Showing papers in "Journal of the Brazilian Chemical Society in 2020"
TL;DR: A scale-up investigation of TDF by in situ infrared spectroscopy monitoring and a forced degradation study to describe a new degradation product are presented and evaluated TDF in vitro for SARS-CoV-2 for the first time.
Abstract: The recent emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led society to live with a serious public health problem. In this sense, repositioning of antiretrovirals has captured the attention of the scientific community. Tenofovir disoproxil fumarate (TDF) is an antiretroviral compound that is used to treat acquired immune deficiency syndrome (AIDS) and hepatitis B. In this short report, we present a scale-up investigation of TDF by in situ infrared spectroscopy monitoring and a forced degradation study to describe a new degradation product. Finally, we have evaluated TDF in vitro for SARS-CoV-2 for the first time foreseeing the using of this medicine in pre-clinical and clinical investigations for the COVID-19 (coronavirus disease 2019) treatment.
32 citations
TL;DR: The results presented in this study clearly support the requirement of improvement of the new resolution since, in the present form, it does not meet the main goal of protecting public health.
Abstract: On November 19, 2018, 30 years after establishment, the updated Brazilian National Air Quality Standards (NAQS) were published. These NAQS were formulated as a fundamental part and instrument of the National Program for the Control of Air Quality and considering, as a reference, the World Health Organization Air Quality Guidelines, published in 2005. An important contribution is the inclusion of PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 µm) as a criteria pollutant and a more restrictive target limit for PM10 (particles that have aerodynamic diameters less than or equal to 10 µm). In this work, the NAQS were discussed using, as a case study, data collected during the 2016 Olympic and Paralympic Games. The lack of PM2.5 data for Brazilian cities results in the calculation of a lower air quality index (AQI), leading to ostensibly good air quality. The results presented in this study clearly support the requirement of improvement of the new resolution since, in the present form, it does not meet the main goal of protecting public health.
23 citations
TL;DR: In this paper, an integrative approach based on the alkaloid profile analysis by leaf spray mass spectrometry (LS-MS) followed by a robust dereplication through high-performance liquid chromatography coupled with diode array detector and atmospheric pressure chemical ionization tandem mass analyzer (HPLC-DAD-APCI-MS/MS) was adopted.
Abstract: Onychopetalum is an Amazonian botanical genus close-related with Bocageopsis and Unonopsis, whose species are used in traditional medicine. Although these genera are widely investigated from the phytochemical viewpoint, the knowledge about Onychopetalum remains almost unexplored. In order to perform a comprehensive characterization of isoquinoline-derived alkaloids from Onychopetalum amazonicum, an integrative approach based on the alkaloid profile analysis by leaf spray mass spectrometry (LS-MS), followed by a robust dereplication through high-performance liquid chromatography coupled with diode array detector and atmospheric pressure chemical ionization tandem mass spectrometry, (HPLC-DAD-APCI-MS/MS) and nuclear magnetic resonance (NMR) analysis was adopted. LS-MS allowed the tentative identification of reticuline, norjuziphine, nornuciferine, O-methylisopiline, nuciferine, N-methyl-O-methylisopiline, anonaine, and N-methylanonaine. HPLC-DAD-MS/MS analysis supported the tentative identification of N-methylasimilobine, asimilobine, norushinsunine, N-methylisopiline, isopiline, liriodenine, and lysicamine. Moreover, the integration of MS and NMR data allowed the additional identification of stepholidine and isocorypalmine. The applied integrative approach proposed herein enabled a comprehensive analysis of the alkaloid content from the O. amazonicum, showing to be a useful strategy for the dereplication of isoquinoline-derived alkaloids.
23 citations
TL;DR: Serpentine is a versatile mineral family rich in Mg silicate with several polymorphic phases, mainly antigorite and lizardite, all of them with similar chemical composition (Mg3Si2O5(OH)4) as discussed by the authors.
Abstract: Serpentine is a versatile mineral family rich in Mg silicate with several polymorphic phases, mainly antigorite and lizardite, all of them with similar chemical composition (Mg3Si2O5(OH)4). Their structures are generally composed of octahedral layers rich in Mg[MgO2(OH)4]6- , attached to a tetrahedral silicate [Si2O5]2- sheet. The unique physicochemical properties of serpentinites and the existence of large reserves in Brazil create new important opportunities for research and technological applications. In this work, serpentinites structures and properties are reviewed, as well as its occurrence and literature describing its applications in construction/ceramics, agriculture, as a silica source, in steel production, as an additive/filler in polymers, in the production of composites, adsorption of cations and organics contaminants, CO2 capture and catalysis. The presence of harmful chrysotile associated with serpentinites, some of its properties and uses are also described.
22 citations
TL;DR: In this article, the authors present an overview of the most important concepts behind the H2 generation, from water splitting, promoted by semiconductor-based systems for readers that were recently introduced to the water splitting topic.
Abstract: The solar-to-chemical energy conversion is promising to tackle sustainability challenges toward a global future. The production of H2 from sunlight represents an attractive alternative to the use of carboniferous fossil fuels to meet our energy demands. In this context, the water splitting reaction photocatalyzed by semiconductors that can be excited under visible or near-infrared light excitation represents an attractive route to the clean generation of H2. In this review, we present an overview of the most important concepts behind the H2 generation, from water splitting, promoted by semiconductor-based systems for readers that were recently introduced to the water splitting topic. Then, we present the main classes of photocatalysts based on semiconductors. For each class of semiconductors, we focused on the examples that lead to the highest activities towards the H2 production and discuss the operation principles, advantages, performances, limitations, and challenges. We cover metal oxides, sulfides, and nitrides. We also discuss strategies in which these materials are combined, including hybridization with metal nanoparticles, other semiconductors, and carbon dots, to achieve improved performances and circumvent the limitations of the individual counterparts.
18 citations
TL;DR: In this paper, a 3D pen was used to draw thermoplastic electrodes inside the pockets of all devices until reaching the copper wires to establish electric contact, and the fabricated electrodes were applied for the detection of dopamine and trace metals as well as to generate electrochemically a Prussian blue modified sensor.
Abstract: This communication demonstrates that a 3D printing pen, commercially-available as a toy for kids, can be used to draw thermoplastic electrochemical sensors using conductive filaments over any desirable format and substrate. A polylactic acid filament containing graphene or carbon black was passed through the 3D pen that works as a handheld 3D printer (fused deposition modeling type). As proof-of-concepts, we select three designs, the first one analogous to a conventional carbon-paste electrode, the second one containing the three electrodes in a cylindrical tube and the third one similar to commercial screen-printed electrodes. The 3D pen was used to draw the thermoplastic electrodes inside the pockets of all devices until reaching the copper wires to establish electric contact. Customized 3D printed substrates were used to guide the application of the 3D pen. The fabricated electrodes were applied for the detection of dopamine and trace metals as well as to generate electrochemically a Prussian Blue modified sensor. Many other designs, conductive filaments and substrates can be combined with a 3D pen to draw electrochemical sensors as well as other electrochemical devices, with applications ranging from medical point-of-care platforms, energy-storage devices as well as for teaching purpose.
18 citations
TL;DR: The objective of this study was to determine whether and how a set of both non-natural and natural HIV-1 protease inhibitors could dock to that novel crystallized severe acute respiratory syndromerelated coronavirus 2 (SARS-CoV-2) main protease and, consequently, to identify potential lead compounds to treat COVID-19 infected patients.
Abstract: So far, there is neither a vaccine nor a specific antiviral drug to prevent or treat COVID-19 (coronavirus disease) infection. Recent studies have been done to investigate the capacity of human immunodeficiency virus type 1 (HIV-1) protease inhibitors be used in the treatment of COVID-19 patients. Some of those drugs have shown to be promising. Natural chemical substances from plants provide a good source of chemicals for the development of potential novel antiviral drugs against viral pathogens including HIV-1. In January 2020, a new promising target useful for structure-based drug design was elucidated and stored in the Protein Data Bank. In this context, the objective of this study was to determine whether and how a set of both non-natural and natural HIV-1 protease inhibitors could dock to that novel crystallized severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) main protease and, consequently, to identify potential lead compounds to treat COVID-19 infected patients. The results showed that two non-natural compounds, danoprevir and lopinavir, and one compound from plant, corilagin, produced strong interactions with the inhibitor binding site of SARS-CoV-2 main protease. It is expected that this work contributes to validate the use of HIV-1 protease inhibitors against SARS-CoV-2.
14 citations
TL;DR: In this article, the authors described the isolation and identification of 12 already known terpenes from oleoresins obtained from three different Copaifera species (C. multijuga, C. pubiflora and C. trapezifolia).
Abstract: Copaifera species (Fabaceae) comprises approximately 70 species of large trees, from which 16 can be found in Brazil. The oleoresins obtained from their trunk are widely used in Brazilian folk medicine, which display important antitumoral potential. Chemically, these oleoresins are mainly composed of a mixture of sesquiterpenes and diterpenes. In this paper we are describing the isolation and identification of 12 already known terpenes from oleoresins obtained from three different Copaifera species (C. multijuga, C. pubiflora and C. trapezifolia) and 2 novel diterpenes (ent-16-hidroxy-3,13 clerodadien-15,18-dioic acid and ent-labda-5,13-dien-15-oic acid) from C. trapezifolia. Both new compounds were identified by nuclear magnetic resonance (NMR) spectroscopic (1H and 13C NMR, correlation 1H-1H (COSY), heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond correlation (HMBC)) and by high-resolution electrospray ionization mass spectrometry (HR-ESIMS) analyses. The cytotoxic potential of these oleoresins, their main non-volatile compounds and their volatile compound fractions were evaluated against a panel of tumoral (MCF-7, ACP01, A549, HeLa) and normal cell lines (MCF-10A, GM07492-A) through XTT (tetrazolium salt) and SRB (sulforhodamine B) assays. The novel diterpene ent-labda-5,13-dien-15-oic acid displayed relevant cytotoxic effect against most of the cancer cell lines with mean inhibitory concentration (IC50) values ranging from 3.57 ± 1.12 to 22.56 ± 1.03 µg mL-1, and a high selectivity level in both assays.
14 citations
TL;DR: In this paper, the authors reported the theoretical and experimental study of fragmentation reactions in the gas phase of five phenolic acids using triple quadrupole mass spectrometry by electrospray ionization in negative ionic mode, as well as the isotope exchange experiments.
Abstract: This work reports the theoretical and experimental study of fragmentation reactions in the gas phase of five phenolic acids using triple quadrupole mass spectrometry by electrospray ionization in negative ionic mode, as well as the isotope exchange experiments. MS/MS spectra were analyzed to suggest the fragmentation mechanisms, while theoretical calculations at the theory level B3LYP/6-311+G** were performed to expose the proposed mechanisms viability for this class of compounds. As expected, compounds with aromatic methoxy substitution presented •CH3 radical elimination as the principal fragmentation pathway, forming dystonic ions. Compounds without methoxy substituents dissociate with higher energies losing the CO2, CO and H2O. The isotopic marking experiments indicated the exchange of hydrogens by deuterases in the hydroxyl protons, which corroborates with the proposed mechanisms.
14 citations
TL;DR: In this paper, the energy-related characteristics of apple bagasse, orange bagasse and cashew-apple bagasse were investigated to identify their potential as bioenergy feedstocks, including proximate analysis, ultimate analysis, atomic molar ratio, heating values, chemical composition, bulk density, bioenergy density, fuel-value-index (FVI), fossil fuel equivalence and potential CO2 retention.
Abstract: This work aims to investigate the energy-related characteristics of apple bagasse, orange bagasse and cashew-apple bagasse to identify their potential as bioenergy feedstocks. For this, a detailed characterization was performed, including proximate analysis, ultimate analysis, atomic molar ratio, heating values, chemical composition, bulk density, bioenergy density, fuel-value-index (FVI), fossil fuel equivalence and potential CO2 retention. Proximate composition revealed moisture, volatile matter, fixed carbon and ash contents in the range of 7.8-9.3%, 67.1-74.2%, 16.2-22.0% and 1.6-5.7%, respectively. Typical values for carbon (44.8-49.9 wt.%), hydrogen (5.5-6.6 wt.%) and oxygen (40.1-44.2 wt.%), with low sulfur (< 0.1 wt.%) and nitrogen (< 2.7 wt.%) contents were found. In regard to bulk density (237.7-554 kg m−3) and bioenergy density (3.93-10.1 GJ m−3), juice processing residues have substantial values when compared with well-known lignocellulosic residues. Recoverable energy potential from the juice processing residues varied from 15.24 to 17.03 MJ kg−1. From FVI analysis, apple bagasse is expected to be more suitable for thermochemical processing. Orange bagasse, on the other hand, has the highest equivalent in fossil fuel volume. Consequently, its use as solid fuel may lead to a decrease in CO2 emissions from reference fuels.
13 citations
TL;DR: A vortex assisted liquid-liquid microextraction method combined with high performance liquid chromatography-diode array detector has been developed for the determination of parabens in foods, cosmetics and pharmaceutical products as discussed by the authors.
Abstract: A vortex-assisted liquid-liquid microextraction method combined with high performance liquid chromatography-diode array detector has been developed for the determination of parabens in foods, cosmetics and pharmaceutical products. In this work, polymeric deep eutectic solvents composed of DL-menthol and polyethylene glycol with three different light grades were prepared successfully for the first time and used as extraction solvents. The influencing parameters on the extraction efficiency including type of extraction solvent, salt addition, composition of deep eutectic solvent, volume of extraction solvent, extraction time and solution pH were evaluated. Under the optimized conditions, using DL-menthol and polyethylene glycol 400 at a molar ratio of 1:1 as the extraction solvent, the method exhibited good linearity with linear coefficients greater than 0.9995. Limits of detection and limits of quantification were in the range of 0.3-2 ng mL-1 and 1-5 ng mL-1, respectively. The proposed method was successfully applied to determine four parabens in seven commercial products. The proposed method is simple, green and efficient, and could be applied to determine parabens in complex matrices.
TL;DR: The concentration of pesticides in the atmosphere of São Paulo and Piracicaba cities and the hazard quotients and cancer risk caused by inhalation of these compounds were calculated and showed no danger to the exposed population, and the cancer risk calculations for heptachlor resulted in values above those recommended by US Environmental Protection Agecy (EPA).
Abstract: Since the 1950s, pesticides have been used in agriculture. The increase in their consumption has been observed in recent years. In this work, it was determined the concentration of pesticides in the atmosphere of São Paulo and Piracicaba cities (sugarcane plantation site) and the hazard quotients and cancer risk caused by inhalation of these compounds were calculated. Twenty-three samples were analyzed and 34 pesticides associated to atmospheric particulate matter (with diameter equal to or less than 2.5 (PM2.5) and 10 μm (PM10)) were investigated by gas chromatograpy-mass spectrometry (GC-MS). Fourteen compounds including organochlorines, organophosphorus, and pyrethroids pesticides, were determined in these samples. The concentrations in the particulate matter ranged from 17 pg m (tebuconazole) in Piracicaba, to 166 pg m (endrin aldehyde) in São Paulo. The highest values of daily inhalation exposure for heptachlor were 9.0 × 10 mg kg day at Piracicaba, and 6.5 × 10 mg kg day at São Paulo, in both cases registered in infants. The values of the hazard quotients are lower than 1.0, indicating that there is no danger to the exposed population, it is health protective. On the other hand, the cancer risk calculations for heptachlor resulted in values above those recommended by US Environmental Protection Agecy (EPA).
TL;DR: In this article, a castor cake biochar production and chemical activation with different reaction conditions using HNO3 and/or H2O2 was described, and the activation treatments promoted modifications in the elemental, morphological and structural biochar characteristics.
Abstract: Biochar is a rich-carbon material highly functionalized, which allows the use as electrodes modifier for preconcentration and voltammetric determination of several species. This work describes a castor cake biochar production and chemical activation with different reaction conditions using HNO3 and/or H2O2. Biochar samples were characterized using scanning electron microscopy, energy dispersive spectroscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman and zeta potential. Carbon paste modified electrodes (CPME) have been constructed using different biochar samples to evaluate the adsorptive capacity for the spontaneous preconcentration and voltammetric determination of Pb2+, Cd2+, Cu2+ and Ni2+ ions, paraquat and methyl parathion pesticides. The activation treatments promoted modifications in the elemental, morphological and structural biochar characteristics. Activated biochar CPMEs showed increase in the current signal around 15 and 2.5 times higher than unmodified and precursor biochar electrode, respectively. N2 sample (HNO3, 60 °C for 3.0 h) presented the better response signals for all compounds. This was attributed to the more effective surface oxidation, promoting a high porosity, acid character and amount of acid functional groups. Besides that, this greater analytical response allows the CPME-N2 application as a passive sampler for the voltammetric determination of inorganic and organic contaminants for environmental management in aqueous matrices.
TL;DR: The strain Bacillus cereus CBMAI2067 (67 ± 3% biodegradation) was more efficient than the bacterial consortium, showing its potential as source of carboxylesterases and proving that, in this case, the use of a unique efficient strain is more adequate.
Abstract: New biocatalysts for bioremediation techniques are necessary nowadays. Therefore, a bacterial consortium isolated from Brazilian Savannah was employed for biodegradation of 100 mg L-1 esfenvalerate in liquid culture medium. The bacterial consortium (Lysinibacillus xylanilyticus CBMAI2085, Bacillus cereus CBMAI2067, Lysinibacillus sp. CBMAI2051 and Bacillus sp. CBMAI2052) biodegraded this pyrethroid efficiently. The assays were conducted in triplicate, and after 12 days, 90% of the pesticide was degraded producing 3-phenoxybenzoic acid (35.0 ± 3.1 mg L-1) and 2-(4-chlorophenyl)-3-methylbutanoic acid (34.0 ± 2.8 mg L-1). The bacterial consortium (52 ± 5% biodegradation) was more efficient in the biodegradation than the average of the same strains solely employed (40 ± 7% biodegradation), showing that the use of consortia is an interesting approach. However, the strain Bacillus cereus CBMAI2067 (67 ± 3% biodegradation) was more efficient than the bacterial consortium, showing its potential as source of carboxylesterases and proving that, in this case, the use of a unique efficient strain is more adequate.
TL;DR: In this paper, two methods employing mid and near infrared spectroscopy associated with chemometrics Partial least squares (PLS) models were built and presented satisfactory results with mean absolute percentage error of prediction and root mean square error (RMSEP) of prediction of 112 and 076% (m/m), respectively, for mid-infrared (MIR) and 183 and 118% for near infrared (NIR) for NIR.
Abstract: Alcohol-based gel hand sanitizers became very popular during the COVID-19 (coronavirus disease 2019) pandemic In Brazil, several irregular factories emerged requiring an efficient control by the police and regulatory agencies to guarantee product quality This problem required a method to determine ethanol content, which led to the development of two methods employing mid and near infrared spectroscopy associated with chemometrics Partial least squares (PLS) models were built and presented satisfactory results with mean absolute percentage error of prediction and root mean square error of prediction (RMSEP) of 112 and 076% (m/m), respectively, for mid-infrared (MIR) and 183 and 118% (m/m) for near-infrared (NIR) The analysis of commercial and seized samples of hand sanitizers showed that only 7 out of 34 samples had an ethanol content of 70% (m/m) or higher This result reinforces the need for constant vigilance by authorities to ensure that the products have the required specifications
TL;DR: In this article, the authors proposed a treatment for vinasse by hydrothermal carbonization, and evaluated the influence of temperature (100 to 200 oC), acidity (1.7 to 8.3%) and reaction time (12 to 48 h).
Abstract: Vinasse is a residue of ethanol production from sugarcane. In view of the problems associated with its disposal, this study aimed to propose a treatment for vinasse by hydrothermal carbonization. The influence of temperature (100 to 200 oC), acidity (1.7 to 8.3%) and reaction time (12 to 48 h) on the hydrothermal treatment was evaluated, as well the characteristics of the solid (hydrochar) and liquid (process water) products. For the solid product, two hydrothermal carbonization conditions stood out as leading to higher carbonization and yields. These conditions were 200 oC, 8.3% acidity and times of 12 and 48 h. For the process water, the carbonization reaction at 200 oC, 8.3% acidity and 48 h produced the highest discoloration and 77% reduction of total organic carbon. Thus, hydrothermal carbonization proved to be an efficient method to treat vinasse, and the hydrochar presents potential for use as fertilizers / soil conditioners, and also the process water after pre-treatment.
TL;DR: In this paper, the effect of extrusion in the nutritional composition, phenolic compounds content of two sorghum, and characterize the profile of chemical constituents by paper spray mass spectrometry (PS-MS).
Abstract: The use of sorghum in human nutrition has been expanded due to its nutritional composition and its functional potential. Extrusion has been used to improve the quality of sorghum. The aim of this work was to assess the effect of extrusion in the nutritional composition, phenolic compounds content of two sorghum, and characterize the profile of chemical constituents by paper spray mass spectrometry (PS-MS). Extrusion increased the carbohydrate and fiber contents and reduced moisture, lipids and ashes, and enabling a higher degree of liberation of phenolic compounds and antioxidant activity. The fingerprint obtained in both ionization modes had been influenced by extrusion, allowing for a greater compounds’ identification on the extruded samples. The analysis of sorghum samples’ main components made distinguishing of the main constituents possible, as well as highlighted the extrusion effect and the influence of the genotypes. This study demonstrated that extrusion enabling a higher liberation of phenolic compounds, which were identified by the PS-MS technique.
TL;DR: The phytochemical profiles in detail were looked into and it was observed that, S. tuberosa leaf extract was cytotoxic in both tumor and healthy cells, and therefore the unexplored co-products in agro industry may have great therapeutic potential and therefore should be screened for biologically active compounds.
Abstract: Agroindustrial residues, such as leaves of fruit plants, can be sources of bioactive molecules, thus adding value to co-products that are rarely explored in agroindustry. In this context, this study aimed to look into the phytochemical profiles in detail and to explore the antitumor potential of S. tuberosa and S. mombin leaves. We observed that, S. tuberosa leaf extract was cytotoxic in both tumor and healthy cells. S. mombin extracts selectively inhibited cell proliferation in the tumor cell line for prostate cancer (PC3) and did not significantly affect healthy cells. The metabolic profiles of the extracts were evaluated by gas chromatography coupled with mass spectrometry and twenty-three metabolites were identified. The correlation of metabolic profiles with cytotoxic tests indicated possible chemical markers that may be responsible for the inhibition of cell proliferation. This study revealed that the unexplored co-products in agroindustry may have great therapeutic potential, and therefore should be screened for biologically active compounds.
TL;DR: In this article, the authors investigated the kinetic of lumefantrine thermal decomposition, an antimalarial, using non-isothermal and isothermal experimental data, and the results provided important information for the pharmaceutical industry to assay levels of acceptable lumen contents.
Abstract: Thermal analysis can be used to determine shelf-life and kinetic parameters in pharmaceutical systems. This work investigates the kinetic of lumefantrine thermal decomposition, an antimalarial, using non-isothermal and isothermal experimental data. The non-isothermal conditions are analyzed applying Vyazovkin method, while isothermal conditions employ models fitting procedure and artificial neural network. Lumefantrine was characterized by powder X-ray diffraction and Fourier transform infrared spectroscopy. The initial stage of lumefantrine thermal decomposition, about 5% of conversion, corresponds to the loss of chlorine and hydroxyl, being correctly predicted by the neural network as a complex event. At room temperature, the D3 model is appropriate to describe the process, once the half-life time is 19 months, in agreement with manufacturer. Isoconversional model determined the activation energy along the whole process while isothermal methodology determined the global value considering the entire process. The results provide important information for the pharmaceutical industry to assay levels of acceptable lumefantrine contents.
TL;DR: In this paper, a method based on the derivatization of polyunsaturated fatty acids and their gas chromatography-mass spectrometry (GC-MS) analysis in the form of methyl esters, was partially modified and optimized for determination of w-3 and w-6 fatty acids in fish oil capsules.
Abstract: The essential w-3 and w-6 fatty acids have important physiological functions, such as prevention of cardiovascular diseases and atherosclerosis, and are commercially sold as fish oil capsules. In the present work, a method previously described in the literature, based on the derivatization of polyunsaturated fatty acids and their gas chromatography-mass spectrometry (GC-MS) analysis in the form of methyl esters, was partially modified and optimized for determination of w-3 and w-6 fatty acids in fish oil capsules. In addition, the w-9 fatty acid oleic acid was also determined with the optimized method, despite the lack of information about its quantities in the acquired products. The method exhibited good linearity and precision, limits of detection and quantification in the ranges from 0.16 to 0.18 mg g-1 and 0.46 to 0.63 mg g-1, respectively, and recoveries above 76%. The method was applied to analyze ten brands of encapsulated fish oil marketed in Salvador, BA, Brazil. Amongst the results, it was shown that one brand had significantly high amounts of linoleic acid, which indicates a probable adulteration of the product.
TL;DR: In this article, the impact of decommissioning on metal concentrations in the bottom sediments of the bay was investigated and the results showed that over these 15 years, Cd and Zn concentrations have decreased by 100 and 70%, respectively.
Abstract: Sepetiba Bay, Rio de Janeiro, Brazil, was home to a zinc smelter until its shutdown in 1998, and during 2011 the remains of the smelter were decommissioned. This study investigates the impact of decommissioning on metal concentrations in the bottom sediments of the bay. In addition to Zn and Cd, Cr, Cu, Ni and Pb are also quantified. The results show that over these 15 years, Cd and Zn concentrations have decreased by 100 and 70%, respectively. Temporal effects are also studied by applying five dated 210Pb cores, which are validated using the Zn and Cd profiles. The observed decrease in the Zn concentration in oysters is correlated with its reduction in the sediment. It was possible to verify the impact of Cr, Cu, Ni and Pb on the sediment quality due to the remaining metallurgical industries in the Sepetiba Bay basin.
TL;DR: The derivatives of pyrazoles were promising as an alternative latent fingermark, presenting high quality images for fingermarks, proving to be a great tool for forensic sciences.
Abstract: Fingerprints are unique to each individual, contributing to human identification in forensic cases. The powder technique being widely used is considered one of the most important in latent fingermarks analysis. In this sense, the present work aimed to synthesize 1-thiocarbamoyl-4,5dihydro-1H-pyrazoles and apply them as powder agents to develop latent fingermarks. The compounds were prepared from an effective and green synthesis via the condensation of chalcones with thiosemicarbazide in ethanol under microwave irradiation. Pyrazoles were tested and compared with a standard white powder (Sirchie) on glass surfaces using sebaceous and natural fingermarks so that molecule 2c has been shown to be more promising providing image clarity. The derivatives of pyrazoles were promising as an alternative latent fingermark, presenting high quality images for fingermarks, proving to be a great tool for forensic sciences.
TL;DR: In this paper, a series of unsymmetrical N,N-disubstituted benzimidazolium salts were synthesized as N-heterocyclic carbene (NHC) (2a-2j) and their AgI complexes.
Abstract: In this study, a series of unsymmetrical N,N-disubstituted benzimidazolium salts were synthesized as N-heterocyclic carbene (NHC) (2a-2j) and their AgI complexes. Their structures were characterized by elemental analyses, 1H and 13C nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy techniques. Further, both the salts and their silver(I)-NHC complexes have been evaluated for their potential antibacterial properties against a panel of bacterial strains namely, Micrococcus luteus, Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus and Pseudomonas aeruginosa. The results show that silver complexes are effective against SalmonellaTyphimurium, Listeria monocytogenes, and Micrococcus luteus with moderate to high activity, and their minimum inhibitory concentrations ranging from 0.0034 to 1.26 mg mL−1. In addition, the benzimidazoles salts 2a-2j and silver-NHC complexes 3a-3j were screened for their antitumor activity. Complex 3e exhibited the highest antitumor effect with half-maximal inhibitory concentration (IC50) value of 4.2 µg mL-1 against MCF-7.
TL;DR: In this paper, subcritical n-propane was used under different temperature and pressure conditions to obtain Brazil nut oil, and the composition of the oil was determined and compared to the oils obtained by conventional methods.
Abstract: In order to provide an effective and environmentally correct alternative for oil extraction, subcritical n-propane was used under different temperature and pressure conditions to obtain Brazil nut oil. The composition of the oil was determined and compared to the oils obtained by conventional methods. The result of the extraction yield obtained using subcritical fluid extraction (SFE) at 60 oC, 6 MPa and granulometry < 1.40 mm (63.13%) presented minor differences to the yield obtained by Soxhlet extraction (SE) (68.44%) and Bligh and Dyer extraction (BD) (59.54%). The composition in fatty acids was similar regardless of the method of extraction used. Oxidized triacylglycerols (TAGs) were found in the oils extracted by SE and BD while they were not detected in the oils extracted by SFE. The quantity of bioactive compounds was higher in the oils obtained by SFE. Thus, the SFE using n-propane preserves the nutritional characteristics and lipophilic components of the oil, besides improving the availability of bioactive compounds from an effective “green extraction” without the use of toxic solvents.
TL;DR: In this article, the authors described the development of the polymeric 3D printed electrodes modified by cobalt-Prussian Blue and their performance in the water oxidation process and showed that the overpotential of Co-Co PBA in 3DPE is lower than the value observed by Co-Fe PBA.
Abstract: The water oxidation is the limiting step in the water-splitting process. Given this scenario, the development of new catalysts is essential in this field. The emergent demand is the use of Earth-abundant elements and catalysts with high performance under mild conditions. Because of this, catalysts such as Prussian Blue analogues (PBA) have been receiving a lot of attention in recent years. In addition, working under neutral conditions allows us to take advantage of the modification of conductive polymeric 3D printed electrodes (3DPE) with Prussian Blue. Thus, we described in this work the development of the polymeric 3D printed electrodes modified by cobalt-Prussian Blue and their performance in the water oxidation process. The 3D printed electrodes modified with Co3[Co(CN)6]2 (Co-Co PBA) have a Tafel slope of 343 mV dec−1 while those modified with Co3[Fe(CN)6]2 (Co-Fe PBA) have a Tafel slope of 378 mV dec−1. This means that both catalysts have the same mechanism for the water oxidation process. On the other hand, the overpotential of Co-Co PBA in 3DPE is lower than the value observed by Co-Fe PBA in 3DPE suggesting the best electrocatalytic activity for Co-Co PBA catalyst.
TL;DR: In this article, the authors investigated photophysical processes in multicomponent solutions composed by natural pigments extracted from Caesalpinia echinata (Brazil-wood) leaves, and concluded that the inner filter effect causes such quenching.
Abstract: Photophysical processes in multicomponent solutions composed by natural pigments, extracted from Caesalpinia echinata (Brazil-wood) leaves, are investigated. Beacuse of the main fluorescent molecules in these solutions are the chlorophyll a, chlorophyll b and pheophytin a, all features are discussed regarding these three pigments. It is observed that the fluorescence bands of these macrocyclic molecules, located around ca. 673 nm, are progressively quenched due to the increase of the solutions’ concentration. Due to a significant overlapping between their fluorescence and absorption Q-bands, it is concluded that the inner-filter effect causes such quenching. Through analysis of steady-state and time-resolved fluorescence, it is verified that the inner filter acts more effectively on the emission assigned to chlorophyll a. Invoking reported extinction coefficients for these pigments in their isolated forms, we can give a qualitative interpretation of such selectivity considering the effectiveness of the overlapping between the absorption and fluorescence bands.
TL;DR: In this paper, a monocationic RuII/arene/triphenylphosphine complexes with p-substituted benzoic acid derivatives were prepared and characterized using various techniques, such as nuclear magnetic resonance (NMR) and matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry, and the crystal structure of 1, 3 and 4 were determined by X-ray diffraction analysis.
Abstract: Mononuclear and binuclear RuII/arene/triphenylphosphine complexes with p-substituted benzoic acid derivatives were prepared and characterized. These monocationic complexes of type [Ru(η6-p-cymene)(PPh3)L] (L = benzoic acid (1), p-hydroxybenzoic acid (2), p-nitrobenzoic acid (3) and terephthalic acid (4)) were characterized using various techniques, such as nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry, and the crystal structure of 1, 3 and 4 were determined by X-ray diffraction analysis. The cytotoxicity of the complexes was evaluated, in vitro, against tumorigenic [MDA-MB-231, MCF-7 (breast), A549 (lung) and DU-145 (prostate)] and non-tumorigenic [MCF-10A (breast), MRC-5 (lung) and PNT-2 (prostate)] cells. The binuclear complex (4) was inactive due to its low solubility. Complexes 1, 2 and 3 showed similar cytotoxicity, however, complex 1 presented better selectivity index against MDA-MB-231 than compounds 2 and 3. Cellular ruthenium absorption was explored by inductively coupled plasma mass spectrometry (ICP-MS) analyzing the whole cells and the culture medium. Complementary studies showed that complex 1 inhibited colony formation, induced morphology changes in cells and promoted cell cycle arrest in the Sub-G1 phase for the MDA-MB-231 cells.
TL;DR: In this article, the authors used pequi bark, typical biomass and abundant in the Brazilian cerrado, in the production of 5-hydroxymethylfurfural (HMF), FF and derivatives such as levulinic acid (LA), obtained from biomass, have emerged as important industrial chemical platforms.
Abstract: In the current search for renewable energy sources, residual biomass has gained ground in the concept of biorefinery. Furanic compounds such as 5-hydroxymethylfurfural (HMF), furfural (FF) and derivatives such as levulinic acid (LA), obtained from biomass, have emerged as important industrial chemical platforms. In this sense, this work aimed to use pequi bark, typical biomass and abundant in the Brazilian cerrado, in the production of HMF, FF and LA using the ionic liquid 1-n-butyl-3-methyl-imidazole bromide ([BMIM][Br]). The analysis of chemical composition of pequi bark showed that it has potential for use in the production of bioproducts, FF, HMF and LA, with yields of 65, 3 and 23.7%, respectively. High glucose conversion rates were found (> 90%). The analysis of variance (ANOVA) was applied to obtain the mathematical model with α = 0.05, verifying the significance of the second order model established for HMF (F = 0.00167) and FF (0.004494). The model fit is satisfactory, obtaining the coefficient of determination (R) for the HMF and for the FF of 0.9599 and 0.08422, respectively. From the results obtained, it can be concluded that pequi bark has good precursor capacity for use in biorefinery processes.
TL;DR: The analysis revealed a M. leucadendra chemotype rich in (E)-nerolidol, which was more toxic to P. xylostella than Azamax®, the agricultural pests Tetranychus urticae and Plutella xylstella in different stages of development.
Abstract: Essential oils from the leaves, stems, flowers and fruits of Melaleuca leucadendra growing in the state of Pernambuco, Brazil, were analyzed using gas chromatography-mass spectrometry (GC-MS). The effects of the oils and their major constituent were evaluated on the agricultural pests Tetranychus urticae and Plutella xylostella in different stages of development. The analysis revealed a M. leucadendra chemotype rich in (E)-nerolidol (81.78 ± 0.90 to 95.78 ± 1.20%). P. xylostella was more susceptible to the oils and major constituent than T. urticae. The fruit oil was 1.5-fold more toxic than the leaf oil to T. urticae eggs. (E)-Nerolidol was 5.5-fold and 4.5-fold more toxic to T. urticae adults than the leaf and fruit oils, respectively. Azamax® used as the positive control was more efficient than the oils and (E)-nerolidol against T. urticae. However, the oils and (E)-nerolidol were more toxic to P. xylostella than Azamax®.
TL;DR: The fingerprint of hydroethanolic extracts was correlated with the cytotoxicity assay and demonstrated a significant difference in the composition of plant extract, which correlates with the principal component analysis (PCA) data that identified three distinct groups indicating, efficiently, metabolic differences between organs of M. urundeuva.
Abstract: Myracrodruon urundeuva (“aroeira-do-sertao”) is a species threatened with extinction due to anthropogenic exploitation. Phytochemical analysis of bark, branch and leaf extracts revealed the presence of several compounds such as flavonoids, phenols, tannins, quercetin derivatives and anacardic acids. Dereplication methodology was performed to tentatively identify 50 compounds analyzed by ultra-performance liquid chromatography coupled with an electrospray ionization quadrupole time-of-flight mass spectrometry operating in MSE mode (UPLC-QTOF-MSE). The extracts exhibited anti-tumor effect in cancer cells HCT-116 (colorectal), SF-295 (glioblastoma), HL-60 (leukemia), and RAJI (leukemia). Also, these results correlate with the principal component analysis (PCA) data that identified three distinct groups indicating, efficiently, metabolic differences between organs of M. urundeuva. Through discriminatory analysis of the orthogonal partial least squares (OPLS-DA), the variable of importance in the projection (VIP) and S-Plot, we were able to determine 30 potential biomarkers. The fingerprint of hydroethanolic extracts was correlated with the cytotoxicity assay and demonstrated a significant difference in the composition of plant extract.