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Benzenesulfonyl incorporated chalcones: synthesis, structural and optical properties
(2020) Custodio, Jean Marcos Ferreira; Gotardo, Fernando; Vaz, Wesley Fonseca; D´Oliveira, Giulio Demetrius Creazzo; Almeida, Leonardo Rodrigues de; Rodriguez, Ruben Dario Fonseca; Cocca, Leandro Henrique Zucolotto; Pérez, Caridad Noda; Boni, Leonardo de; Napolitano, Hamilton Barbosa
Although the optical properties and applicability of chalcones as potential nonlinear optical(NLO) materials is well known, hybrids having both chalcone and sulfonamide portions are relatively scarce. In this sense, we are seeking to show if combining both into a double functionalized compound will still have similar or better NLO responses. For this, we have synthetized three sulfonamide-chalcone analogues by changing the substituent bonded to the sulfonamide ring (I ¼ ethoxy; II ¼ Cl and III ¼ Br). These compounds were characterized by spectroscopic methods (NMR, IR and HRMS) and thermal methods (HSM and DSC/TGA). Their crystal structures were determined by Single Crystal X-ray Diffraction (SCXRD) and their molecular structures were compared. Crystallographic results showed that one compound crystallizes in a triclinic system whereas the others crystallize in a monoclinic crystal system. Moreover, their crystal packing is dominated by CeH/O interactions. In addition to this study and to first characterize these compounds, linear and nonlinear optical (NLO) properties were performed on all three compounds dissolved in dimethyl sulfoxide. One-photon and two-photon absorption (2PA) spectra and incoherent second harmonic generation were obtained by employing different spectroscopic techniques. The interesting results observed in the linear and NLO measurements showed that different groups bounded to the same main backbone did not significantly modify their optical properties, although they strongly affect their crystal structures. s2PA spectra reveal that the first excited state is allowed by both 1PA and 2PA, which indicates asymmetry in the charge distribution along the p-conjugated molecule structure. NLO properties of compounds I-III agree with other chalcones previously studied, which indicates that adding the benzenesulfonyl group does not influence these properties. Considering the similar experimental values for different substituents, the results further motivate investigation on substituent-based optical properties for other sulfonamide-chalcone hybrids
Sobre o sentido e a eficácia da atividade de estudo: uma reflexão no seio da teoria da relação com o saber
(2022-04) Ribeiro Júnior, Ramon Marcelino; Vilela, Gabriel Amorim; Bento, Brenda Souza; Echeverría, Agustina Rosa
This paper presents aspects of how student activity is understood within Bernard Charlot's theory on the relationship with knowledge. We carried out a conceptual analysis of his work. First, we considered the centrality of the discussion of "sense" in understanding human activity to present twoof the main reasons that led us to this theory. Next, we presented the theory focusing on elements of its genesis and on basic questions around which the theory was built. Then, we discuss the concepts of "sense" and "effectiveness" of the study activity. Finally, we approached two fundamental assumptions of the theory to deepen the understanding of this activity: the indirect character of educational actions, and the need to build an epistemic subject as a central aspect in organizing and accomplishment of a different school and a different relationship with knowledge.
Avaliação da porosidade em polímeros monolíticos de metacrilato de metila e divinilbenzeno (MMA-DVB)
(2018-06) Sousa, Rafael B. de; Cardoso, Victor Mendonça; Paula , Thales André de Oliveira; Silva , Valmir Jacinto da; Rossi, Maria L.; Rabelo, Denilson
Monolithic polymers are a class of materials that has grown rapidly in recent years. Porosity these materials is determined by type of inert diluent and degree of dilution. Thus, the present work used solvating and non-solvating diluents for the polymer chains, as well as two degrees of dilution, to produce monolithic polymers of MMA-DVB, with different surface areas, morphological characteristics and porosities. The non-solvating diluent and higher degree of dilution, yielded polymers with higher surface area and higher volume of pores. The solvating diluent and less degree of dilution, yielded polymers with lower surface area and lower pore volume, showing that both the type of diluent and the degree of dilution are parameters that influence the porosity of these materials.
Versatile fabrication of paper-based microfluidic devices with high chemical resistance using scholar glue and magnetic masks
(2017) Cardoso, Thiago Miguel Garcia; Souza, Fabricio Ribeiro de; Garcia, Paulo de Tarso; Rabelo, Denilson; Henry , Charles S.; Coltro, Wendell Karlos Tomazelli
Simple methods have been developed for fabricating microfluidic paper-based analytical devices (μPADs) but few of these devices can be used with organic solvents and/or aqueous solutions containing surfactants. This study describes a simple fabrication strategy for μPADs that uses readily available scholar glue to create the hydrophobic flow barriers that are resistant to surfactants and organic solvents. Microfluidic structures were defined by magnetic masks designed with either neodymium magnets or magnetic sheets to define the patter, and structures were created by spraying an aqueous solution of glue on the paper surface. The glue-coated paper was then exposed to UV/Vis light for cross-linking to maximize chemical resistance. Examples of microzone arrays and microfluidic devices are demonstrated. μPADs fabricated with scholar glue retained their barriers when used with surfactants, organic solvents, and strong/weak acids and bases unlike common wax-printed barriers. Paper microzones and microfluidic devices were successfully used for colorimetric assays of clinically relevant analytes commonly detected in urinalysis to demonstrate the low background of the barrier material and generally applicability to sensing. The proposed fabrication method is attractive for both its ability to be used with diverse chemistries and the low cost and simplicity of the materials and process.
Mn(iii)–porphyrin catalysts for the cycloaddition of CO2 with epoxides at atmospheric pressure: effects of Lewis acidity and ligand structure
(2021-01-04) Cabral, Bruno Noschang; Milani, Jorge Luiz Sônego; Meireles, Alexandre Moreira; Martins, Dayse Carvalho da Silva; Ribeiro, Stephany Larissa da Silva; Rebouças, Júlio Santos; Donnici, Claudio Luis; Chagas, Rafael Pavão das
A series of eight Mn(III)–porphyrin (MnP) complexes with electron-withdrawing substituents at the meso and/or β-pyrrole positions of the macrocycle was designed to uncover electronic and structural aspects of MnP catalytic activity in the cycloaddition of CO2 with epoxides. The complexes, when combined with tetrabutylammonium halides, were active catalysts producing the respective cyclic carbonate under mild conditions. The non-β-brominated complex H3[MnT4CPP] served as a structural framework for the design of a series of homologous complexes, leading to the synthesis of the new β-brominated catalysts H3[Mn(BrxT4CPP)] (x = 2, 4, or 6). The β-brominated catalyst series allowed the investigation of the influence of structural effects versus electronic effects on the catalytic system, demonstrating a good correlation between the catalytic activity and the number of bromine substituents at the β-pyrrole positions. The non-planar distortions of the macrocycle and the consequent steric hindrance are determinant for the reaction outcome. The decrease in catalytic activity despite the increase in Lewis acidity of the metal center highlighted the effect of the out-of-plane distortion on the catalytic activity of manganese porphyrins.
Production of hydrogen from bioethanol in Cu–Ni/NbxOy catalysts obtained by different preparation methods
(2016-05-25) Silva, Fernando Alves da; Pontes, Isabela Dancini; Gleicielle Tozzi , Wurzler; Alonso, Christian Gonçalves; Medina Neto, Antonio; Scaliante, Mara Heloisa Neves Olsen; Souza, Marcos de; Fernandes, Nadia Regina Camargo
Ethanol steam reforming for hydrogen production was evaluated using Cu–Ni/NbxOy catalyst prepared by ion exchange (IE), wet impregnation (WI) and co-precipitation (CP). The catalysts were characterized by textural analysis, chemisorption of H2 and N2O for metallic area determination, XDR (calcined and in situ reduced samples), TPR-H2, TPD-NH3, MET/EDX e TPO-O2. Differences in crystal structure and metal-support interaction have altered the reducibility of the catalysts, besides metal surface area and crystallite size of Cu and Ni. The catalytic tests, using ethanol:water molar ratio of 1:10, temperature of 450 and 500 °C, demonstrated high H2 yield and stability, except for the IE catalyst at 500 °C, which favored the ethylene formation by ethanol dehydration. The main route for H2 obtainment in all cases was ethanol decomposition. The temperature increasing up to 500 °C favored the by-product CH4 reforming. The weakest metal-support interaction on WI catalyst provided the fully reduced metal phase, however, support characteristics achieved by this preparation method led to the filamentous coke formation. TEM images showed that different crystalline structures of the support modified the mechanism of the reaction and consequently the type of coke deposited on the surface. The CP catalyst showed low coke deposition and no metal sintering, stoichiometric H2/CO2 ratio, less than 5% of CH4, and no CO, which makes it the best candidate for hydrogen production by ethanol steam reforming.
Niobium oxides as heterogeneous catalysts for Biginelli multicomponent reaction
(2020) Nascimento, Letícia Gomes do; Dias, Isabela Milhomem; Souza, Guilherme Botelho Meireles de; Pontes, Isabela Dancini; Fernandes, Nadia Regina Camargo; Souza, Paulo Sérgio de; Oliveira, Guilherme Roberto de; Alonso, Christian Gonçalves
This study reports a simple, reusable, and recoverable niobium-based heterogeneous catalysts for Biginelli multicomponent reactions. Different methods of catalysts preparation were investigated. For this purpose, HY-340 (Nb2O5·nH2O) and Nb2O5 were chemically and/or thermally treated and investigated as catalysts for dihydropyrimidinones (DHPMs) production. The catalysts were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, temperature-programmed desorption of NH3, adsorption/desorption of N2 at −196 °C, and thermogravimetric and differential thermal analysis. The characterization results showed that niobium oxides have the potential to be used as catalysts because of high crystallinity and large surface area. Among the tested catalysts, Nb2O5 chemically treated (Nb2O5/T) showed the best catalytic performance. In the absence of solvents, 94% yield of DHPMs was achieved. Also, Nb2O5/T can be reused three times without a significant yield decrease. Additionally, a feasible reaction pathway was suggested based on the Knoevenagel mechanism for DHPM synthesis using niobium-based catalysts.
Chemical Features and Bioactivities of Lactuca canadensis L., an Unconventional Food Plant from Brazilian Cerrado
(2021) Liberal, Ângela; Coelho, Carla T. P.; Fernandes, Ângela; Cardoso, Rossana Veviana Centeio; Dias, Maria Inês; Pinela, José; Alves, Maria José; Severino, Vanessa Gisele Pasqualotto; Ferreira, Isabel Cristina Fernandes Rodrigues; Barros, Lillian
Throughout the world, people’s diet is generally quite restricted regarding the variety of plants used in their daily regime. The Unconventional Food Plant (UFP) Lactuca canadensis L. is an edible species of wild lettuce sparsely described in literature and considered to be native from the eastern and central parts of North America. To valorize this species as potential alternative food, an analysis of its nutritional, chemical, and bioactive properties was performed. The results specify the occurrence of organic acids, mainly quinic acid (127.9 ± 0.6 g/kg dry weight (dw)), polyunsaturated fatty acids (65.3%), among which are linolenic acid (44.4 ± 0.4 %), and tocopherols, mostly α-tocopherol (61.2 ± 0.7 mg/kg dw). Additionally, eight phenolic compounds were also identified, among which luteolin-O-glucuronide was found in larger amounts in both infusion and hydroethanolic extracts (5.46 ± 0.09 and 4.6 ± 0.1 mg/g dw, respectively). Carbohydrates and proteins were the main macronutrients (603 ±1 and 177.5 ± 0.3 g/kg dw, respectively), followed by ashes (166.5 ± 0.9), indicative of a great amount of minerals. Additionally, good antioxidant and antibacterial activities were detected in the analyzed extracts. In general, our results contribute to extend the range of different, unexploited, and nutritionally balanced plant foods, such as Lactuca canadensis, that can and should be included in the daily diet.
Antiulcerogenic activity of species Annona coriacea Mart. and Spiranthera odoratissima A. St. Hil
(2017-12) Estrela, Fernanda Neves; Silva, Keise Rodrigues; Cruz, Álefe Cardoso; Souza, Patrícia Fernandes de; Costa, Leonardo Oliveira; Junqueira, João Gabriel Moraes; Leal, Geraldo Sadoyama =; Paula, Lucia de; Consolaro, Helder Nagai; Terezan, Ana Paula; Severino, Vanessa Gisele Pasqualotto
Background: Medicinal plants from the Brazilian Cerrado are used in folk medicine to treat several diseases such as gastric disorders. Purpose: The present work evaluated the antiulcerogenic and antimicrobial effects of the ethanolic extracts obtained from leaves of two Cerrado plant species. Methods: The action of ethanolic extracts of Spiranthera odoratissima (SOL) and Annona coriacea (ACL) were evaluated in experimental in vivo models in rats that simulated this disease in human gastric mucosa. Additionally, a pharmacological study to test antimicrobial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were also evaluated by microdilution methods. Results: The pretreated with SOL (100, 200 and 300 mg/kg, p.o.) promoted significant inhibition of mucosal injury (93, 99 and 98% inhibition; respectively). This inhibition also was detected in ACL treatment (50, 100, 200 and 300 mg/kg; 67, 52, 48 and 67% inhibition, respectively). The both extracts SOL (100 mg/ kg) and ACL (50 mg/kg) also reduced significantly the formation of gastric lesions induced by indomethacin (73 and 63%, respectively) when compared to animals treated with respective vehicle. The phytochemical profile from SOL and ACL indicated the presence alkaloids as a main constituent of these extracts. ACL but not displayed antimicrobial activities in vitro. Conclusion: Spiranthera odoratissima and Annona coriacea species present gastroprotective activity, supporting previous claims that its traditional use can treat gastrointestinal disorders.
Plants used for treatment of breathing disorders by the Coqueiros Community, Catalão (Go), Brazil
(2018-04) Gomides, Nubia Alves Mariano Teixeira Pires; Guarim Neto, Germano; Martins, Marcos Pereira; Kato, Lucília; Severino, Vanessa Gisele Pasqualotto
The searching for cure through medicinal plants dates back to the earliest times of human civilization, and it currently stands out due to the availability of several promising species for pharmacological studies. In this study, we evaluated the ethnomedical knowledge of the Coqueiros Community, in the municipality of Catalão (GO), specifically investigating the use of plants for treating respiratory system diseases. In order, to do this we interviewed 32 inhabitants of this community, who informed 20 different species. When comparing the data obtained from common knowledge with the scientific knowledge found in specialized literature, we noted that 90% of the mentioned species had been reported in literature as alternative therapies for respiratory system diseases.
Tapirira guianensis Aubl. extracts inhibit proliferation and migration of oral cancer cells lines
(2016-11) Oliveira, Renato José Silva; Lopes, Gabriela Francine Martins; Camargos, Luiz Fernando de; Ribeiro, Ana Maciel; Santos, Fábio Vieira dos; Severino, Richele Priscila; Severino, Vanessa Gisele Pasqualotto; Terezan, Ana Paula; Thomé, Ralph Gruppi; Santos, Hélio Batista dos
Cancer of the head and neck is a group of upper aerodigestive tract neoplasms in which aggressive treatments may cause harmful side effects to the patient. In the last decade, investigations on natural compounds have been particularly successful in the field of anticancer drug research. Our aim is to evaluate the antitumor effect of Tapirira guianensis Aubl. extracts on a panel of head and neck squamous cell carcinoma (HNSCC) cell lines. Analysis of secondary metabolites classes in fractions of T. guianensis was performed using Nuclear Magnetic Resonance (NMR). Mutagenicity effect was evaluated by Ames mutagenicity assay. The cytotoxic effect, and migration and invasion inhibition were measured. Additionally, the expression level of apoptosis-related molecules (PARP, Caspases 3, and Fas) and MMP-2 was detected using Western blot. Heterogeneous cytotoxicity response was observed for all fractions, which showed migration inhibition, reduced matrix degradation, and decreased cell invasion ability. Expression levels of MMP-2 decreased in all fractions, and particularly in the hexane fraction. Furthermore, overexpression of FAS and caspase-3, and increase of cleaved PARP indicates possible apoptosis extrinsic pathway activation. Antiproliferative activity of T. guianensis extract in HNSCC cells lines suggests the possibility of developing an anticancer agent or an additive with synergic activities associated with conventional anticancer therapy.
New degraded quinone diterpenoid from the stems of Byrsonima coccolobifolia Kunth. (Malpighiaceae)
(2018-02) Sousa, Lorena Ramos Freitas de; Santos, Marcos Henrique Faleiros; Severino, Vanessa Gisele Pasqualotto; Severino, Richele Priscila; Vieira, Paulo Cezar
A chemical investigation of two specimens of Byrsonima coccolobifolia collected in the southeast cerrado and from central Brazil was performed. A new degraded diterpenoid, byrsonimaquinone, was isolated from the stems along with known compounds. This is the first study on the roots of B. coccolobifolia, and several triterpenes, such as α-amyrin, β-amyrin, oleanolic acid, and glochidonol, along with a mixture of stigmasterol, β-sitosterol and campesterol, were identified. These compounds were identified by spectroscopic analysis techniques, including 1D and 2D NMR, GC-MS and high-resolution mass spectrometry.
Role of the carotid bodies in the hypertensive and natriuretic responses to NaCl load in conscious rats
(2018-12) Silva, Elaine Fernanda da; Melo, Aryanne Batista Soares de; Lobo Júnior, Eulício de Oliveira; Rodrigues, Karla Lima; Naves, Lara Marques; Coltro, Wendell Karlos Tomazelli; Rebelo, Ana Cristina Silva; Oliveira, André Henrique Freiria de; Menani, José Vanderlei; Pedrino, Gustavo Rodrigues
Hyperosmotic challenges trigger a hypertensive response and natriuresis mediated by central and peripheral sensors. Here, we evaluated the importance of the carotid bodies for the hypertensive and natriuretic responses to acute and sub-chronic NaCl load in conscious rats. Male Wistar rats (250–330 g) submitted to bilateral carotid body removal (CBX) or sham surgery were used. One day after the surgery, the changes in arterial blood pressure (n = 6–7/group) and renal sodium excretion (n = 10/group) to intravenous infusion of 3 M NaCl (1.8 mL/kg b.w. during 1 min) were evaluated in non-anesthetized rats. Another cohort of sham (n = 8) and CBX rats (n = 6) had access to 0.3 M NaCl as the only source of fluid to drink for 7 days while ingestion and renal excretion were monitored daily. The sodium balance was calculated as the difference between sodium infused/ingested and excreted. CBX reduced the hypertensive (8 ± 2 mmHg, vs. sham rats: 19 ± 2 mmHg; p < 0.05) and natriuretic responses (1.33 ± 0.13 mmol/90 min, vs. sham: 1.81 ± 0.11 mmol/90 min; p < 0.05) to acute intravenous infusion of 3 M NaCl, leading to an increase of sodium balance (0.38 ± 0.11 mmol/90 min, vs. sham: - 0.06 ± 0.10 mmol/90 min; p < 0.05). In CBX rats, sub-chronic NaCl load with 0.3 M NaCl to drink for 7 days increased sodium balance (18.13 ± 4.45 mmol, vs. sham: 5.58 ± 1.71 mmol; p < 0.05) and plasma sodium concentration (164 ± 5 mmol/L, vs. sham: 140 ± 7 mmol/L; p < 0.05), without changing arterial pressure (121 ± 9 mmHg, vs. sham: 116 ± 2 mmHg). These results suggest that carotid bodies are important for the maintenance of the hypertensive response to acute hypertonic challenges and for sodium excretion to both acute and chronic NaCl load.
Hydrodynamic injection on electrophoresis microchips using an electronic micropipette
(2017-01) Moreira, Ellen Flávia; Santos, Gabriel Rodrigo Alexandre dos; Lobo Júnior, Eulício de Oliveira; Martins, Kariolanda Cristina de Andrade Rezende; Coltro, Wendell Karlos Tomazelli
Here we report for the first time the use of an electronic micropipette as hydrodynamic (HD) injector for microchip electrophoresis (ME) devices. The micropipette was directly coupled to a PDMS device, which had been fabricated in a simple cross format with two auxiliary channels for sample volume splitting. Sample flow during the injection procedure was controlled in automatic dispenser mode using a volume of 0.6 µL. Channel width and device configuration were optimized and the best results were achieved using a simple cross layout containing two auxiliary channels with 300 µm width for sample splitting. The performance of the HD injector was evaluated using a model mixture of high-mobility cationic species. The results obtained were compared to the data obtained via electrokinetic (EK) injection. Overall, the HD provided better analytical performance in terms of resolution and injection-to-injection repeatability. The relative standard deviation (RSD) values for peak intensities were lower than 5% (n=10) when the micropipette was employed. In comparison with EK injection, the use of the proposed HD injector revealed an unbiased profile for a mixture containing K+ and Li+(300 µmol L−1 each) over various buffer concentrations. For EK injection, the peak areas decreased from 2.92 ± 0.20–0.72 ± 0.14 V s for K+ and from 1.30 ± 0.10–0.38 ± 0.10 V s for Li+ when the running buffer increased from 20 to 50 mmol L−1. For HD injection, the peak areas for K+ and Li+ exhibited average values of 2.48±0.07 and 2.10±0.06 V s, respectively. The limits of detection (LDs) for K+, Na+ and Li+ ranged from 18 to 23 µmol L−1. HD injection through an electronic micropipette allows to automatically dispense a bias-free amount of sample inside microchannels with acceptable repeatability. The proposed approach also exhibited instrumental simplicity, portability and minimal microfabrication requirements.
Chemical composition and antimicrobial activity of essential oils from Xylopia aromatica (Annonaceae) flowers and leaves
(2018-10-09) Nascimento, Michelle Nauara Gomes do; Junqueira, João Gabriel Moraes; Terezan, Ana Paula; Severino, Richele Priscila; Silva, Thayná de Souza; Martins, Carlos Henrique Gomes; Severino, Vanessa Gisele Pasqualotto
The essential oils (EO) from flowers and leaves were obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The main compounds found in the flower oil were pentadecan-2-one (16.38%), bicyclogermacrene (9.74%) 7-epi-α-eudesmol (7.76%), khusinol (7.23%), n-tricosane (6.17%), heptadecan-2-one (5.83%), geranyl-α-terpinene (4.46%) and cedr-8(15)-en-9α-ol (4.40%). The leaf oil contained predominantly spathulenol (27.11%), khusinol (13.04%), bicyclogermacrene (8.52%), globulol (6.47%), cis-guaia-3,9-dien-11-ol (5.98%), 2-epi-α-cedren-3-one (4.69%) and elemicin (4.32%). The antimicrobial activity of the EO was tested against Gram-positive and Gram-negative bacterial strains and fungi. The flower and leaf oils exhibited the lowest minimum inhibitory concentrations (MIC) against Streptococcus pyogenes ATCC 12345 (200 and 100 µg mL-1 respectively). As for antifungal potential, the EO from leaves showed moderate activity (500 µg mL-1) against Candida albicans. This study offers the first report about the chemical composition and antimicrobial activity of the EO from X. aromatica flowers and contributes to the body of knowledge about this species.
In vivo and in vitro volatile constituents of the flowers of Xylopia aromatica by HS-SPME/GC-MS
(2021-05) Junqueira, João Gabriel Moraes; Nascimento, Michelle Nauara Gomes do; Costa, Lucas Gustavo da; Romualdo, Lincoln Lucilio; Aquino, Francisco Wendel Batista de; Abubakar, Mustapha N.; Terezan, Ana Paula; Cunha, Gustavo Odeone da Silva; Severino, Vanessa Gisele Pasqualotto
Xylopia aromatica (Lam.) Mart. (Annonaceae) is a typical species from the Brazilian cerrado that presents medicinal properties. The plant is distinguished by its large white flowers which produce a pleasant fragrance. X. aromatica is characterized by a wide range of medicinal application. These characteristics have motivated us to investigate the flowers volatile organic compounds (VOCs) via in vivo and in vitro protocols by a headspace solid-phase microextraction (HS-SPME) technique combined with gas chromatography-mass spectrometry (HS-SPME/GC-MS). Four different fibers, extraction times and temperatures were the parameters changed to lead to the maximum profiling of the volatile constituents. Data were analyzed using principal component analysis (PCA). A total of 77 VOCs were extracted from the floral scent, with 52 and 68 extracted from in vivo and in vitro sampling, respectively, of which 48 were reported for the first time in the literature as volatile constituents from X. aromatica flowers. The extraction and identification of VOCs were successfully performed through HS-SPME/GC-MS. The PCA data allowed the identification of parameters that led to the maximum number of VOCs, which were polyacrylate (PA) and carboxen/polydimethylsiloxane (CAR/PDMS) fibers, 60 min extraction time and temperature of 29.0 °C. Among the volatile constituents identified, sesquiterpenes predominated, comprising about 61.04%.
Biotransformation of labdane and halimane diterpenoids by two filamentous fungi strains
(2017-11) Monteiro, Afif Felix; Seidl, Cláudia; Severino, Vanessa Gisele Pasqualotto; Cardoso, Carmen Lúcia; Castro-Gamboa, Ian
Biotransformation of natural products by filamentous fungi is a powerful and effective approach to achieve derivatives with valuable new chemical and biological properties. Although diterpenoid substrates usually exhibit good susceptibility towards fungi enzymes, there have been no studies concerning the microbiological transformation of halimane-type diterpenoids up to now. In this work, we investigated the capability of Fusarium oxysporum (a fungus isolated from the rhizosphere of Senna spectabilis) and Myrothecium verrucaria (an endophyte) to transform halimane (1) and labdane (2) acids isolated from Hymenaea stigonocarpa (Fabaceae). Feeding experiments resulted in the production of six derivatives, including hydroxy, oxo, formyl and carboxy analogues. Incubation of 1 with F. oxysporum afforded 2-oxo-derivative (3), while bioconversion with M. verrucaria provided 18,19-dihydroxy (4), 18-formyl (5) and 18-carboxy (6) bioproducts. Transformation of substrate 2 mediated by F. oxysporum produced a 7α-hydroxy (7) derivative, while M. verrucaria yielded 7α- (7) and 3β-hydroxy (8) metabolites. Unlike F. oxysporum, which showed a preference to transform ring B, M. verrucaria exhibited the ability to hydroxylate both rings A and B from substrate 2. Additionally, compounds 1–8 were evaluated for inhibitory activity against Hr-AChE and Hu-BChE enzymes through ICER-IT-MS/MS assay.
Bibliometric analysis as a tool for the study of the Croton genus and antioxidant evaluation of Croton antisyphiliticus Mart (Euphorbiaceae)
(2022) Prado, Stéphanie Vilela; Simão, Jorge Luiz Souza; Abubakar, Mustapha Ngaski; Severino, Vanessa Gisele Pasqualotto
The targeted investigation on the biological activity of the species of the genus Croton using bibliometric analysis as a tool for the search allows for a systematic review of the literature, as well as the assessment of current quantitative research trends on the subject. In this research, the bibliometry of Croton species based on analysis of the antioxidant activity available and published in Web of Science and PubMed databases were carried out. In view of the lack of data regarding the antioxidant activity for C. antisyphiliticus Mart., the ethanolic extracts as well as fractions from the roots, stem and leaves were evaluated against the DPPH radical scavenging activity. The results showed high DPPH antioxidant activity for the leaves (IC50 35.53 µg mL-1), stem (IC50 47.14 µg mL-1) and fraction from stem (IC50 15.7 µg mL-1). Thus, we can infer that bibliometric analysis could be considered an important tool to guide research not only on the antioxidant activity of C. antisyphiliticus, but of other species as well. Furthermore, the reviewed information about the antioxidant potential of the genus Croton, findings from this research on the C. antisyphiliticus species are of significant value which contributes to the chemotaxonomic characterization of this species.
IP-Se-06, a Selenylated Imidazo[1,2-a]pyridine, modulates intracellular redox state and causes Akt/mTOR/HIF-1α and MAPK signaling inhibition, promoting antiproliferative effect and apoptosis in glioblastoma cells
(2022) Santos, Daniela Coelho dos; Khan, Jamal Rafique; Saba, Sumbal; Grinevicius, Valdelucia Maria Alves de Souza; Wilhelm Filho, Danilo; Souza, Ariane Zamoner Pacheco de; Braga, Antonio Luiz; Pedrosa, Rozangela Curi; Silva, Fabiana Ourique da
Glioblastoma multiforme (GBM) is a notably lethal brain tumor associated with high proliferation rate and therapeutic resistance, while currently effective treatment options are still lacking. Imidazo[1,2-a]pyridine derivatives and organoselenium compounds are largely used in medicinal chemistry and drug development. This study is aimed at further investigating the antitumor mechanism of IP-Se-06 (3-((2-methoxyphenyl)selanyl)-7-methyl-2-phenylimidazol[1,2-a]pyridine), a selenylated imidazo[1,2-a]pyridine derivative in glioblastoma cells. IP-Se-06 exhibited high cytotoxicity against A172 cells (IC50 = 1.8 μM) and selectivity for this glioblastoma cell. The IP-Se-06 compound has pharmacological properties verified in its ADMET profile, especially related to blood-brain barrier (BBB) permeability. At low concentration (1 μM), IP-Se-06 induced intracellular redox state modulation with depletion of TrxR and GSH levels as well as inhibition of NRF2 protein. IP-Se-06 also decreased mitochondrial membrane potential, induced cytochrome c release, and chromatin condensation. Furthermore, IP-Se-06 induced apoptosis by decreasing levels of Bcl-xL while increasing levels of γ-H2AX and p53 proteins. Treatment with IP-Se-06 induced cell cycle arrest and showed antiproliferative effect by inhibition of Akt/mTOR/HIF-1α and ERK 1/2 signaling pathways. In addition, IP-Se-06 displayed significant inhibition of p38 MAPK and p-p38, leading to inhibition of inflammasome complex proteins (NLRP3 and caspase-1) in glioblastoma cells. These collective findings demonstrated that IP-Se-06 is a bioactive molecule that can be considered a candidate for the development of a novel drug for glioblastoma treatment.
Versatile electrochemical synthesis of selenylbenzo[b]furan derivatives through the cyclization of 2-alkynylphenols
(2022) Doerner, Carlos; Nicoleti, Celso Rodrigo; Scheide Neto, Marcos Roberto; Durigon, Daniele Cocco; Idiarte, Vinícius Damasceno; Sousa, Martinho José Alves de; Mendes, Samuel Rodrigues; Saba, Sumbal; Santos Neto, José Sebastião dos; Martins, Guilherme Ariel Machado; Khan, Jamal Rafique; Braga, Antonio Luiz
We report an electrochemical oxidative intramolecular cyclization reaction between 2-alkynylphenol derivatives and different diselenides species to generate a wide variety of substituted-benzo[b]furans. Driven by the galvanostatic electrolysis assembled in an undivided cell, it provided efficient transformation into oxidant-, base-, and metal-free conditions in an open system at room temperature. With satisfactory functional group compatibility, the products were obtained in good to excellent yields.

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