Resumo em Inglês:

Diabetes has become a severe chronic disease worldwide with patients significantly increasing daily. Due to the side effects of insulin and oral hypoglycaemic agents employed in diabetes treatment, scientists are working hard to develop alternative approaches from natural plants that inhibit α-amylase and α-glucosidase. Consequently, by performing a phytochemical analysis on the bark of Endiandra kingiana, the present study isolated 11 cyclic polyketides. Analyses with one-dimensional and two-dimensional nuclear magnetic resonance (1D- and 2D-NMR), high-resolution electron ionization mass spectrometry (HRESIMS), and comparison with previous literature confirmed the compounds characteristics. Subsequently, the compounds were screened for in vitro α-amylase and α-glucosidase inhibiting activities. Compounds 9 and 2 exhibited potent inhibition towards α-amylase at 0.0008903 ± 0.5 and 0.02 ± 0.3 mg mL-1 of half-maximal inhibitory concentration (IC50) values, respectively. In the α-glucosidase inhibition assay, compounds 10 and 5 demonstrated good inhibition with IC50 values of 0.11 ± 0.08 and 0.14 ± 0.05 mg mL-1, respectively. The molecular docking examination demonstrated that the compounds adhered to the active sites on the C-terminal of the human pancreatic α-amylase (Protein Data Bank Identification (PDB ID): 2QV4, resolution: 1.97 Å) and maltase-glucoamylase (MGAM) (PDB ID: 3TOP, resolution: 2.88 Å), agreeing with α-amylase and α-glucosidase enzymes inhibitory reactions.

Resumo em Inglês:

The cariogenic processes are mainly caused by the bacterium Streptococcus mutans (S. mutans) and consist of the demineralization of the tooth that occurs when the acid production overcomes the natural repair or if a problem occurs in the last one. In this work, we performed the synthesis of twenty-one 1,4-naphthoquinones tethered to 1,2,3-1H-triazoles (8a-8k and 9a-9j), antibacterial evaluation against the S. mutans in vitro and the acute toxicity of the better ones in vivo. We observed strong inhibition results in the disc diffusion test ranging, the halos of inhibitions, from 18.66 (± 0.57) to 29 (± 2.64) mm, and good values in the minimum inhibitory concentration (5 to 50 μg), for the compounds 9e, 9h, 9i and 9j: Furthermore, they do not have a cytotoxic effect at the concentrations tested. Besides that, in the in vivo test, they show some slight alteration in the histopathological analyses and the biochemistry. Thus, we found four potential candidates to become instruments for the treatment of cavities.

Resumo em Inglês:

In this study, the interaction between benzothiazole (BTA, concentration of a drug required for 50% inhibition in vitro (IC50) = 0.77 mM) and benzimidazole (BIA, IC50 = 2.14 mM) with urease was quantitatively assessed, using UV-Vis, molecular fluorescence, and circular dichroism. The results showed that both compounds interact with urease by a static fluorescence quenching mechanism with a non-fluorescent complex formation. The main forces responsible for stabilizing the supramolecular complex between BTA and urease were hydrophobic while, for BIA, van der Waals interactions and hydrogen bonds were the main ones. Urease conformation changes due to the interaction process were analyzed by circular dichroism and synchronous fluorescence. Besides, a competitive assay with substrate and inhibitors was used to evaluate the preferential urease site of interaction with BTA and BIA. Our experimental and theoretical studies supported that both, BTA and BIA, are mixed-inhibitors of ureases with a slight preference to the active site of such enzymes. Finally, both BTA and BIA showed to possess anti-Helicobacter pylori (one reference strain and six clinical isolates) activity, presenting minimal inhibitory concentration (MIC) values ranging from 38-150 and 20-164 µM, respectively. The urease inhibitors omeprazole and hydroxyurea showed MIC values in the range of 46-185 µM and 1683-> 3366 µM, respectively.

Resumo em Inglês:

The pequi pericarp corresponds to the largest portion of the fruit and has a high nutritional value, but it is discarded as an agro-industrial residue. The present study aimed to prepare and characterize flours from the pequi pericarp in terms of their proximate composition, its antioxidant potential before and after the in vitro digestibility process and chemical profile, aiming at the full use of this fruit. The samples of pequi pericarp flours from the cities of Sete Lagoas, Paraopeba and Felixlândia were analyzed. The profile of chemical compounds present in the flours was determined using paper spray mass spectrometry. The in vitro simulated digestion technique was used to verify the stability of the phenolic compounds and the maintenance of the antioxidant capacity of the samples. The flours from the pequi pericarp showed to have higher levels of protein, ash and dietary fiber, compared to the data described in the literature for the pulp of the fruit. The analysis of paper spray mass spectrometry allowed the identification of 46 chemical compounds including amino acids, sugars, organic acids and phenolic compounds. The analysis of the main components showed that there was no chemical variation among the fruits from the cities studied. Through the in vitro digestibility technique, it was possible to observe an increase in the bioaccessibility of phenolic compounds, contributing to increase the already significant antioxidant capacity of the samples. It was concluded that the pequi pericarp flour has the potential to be used as a food ingredient due to the high bioaccessibility of its bioactive compounds, capable of reducing the risk of developing diseases caused by oxidative stress.

Resumo em Inglês:

This work describes the synthesis, molecular structure, and packaging of the compounds 6-bromo-2,3-dimethoxybenzaldehyde (6-BRB) and 5-bromo-2,3-dimethoxybenzaldehyde (5 BRB). Characterization in the solid-state was carried out by X-ray diffraction, and the analysis of the interactions was described by the Hirshfeld surface, which helps in understanding the effect of replacing the bromine position in the aromatic ring. Both compounds (6-BRB and 5-BRB) crystallized in the space group P21/c and are stabilized with C-HO interactions, but only the 6-BRB has a halogen-type interaction. Theoretical calculations, carried out by the density functional theory at the CAM-B3LYP/6-311++G(d,p) level of theory in gas phase, provided information on their electronic properties. The geometric properties were compared to experimental data, and the analyses of the frontier molecular orbitals and the molecular electrostatic potential (MEP) maps were obtained to predict the physical-chemical properties. The supramolecular arrangements were analyzed throughout complexation interactions and corrected by counterpoise method. Hyperconjugation energies were employed to examine the stability of the intermolecular interactions of the compounds. The interaction intensities were determined through the topological parameters obtained through the quantum theory of atoms in molecules model.

Resumo em Inglês:

Diabetes is a chronic metabolic disorder characterized by insufficient insulin production, the cells’ inability to use this insulin, or a combination of both, leading to secondary complications such as diabetic neuropathy and retinopathy. One way to prevent or control such complications is the use of aldose reductase (AR) inhibitors. In this work, we synthesized and tested new candidates for human AR inhibition containing a 2-thiopyrimidin-4-one heterocycle as a central ring. The fifteen derivatives were tested in vitro and their binding modes were evaluated via molecular docking simulations. AR inhibition assays showed that all synthesized compounds were able to inhibit the AR enzyme at 50 μM. From these results, seven compounds were noteworthy and had their half maximal inhibitory concentration (IC50) values estimated, ranging from 2.0 to 14.5 μM. Molecular docking simulations showed that these compounds bind specifically to the catalytic subpocket and the results indicate a good association between in vitro and in silico studies.

Resumo em Inglês:

In this study, for the first time, histamine-functionalized magnetic nanoparticles (HIS-MNP) were used as sorbent phase combined with bar adsorptive microextraction (BAµE) for the determination of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) in water samples by high performance liquid chromatography coupled with diode array detection (HPLC-DAD). Extraction and desorption conditions, including desorption time and solvent, ionic strength effect and extraction time, were investigated. The extractions were performed for 90 min, 30% of NaCl and sample pH 5. Desorption was carried out using 250 μL of acetonitrile:methanol (25:75 v/v) for 30 min. The limits of detection (LODs) were of 1.5 μg L-1 and limits of quantification (LOQs) were 5.0 μg L-1 for all analytes. The intra-day precision ranged from 1% for EP, PP and BP to 3% for MP, EP, PP and BP. The inter-day precision ranged from 3% for EP to 18% for BP. The relative recoveries varied from 81 to 125%, and relative standard deviations (RSD) ranged between 1 and 16%.

Resumo em Inglês:

The conjugated molecules based on pyrene and dithienopyrrole derivatives including 4-(2-ethylhexyl)-2-(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EP4HP) and 4-(2-ethylhexyl)-2,6-di(pyren-1-yl)-4H-dithieno[3,2-b:2’,3’-d]pyrrole (EDP4HP) have been successfully synthesized via C-H direct arylation reaction. The structures of these conjugated molecules were determined via nuclear magnetic resonance and Fourier-transform infrared spectroscopy (FTIR). The optical properties of conjugated molecules were evaluated via ultraviolet visible (UV-Vis) and fluorescence spectroscopies. The conjugated molecules exhibited the efficient fluorescence quenching toward herbicide mesotrione as nitroaromatic pesticides that could be promising candidates as the chemosensor for tracing of nitroaromatic pesticides.

Resumo em Inglês:

A method to pretreatment of biomasses using glycerol as a green solvent was developed. Optimization of organosolv pretreatment was performed using a 23 factorial design, investigating synergism among the variables particle size (from < 0.85 to > 2.0 mm), FeCl3 concentration (0.025-0.175 mol L-1), and temperature (160-220 °C). Although the effects of the variables differed according to the type of lignocellulose, it was nonetheless possible to find an optimal condition in common (< 0.85 mm; 0.025 mol L-1; 220 °C), which was economically and environmentally sustainable, employing a small amount of catalyst. The biomasses pretreated using this combination of factors exhibited enzymatic digestibility exceeding 93% after 48 h, reflecting efficient reduction of recalcitrance as a result of high removal of hemicellulose (ca. 90%), provided by the use of FeCl3, together with substantial delignification. There was low formation of inhibitors in the hydrolysate, indicating that it could be directly fermented. The lignin removed to liquors could be easily recovered by centrifugation. Tests carried out under the optimal condition revealed that after the pretreatment the biomass could be directly used in enzymatic hydrolysis, without washing and wet. Furthermore, after simple treatment, crude glycerol was as effective as commercial glycerol.

Resumo em Inglês:

The 3-chymotrypsin-like protease (3CLpro) is an attractive target for the development of anti-SARS (severe acute respiratory syndrome) drugs. In this work, a series of oxazolidinone derivatives 3a-3v were synthesized and their inhibitory activities against SARS coronavirus 2 (SARS-CoV-2) 3CLpro were evaluated by the fluorescence resonance energy transfer (FRET)-based enzymatic assay. Among synthesized compounds, 3g displayed the best inhibitory activity, with a half maximal inhibitory concentration (IC50) value of 14.47 μM. Also, docking studies implied that compound 3g was fitted into the active pocket of 3CLpro, forming a hydrogen bond with Glu166.