Resumo em Inglês:

Pinacolone and benzopinacolone derivatives are an important class of organic compounds due to their uses in polymer synthesis and more recently as biologically active compounds. The conventional synthesis of such molecules is generally done in two steps, the pinacol coupling followed by the pinacol/pinacolone rearrangement. Aiming to prepare benzopinacolone derivatives in a greener fashion, we present here a one-step synthesis from acetophenones in the presence of zinc and tert-butyl chloride. To develop the methodology, conditions to prepare 3,3-diphenyl-2-butanone from acetophenone were optimized. To assess the scope, different substituted acetophenones were tested, resulting in the corresponding benzopinacolones at moderate yields (20-50%) with high purity. Structural elucidations were performed by 1H and 13C NMR (nuclear magnetic resonance spectroscopy) and GC-MS (gas chromatography-mass spectrometry).

Resumo em Inglês:

The objective of this work was to evaluate the total concentration and bioaccessible fractions of Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Pb, V and Zn in berry fruits and analyze the influence of different cultivars and growing conditions on the obtained results. The variations in bioaccessible concentrations were from 7.7-30, 17-29, 22-50, 1.8-96, 22-33 and 20-51% of the total concentration, for Ba, Cu, Fe, Mn, Pb and Zn, respectively. Copper showed greater bioaccessibility in blackberry and blueberry. For Fe, bioaccessibility was observed in all strawberries and blueberries and in some blackberries. Zinc presented higher bioaccessible fractions in strawberries. For V, only the sample Blackberry 124 showed bioaccessible concentration, (11% of the total concentration). Regarding the different forms of cultivation, the strawberries that received radiation from the red and white lamps presented a higher production of fruit compared to the other systems, however, in relation to the absorption of nutrients, a small variation was observed between the fruits.

Resumo em Inglês:

Diaporthe phaseolorum, an endophyte isolated from Combretum lanceolatum, has exhibited diverse biological activities including antimicrobial, leishmanicidal, antitumoral, and herbicidal properties. Regardless of these activities, there remains limited research on its chemical constituents. Therefore, this study aimed to investigate the metabolome of D. phaseolorum employing mass spectrometry data dereplication through molecular networking and MolNetEnhancer tools. Twenty two molecular families were annotated, including prenol lipids, benzenoids, organoheterocyclic compounds, and nucleosides. Among the 41 nodes annotated, 36 metabolites were confirmed via spectral references, including alismol, farnesol, linoleic acid, tyramine, N-acetyl-tyramine, 5-methoxy-1H-indole-3-carbaldehyde, 6-pentyl-2H-pyran-2-one, and adenosine. Further node annotation was achieved through MolNetEnhancer, resulting in the classification of an additional 68 nodes into various molecular families. Consequently, this study represents a significant contribution to the identification of the D. phaseolorum metabolome, highlighting its secondary metabolites and providing valuable chemical insights to elucidate its demonstrated biological activities.

Resumo em Inglês:

Analysis of variance (ANOVA)-simultaneous component analysis (ASCA) is a method of choice for factorial design studies of environmental impacts on plant metabolomes and can be used to quantitatively carry out this comparative analysis. The impacts of seven mixture design extractor systems made up of ethanol, dichloromethane, and hexane and their 1:1 binary and 1:1:1 ternary solvents for several replicate experiments (n = 3, 4, 5) were assessed using ASCA models determined from Fourier-transform infrared (FTIR), near-infrared (NIR), and UV-Vis spectroscopic measurements on yerba mate leaf extracts. This analysis considered two-factor effects: secondary sexual dimorphism (male and female plants) and cultivation systems (monoculture and agroforestry), as well as their interaction effect. The three binary solvents were found to be more efficient extractor systems for all four detectors as they found 83 main and interaction effects significant at or above the 95% confidence level compared with only 47 for the pure solvent extracts. Binary solvent extracts resulted in averages between 44.04 and 86.61% for the ASCA total effect variances compared with 40.62 to 71.07% for pure extractors. Of the 60 significant effects found for experiments with 5 repetitions 53 or 88% were obtained with only triplicate determinations. The choice of spectroscopic technique and solvent system have large impacts on metabolomic analysis results.

Resumo em Inglês:

Acquired immunodeficiency syndrome is an infectious disease caused by human immunodeficiency virus (HIV). Pharmacological antiretroviral therapy, along with therapeutic monitoring of drug plasma concentrations, facilitates adequate and effective follow-up in each patient. Our main objective was to develop and validate a high-performance liquid chromatography with ultraviolet detector (HPLC-UV) bioanalytical method for the simultaneous quantification of plasma concentrations of three commonly used antiretrovirals in Colombia: efavirenz, lopinavir, and ritonavir. This method is intended for therapeutic drug monitoring in persons living with HIV locally or in developing countries. The method is selective, specific, accurate, precise, and stable over the concentration range of 250 and 20,000 ng mL -1 for the drugs. It was successfully applied to measure the plasma levels of efavirenz, lopinavir, and ritonavir in HIV patients, which ranged from 251.0 ± 10.4 to 7186.2 ± 10.2, 8188.2 ± 5.9 to 15,312.5 ± 6.6, and 246.1 ± 6.5 to 1189.0 ± 6.4 ng mL-1, respectively.

Resumo em Inglês:

This study aims to propose a new method for derivatizing fatty acids (FAs) from human milk (HM), eliminating the lipid extraction step, and simplifying the preparation for gas chromatography with a flame ionization detection (GC-FID) analysis to quantify the FAs. The Design Expert software optimized the reaction times, concentrations, and sample amount. The proposed method (PM) was validated for lyophilized HM and results for the figures of merit for precision in relative standard deviation (RSD) (RSDintra-day 1.34-4.03% and RSDinter day 2.08 5.16%), accuracy (99.87-102.16%), and robustness are within a linear range of 3 to 38% lipids in HM samples. The atmospheric solids analysis probe tandem mass spectrometry (ASAP-MS/MS) technique confirmed the efficiency of PM by expressing the molecular composition of triacylglycerol formed by FAs from the GC-FID technique. The PM requires a small sample size and conducts derivatization directly in the sample matrix, minimizing extraction errors.

Resumo em Inglês:

The species Oryza sativa (rice) and Musa cavendishii (banana) are sources of cellulose-rich waste biomass in the Amazon region, Tocantins State. This research investigates the nanoscale production of cellulose through the interactions between three choline amino acid ionic liquids Ch[AA]IL and the respective fibers by pretreatment. To this end, the synthesis of three ILs was carried out: choline arginate Ch[Arg], choline glycinate Ch[Gly] and choline lysinate Ch[Lys], characterized by Fourier transform infrared spectroscopy (FTIR). The samples resulting from the pretreatment were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It was possible to infer from the SEM micrographs that Ch[Arg] caused greater fiber breakage than the other ILs. The TEM analyses identified fibers up to 16 nm in diameter. Positive effects were observed in the diffractograms, although no crystallinity was obtained in the pretreated samples. Thermogravimetry curves showed that the fibers treated with Ch[Arg] showed higher thermal stability.

Resumo em Inglês:

Gold and platinum bimetallic nanoparticles, Au@PtNPs, have gained attention due to their plasmonic properties. The controlled synthesis of Au@PtNPs involves complex parameters, and the resulting synergy between Au and Pt introduces possibilities for tailoring their properties. This study explores the effects of key-parameters of synthesis (gold core diameters, reaction time, and Pt concentration) on the final properties of Au@PtNPs. Gold nanoparticles of varying diameters were synthesized and used as cores for the reduction of hexachloroplatinic acid, forming a surrounding shell of Pt nanoparticles. The parameters were systematically tuned to understand their impact on morphology, dimension, stability, and plasmonic properties of Au@PtNPs. Increasing Pt precursor concentration resulted in thicker and denser Pt shells, broadening the localized surface plasmon resonance (LSPR) band and improving Au@PtNPs stability. These properties are essential for applications such as photothermal treatment. The synthesis achieved satisfactory products within just 1 h of Pt4+ reduction at mild temperature without using surfactants. Only limited changes in plasmonic properties were observed after 4 h of synthesis, suggesting an optimal reaction period. Manipulating Au core diameter provided LSPR band control, with smaller cores exhibiting greater broadening towards the infrared region. This systematic exploration provided valuable insights for understanding key-parameters governing the synthesis and properties of Au@PtNPs.

Resumo em Inglês:

Parthenolide (PTN) is a secondary metabolite of the plant Tanacetum parthenium (L.) Schulz Bip. and is considered the chemical marker of this species. This sesquiterpene lactone (germacrene skeleton) has been described as responsible for the biological activity of the leaf extract. In addition, several studies in the literature have demonstrated its antiparasitic and antineoplastic activity. However, there is a need for knowledge of other safety parameters, such as pharmacokinetic, pharmacodynamic and toxicity evaluations. Therefore, in this investigation, the in vitro metabolism of parthenolide was performed with rat liver microsomes and biomimetic metabolism (such as cytochrome P-450 system) using organometallic catalysts. The biomimetic procedure was validated since the major compound of biomimetic oxidative reaction with meta-chloroperbenzoic acid catalyzed by metalloporphyrin 5,10,15,20-tetrakis(pentafluorophenyl)-porphyrin iron(III) chloride was also observed with rat liver microsomes. Previous chemoenzymatic synthesis studies of PTN afforded the same epoxide formation, this major oxidative compound was isolated and fully characterized as (1 R,10R)-epoxyparthenolide based on experimental and theoretical calculations of infrared (IR) and vibrational circular dichroism (VCD) data at the B3PW91/6-311G. Furthermore, for the first time, this metabolite was evaluated for trypanocidal and leishmanicidal activity. The mean inhibitory concentration (IC50) values were lower for PTN than its metabolite and showed significant cytotoxic effects for both parasites. This finding holds promise for addressing neglected diseases.

Resumo em Inglês:

Poly(amidoamine)-type dendrimers (PAMAM) were synthesized by divergent routes, and generations (G0.5, G1.0, G1.5, G2.0 and G2.5) along with hydroxylated half-generation polymers (G0.5-OH, G1.5-OH and G2.5-OH) were characterized by Fourier-transform infrared spectroscopy, thermogravimetric analysis and differential scanning calorimetry. Carbon dioxide (CO2) capture tests were performed using thermogravimetric analysis. Among the absorption temperatures tested, 60 °C was the most promising: 0.77, 1.08, and 1.14 mol CO2 L 1 for G0.5-OH, G1.5-OH and G2.5-OH, respectively, of CO2 and partial pressure of 45 kPa. This showed that dendrimers with larger molecular structures have more hydroxyl groups and consequently capture more CO2. However, at low partial pressures (< 2 kPa), CO2 solubility in PAMAM increased with temperature reduction, confirmed by Henry’s solubility constant (398.4 mol m3 kPa 1, in G2.5-OH at 40 °C). According to the thermodynamic properties of CO2 solubilization, the process was spontaneous (∆Gsol < 0) and exothermic (∆Hsol < 0).

Resumo em Inglês:

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by extracellular accumulation of amyloid-β (Aβ) peptides in the brain. This study demonstrates the direct association of the disposable pipette extraction (DPX) with tandem mass spectrometry (MS/MS) for the analysis of Aβ peptides in cerebrospinal fluid (CSF) samples. Different parameters were optimized in order to improve detectability in the MS/MS including mobile phase percentage of ammonium hydroxide, mobile phase flow rate and acquisition mode. Also, this method used an electrospray ionization (ESI) low-flow probe and direct infusion of an organic solution in the MS/MS. The DPX-MS/MS method showed adequate linearity for determining Aβ peptides in CSF-linearity ranged from 0.1 to 1.5 ng mL 1. The coefficients of determination were higher than 0.99; the precision coefficient of variation (CV) ranged from 0.3 to 12.7%; and the accuracy relative standard deviation (RSD) ranged from -13.6 to 13.2%.

Resumo em Inglês:

This work developed an effective and eco-friendly analytical method to support quality control for Brazilian Bill proposal No. 5332/2009. The bill advocates the creation of the “Brazilian bread” by mandating the incorporation of cassava byproducts into wheat flour, with the aim of reducing Brazil’s external dependency on wheat imports and promoting domestic cassava family farming. For this, a handheld near-infrared (NIR) spectrophotometer was utilized for on-site determination of cassava starch in commercial wheat flour. The quantitative analysis, which utilized NIR spectra pre-processed with offset correction (OFF) combined with linear baseline correction (LBC), alongside the successive projections algorithm for interval selection in partial least squares (iSPA-PLS), exhibited superior predictive capability, achieving a relative error of prediction below 8%. Furthermore, the classification process, which involved NIR spectra pre-processed with LBC and iSPA-PLS for discriminant analysis (iSPA-PLS-DA), yielded an impressive 94% overall accuracy, with only 3 misclassifications in the test set.

Resumo em Inglês:

In this work, a miniaturized version of the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was optimized, validated, and applied for extracting eight pesticide residues in anuran liver tissue samples. The extracts were quantified by high-performance liquid chromatography with diode array detection, and the detected residues in liver tissue samples were identified by tandem mass spectrometry-liquid chromatography. The optimized extraction method entailed the scale reduction of the QuEChERS method twenty times using 500 mg of liver tissue sample, 200 mg Mg2SO4, 50 mg NaCl, 1.5 mL of acetonitrile, and a mixture of 25 mg C18 + 25 mg PSA (primary-secondary amine) as dispersive solid-phase extraction sorbent. The method was validated using liver tissue samples spiked at two levels of pesticide concentrations according to the SANTE/11312/2021 document. Recoveries ranged from 91-110% with a relative standard deviation < 20%. The method robustness assessed by the Steiner and Youden test resulted in recovery rate variations of less than 2% for all pesticides after deliberated changes in seven variables. The validated method was applied to 72 liver tissue samples from two anuran species, registering residues of some pesticides in 31 samples. The proposed method proved to be efficient, precise, and robust for determining pesticide residues in anuran liver tissues.

Resumo em Inglês:

The present work reports the in situ fabrication of Ag nanoparticles (AgNPs) in polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) over pre-patterned hydrophobic stripes on a hydrophilic glass surface. Microcontact printing (μCP) using octadecyltrichlorosilane (OTS) as “ink” was used to obtain these chemically modified substrates. A comparison of the results of the PS-b-P2VP self-assembly over a bare glass substrate and a pre-patterned glass substrate demonstrated the influence of the pattern on the film morphology. Polymeric films of Ag+ and PS-b-P2VP were prepared on a pre-patterned substrate and heated at 150 °C to enable the self-reconstruction of the polymeric matrix and the in situ formation of AgNPs (average particle size of approximately 100 nm). The AgNP/PS-b-P2VP thin films were characterized using UV-Vis spectroscopy and atomic force microscopy. The results demonstrate that the concentration of the solutions of Ag+/PS-b-P2VP used to prepare the films strongly influences the morphologies and dispersion of AgNPs. Moreover, the surface-enhanced Raman spectroscopy (SERS) activity of the fabricated polymer nanocomposites using Nile Blue as a molecular probe shows the importance of the chemical modification of the substrate in the enhancement of the SERS signal.

Resumo em Inglês:

In the Amazon, Euterpe oleracea Mart. (açaí), is part of the identity of traditional communities, and the fruit is integrated into their everyday sociocultural dynamics. Hydrolysis and pyrolysis of residual biomass can be alternatives to yield sugars, ethanol, biochar and bio-oil. The açaí seeds subjected to oxidative pretreatment followed by acid hydrolysis increased cellulose to fermentable sugars (reaching 23.5%) and second-generation ethanol production (17.441 L t−1). Açaí oil (ca. 30%) was extracted using a Soxhlet apparatus (using hexane as solvent) and detected through gas chromatography coupled to mass spectrometry (GC-MS), where acids accounted for 82.43% of the total composition, while alcohols comprised only 13.15%. For pyrolysis, temperatures (500 and 550 °C), time (20 and 30 min), and activation temperature (750 and 800 °C) were evaluated, resulting in yields of ca. 22% for biochar and 30% for bio-oil. For the bio-oil, the main compounds detected by GC-MS were acids (16.3%), aldehydes (13.08%), amides (12.19%), alcohols (6.72%), and phenols (4.64%). The obtained biochar displayed surface area values of 553.7 m2 g−1 and 10% crystallinity, indicating its more amorphous nature.

Resumo em Inglês:

The selective separation of precious metals from complex aqueous solutions is important in protecting the environment, aquatic ecosystems, water resources and recycling resources. In this study, cysteine-containing polymeric nanoparticles were synthesized using the molecular imprinting (MIP) technique with the mini-emulsion polymerization method. The basis of the polymer design is inspired by affinity of silver to cysteine in biological systems. The synthesized silver ion imprinted (Ag+-IIP) poly(hydroxyethylmethacrylate-N -methacryloyl-L-cysteine) poly(HEMA-MAC) nanoparticles were characterized by elemental analysis, zeta sizer, Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). The effects of pH, ionic strength and interaction time on adsorption of Ag+ ions were investigated. In experimental studies, the highest adsorption amount (196.9 mg g1 nanoparticle) was reached in a short period of 40 min at pH 5.0 and 150 mg L-1 concentration. Selectivity studies of synthesized Ag+-IIP nanoparticles against silver (Ag+) ions were carried out in the presence of lithium (Li+), barium (Ba2+), mercury (Hg2+) and cadmium (Cd2+) ions. Experimental results indicate that nanoparticles adsorb Ag+ ions with high selectivity. Ag+-IIP nanoparticles have 3.7, 3.1, 2.4, and 2.6 times more selective or higher affinity for Ag+ ions compared to Li+, Ba2+, Hg2+ and Cd2+ ions, respectively, compared to Ag+-non-imprinted (NIP) nanoparticles.

Resumo em Inglês:

The coronavirus disease (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has had a profound impact on global health and socio-economic conditions. To date, various vaccines have been administered worldwide in an effort to curb the spread of the virus. Despite vaccination efforts, there have been complications. Existing antiviral drugs have shown limited effectiveness, prompting the use of computational methods to understand the dynamics of the virus and develop suitable treatments. The current study focuses on using biocompatible para-sulfonato-calix[4]arenes to dock against two key proteins of SARS-CoV-2, namely ribonucleic acid (RNA)-dependent RNA polymerase, and helicase. Docking results indicate a strong binding affinity of these compounds to the target proteins, with higher scores compared to commonly used medications. Molecular dynamics (MD) simulation validates the docking results, showing stable protein-ligand complexes over time. The compounds are also screened for absorption, distribution, metabolism, and excretion properties and toxicity, suggesting their potential as lead candidates for inhibiting the virus’s key proteins. However, further in vivo and in vitro studies are recommended to confirm these findings.

Resumo em Inglês:

Phosphate species can affect aquatic ecosystems, as excess of this nutrient can cause eutrophication, generating environmental impacts. Lamellar double hydroxides have shown promise in removing phosphate at low concentrations (10-50 mg L 1). In this context, lamellar double hydroxides were synthesized interspersed with nitrates and humic substances, searching for a new product that favors phosphorus adsorption. X-ray diffraction showed the presence of characteristic peaks of lamellar double hydroxides and thermogravimetric analysis showed the decomposition behavior of lamellar structure. The adsorption capacity occurred quickly (< 30 min), being more efficient for lamellar double hydroxides with NO3. The maximum adsorption capacity showed results of 35.03 and 44.20 mg g 1 for lamellar double hydroxides with humic substances and lamellar double hydroxides with NO3, respectively. The complexation capacity showed that pH directly influences complexation, being greater for lamellar double hydroxides with humic substances at pH 6.5. Thus, nanostructured materials with humic substances are promising for use in contaminant remediation and adsorption can be a fast and efficient technique for use in soil and water.

Resumo em Inglês:

The present work focused on the screening process of different inorganic oxides and different temperatures for the epoxidation reaction of macaw palm vegetable oil without using solvent, a promising Brazilian biomass that can substitute other vegetable oils (e.g., soybean oil) in technological applications. This oil has an iodine value of 108.48 g of I2 per 100 g being categorized as a semi-dry oil. The epoxidized vegetable oil can be applied in manifold areas in polymer science. The epoxidation reaction here presented avoided organic solvents and organic acids and aimed to produce a greener route using metal oxides or niobium phosphate as a peroxide-activating catalyst. The experimental parameters were maintained as 10 mol% of catalyst loading and a time of 24 h; however, the temperature for some catalysts was changed to improve the epoxide conversion. Experiments were measured by proton nuclear magnetic resonance (1H NMR). Experiments using titanium oxide (TiO2) as a catalyst reached a conversion greater than 84.7%, while experiments using aluminium oxide (Al2O3) or lanthanum oxide (La2O3) achieved conversions of 22.6 and 30.1%, respectively. Furthermore, it was observed that both niobium compounds instantly react with hydrogen peroxide to form peroxy derivatives.