration resulted in better extractions for bacupari, peach palm, and tucumã.

Resumo em Inglês:

Organotin compounds (OTCs) are pollutants that affect the reproduction of some marine organisms and can cause autoimmune diseases in humans. Most of the techniques used for detection and monitoring of OTCs in the environment have limitations due to several stages of sample pre-processing. Here, we demonstrated the use of the α-hemolysin (αHL) nanopore as an alternative platform for the detection of the cyhexatin and diphenyltin dichloride (DPhT) in aqueous systems. The detection process is based on the analysis of the residence times of each OTCs within the unitary nanopore, as well as, on the amplitudes of the blockages in the ionic current flowing through it. Cyhexatin and DPhT induced two and three patterns in the amplitude of the blockages in the ionic current, respectively. Residence time value of the cyhexatin inside the nanopore was higher than the value presented by the DPhT. Molecular docking was used to evaluate the interactions between OTCs and nanopore constriction, mainly identifying cation-π and hydrogen interactions. Classical atomistic molecular dynamic simulations confirm moderate aggregative behavior of these OTCs in solution in cationic form, especially for cyhexatin species. The nanopore detects OTCs at nanomolar level and it is possible to use this nanopore to monitor OTCs in aqueous systems.

Resumo em Inglês:

Dyeing of cellulose with reactive dyes (RDs) is an important commercial process because the fibers/fabrics have vivid colors with excellent fastness, since the RD is covalently bonded to cellulose. The subject of the present study is dying of cotton-polyethylene terephthalate (PET) blends using a flow system where the RD absorbance is contentiously monitored by UV-Vis spectroscopy. This allows the collection of extensive data points (≥ 300) to calculate the rate constants, hence the corresponding activation parameters. At a fixed pH = 11.2, a pseudo second-order rate law fits the absorbance vs. time data satisfactorily. At a constant temperature, the order of the dyeing rate constant (k2) is higher for the blend containing 88.9% cotton. The dyeing activation energy, on the other hand, is higher for the blend containing 50% cotton. These results were attributed to the adverse effects of (hydrophobic) PET on the diffusion of RD into the blend. We calculated an equation that shows the dependence of k2 on the temperature and cotton wt.% of the blend.

Resumo em Inglês:

This work describes the multigram-scale synthesis of the building-block N1 (7 chloroquinolin-4-yl)ethane-1,2-diamine via sonochemistry and its use in the synthesis of seven new quinoline-thiazole hybrids endowed with interesting anticancer activity. Target compounds were planned based on the drugs chloroquine and primaquine and the desired thiazoles were obtained through the Hantzsch thiazole synthesis, without the use of catalysts, by reacting key intermediate 1-(2-((7-chloroquinolin-4-yl)amino)ethyl)thiourea, obtained in two-steps from N1 (7-chloroquinolin-4-yl)ethane-1,2-diamine, with different 2-bromoacetophenones. The novel molecules were assessed against four different leukemia cell lines (HL60, K562, KASUMI-1, and KG-1) plus normal fibroblasts (L929), using the 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, and showed, overall, a high cytotoxic profile, but with interesting selectivity index, especially against K562 cells (1.89 to 5.50), when compared to standard doxorubicin (3.51). Docking studies suggest that all tested derivatives are able to interact with BCR-ABL1 tyrosine kinase enzyme, and, therefore, these molecules may be promising leads against chronic myeloid leukemia.

Resumo em Inglês:

Biochar is a material of great ecological interest obtained from the carbonization of biomass. Its structure is composed of graphene-like aggregates, and it contains useful functional groups such as carboxyl. Using these groups, biochar functionalization with triazole groups that improve support characteristics has been achieved to anchor and stabilize catalytically active gold nanoparticles (Au NPs). The Au NPs obtained were homogeneously distributed under biochar, with a size of 7.7 ± 3.5 nm. The efficiency of the nanomaterial was shown in nanogold-catalyzed hydrogen evolution from an aqueous solution containing B2(OH)4, with a maximum hydrogen generation of 715 under optimized conditions (0.070 mmol of Au NPs and 0.300 mol L-1 of NaOH). This nanomaterial showed excellent efficiency in four successive catalytic cycles.