Resumo em Inglês:

CNFD (6b,7-dihydro-5H-cyclopenta[b]naphtho[2,1-d]furan-5,6(9aH)-dione) is a semisynthetic naphthoquinone derived from lawsone that has cytotoxic action in different tumor lines and anticancer activity in vivo. Therefore, this molecule is a relevant candidate for drug development, but there is still no information on its human metabolism and systemic elimination. This study aimed to investigate the in vitro metabolism of this naphthoquinone by human liver microsomes. Initially, in order to determine the in vitro enzymatic kinetic parameters, a high performance liquid chromatography (HPLC) method to quantify the CNFD was developed and validated. In addition, the enzymatic kinetic data, the predicted pharmacokinetic in vivo parameters and the phenotyping study were presented. The main metabolism sites and metabolites have been suggested in silico. The developed HPLC method was linear, reproducible, selective, accurate, and stable. The enzymatic kinetic parameters revealed a sigmoidal profile. In vitro to in vivo extrapolation hepatic metabolic clearance was 10.39 mL min-1 kg-1 protein and the liver extraction rate was 51%. The clearance in vivo associated with a hepatic extraction ratio indicates that the hepatic metabolism is the main route of elimination. Although all cytochrome P450 enzymes evaluated metabolized CNFD, CYP2C9 and CYP3A4 showed higher metabolic capacity. For the first time, metabolism studies of CNFD were demonstrated.

Resumo em Inglês:

The glycerol oxidative dehydration to organic compounds, especially acrolein and acrylic acid, was studied over vanadium, molybdenum, and cobalt oxides supported on niobium oxide and niobium phosphate catalysts. At 300 °C, the glycerol conversion was 100% over all catalysts tested, and acrolein was the main product observed, without significant deactivation within the time on stream studied. Except for Co/V/Nb2O5, acrylic acid was formed over all catalysts, but the selectivity was not higher than 10%. Acetaldehyde and acetic acid were the other organic oxygenated products formed. Although the catalysts supported over Nb2O5 presented significantly lower acidity than the catalysts supported over NbOPO4, they showed 100% glycerol conversion, indicating that the dehydration of glycerol does not require strong acidity. These data indicate the potential of niobium-based supports in the development of an active and selective catalyst for the glycerol oxidehydration to acrolein and acrylic acid, chemicals of great importance in the industry.

Resumo em Inglês:

The development of efficient, stable, and non-precious metal water oxidation catalysts (WOCs) is a matter of importance for sustainable energy research. In this work, iron cobaltite (FeCo2O4) nanoparticles were prepared by the coprecipitation method, and we present the effect of heat treatment (250, 350, 450, 650 and 900 °C) on the catalytic properties. Catalytic activity tests of FeCo2O4 nanocatalysts were performed in the presence of ammonium cerium(IV) nitrate (CAN), and the formation of oxygen was followed using a Clark-type oxygen electrode. The samples were characterized by infrared (IR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and their surface areas were determined by the Brunauer, Emmett, and Teller (BET) method. Fourier transform infrared (FTIR) data confirm a metal-oxygen bond at the octahedral and tetrahedral sites. XRDs data were characteristic of spinel-like cubic materials. The XPS results confirmed the presence of trivalent and divalent cobalt and iron ions in the samples and showed that the non-heated sample has a greater amount of cobalt on the nanoparticles’ surface than those heated to 900 °C. The surface area decreased from 92.00 m2 g-1 for the material that was unannealed to 2.00 m2 g-1 for the sample annealed at 900 °C. The unannealed nanomaterials showed an oxygen production of 790 mmol s-1 g-1. This was 790 times greater than the oxygen production from nanomaterials heated to 900 °C. Although the surface structure of nanomaterials is unclear, the amount of surface cobalt appears to have implications for catalytic activity. Optimization of superficial cobalt content may be key to improving catalytic activity.

Resumo em Inglês:

The antifungal potential of volatile organic compounds (VOCs) produced by actinobacterial strains Streptomyces sp. (ACTB-77) and Amycolatopsis sp. (ACTB-290) from the rhizosphere of Caatinga plants against Colletotrichum musae was investigated. VOCs produced by these microorganisms (axenic and co-culture) were investigated using headspace-solid phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). Although no exclusive VOC peaks were observed in the co-culture with ACTB-77, the same experiment involving ACTB-290 yielded five new peaks, including two identified alcohols, suggested as bioreductive products of the corresponding ketones by the fungus. Statistical analysis revealed that co-culture ACTB-77/C. musae has a closer similarity to the fungus than to the actinobacteria, while the co culture ACTB-290/C. musae showed closer similarity to the actinobacteria. These confirmed the more pronounced antifungal activity of the ACTB-290 strain, as observed in the fungus growth inhibition experiments. The antifungal activity of ACTB-290 was associated to its sulfur-containing metabolites, while linalool was suggested as responsible for the ACTB-77 activity.

Resumo em Inglês:

The dielectric barrier discharge ionization detector (BID) is one of the most modern detectors commercially available for gas chromatography (GC). Its technology based on the sample ionization through the energy released from the helium plasma generation process gives it the ability to act as a universal detector and a greater response to various types of compounds compared to the well-established flame ionization detector (FID). In this study, polycyclic aromatic hydrocarbons (PAHs), organophosphates (OPPs) and organochlorines pesticides (OCPs) were investigated. The parameters that could explain the performance of the BID and FID detectors were: structural factors, ionization energy (IE) and energy of the highest occupied molecular orbital (EHOMO), which were obtained by density functional theory (DFT). The relative (BID/FID) responses to PAHs and pesticides were about 1.8 and 3.0 times greater than FID, respectively. Less structural dependence of the BID signal compared to the FID signal was observed. Among the parameters calculated by DFT, the IE was the one that most seemed to have influenced the response of the two detectors studied. The theoretical data proved to be quite consistent to explain the trends observed experimentally, especially to the BID.

Resumo em Inglês:

Eugenol (C10H12O2, 4-allyl-2-methoxyphenol) is a phenolic natural product that has several biological activities and possibilities of applications. It is herein described the synthesis of eugenol-fluorinated triazole derivatives and evaluation of their fungicidal activity. The reaction of eugenol with epichlorohydrin resulted in the preparation of (±)-2-((4-allyl-2-methoxyphenoxy)methyl)oxirane (1) in 88% yield. The azidolysis of 1 with sodium azide gave the azido-alcohol (±)-1-(4-allyl-2-methoxyphenoxy)-3-azidopropan-2-ol (2) in 94% yield. The CuAAc reaction between compound 2 and different terminal alkynes afforded a series of eleven derivatives (3a 3k) within 48-80% yield. All the synthesized compounds were characterized by infrared (IR) and nuclear magnetic resonance (1H and 13C) spectroscopies and high-resolution mass spectrometry. The in vitro inhibitory activity of the compounds on the mycelial growth of a strain of Colletotrichum sp., that causes anthracnose disease on papaya fruits, was evaluated. The best result was observed for compound 1-(4-allyl-2-methoxyphenoxy)-3-(4-(2-fluorophenyl)-1H-1,2,3-triazol-1-yl)propan-2-ol (3d) that showed a mean growth-inhibition zone of 5.10 mm in a well-diffusion assay, and may serve as a template for additional structural modifications, aiming for more potent fungicidal activity.

Resumo em Inglês:

Heterostructures constructed with mesoporous silica and layered double hydroxides are interesting for catalytic and drug delivery applications. Different arrangements between these phases are possible. In this study, we prepared heterostructures by embedding layered double hydroxides phases [M4Al2(OH)12](CO3) (M = Mg2+ or Zn2+) within the MCM41 mesoporous silica type phase. According to our results, the most critical step of this preparation is the removal of the organic template used to create the mesopores in the silica phase, which can be done by calcination or extraction with solvent, normally a mixture of ethanol and a mineral acid. The results reported in this study demonstrate that both can cause structural changes in the components of the heterostructure at different extensions. Calcination promoted the collapse of the layered hydroxide phases. Attempts made for their reconstruction through rehydration, which is a quite known process, were not completely effective and also dependent on the chemical composition of the layered phase. The complete template removal with preservation of the layered phases was possible using the extraction method but by replacing the mineral acid with NH4Cl. However, some discrete structural changes were identified possibly due to a partial lixiviation of Al3+ from the double hydroxide layers.

Resumo em Inglês:

The inhibitory activity of thirty-one sesquiterpenes identified from Brazilian essential oils (Copaifera langsdorffii Desf., Croton cajucara Benth. and Siparuna guianensis Aublet.) were analyzed by in silico molecular docking. The compounds were characterized by gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame-ionization detection (GC-FID), and then, applied against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) proteins and human angiotensin-converting enzyme 2 (hACE2). Applying molecular docking and AutoDock Vina software, a total of 496 individual interactions were detected for sesquiterpenes along with SARS-CoV-2 proteins and hACE2 human angiotensin converting enzyme-2 protein. The findings showed considerable binding affinity of sesquiterpenes with the tested macromolecules. In that, β-selinene from C. langsdorffii displayed the best energy (−7.2 kcal mol-1) and showed strong interactions with the amino acids of the SARS-CoV-2 M-Pro protein. Spathulenol from C. cajucara strongly interacted with human ACE2, with a binding energy of −7.1 kcal mol-1. Meanwhile, γ-eudesmol from S. guianensis presented the lowest binding energy (−7.5 kcal mol-1) by interacting with the SARS-CoV-2 M-Pro complex. Additionally, measurements were performed aiming to evaluate the best sesquiterpenes binding interactions with the main proteins and its homologue files. According to results, these Brazilian essential oils hold antiviral potential being a rich source for further in vitro and in vivo studies focusing on herbal therapeutic adjuvants against SARS-CoV-2 infections.

Resumo em Inglês:

This work reports the development of a simple and fast method for the spectrophotometric determination of Fe in diesel oil using the classic reaction with 1,10-phenanthroline after its extraction induced by emulsion breaking (EIEB). The extraction parameters of EIEB were optimized (concentration of HNO3 and Triton X-100® in the emulsifying solution) as well as the adjustment of the pH of the final solution, a necessary step to complete the colorimetric reaction. The developed method presented a limit of detection of 0.004 mg L-1 and a limit of quantification of 0.013 mg L-1 and was applied in the analysis of six samples of diesel oil with different specifications. The results were statistically similar to those obtained by graphite furnace atomic absorption spectrometry (GF AAS). A recovery test was also performed by spiking the samples with 1.0 mg L-1 of Fe in the form of an organometallic compound, yielding recovery percentages between 83 and 108%.

Resumo em Inglês:

Croton zehntneri Pax et Hoffm. is a plant from Northeastern Brazil, whose main component of its essential oil is estragole. Its thermal instability and low aqueous solubility prevent its technological application. This study aimed to prepare and characterize the Croton zehntneri essential oil (CZEO) complexed with β-cyclodextrin (β-CD), and to evaluate antioxidant activity of free and complexed-CZEO in vitro systems by the elimination of 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH•), 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS•+), hydroxyl and nitric oxide, as well as their ability to transfer electrons by the reducing potential. The infrared spectroscopy and thermal techniques demonstrated the formation of the inclusion complex (Est/β-CD) obtained by spray drying method. The free CZEO and its Est/β-CD at 0.9, 1.8, 3.6, 7.2, 14.4 and 28.8 µg mL-1 showed the ability to remove DPPH• (EC50 (half maximal effective concentration) 26.06 and 9.46 µg mL-1, respectively) and ABTS•+ (EC50 22.73 and 4.47 µg mL-1, respectively), nitric oxide inhibition (EC50 17.65 and 2.68 µg mL-1, respectively), hydroxyl radical sequestration (EC50 23.42 and 2.34 µg mL-1, respectively) and reducing potential (EC50 46.48 and 12.47 µg mL-1, respectively). The formation of the inclusion complex significantly increases its antioxidant potential.