Papers by Marília Goulart
Synthesis, pharmacological evaluation and electrochemical studies of novel 6-nitro-3,4-methylenedioxyphenyl-N-acylhydrazone derivatives: Discovery of LASSBio-881, a new ligand of cannabinoid receptors
Bioorganic & Medicinal Chemistry, 2007
We describe herein the discovery of LASSBio-881 (3c) as a novel in vivo antinociceptive, anti-inf... more We describe herein the discovery of LASSBio-881 (3c) as a novel in vivo antinociceptive, anti-inflammatory, and in vitro antiproliferative and antioxidant compound, with a cannabinoid ligand profile. We observed that LASSBio-881 (3c) was able to bind to CB1 receptors (71% at 100microM) and also to inhibit T-cell proliferation (66% at 10microM) probably by binding to CB2 receptors, in a non-proapoptotic manner, different from anandamide (1). It was also demonstrated that LASSBio-881 (3c) had an important antioxidant profile toward free radicals (DPPH and hydroxyl), probably due to its particular redox behavior, which reflects the presence of both nitro and 3,5-di-tert-butyl-4-hydroxyphenyl sub-units, as demonstrated by cyclic voltammetry studies. In addition, we showed that these structural sub-units are essential for the observed pharmacological activity.
Acta Tropica, Jul 1, 2002
The toxicity of soluble derivatives (potassium salt) of lapachol and isolapachol in different sta... more The toxicity of soluble derivatives (potassium salt) of lapachol and isolapachol in different stages of the life cycle of Schistosoma mansoni is evaluated. The potassium salts of isolapachol and lapachol showed significant molluscicidal activity against the adult snail (LC 90 B7 ppm) and snail egg masses (LC 90 B 3 ppm). Cercaricidal assays revealed strong activities for both compounds. Lethality assays against brine shrimp eggs (Artemia salina Leach) indicated very high toxicity for the potassium salt of isolapachol (LC 90 = 1.54 ppm), differently from the potassium salt of lapachol that can be considered non toxic (LC 90 =176.3 ppm). The same tendency is observed with piscicidal activity, for which the isolapachol salt has showed higher toxicity. The obtained selectivity ratios concerning LC 50 and LC 90 for lapachol, in relation to Tilapia nilotica lethality assay are 2.33 and 1.26, respectively. Despite the piscicidal toxicity, the use of the salt of lapachol can be recommended for field tests in Schistosomiasis, with caution.
Exploiting synergistic effects: Cheap ultra-sensitive electrochemical rutin detection using WO3/rGO nanocomposite in combination with multiwalled carbon nanotubes
Microchemical Journal, Oct 1, 2023
Synthesis and Characterization of Nanostructured Molecularly Imprinted Sol-gel as Selective Electrochemical Sensor for Detection of 4-Nitrophenol
4-Nitrophenol (4-NP) is a highly hazardous and toxic phenol, which can cause significant damages ... more 4-Nitrophenol (4-NP) is a highly hazardous and toxic phenol, which can cause significant damages to the health and to the environment [1,2]. Thus, the interest in its determination in environmental samples has led to the development of several quantification methods. The present work describes the development of a highly sensitive and selective molecularly imprinted electrochemical sensor (MIS) for its detection. The MIS film was prepared in three steps. The first used vinyltrimethoxysilane-modified MWCNTs (MWCNTs-VTMS), a procedure adapted from Correa et al.[3]. Thereafter, VTMS and AIBN were added to the previous mixture (MWCNT- VTMS and DMF). The flask was placed in a thermal oil bath at 70°C, under stirring, for 48 hours. At the second step, for the preparation of the GCE modified with MWCNTs-VTMS, the resulting suspension was dropped onto the GCE surface, and allowed to dry, at room temperature. At last, the imprinted sensor was prepared using the acid catalyzed hydrolysis and ...
Synthesis and Characterization of Nanostructured Molecularly Imprinted Sol-gel as Selective Electrochemical Sensor for Detection of 4-Nitrophenol
2018-Sustainable Industrial Processing Summit, Apr 3, 2018
Journal of Electroanalytical Chemistry, Dec 1, 2003
In the present work, 2,3-dimethyl-1,4-naphthoquinones, substituted at one or both side chains wit... more In the present work, 2,3-dimethyl-1,4-naphthoquinones, substituted at one or both side chains with bromine were prepared and submitted to electrochemical studies (cyclic voltammetry and electrolysis), in aprotic medium (DMF + 0.1 mol l À1 TBAP), using different electrodes (Hg, GC and Au), to observe the role of bromide, as a good leaving group, in their electroreductions. The cyclic voltammograms are complex. Combined results from CV, chronoamperometry and analysis of the products of electrolysis, mainly dimers and the parent unsubstituted quinone, allowed the qualitative definition of the electrodic mechanism for the reduction of the brominated quinones. A reversible electronic transfer to the quinonoid group followed by the cleavage of C-Br, in an EC type mechanism, more specifically a reductive elimination, is suggested. The quinonoid radical is generated and suffers dimerization to electroactive dimers or a second electron uptake, furnishing the anion that can be protonated to yield 2,3-dimethyl-1,4-naphthoquinone, also electroactive. The additional waves are probably related to the reduction of quinomethide-derived products, upon comparison with a synthetic dimer. Computational studies corroborate the electrochemical observations. Despite the lack of unequivocal proof of quinonemethide generation, its intermediacy is highly probable and this has been proved to be essential for the biological activity of these compounds.
Phytochemistry, 1980
Two new alkaloids, 8-methoxycanthin-6-one and 3-methoxycanthin-2,6-dione, were isolated from the ... more Two new alkaloids, 8-methoxycanthin-6-one and 3-methoxycanthin-2,6-dione, were isolated from the EtOH extract of the bark of Simaba cuspidata Spruce ex Engl. Elucidation of the structure of the latter compound included '% NMR spectral comparison with 2-methoxypyridine-N-oxide and N-methoxy-2pyridone.
Bioorganic & Medicinal Chemistry, Nov 1, 2013
In our continued search for novel trypanocidal compounds, twenty-six derivatives of para-and orth... more In our continued search for novel trypanocidal compounds, twenty-six derivatives of para-and orthonaphthoquinones coupled to 1,2,3-triazoles were synthesized. These compounds were evaluated against the infective bloodstream form of Trypanosoma cruzi, the etiological agent of Chagas disease. Compounds 17-24, 28-30 and 36-38 are described herein for the first time. Three of these novel compounds (28-30) were found to be more potent than the standard drug benznidazole, with IC 50 /24 h values between 6.8 and 80.8 lM. Analysis of the toxicity to heart muscle cells led to LC 50 /24 h of <125, 63.1 and 281.6 lM for 28, 29 and 30, respectively. Displaying a selectivity index of 34.3, compound 30 will be further evaluated in vivo. The electrochemical properties of selected compounds were evaluated in an attempt to find correlations with trypanocidal activity, and it was observed that more electrophilic quinones were generally more potent.
Preparation and characterization of microcapsules loaded with polyphenols-enriched Uncaria tomentosa extract using spray-dryer technique
Journal of Thermal Analysis and Calorimetry, Jul 4, 2022
Journal of Solid State Electrochemistry, Jan 2, 2019
This paper reports the development of a photoelectrochemical platform based on indium tin oxide (... more This paper reports the development of a photoelectrochemical platform based on indium tin oxide (ITO) electrode modified with carboxyl-functionalized cadmium telluride quantum dots (CdTe) and poly(D-glucosamine) (PDG) for the determination of propyl gallate in edible oil samples. The photoelectrochemical (PEC) sensor was designed as ITO/CdTe/PDG and characterized by amperometry and electrochemical impedance spectroscopy. The ITO/CdTe/PDG PEC sensor showed higher photocurrent response for the propyl gallate compared to the photocurrents obtained for the bare ITO and ITO/CdTe electrodes. The amperograms showed that the photocurrent of the propyl gallate is much larger in the presence of oxygen suggesting that the presence of this molecule in the solution is essential to increase the sensitivity of the system. In addition, high selectivity was obtained when the proposed sensor was evaluated in samples containing other antioxidants and some ions. The linear range of response and detection limit for the determination of propyl gallate were 0.3 to 150 μmol L −1 (n = 10) and 0.13 μmol L −1 , respectively. Recovery tests for propyl gallate in edible oils showed recovery percentages between 96.2 and 111.3%.
Tetrahedron, Jun 1, 1999
Diethyl fumarate was chosen as a model in search for better conditions to achieve selective elect... more Diethyl fumarate was chosen as a model in search for better conditions to achieve selective electroeatalytie hydrogenation. In addition to carbon felt, several catalytic cathode surfaces have been examined, including Fe, Pt, Ni, Pb, AI, Cu, Zn, ud stainless steel Other variables like current density (58 to 285 mA.dm'2), supporting electrolyte (NaCI, KBr, NaBr, Nal, NaF), solution pH* (3.0 to 9.0) ud co-solvent (CH3CN, t-BuOH, MeOH and THF) were tried. The majority of the reactions were carried out at constant current in an undivided cell fitted with the chosen working electrode and DSA ° (RuOTfrio2) as the auxiliary electrode, in H20/eo-solvent (4:1). The best results for hydrogenation (84 % chemical yield) were obtained using Fe as cathode, a current density of 175 mA.dm "2, in H20/CH3CN (4:1) at pH* 5.5. NaBr and KBr are also useful electrolytes for hydrogenation, pH* variation does not seem to affect product ratio. THF as co-solvent and NaF as supporting electrolyte should be avoided, as well as carbon felt and Ni as electrodes.
Free Radical Biology and Medicine, 2019
Mitochondrial disfunction and ROS production are essential for anti-Trypanosoma cruzi activity of... more Mitochondrial disfunction and ROS production are essential for anti-Trypanosoma cruzi activity of β-lapachone-derived naphthoimidazoles, Free Radical Biology and Medicine,
American Journal of Analytical Chemistry, 2011
An alternative spectrophotometric method has been developed for total iron determination using fl... more An alternative spectrophotometric method has been developed for total iron determination using flow injection analysis (FIA). The procedure is based on the coordination reaction between hydralazine and Fe 2+ ions, which results in the formation of a purple complex monitored at 538 nm. For determination of total iron, Fe 3+ ions were reduced using ascorbic acid. Under optimized conditions, a linear calibration graph (0.1 -6.0 g•ml -1 ; n = 6) was obtained. The method allows LOD (3 of blank/slope = 0.06 g•ml -1 ) and LOQ (10 of blank/slope = 0.22 g•ml -1 ). The RSD ((s/ x ) × 100) for a mixed standard containing 0.60 g•ml -1 Fe 2+ and Fe 3+ was 0.10% (n = 10). Recoveries of spiked samples were 94.3% -106.0%. The analytical frequency was 60 h -1 . The effect of possible interferences has been studied. The procedure was successfully applied for analysis of environmental samples. The real samples results were comparable with those obtained by the official method considering a paired t-test and 95% of confidence level.
Composição Do Leite Humano e Fatores Maternos Que Influenciam Seus Constituintes
Editora Humanize eBooks, 2023
Journal of the Brazilian Chemical Society, 2017
This work describes the electrochemical performance of a novel composite based on nickel tetrasul... more This work describes the electrochemical performance of a novel composite based on nickel tetrasulfonated phthalocyanine (NiTsPc), deoxyribonucleic acid from calf thymus (CT-DNA) and reduced graphene oxide (rGO) for the electroanalysis of reduced β-nicotinamide adenine dinucleotide (NADH), through electrocatalytic oxidation. The modified electrode was denoted as CT-DNA/NiTsPc/rGO. Fourier transform infrared and ultraviolet-visible spectroscopies were performed to characterize the composite material. The electrochemical performance of the composite for NADH oxidation was investigated by cyclic voltammetry (CV), chronoamperometry and differential pulse voltammetry (DPV). The CT-DNA/NiTsPc/rGO modified glassy carbon electrode (GCE) showed an excellent electrocatalytic activity for NADH oxidation with apparent electrocatalytic rate constant (k obs ) of 7.35 × 10 5 L mol -1 s -1 and linear response range for NADH from 1 up to 1350 µmol L -1 for n = 12 (r = 0.999). The proposed sensor shows sensitivity, detection limit and quantification limit of 0.014 µA L mol -1 , 0.3 and 1 µmol L -1 , respectively. The prepared sensor was further tested for the determination of NADH in artificial human urine samples, showing promising biomedical applications.
Reactive Oxygen Species Release, Alkylating Ability, and DNA Interactions of a Pterocarpanquinone: A Test Case for Electrochemistry
ChemElectroChem, Nov 7, 2016
The electrochemistry of a redox‐based bioactive pterocarpanquinone, designated as LQB‐118, and it... more The electrochemistry of a redox‐based bioactive pterocarpanquinone, designated as LQB‐118, and its precursor chromenquinone (CQ) was investigated in protic and aprotic media with a focus on the reduction mechanism in both media, the reactivity with oxygen, and the interaction with biological targets, such as DNA. UV/Vis spectroelectrochemistry clarified the proposed mechanism. The appearance of bands at λ=331, 400, and 600 nm suggests the generation of transient quinonemethides (QM). Electrochemical experiments revealed homogeneous electron transfer to oxygen. LQB‐118 itself interacts with calf‐thymus DNA and ssDNA in solution. It, and its electrogenerated intermediates, have been shown to decrease the diagnostic oxidation peaks of guanosine and adenosine residues. These results, together with electrochemical evidence for the formation of QMs and the reductive addition of thiols, partly explain the reported cytotoxic and parasiticidal effects of this quinone. Overall, the electrochemical methods do well to predict the molecular mechanism of the biological activity of the present class of compounds. As an additional competitive advantage, electrochemistry allows reductive cleavage in situ, the characterization of the generated intermediate, the calculation of the number of transferred electrons, and positively mimics in vitro and in vivo experiments.
Tetrahedron Letters, 1987
The radical-anion of fuchsone (11, and the dianions of related quinonemethides, are generated at ... more The radical-anion of fuchsone (11, and the dianions of related quinonemethides, are generated at low cathodic potentials and act as bases in high yielding Wittig reactions; the phenolic product may be oxidatively reconverted into quinonemethide.
Pré-Eclâmpsia: Origem, Definição, Fatores De Risco, Fisiopatologia, Gravidade Da Doença e Desfechos Maternos e Perinatais Adversos
Editora Humanize eBooks, 2023
Introdução: O período gestacional descreve um estado fisiológico natural, envolvendo modificações... more Introdução: O período gestacional descreve um estado fisiológico natural, envolvendo modificações orgânicas, físicas e psicossociais, que devem ser monitoradas por uma equipe multiprofissional, com intuito de auxiliar de forma integral e singular na promoção à saúde, assim como, na prevenção de eventos perinatais adversos. Este cuidado pode ser assegurado no pré- natal, proporcionando qualidade de vida para o binômio materno-infantil. Contudo, apesar dos avanços na assistência pré-natal, os índices acerca da mortalidade materna e neonatal em gestações que desenvolvem pré-eclâmpsia (PE) são preocupantes. Esta é uma patologia sistêmica, multifatorial, heterogênea e que, independentemente dos esforços, sua etiopatogenia permanece sem elucidação, em virtude de sua complexidade. Objetivo: Reunir evidências atuais sobre a PE, desde sua origem, definição, fatores de risco, fisiopatologia, gravidade da doença e desfechos maternos e perinatais adversos. Metodologia: Trata-se de uma revisão com critérios de busca e elegibilidade pré-estabelecidos. Os termos MeSH utilizados foram: (“Preeclampsia” OR “Pregnancy Toxemias” OR “Edema-Proteinuria-Hypertension Gestosis” OR “Hypertension Gestosis”) AND (“Prognosis” OR “prediction” OR “definition” OR “origin” OR “risk factors” OR “pathophysiology” OR “severity” OR “adverse maternal outcomes” OR “adverse perinatal outcomes”). Depois de finalizada todas as etapas de seleção, os dados foram extraídos dos artigos e tabulados em planilha eletrônica. Resultados e Discussão: Após a ampla investigação na literatura científica, foi possível identificar que houve modificações nos parâmetros diagnósticos da PE, sendo a proteinúria um achado facultativo atualmente, isto, quando na presença de outros fatores. Além disto, dentre os fatores de risco apontados, constatou-se a idade cronológia, paridade, etnia, tabagismo, genética, condições sociodemográficas e estado nutricional associados ao desenvolvimento da PE. Também, que seus aspectos fisiopatológicos estão intimamente associados ao aumento do estresse oxidativo e citocinas pró-inflamatórias, com repercussoes nocivas ao binômio materno-fetal. Considerações Finais: Diante do supraelencado, conclui-se que o levantamentos científicos é de suma importância para colaborar com o conhecimento universal, visando contribuir com a tomada de decisões de profissionais de saúde, assim como, com a integração de cuidados à saúde da mulher e da criança.
Antioxidants, Jan 7, 2022
Gestational diabetes mellitus (GDM) is characterized by a set of metabolic complications arising ... more Gestational diabetes mellitus (GDM) is characterized by a set of metabolic complications arising from adaptive failures to the pregnancy period. Estimates point to a prevalence of 3 to 15% of pregnancies. Its etiology includes intrinsic and extrinsic aspects of the progenitress, which may contribute to the pathophysiogenesis of GDM. Recently, researchers have identified that inflammation, oxidative stress, and the gut microbiota participate in the development of the disease, with potentially harmful effects on the health of the maternal-fetal binomial, in the short and long terms. In this context, alternative therapies were investigated from two perspectives: the modulation of the intestinal microbiota, with probiotics and prebiotics, and the use of natural products with antioxidant and anti-inflammatory properties, which may mitigate the endogenous processes of the GDM, favoring the health of the mother and her offspring, and in a future perspective, alleviating this critical public health problem.
Combinatorial Chemistry & High Throughput Screening, Feb 1, 2013
One of the most exciting research topics in the last decade has been the discovery of dietary com... more One of the most exciting research topics in the last decade has been the discovery of dietary compounds that have protective effects against oxidative processes. These naturally occurring compounds have been described to have a well-defined role as antioxidants in biological systems, essentially by scavenging harmful free radicals through different mechanisms. Several of them are based on electron-transfer mechanisms. As a result, electrochemistry has been employed to evaluate antioxidant activity as it can provide direct and detailed information on their redox processes. Quantitative correlations have been already established between the antioxidant properties and redox potentials suggesting that electrochemical measurements can be considered a worthy analytical assay to evaluate the antioxidant activity. In this context, one can remark the application of electrochemical sensors as useful tools for the evaluation of antioxidant capacity. In this issue, we have invited scientists who are at the forefront area of the research on the application of electrochemistry in the antioxidant arena to share their skills and knowledge in a series of original research as well as review articles that include modern advances and new trends in this topic. We hope that the readers will find the information featured in this issue useful and informative for their own research.
Uploads
Papers by Marília Goulart