Logomarca do periódico: Journal of the Brazilian Chemical Society

Open-access Journal of the Brazilian Chemical Society

Publicação de: Sociedade Brasileira de Química
Área: Ciências Exatas E Da Terra
Versão impressa ISSN: 0103-5053
Versão on-line ISSN: 1678-4790
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Sumário

Journal of the Brazilian Chemical Society, Volume: 36, Número: 5, Publicado: 2025

Journal of the Brazilian Chemical Society, Volume: 36, Número: 5, Publicado: 2025

Document list
Editorial
The Role of the Journal of the Brazilian Chemical Society (JBCS) in Advancing Scientific Research in Northeastern Brazil Machado, Giovanna
Review
Roles of Oligo(ethylene glycol) to Improve Sensing Systems Kunst, Taciana H. Menezes, Paulo Henrique Paim, Ana Paula S.

Resumo em Inglês:

Sensing systems are important and widely used tools for analytical determinations. The search for the synthesis of novel, low-cost, effective, and environmentally friendly sensing systems is a tendency; however, these systems still face several limitations. Oligo(ethylene glycol) (OEG) has been incorporated into sensing systems to circumvent some drawbacks. This review aims to show the roles that OEGs can perform and make them easy to access. Several articles dealing with OEG-containing sensing systems and addressing analytical applications were compiled. Each article is given on comparative tables focusing on the OEG, detection, and analytical parameters, and some notorious examples are also discussed in the text. More than ten roles of OEGs were found and commented on. These roles and their ability to advance sensing systems show that OEGs are versatile and efficient compounds. OEGs are expected to be a tool for the rational design and performance improvement of sensing systems.
Article
Analysis of Cocaine, Benzoylecgonine, and Ecgonine Methyl Ester in Hair Strands Via Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS) Donateli, Patrícia Santos, Nayara A. dos Charneau, Sébastien Sousa, Marcelo V. de Sabino, Bruno D. Romão, Wanderson

Resumo em Inglês:

Hair can provide chemical information about drug use. This study employed matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) to detect drugs in hair samples. The technique was used to detect cocaine (COC, molecular weight (Mw) = 303.14 Da) and its main metabolites, benzoylecgonine (BZE, Mw = 289.13 Da), cocaethylene (COCE, Mw = 317.16 Da) and ecgonine methyl ester (EME, Mw = 199.12 Da) in hair strands using 2,5-dihydroxybenzoic acid (DHB, 7.0 mg mL-1) and α-cyano-4-hydroxycinnamic acid (CHCA, at concentrations of 1.5, 3.0, 7.0, and 10 mg mL-1) as the evaluated matrices. Among these, CHCA was selected. Subsequently, the qualitative results obtained by MALDI(+) MS were correlated with the quantitative analyses of gas chromatography-mass spectrometry (GC-MS), demonstrating a significant correlation in responses (70%), with the detection of analytes by MALDI(+) MS even at low concentrations, determined by GC-MS. The concentration ranges obtained by GC MS analysis were from 0.6 to 4.1 ng mg-1 of COC, and from 0.05 to 0.4 ng mg-1 of COCE. The effect of pre-washing on the detection of COC and its metabolites was also evaluated, and the results indicated less influence from the pre-washing stage and confirmed the reduction in COC detection in hair exposed to bleaching.
Article
Influence of Current Density and Chloride Concentration on the Electrooxidation of Ammonia and Organic Matter in Ammonia-Laden Effluents Brigido, Caroline R. S. Lemos, Flávio A. Santos, Iranildes D. dos Dutra, Achilles J. B.

Resumo em Inglês:

Electrooxidation is an efficient method for treating effluents with high concentrations of ammoniacal nitrogen and organic matter (R), in the presence of chloride ions (Cl-). The present study aimed at degrading ammoniacal nitrogen and organic matter from an effluent generated at a fertilizer storage port terminal. For this purpose, a batch electrochemical reactor with mechanical agitation was used, with a Ti/RuO2 anode. The parameters studied were the current density that varied in 20, 40 and 60 mA cm-2, the concentration of chloride ions that was 0.04, 0.74, 0.90 to 0.81 mol L-1 and the electrolysis time that varied from 4.0, 5.0, 7.0 and 8.0 h. A 22 experimental design was conducted to determine the significance level of the parameters studied. The results obtained indicated the removal of 99.99% of N-NH3 and 75.60% of total organic carbon (TOC) when a current density of 60 mA cm-2 and a Cl- concentration of 35.5 g L-1 were applied, after 4.0 h of electrolysis.
Article
Volatile and Non-Volatile Compounds Profiling of Brazilian Pitanga (Eugenia uniflora L.) Varieties During Ripening using Gas Chromatography-Mass Spectrometry Approach Pascoal, Grazieli B. Meza, Silvia L. R. Tobamela, Eric C. Franzon, Rodrigo Cezar Massaretto, Isabel L. Purgatto, Eduardo

Resumo em Inglês:

Brazil is home to a rich biodiversity of native edible fruits renowned for their health-promoting compounds and flavors. Among these, Eugenia uniflora L. (Brazilian pitanga) is particularly notable. The fruit varies in color from yellow to purple and is prized for its intense aroma and versatile taste profile. However, information about the compounds responsible for their nutritional and sensory potential is still limited. This study analyzed volatile compounds and metabolites in yellow, red and purple pitanga fruits (Eugenia uniflora) at various ripening stages, exploiting a metabolomics approach. Yellow pitanga had 30 volatile compounds, with esters (40%), terpenes (26.67%) and aldehydes (16.67%) constituting 83.34% of identified volatile compounds. Red pitanga featured 26 volatile compounds, primarily terpenes and esters (each 30.77%) and aldehydes (15.38%), making up 76.92%. Purple pitanga contained 39 volatile compounds, with terpenes and esters (each 35.90%) and aldehydes (17.95%), totaling 89.75% of identified volatile compounds. Across all pitanga types, 124 metabolites were identified, including saturated fatty acids (17.74%), terpenes (17.74%) and sugars (16.93%), constituting 52.41% of identified metabolites. Future studies should provide nutritional information, consumption methods and industrial applications for pitanga fruits, focusing on sensory analysis, health benefits, preservation and breeding to enhance bioactive compounds and flavor.
Article
Dye Contaminant Removal: Adsorption on Thermoplastic Starch/Kraft Lignin Composites and Photodegradation Freitas, Amanda S. M. de Rodrigues, Jéssica S. Amaro, Stefanny F. Ramos, Beatriz M. Ferreira, Marystela

Resumo em Inglês:

This study investigated the removal of contaminants in water by adsorption on thermoplastic starch (TPS) and kraft lignin (KL) composites. A study on the desorption of methylene blue (MB) and methyl orange (MO) dyes in water was also carried out, followed by the photodegradation of solutions containing dissolved dyes. Initially, the surface morphology of the TPS and TPS-KL films was analyzed by scanning electron microscopy, revealing advantageous characteristics for efficient adsorption of contaminants. Fourier transform infrared spectroscopy (FTIR) analysis made it possible to characterize the TPS and TPS-KL composites. The results demonstrate the reversibility of the process and confirm the lack of permanent chemical modification in the polymer matrix, indicating that the adsorption/desorption process is physical rather than chemical. This suggests that the adsorbent material can be reused without losing its fundamental structural properties. Furthermore, the study allows for verification of the chemical changes on the surfaces of the materials involved. Ultraviolet-visible spectroscopy (UV-Vis) results show that for MO, both substrates exhibited low adsorption capacity, with efficiency values close to 20%. In contrast, for MB, both composite materials displayed excellent dye adsorption rates, achieving efficiencies of 78% or higher. The photodegradation of adsorbed dyes revealed promising results.
Article
Synthesis and Evaluation of Biological Activities of Thieno-[2,3-d]-pyrimidine Derivatives Guo, Yue Qian, Chenglu Yang, Rongrong Han, Zhongfei Sun, Guoxiang Sun, Yaquan

Resumo em Inglês:

A series of novel thieno[2,3-d]pyrimidine derivatives were designed, synthesized and evaluated for their biological ability. 2-Amino-4,7-dihydro-5H-thieno[2,3-d]pyrano-3-cyanonitrile was synthesized by Gewald reaction using pyranone as substrate, malonitrile and sulfur powder as raw materials and triethylamine as base at room temperature. Subsequent amination with N,N-dimethylformamide dimethyl acetal (DMF-DMA) gave N'-(3-cyano-4,7-dihydro-5H-thieno[2,3-c]pyran-2-yl)-N,N-dimethylmethanimidamide. In this article, the 23 thieno[2,3-d] pyrimidines were obtained by Dimroth rearrangement condensation with different anilines, 16 of them being new compounds. Meanwhile, all compounds were assessed for breast cancer MDA-MB-231 cell line bioactivity with paclitaxel (PTX) as the positive control, and all compounds in the series showed inhibitory effects on breast cancer cell MDA-MB-231. The IC50 of compound l against MDA-MB-231 is 27.6 μM, which is similar to that of PTX with an IC50 of 29.3 μM. This means that compound l exhibits comparable inhibitory activity to PTX in MDA-MB-231 cells and may be considered as a potential anti-MDA-MB-231 inhibitor.
Article
The Influence of the Acyl Side Chain on Pyrene Excimer Formation as a Model for Asphaltene Aggregation Alvarenga, Suyane D. S. de Garden, Simon J. Forero, Josué S. B. Teixeira, Raquel S. P. Souza, Rodrigo S. Gonçalves, Yan M. H. Horta, Bruno A. C. Gomez, Javier A. G. Santos, Luiz H. C. dos Ribeiro, Emerson S. Corrêa, Rodrigo J.

Resumo em Inglês:

Asphaltene aggregation mechanism is still a nebulous and controversial issue. Many authors argue that the aggregation of its components is due to π-stacking interactions, nonetheless, alkyl chains, heteroatoms, and even acidic groups are also constituents of asphaltenes and can play an important role in the chemistry of asphaltene. Excimers from pyrene are easily detected by fluorescence and were used in the current study to probe the effect of the side chain on the π-stacking capacity of pyrene. Pyrene was acylated with acyl chains varying from two to twelve carbon atoms, and the effect of the variation of the acyl chain length on excimer formation was followed by fluorescence emission spectroscopy. The results revealed that as the side chain grows from two to twelve carbon atoms the excimer/monomer ratio decreases and the excimer heat of formation drops from ΔH = -6.00 to -1.29 kcal mol-1. Further, the crystal structure of octanoyl pyrene (PC8) indicates that in the crystal structure, the aromatic moiety faces the acyl chain. This result was corroborated by density functional theory (DFT) calculations. Finally, the results were compared with two different asphaltenes and indicate that π-stacking cannot be assumed as the main driving force for asphaltene aggregation.
Article
Synthesis, Antileishmanial Activity, and in silico Study of 2-Hydroxy 3 (1,2,3 triazolyl)propyl Vanillin Derivatives Santiago, Samira S. Freitas, Camila S. Costa, Adilson V. Oliveira, Mariana B. de Faria, Aidene F. C. Belarmino, William S. Moura, Gisely F. Santos, Nayara A. dos Romão, Wanderson Lacerda Júnior, Valdemar Oliveira, Fabrício M. de Oliveira, Osmair V. Coelho, Eduardo A. F. Teixeira, Róbson R.

Resumo em Inglês:

This study details the preparation, antileishmanial assay, and in silico analysis of twenty 2-hydroxy-3-(1,2,3-triazolyl)propyl vanillin derivatives. These compounds were synthesized in three steps and evaluated against Leishmania infantum, Leishmania amazonensis, and Leishmania braziliensis promastigotes. Compounds 3s and 3t were the most effective, showing good activity against all Leishmania species tested. Molecular docking indicated that all compounds bind favorably to the sterol 14α-demethylase (CYP51) enzyme from L. infantum. ADMET (absorption, distribution, metabolism, excretion and toxicity) analysis indicated good oral bioavailability, non blood-brain barrier penetration, and high gastrointestinal absorption. Posaconazole and compounds 3e, 3s, and 3t remained stable in the CYP51 binding region during 100 ns molecular dynamics (MD) simulations. Root mean square deviation (RMSD) and root mean square fluctuations (RMSF) analyses from the MD trajectory revealed significant conformational fluctuations of the CYP51 N-terminal, suggesting occasional expulsion of 3e, potentially explaining its higher IC50 (half-maximal inhibitory concentration) values. Pairwise decomposition analyses from molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) calculations highlighted the importance of hydrophobic residues in interacting with the synthesized derivatives.
Article
Novel Terpene-Reinforced Photopolymerizable Resins Derived from Methacrylate Salts of Imidazole Lins, Ilária M. S. Vieira, Anderson G. Ribeiro, Rubson P. S. Santos, Dayane K. D. N. Maciel, Larissa G. Santa-Cruz, Petrus A. Alves Júnior, Severino Anjos, Janaína V. dos

Resumo em Inglês:

This research aims to develop new 3D (three-dimensional) printable resins made from methacrylate salts of imidazole, 2-methyl-imidazole, and 1-methyl-imidazole, with glycerol trimethacrylate serving as a crosslinking agent. With their backbone structure, these resins are easy and rapid to prepare, offering an alternative to conventional ones. Reinforced with terpene-based additives such as α-pinene, (R)-limonene, trans-ethyl cinnamate, and safrole, they present a diverse range of fifteen resin formulations. Each resin underwent printability tests, including printing tests, which revealed accuracy, precision, and dimensional stability compared to a commercial resin and its respective digital 3D models. Mechanical tests further demonstrated that adding alpha-pinene and (R)-limonene enhanced hardness, while safrole had the opposite effect. Resins containing α-pinene and (R)-limonene as additives showcased an elasticity modulus comparable to the commercial resin. According to mechanical tests, a cytocompatibility assay was conducted for the best resin, showing that this resin holds potential for developing drug delivery systems and other biomedical devices.
Article
Exploring the Potential of Waste Biomass from the Brazilian Legal Amazon in Bioproducts Production: a Comprehensive Analysis and Promising Perspectives Borges, Mariana S. Santos, Jéssyka R. Pedroza, Marcelo M. Rambo, Magale K. D. Bertuol, Daniel A. Frizzo, Clarissa P. Burrow, Robert A. Scapin, Elisandra

Resumo em Inglês:

The Legal Amazon Region has numerous lignocellulosic biomasses with unknown technological properties, contrasting with an urgent demand for energy transition towards a more sustainable economy. This study analyzed the biomasses of baru husk (BH), cupuaçu husk (CH), and pequi seed (PS) through slow pyrolysis at 650 °C to assess the suitability of the bio-oils and biochars as potential biorefinery bioproducts. The physicochemical characterizations showed that all residues are potential candidates for bioproduct production, with CH biomass obtaining the best results for biochar production due to its high carbon content (80.65%) and surface area of 298.0491 m2 g-1, while BH and PS are more suitable for bio-oil production due to their high volatile matter content (> 84%). The main compounds in the bio-oil identified by gas chromatography-mass spectrometry (GC-MS) were phenolic (48.5, 56.7, and 60.36% for BH, CH, and PS, respectively) and furanic (22, 12.17, and 10.28% for BH, CH, and PS, respectively). Finally, it is concluded that based on the physicochemical and morphological characteristics obtained in this study, the pyrolysis products have potential for future investigation in various processes such as adsorption, carbon sequestration, and obtaining valuable chemical compounds, contributing to the promotion of the bioeconomy through sustainable waste management.
Article
Computational and Experimental Study of PVA with F127 and Citric Acid for Electrospinning Rossin, Ariane Regina S. Martinelli, Vinicius Basso, Ernani A. Gibin, Mariana S. Zanuto, Vitor S. Vilsinski, Bruno Henrique Radovanovic, Eduardo Caetano, Wilker Dragunski, Douglas C.

Resumo em Inglês:

Despite the widespread application of electrospun membranes across various scientific fields, there remains a need for a deeper understanding of the molecular interactions between polymers and other compounds in precursor solutions for electrospinning. This study evaluates the molecular conformations of poly(vinyl alcohol) (PVA) with different degrees of hydrolysis (PVA87 and PVA99) and high molar mass, crosslinked with citric acid (CA), using molecular modeling. The solution properties, including rheology and conductivity, were compared to obtain electrospun nanofibers. Additionally, Pluronic-F127® (F127) was incorporated into the PVA/CA system for advanced applications. The molecular modeling results indicate that the degree of hydrolysis affects the intermolecular forces of PVA and the effective binding of CA to the polymer chain. The interactions within the PVA/CA/F127 system vary with the degree of hydrolysis. The high viscosity of PVA99, due to interand intramolecular bonds, negatively impacts fiber morphology and formation. Thermal and Raman analyses confirmed crosslinking. Under the conditions used, the PVA99/CA/F127 system is unsuitable for electrospinning. In contrast, the electrospinning and crosslinking of PVA87/CA/F127 with high molar mass yielded better results, enhancing the potential of these nanofibers for drug delivery applications.
Article
Higenamine Detection and Metabolism Study Using High-Performance Liquid Chromatography Coupled to AgIII-Luminol Chemiluminescence Wang, Haoran Sha, Hanyu Liu, Mengying Shi, Hongmei Ma, Li

Resumo em Inglês:

Herein, we developed a sensitive, selective, efficient, and low-cost method for higenamine (HG) detection. This method employs high-performance liquid chromatography with a chemiluminescence detector (HPLC-CL) coupled with an AgIII-luminol system. Lotus plumule and human urine samples were purified using a mixed weak cation exchange column (PWCX) solid-phase extraction cartridge, and a C18 column was employed for chromatographic separation using an aqueous solution of acetonitrile and 0.1% formic acid as the mobile phase. Under optimal conditions, the chemiluminescence (CL) signal decreased linearly with the logarithm of the concentration of HG in the range of 5-800 ng mL-1. The limit of detection (LOD) and limit of quantification (LOQ) of HG in the urine sample were 0.41 and 1.35 ng mL-1, respectively. The average recovery of HG in the urine and lotus plumule samples at three levels ranged from 80.02 to 110.40% with a relative standard deviation of less than 10%. Furthermore, we proposed a mechanism for CL signal reduction in the system. Finally, the urinary pharmacokinetics of HG in humans were studied to provide valuable information and reference for athletes on medication or diet during events.
Article
Study of the Chemical Diversity in Spondias tuberosa Leaves During the Phenological Evolution Stages: Metabolomic and Chemometric Approaches Associated with Antioxidant and Antiglycant Activities Nascimento, Francisco Wendell M. do Gondim, Tamyris A. Ribeiro, Paulo R. V. Lima, Maria Auxiliadora C. de Oliveira, Viseldo R. de Câmara Neto, João Francisco Ribeiro, Maria Elenir N. P. Ferrari, Anna Beatriz S. Zeraik, Maria Luiza Guedes, Jhonyson A. C. Zocolo, Guilherme J.

Resumo em Inglês:

Spondias tuberosa (umbu) has been studied from the perspective of natural product and pharmacology, revealing relevant biological activities. Therefore, from the point of view of chemical and biological studies, deepening knowledge about this species is of great importance. Additionally, the evaluation related to the metabolic variations of the same species during different phenological evolution stages is also an interesting aspect of the research. Thereby, ultra performance liquid chromatography coupled to mass spectrometry (UPLC-QToF-MSE) was used to trace the chemical profile from umbu leaves at different phenological stages, allowing the detection of 40 metabolites, which 16 were annotated, such as phenolics and anacardic acids. Furthermore, the use of chemoinformatics tools allowed obtaining information on phenological development in the three leaves phases: post-flowering (young leaves), full production and senescence. The antiglycation activity assay revealed a potential inhibition of the formation of advanced glycation end-products (AGEs) in the leaves at different phenological stages. The antioxidant activity was satisfactory and in agreement with previously reported results, evidencing the potential for using umbu leaves, currently completely discarded, as an alternative source of antioxidants, which may provide increased added value to the cultivation of umbu, stimulating family farming and the recovery of tree density in degraded areas.
Article
Sensitive Determination of Bisphenol A In Urine Using Automated Solid-Phase Extraction Followed by LC-MS/MS Analysis: Application to a Human Biomonitoring Study in Brazil Souza, Camila F. de Peteffi, Giovana P. Loredo, Cloé D. Bastiani, Marcos F. Bondan, Amanda P. Grassi, Giovanna S. Ferrareze, Carolina W. Winter, Paola Hahn, Roberta Z. Antunes, Marina V. Linden, Rafael

Resumo em Inglês:

Bisphenol A (BPA), an endocrine disruptor present mostly in polycarbonate plastics and epoxy resins, can migrate into food and beverages, resulting in human exposure. This study aimed to develop and validate an improved liquid chromatography-tandem mass spectroscopy (LC-MS/MS) method for measuring BPA levels in urine, applying this method for BPA exposure evaluation in a Brazilian cohort, along with BPA hair levels. Samples from 100 volunteers were collected. Urine samples were extracted using an automated solid-phase extraction procedure. The assay had a 6.5-min run time, a linear range of 0.10-25 ng mL-1, precision of 3.8-18.1%, and accuracy of 96.6-103.4%. BPA was detected in all tested urine samples (median 0.86 ng mL-1). In hair, 47% of samples had detectable BPA concentrations (median 4.8 ng g-1). No correlation was found between BPA levels in urine and hair. All levels were below the safety threshold, indicating minimal risk for the studied population, with higher urinary BPA linked to canned product consumption and higher hair levels to a healthier diet.
Article
Extracts from Tissue Cultures of Crotalaria spp. as Potential Natural Alternative for Controlling Root-Knot Nematodes Honório, Amanda P. Blank, Daiane E. Demuner, Antonio J. Souza, Gustavo S. F. Buonicontro, Dalila S. Varejão, Eduardo V. V. Zocolo, Guilherme J. Guedes, Jhonyson A. C. Firmino, Maria J. M. Carvalho, Jilma L. B. R. D. Santos, Marcelo H. Faria, Daniele V. Vieira, Lorena M. Otoni, Wagner C. Machado, Franklin J.

Resumo em Inglês:

Plants of the genus Crotalaria are known for their antagonistic effect against nematodes. It has been found that pyrrolizidine alkaloids are the main metabolites involved in such antagonistic activity. Aiming at obtaining extracts with higher alkaloid content and enhanced potential for use as bionematicides, we investigated the chemical composition and nematicidal activity of extracts obtained from Crotalaria juncea and Crotalaria ochroleuca cultivated in vitro through micropropagation. Remarkably, extracts from the callus of C. ochroleuca (lethal concentration of 95% (LC95) = 157.7 μg mL-1) and C. juncea (LC95 = 189.9 μg mL-1) exhibited high toxicity against Meloidogyne javanica. The ultra performance liquid chromatography coupled to quadrupole time-of-flight with high mass spectrometry (UPLC-QTOF-MSE) analysis revealed the presence of pyrrolizidine alkaloids, flavones, flavone glycosides, and isoflavones. These findings highlight the potential of tissue culture to obtain extracts from Crotalaria species compared to conventionally cultivated plants and provide a higher concentration of metabolites with nematicidal effects, paving the way for sustainable agriculture.
Article
Chitosan Pretreatment: Evidence of Enhanced Mechanical Stability and Adsorption Capacity to Produce a Hybrid Material Rodrigues, Sueslley G. G. Lopes, Gisele S. Longhinotti, Elisane Diógenes, Izaura C. N.

Resumo em Inglês:

Securing a food supply is a global issue that must be integrated into a sustainable framework to mitigate the effects of climate change. This study focuses on the synthesis of a hybrid material for detecting heterocyclic aromatic amines (HAAs), which are potential mutagenic and carcinogenic compounds generated during the heat processing of food. A novel approach was applied to produce films based on chitosan biopolymer incorporated with [Fe(CN)5(OH2)]3-, CS-Fe, which functions as the active moiety for the detection of quinoxaline (IQx), a molecule similar to HAAs. The pretreatment of the chitosan (CS) films significantly improved mechanical stability and more than doubled the adsorption capacity for [Fe(CN)5(OH2)]3-. The measurements from real samples indicated that the CS-Fe film can selectively detect IQx, even amidst common interfering amino acids like methionine, tryptophan, and histidine. In summary, the CS-Fe film may be regarded as an eco-friendly and cost-effective material suitable for food safety applications.
Article
Sustainable Water Management for Steam Generation in Sugarcane Biorefineries: Applying PCA and MST Clustering in Sample Analysis Souza, Érik Geraldo S. Pereira, Fabiola M. V.

Resumo em Inglês:

Our study on sustainable water management in sugarcane biorefineries, which utilizes water as a primary resource for generating bioenergy through steam production, has employed a novel approach. High water quality is crucial for optimal efficiency, particularly in boiler operations. We have utilized unsupervised methods, such as principal component analysis (PCA) and minimum spanning tree (MST), alongside instrumental analysis data, to assess water quality in steam production. The PCA exploratory analysis identified three distinct clusters, with the relevant variables being conductivity and SiO2 content, to differentiate the purity of a dataset of 120 samples. MST-based clustering corroborated the PCA findings, forming three clusters: sample 1 represented the purest water, while samples 3 and 6 were in different clusters, indicating less purity in boiler feedwater. These unsupervised methods are highly effective, providing accurate and reliable data analysis and significantly benefiting sugarcane biorefineries by eliminating subjective biases. The findings of this study promise to improve water management practices in sugarcane biorefineries, leading to more efficient and sustainable operations.
Article
A New Non-Cyanogenic Cyanoglycoside with Promising α-Glycosidase Inhibitory Activity from the Roots of Cordia trichotoma Rocha, Késya A. D. Lopes, Francisca R. S. Pinto, Francisco C. L. Pinheiro, Francisco M. G. N. Marques, Samuel P. D. Trevisan, Maria Teresa S. Silveira, Edilberto R. Pessoa, Otília D. L. Santiago, Gilvandete M. P.

Resumo em Inglês:

Three undescribed non-cyanogenic cyanoglycosides, designated as trichotomoside A (1), B (2), and C (3) along with three known ones (4-6) were isolated from the roots of Cordia trichotoma. In addition, miscellaneous compounds such as acid (1’R,3’S,5’R,8’S,2Z,4E)-dihydrophaseic 3’-O-β-D-glycopyranoside (7), N-(2E)-3-[(2S,3R)-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydro-1-benzofuran5-yl]acryloylglycine (8), syringaldehyde (9), scoparone (10), 12,16-epoxyglobiferin (11), α-cadinol (12), trichotomol (13), and 1-(3’-methoxypropanoyl)-2,4,5-trimethoxybenzene (14) were also isolated. The structures of all compounds were elucidated by an extensive analysis of spectroscopic data (infrared (IR), nuclear magnetic resonance (NMR), and high-resolution electrospray ionization mass spectrometry (HRESIMS)). The non-cyanogenic cyanoglycosides (1-6) were screened for their α-glucosidase inhibitory activities. None of the compounds exhibited antioxidant or xanthine oxidase activity. Compound 3 exhibited considerable inhibitory ability on α-glucosidase, showing a halfmaximal inhibitory concentration (IC50) = 646 ± 69 μmol L-1 close to the standard acarbose (IC50 = 521 ± 23 μmol L-1), demonstrating its promising antidiabetic action.
Article
Use of Greenhouse Cell for Rhodamine B (RhB) Removal Djehiche, Mokhtar Bachiri, Marwa Lahmar, Nedjma

Resumo em Inglês:

This study investigates the degradation of Rhodamine B (RhB) by persulfate (PS) activated by solar heating in greenhouse cells (GhC). The optimal configuration of the GhC was first determined, and an assessment was carried out to determine the effect of atmospheric temperature, wind speed, and humidity on its temperature. The mathematical model developed in this study was used to simulate the evolution of RhB concentration during degradation in the GhC at different initial PS concentrations ([RhB]t = [RhB]0·exp(-A × exp(-Ea/RT) × t) where, A is the pre-exponential factor, Ea is the activation energy, R is the perfect gas constant, and T the absolute temperature. The degradation of RhB by activated PS under artificial heating allowed for an investigation of the effects of initial PS concentration (0.1, 0.5, 1 and 2 g L-1) and temperature (25, 40, 50, 60, and 70 °C) on the process. The optimal working conditions and thermodynamic parameters (Ea = 85.3 kJ mol-1) were determined and incorporated into the mathematical model. Indeed, this model accurately reproduced RhB concentrations in GhC. The GhC performs best under conditions of high ambient temperature, high initial PS concentration, low humidity, little or no wind, and maximum sunlight exposure during midday.
Article
A Spectrophotometric Study of the Interaction of Quercetin and Tannic Acid with Mimetic Systems of Cancerous and Healthy Cells Oliveira, Pablo A. Mendes, Leandro A. Silva, Vitor O. Scarparo, Paulo V. Conceição, Layra C. Maia, Pedro I. S. Moreto, Jéferson A. Slade, Natália B. L.

Resumo em Inglês:

Quercetin (QUE) and tannic acid (TA) are among the antioxidants that have been shown efficiency in the treatment and prevention of cancer, cardiovascular and neurodegenerative diseases. However, little is known about the mechanisms by which these activities occur. Hereupon, this work presents a spectrophotometric study on their interaction with mimetic systems of cancerous and healthy cells. The objective was to evaluate the relevance of changes in pH and lipid composition of cell membranes, triggered by cancer development, in the target-antioxidant interaction. Therefore, intrinsic spectrophotometric properties of these compounds were monitored under different conditions. Results showed that QUE and TA were able to partition significantly from the aqueous medium to the model membranes. However, the partitioning was shown to be dependent on the lipid composition and pH. Partition coefficients, partition free energy, spectral shifts and turbidity parameters were also obtained, indicating that there is a balance between electrostatic and non-electrostatic interactions in the system that depends on the hydrophobicity/hydrophilicity of the polyphenols and the number of groups available for hydrogen bonding. In fact, this reveals that lipid composition and pH of the cellular microenvironment play an important role in their activity, influencing their ability to differentiate between healthy from cancer cells.
Article
Evaluation of the Uncertainty in the Measurement of Nanoparticle Size and Concentration by Single Particle Inductively Coupled Plasma Mass Spectrometry Technique Geraldes, Adriana N. Hortellani, Marcos A. Rostelato, Maria Elisa C. M. Sarkis, Jorge E. S.

Resumo em Inglês:

Single-particle inductively coupled plasma-mass spectrometry (sp-ICP-MS) is a powerful technique that enables the simultaneous measurement of nanoparticle size and the quantification of metal-containing nanoparticles at real concentrations. These measurements are critical for understanding the potential uses of nanoparticles in various fields. However, sp-ICP-MS is not yet considered a mature methodology. Standardization is necessary, particularly in assessing the reliability of size distribution measurements. This study aims to standardize sp-ICP-MS by assessing the reliability of size distribution measurements for polyvinylpyrrolidone-coated silver nanoparticles and quantifying the input quantities contributing to uncertainties. The uncertainties in calibration, repeatability, and trueness were evaluated based on the thresholds defined by International Organization for Standardization (ISO) standards. Calibration uncertainty was found to be 8.1%, while repeatability was 0.04%, both within the stipulated range of less than 10%. The expanded uncertainty was calculated to be 17%, with a 95% coverage probability for the reference material. Limits of detection (LOD) and quantification (LOQ) for dissolved concentration, particles per mL, and size were determined to be 0.37 μg L–1, 97.5 particles mL–1, and 24.6 nm, respectively. These results demonstrate that the reliability and repeatability of sp-ICP-MS meet ISO-defined thresholds, suggesting that with further standardization, sp-ICP-MS could become a reliable methodology for nanoparticle analysis.
Article
Drug Repurposing Strategy to Develop New AZT Derivatives Targeting SARS-CoV-2 Mpro: Synthesis, Computational Studies, and Enzymatic Evaluation Morais, Pedro A. B. Guedes, Natália A. Fontes, Caroline S. Gazolla, Poliana A. R. Paula, Heberth de Bigui, Walter C. C. Romão, Wanderson Costa, Gabriela V. Costa, Adilson V. Queiroz, Vagner T. de Lacerda Júnior, Valdemar

Resumo em Inglês:

This study focused on the synthesis and inhibitory activity of AZT (3’-azido-3’-deoxythymidine) 1,2,3-triazole derivatives against the main protease of severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2), supported by molecular dynamics. The triazoles were synthesized through CuAAC (copper(I)-catalyzed alkyne-azide cycloaddition) with microwave irradiation. Fourier transform infrared spectroscopy (FTIR), 1H and 13C NMR (nuclear magnetic resonance) and mass analyses confirmed the structures of 3a-3j. A luminescence assay was carried out to evaluate main protease (Mpro) inhibition. Molecular dynamics simulation was performed using GROMACS 2023.2. Ten AZT derivatives were synthesized in good yields of 58.7 to 97.7% and NMR data presented correspondent signals for AZT, such as H-8 at 7.76-7.83 and CH3-9 at 1.77-2.06 as singlets, and H-triazole at 8.03-9.05 as a singlet. Compound 3j revealed low micromolar inhibitory activity with a half-maximal inhibitory concentration (IC50) value of 25.15 μM. The molecular dynamics simulation showed stable binding interactions over a 200 ns simulation with hydrogen bonds involving Arg188, Glnl89, and Gln192 residues, which is similar to nirmatrelvir. The drug repurposing and molecular hybridization approach revealed that AZT is a valid option as a skeleton for new SARS-CoV-2 agents.
Article
Influence of Adding High Flash Point, Special Jet Fuel for Brazilian Navy (QAV-5), in Brazilian Marine Gasoil (ODM), on Fuel Viscosity, Specific Gravity, Cetane Index and Lubricity Louzeiro, Camila R. Souza, Cristiane G. de Andrade, Débora F. de A. d’Avila, Luiz

Resumo em Inglês:

The degradation of Type 5 aviation kerosene, used in navy aircraft, (QAV-5) during the storage period was evaluated by thermal oxidation test (JFTOT) and current gum test. QAV-5 failed to meet jet fuel specifications after 16 weeks of accelerated aging, due to compromised thermal stability and substantial gum generation. Pure blends of QAV-5 and aviation kerosene and marine diesel oil (QAV 5/ODM) in proportions of 25, 50 and 75% (v/v) were analyzed according to the marine diesel oil (ODM) specification, in week zero and at intervals of four weeks throughout the aging process. Fuel viscosity, specific gravity, cetane number and lubricity decreased as the QAV 5 content in the mixture increased. The viscosity of QAV-5, however, increased with storage time. The employment of pure QAV-5 diesel engines is not advisable unless the use of aviation fuel is expressly permitted. By the fuel haze lubricity test (FLHT), QAV-5/ODM blends with up to 88% (v/v) QAV 5 content can be used in diesel engines without damaging the fuel system. However, confirmation by standard high frequency reciprocating rig (HFRR) testing would be advisable for QAV-5/ODM mixtures with QAV-5 volumetric content above 75%.
Article
Analysis of Pesticides by Ultra-High Performance Liquid Chromatography in Combination with High Resolution Mass Spectrometry (UPLC-Orbitrap MS): Case Study for Application on River Water Samples in Vietnam Duc, Nam Vu Le, Thuy Minh Thi, Xuyen Nguyen Van, Hoi Bui Vu, Cam Tu Thi, Hong An Vu Chu, Dinh Binh

Resumo em Inglês:

This study introduced mass spectrometry (MS)-based method for analysis of 118 pesticides after applying solid phase extraction (SPE) for 26 water samples collected in Red River, Northern Vietnam. The excellent limit of quantitation of the developed method ranged from 0.0005 to 0.015 µg L-1. Intraand inter-day repeatability of the developed method was achieved below 15%. Specific procedure of the liquid chromatography Orbitrap mass spectrometry (LC-Orbitrap MS)-based analytical method for target compounds was identified by retention time, precursor ion, product ions, accurate mass of precursor and product ions and fragmentation pathway in high resolution mass spectrometry. Mass accuracy of all precursor ions and product ions were achieved below 5 ppm in this work. It demonstrated that the concentration of most studied analytes was below the allowable level according to National Technical Regulation in Vietnam (QCVN 08:2023/BTNMT). Alachlor, fenobucarb and acetochlor were often determined at levels in the range between 0.099-8.978, 0.058 18.776, and 0.073 1.460 µg L-1, respectively. Their concentrations were much higher than regulated pesticides mentioned in QCVN 08:2023/BTNMT (0.02 to 1.0 µg L-1 for chlorinated pesticides). Therefore, it is necessary to propose a national regulation regarding the levels of the three analytes above to control pesticide pollution in Vietnam.
Short Report
One-Pot Sodium Azide-Free Synthesis of Aryl Azides from Anilines Moraes, Leonardo G. C. de Guidinele, Maria Cristina B. Ferreira, Vitor F. Rocha, David R. da

Resumo em Inglês:

This work presents an easy and efficient one-pot protocol for the synthesis of aryl azides without using sodium azide or hydrazine hydrate starting from anilines via aryl hydrazines. This protocol can be applied to anilines bearing groups with donating or withdrawal electronic characteristics.
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