Resumo em Inglês:

Plants and essential oils (EOs) have been used for centuries in folk medicine to treat diverse disorders, including analgesic to pain relief. In this context, the antinociceptive activity of EOs has been attracted attention since the management of pain continues being a major challenge for medicine. This review provides an overview of published reports on the antinociceptive activity of EOs and their constituents from 2000 until the first half of 2015. In this review are compiled the data on the antinociceptive activity of 63 EOs and 26 of their constituents with a discussion about the nociception model used to access the analgesic effect. These data were also analyzed in relation to ethnopharmacological and toxicological data available in the literature. As can be seen by the analysis of more than 300 articles, EOs and their constituents show antinociceptive effects in different models and their action mechanism is quite variable. Although there are a few essential oils or their isolated constituents on the phytopharmaceuticals market, this review intends to put in evidence the often-underexploited vast source of natural compounds with therapeutic potential in pain relief.

Resumo em Inglês:

Plant flavonoids have been increasingly studied for its importance in plant metabolism, inter-species interactions and human health-promoting effects. Each botanical species has a distinct flavonoid profile, and as such, this work aimed to develop and apply a high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method to quantify specific flavonoids in different plants and parts. Six flavonoids (isoquercitrin, quercetin, naringin, naringenin, hesperidin and rutin), two isoflavonoids (daidzin and daidzein) and one coumarin (umbelliferone) were targeted. Calibration curves showed good correlations (R2 > 0.994) and limits of quantification (≤ 500 ng mL-1). The method was applied for detection of analytes in common bean seeds (Phaseolus vulgaris), soybean leaves (Glycine max), and sour orange (Citrus aurantium), sweet orange (Citrus sinensis), and Tahiti lime (Citrus latifolia) flavedo after ultrasound assisted acidic hydroalcoholic extraction. The method was tuned for quick and efficient extraction. Principal component analysis was helpful for the discrimination of matrices based on their flavonoid profiles.

Resumo em Inglês:

The radical addition of triorganotin hydrides, R3SnH (R =n-butyl, phenyl, neophyltin), to four unsaturated diesters of (11R,12R)-9,10-dihydro-9,10-ethaneanthracene-11,12-dimethanol leads to products of cyclohydrostannation with an average yield of around 80%. Whereas the addition of these hydrides to diacrylate and dimethacrylate leads to the expected mixtures containing two and four distereoisomeric cyclized products respectively, the addition to di-2-methyl- and di-2-phenylcinnamate yields only four out of the sixteen possible stereoisomers. The observed high stereoselectivity is consistent with a radical tandem cyclohydrostannation mechanism. Full proton (1H), carbon 13 (13C) and tin 119 (119Sn) nuclear magnetic resonance (NMR) data are given.

Resumo em Inglês:

Reversible acetylcholinesterase inhibitors are an important group of drug compounds that are used medicinally to treat Alzheimer's disease. In this study, dissociation constant values (pKa) of some reversible acetylcholinesterase inhibitors (donepezil, rivastigmine and galantamine) having different functional groups were determined in different percentages of acetonitrile (MeCN)-water and methanol (MeOH)-water binary mixtures using reversed phase liquid chromatography (RPLC) method. In this way, a complete description of the retention behavior of each solute in the space defined by the pH and organic modifier percentages variables was obtained. The linear relationships established between retention factors of the species and the polarity parameter of the mobile phase (ETN) was proved to predict accurately retention in liquid chromatography (LC) as a function of the acetonitrile and methanol content. In result, the estimated aqueous pKa values of studied basic compounds were assessed by comparing them with literature data.

Resumo em Inglês:

A simple and accurate chiral high performance liquid chromatography (HPLC) method was developed for determination of Levofloxacin and its chiral impurity (R)-enantiomer. The chiral impurity Levofloxacin separation method was optimized by Box-Behnken design and validated by an innovative analytical approach recently developed in our laboratory. This last approach as well as uncertainty estimation consists of building a graphical decision-making tool, based on the β,γ-content tolerance interval, called the uncertainty profile. The proposal approach applied to the optimized chiral separation method of Levofloxacin shows its fitness.

Resumo em Inglês:

Two new meroterpenoid hydroquinones,rel-(4bE,6Z,8E,9aS,10S)-1,4-dihydroxy-9a,10-dihydro-10,12-epoxy-5-methylbenzo[a]azulen-12-one andrel-(4bZ,6Z,8E,9aS,10S)-1-hydroxy-9a,10-dihydro-4,11:10,12-diepoxy-benzo[a]azulen-11,12-dione, along with the known peptide derivative (S)-N-benzoylphenylalanine-(S)-2-benzamide-3-phenylpropyl ester, were isolated from the roots of Cordia globosa. Their structures were determined by 1D and 2D nuclear magnetic resonance (NMR) spectrometry, Fourier transform infrared (FTIR) spectroscopy and high resolution atmospheric pressure chemical ionization mass spectrometry (HRAPCIMS) data analysis. The new compounds were tested against three human cancer cell lines (colon adenocarcinoma, ovarian carcinoma and glioblastoma), but none of them exhibited any activity.

Resumo em Inglês:

In this work, it was described the preparation and the characterization of a solid acid catalyst obtained by the mixture of Cr/Al oxides (CRAL). The catalyst was tested in the transesterification reaction of babassu oil with 5% of free fatty acid (FFA). The results of textural and acidity characteristics of CRAL were: area (56 m2 g-1), pore size (7.0 µm), total acidity (182.28 µmol g-1), wherein Brönsted sites are the most active. Powder X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) show three phases of the catalyst (Cr2O3/Na2Cr2O3/Al2O3), 0.25:0.25:0.50, respectively. The reaction reached conversion about 98.6% under the conditions: alcohol/oil molar ratio (24:1), catalyst to oil mass ratio of 3.0%, 15 h and 70 ºC. The turnover frequency (TOF) found was 24.5 × 10-4 s-1. Kinetic of the reaction was researched over a temperature range of 60-80 ºC. A pseudo first-order model was proposed with the activation energy (Ea) of 49.18 kJ mol-1. CRAL is active in the biodiesel production for just one cycle, because in the second one it loses its activity. The leaching of catalyst is about 13%, demonstrating that the catalyst is not totally heterogeneous.

Resumo em Inglês:

In this work, solutions of oxidant salts were evaluated as alternative to nitrate solution for the ignition step in microwave-induced combustion (MIC) method. Aqueous solutions of KClO4, K2Cr2O7, KMnO4 and K2S2O8 in several concentrations were evaluated and it was observed that the ignition was dependent on the concentration and type of igniter solution. Moreover, it was possible to observe that ignition and combustion times are not related with sample mass, which was confirmed by evaluating sample masses ranging from 100 to 500 mg of whole milk powder. Certified reference materials were digested using K2Cr2O7 as igniter solution and digests analyzed by inductively coupled plasma optical emission spectrometry (ICP OES), with good agreement to certified values. The obtained results suggest that MIC can be performed using solutions of oxidants salts. In addition, the proposed study contributed to a better undestanding and explaining the ignition with microwaves.

Resumo em Inglês:

A new series of Mannich bases derived from 2-hydroxy-1,4-naphthoquinone (lawsone), substituted benzaldehydes and two primary amines, and their Cu2+ complexes were synthesized and evaluated for their potential as selective cholinesterase inhibitors (ChEIs). Immobilized capillary enzyme reactors (ICERs) bearing butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) were used not only for the on-flow screening assay but also for determining the inhibitory potency and equilibrium binding constants of the lead inhibitors. Eight copper complexes were identified and characterized as potent reversible and selective ChEIs with inhibitory potencies (IC50) and constants of inhibition (Ki) ranging from 1.24 to 11.5 µmol L-1. One of the compounds was particularly promising, showing IC50 and Ki values of 1.24 ± 0.01 and 1.06 ± 0.01 µmol L-1, respectively, for huAChE. These values were lower than those for the standard inhibitor galanthamine (IC50 = 206 ± 30.0 and Ki = 126 ± 18.0 µmol L-1). Even though, it is showing noncompetitive inhibition of huAChE and linear mixed-type inhibition of eeAChE. These complexes showed a promising cholinesterase inhibitory activity and can be used as model inhibitors.

Resumo em Inglês:

A simple, eco-sustainable method for theN-(9-fluorenylmethoxycarbonyl) (N-Fmoc) protection of various structurally amines under ultrasonic irradiation is reported. The corresponding N-Fmoc derivatives were obtained in good to excellent yields within short reaction time. The reaction proceeds without the formation of any side product. Mildness, efficiency and easier work are the main advantages of this new protocol.

Resumo em Inglês:

We herein report the synthesis of hybrid kauranoid molecules of type 1,2,3-triazole-1,4-disubstituted aiming to improve the antimalarial activity of kaurenoic and xylopic acids. The CuI-catalyzed cycloaddition of azides and kauranoid terminal alkynes was explored as a hybridization strategy. Kauranoid terminal alkynes were prepared from kaurenoic and xylopic acids that were isolated from Wedelia paludosa D. C. (Asteraceae) and Xylopia frutescens Aubl. (Annonaceae). A total of 15 kauranoid derivatives, including nine new triazoles, were obtained and five out of these were more active than the original diterpenes. Interestingly, an increased activity was observed for a kauranoid propargyl ether. Interaction between ent-kaurane diterpene derivatives and Ca2+-ATPase (PfATP6) was investigated. Synthesis of diterpene derivatives emerges as a possible route to be explored in the quest of potentially new inhibitors of PfATP6.

Resumo em Inglês:

A new chemiluminescence (CL) method has been proposed for the simple determination of aspirin (acetylsalicylic acid, ASA). The method is based on the enhancement effect of ASA in the CL reaction of tris(1,10 phenanthroline)ruthenium(II), Ru(phen)32+, with cerium(IV) (CeIV) in acidic medium. Under optimum conditions, the CL intensity was proportional to the concentration of the drug in solution over the range 0.72-72.00 µg mL-1 ASA. The limit of detection (S/N = 3) was 0.45 µg mL-1. In the method proposed, limit of detection was at least 30 times lower than the therapeutic concentration of ASA. The percent of relative standard deviation for determination of 10 replicates at level of 28.8 µg mL-1 of ASA was 5.8% and the minimum sampling rate was 30 samples per hour. Effects of some ingredients were investigated and the proposed method was applied successfully for the determination of ASA in pharmaceutical formulations and plasma samples. A time resolve CL approach was used to reduce the effect of interferences from cysteine and ascorbic acid in plasma samples. The possible CL reaction mechanism was also discussed.

Resumo em Inglês:

The purpose of this study was to synthesize TiO2-polymer composites able to act as photocatalyst membranes. TiO2 catalysts were prepared using the sol-gel method to contain 0.0, 0.5, 1.0, and 2.0 wt.% of embedded Ag particles, subsequently incorporated into natural rubber latex at a weight fraction of 15%. Samples of these ceramic powders were suspended in a latex emulsion (natural rubber), cast in Petri dishes and slowly dried in an oven. The resulting materials were evaluated by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray, diffuse reflectance spectroscopy, differential scanning calorimetry, thermogravimetry, and photocatalytic assaying using methylene blue as an organic pollutant reference. All composite membranes exhibited good photoactivity conferred by TiO2 powder, with 98% dye fading after 300 min of ultraviolet irradiation.

Resumo em Inglês:

A pressurized continuous flow system using electromagnetic induction heating technique has been developed for the determination of trace and minor element content in biological samples by microwave induced plasma-optical emission spectrometry (MIP-OES). The system allows the continuous solubilization of samples at an optimized temperature of 120 °C and pressure of 3.5 bar in 40 min. A system was used to perform off-line solubilization of slurried samples of biological tissues, non-fat milk powder and lichen (3% m/v). Recovery of trace and minor elements averaged 99.2 ± 0.1% was performed by MIP-OES using external calibration technique. The accuracy of the method was proved using certified reference materials from the National Research Council Canada (NRCC, Dogfish Liver, DOLT-2), National Institute of Standards and Technology (NIST, (Non-Fat Milk Powder, NIST 1549) and International Atomic Energy Agency (IAEA, Lichen, IAEA-336). Satisfied analytical results were also obtained in real sample analysis of milk powder, barley and cinnamon.

Resumo em Inglês:

The dihydrobetulinic acid is a known competitive inhibitor of topoisomerase IB from Leishmania donovani, a validated target for developing new antileishmanial drugs. However, its binding mode and interaction pocket have not been established yet. We combined docking and molecular dynamics simulations to identify the most probable binding pocket. Our best model strongly suggests a cavity involving the residues arginine 314 and arginine 410 from chain A, and the catalytic tyrosine 222 from chain B as the interaction site and a substructure of this terpene inhibitor as essential for the process of molecular recognition. Then, a new class of inhibitors with increased affinity could be designed by structure-based approaches.

Resumo em Inglês:

Unonopsis (Annonaceae) is a neotropical genus constituted by nearly fifty species, with fifteen described in Brazil. In the state of Amazonas seven species are found, including U. guatterioides, which displays problems from the botanical viewpoint. Previous studies showed this genus as a promising source of aporphinoid alkaloids. In order to investigate the potential of the leaf alkaloid fingerprint for chemotaxonomic approaches, twelve Unonopsis specimens, representing five species commonly found in the state of Amazonas were subjected to acid-base partitioning to yield the respective alkaloidal fractions. These fractions were analysed by direct infusion electrospray ionization multiple stage mass spectrometry (ESI-MSn). The obtained data were treated through chemometric tools [principal components analysis (PCA) and hierarchical cluster analysis (HCA)]. Multivariate analysis pointed to aporphine, proaporphine and tetrahydroprotoberberine alkaloids as the responsible compounds for segregation of the investigated species, being these alkaloids tentatively identificated by multiple stage mass spectrometry. The alkaloid fingerprint along with multivariate analysis provided a simple and effective approach to differentiateUnonopsis species commonly found in the state of Amazonas.

Resumo em Inglês:

AC corrosion enhancement of buried steel pipe is induced by high stray AC electromagnetic field and to the faradaic rectification due to non-linearity of current-potential characteristics. In Part I, this phenomenon was evaluated by neglecting the electrical resistance of soil electrolyte. In this part, we will examine when this resistance is no longer negligible. The mathematical model can be expressed by an ordinary nonlinear differential equation. In this part, the corrosion mechanism is modelled by two reactions obeying Tafel law, one for anodic dissolution of steel and another for cathodic process. This corrosion mechanism is valid when the corrosion current density is much higher than the diffusion limited current of dissolved oxygen. Compared with the system where the electrolyte resistance is negligible, the corrosion enhancement induced by AC signal is markedly attenuated because of the ohmic drop through the electrolyte resistance, and the double layer capacitance constitution a bypass circuit.

Resumo em Inglês:

In this study pequi (Caryocar brasiliense) shells were evaluated in relation to their potential for the adsorption of PbII ions in aqueous systems. The adsorbent was characterized by point of zero charge (PZC), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and PbII ions were detected by flame atomic absorption spectrometry (FAAS). The adsorption parameters studied were solution pH, adsorbent mass, contact time and the optimum adsorption conditions were found to be 7.0, 50 mg and 30 min, respectively, using 15 mL of the metal solution. A study on the adsorption kinetics and isotherms was performed applying the optimized conditions. The adsorption process followed a pseudo-second-order model. The experimental adsorption data were fitted to the Langmuir and Freundlich isotherm adsorptions and a very good fit to the Langmuir linear model was observed. The maximum adsorption capacity was found to be 35.52 mg g-1.

Resumo em Inglês:

Commercially available immunoassay tests are designed to detect the presence of amphetamine/methamphetamine or methylenodioxyamphetamines. However, it is known that Brazilian truck drivers also report the use of other illicit amphetamines, such as amfepramone and fenproporex. Thus, a method was developed and validated in order to quantify amphetamine-type stimulants (amphetamine, fenproporex and amfepramone) in urine by high performance liquid chromatography with diode array detection (HPLC-DAD). Prior to this, a liquid-liquid extraction (LLE) with diethyl ether was performed in order to extract the analytes. The limit of detection was 150 ng mL-1. The method showed to be precise (relative standard deviation, RSD < 15%) and the recovery values for the three analytes were greater than 50%. The linearity ranged from 150 to 1000 ng mL-1(r2 > 0.99). Urine samples randomly collected from 385 truck drivers in Brazilian roads were submitted to the developed method. Nine samples were tested positive for amphetamine and one was tested positive for fenproporex and amphetamine.

Resumo em Inglês:

The solubility of CoIII 5,10,15,20-tetra(4-carboxyphenyl)porphyrin and axial complex with methylimidazole in the mixtures of triethyleneglycol-water and tetraethyleneglycol-water was measured in the whole range of polyethyleneglycols (PEG) fractions at 298.2 K using the isothermal saturation method. The composition of the mixture at which the maximal solubility was observed has been revealed. The cosolvent force of PEGs was quantified according to the linear logarithmic model proposed by Yalkowsky applied in the ranges (cosolvent volume fraction, f): 0 ≤ fPEG ≤ 0.24 in triethyleneglycol-water and 0 ≤ fPEG ≤ 0.3 in tetraethyleneglycol-water mixtures. A mathematical approach based on the tenets of the molecular association theory and a simple lattice model (ASL = association solution + lattice) was used to estimate the solubility values of the investigated porphyrins in water-PEG solutions. The ASL model appeared to present a simple means of estimating the solubility of CoIII5,10,15,20-tetra(4-carboxyphenyl)porphyrin and axial complex with methylimidazole in polyethyleneglycol-water mixtures using a single variable parameter.