0000000000073206
AUTHOR
Gerardo Cebrián-torrejón
showing 19 related works from this author
Electrochemical Monitoring of the Pharmacological Activity of Natural Products
2015
Abstract Electrochemical techniques have largely been applied to characterize the redox reactivity of natural and synthetic compounds and to determine natural and synthetic compounds in solution. A series of new applications of electrochemistry that has emerged in the last few decades and aims to obtain information on the pharmacological activity of natural products is reviewed. Such applications involve the following: (1) electrochemical testing of specific pharmacological activity via electrochemical screening; (2) in situ evaluation of drug–substrate interactions, including the study of pharmacologically active natural products and their metabolites; (3) electrochemical mimicry of select…
Marine inspired antiplasmodial thiazinoquinones: synthesis, computational studies and electrochemical assays
2015
In the search for new antimalarials, we used the quinone scaffold of marine secondary metabolites as a chemical starting point to synthesize new thiazinoquinone compounds. Most of synthetic derivatives have shown a significant pharmacological activity and some structural requirements, critical for both the antiplasmodial effect and cytotoxicity, have been evidenced. The redox properties of the prepared compounds have been investigated by computational studies and electrochemical assays, which indicated that a higher antiplasmodial activity of some thiazinoquinones is related to their greater ability to form the semiquinone species and strongly interact with free Fe(III)-protoporphyrin IX.
Insights of Tris(2-pyridylmethyl)amine as anti-tumor agent for osteosarcoma: experimental and in silico studies
2021
Abstract Osteosarcoma (OS) is a malignant bone tumor and its occurrence is associated with high levels of microRNAs (miRNAs) and critical protein sinvolved on intracellular signaling pathways. Cisplatin and Doxorubicin are employed on chemotherapy, but their use cause side effects and contributes to multidrug resistance. Since several tripodal amines have been studied as anticancer agents, tris(2-pyridylmethyl)amine (TPA) was investigated against osteosarcoma cells. Here we show that TPA exhibits activity against MG-63 and Saos-2 cells. Cyclic voltammetry results indicate an interaction between TPA and dsDNA, denoted by blocking of the proton-assisted reduction of the 2-pyridylmethyl moiety…
Electrochemical ecology: VIMP monitoring of plant defense against external stressors
2015
The use of the voltammetry of immobilized particles (VIMP) approach, by means of the voltammetric response of microparticulate films from ethanolic leaf extracts in contact with aqueous electrolytes and direct contact probe leaf voltammetry, to monitor the defense of plants against external stressors is described. This approach is applied to study the chemical communication between plants of Peperomia obtusifolia A. Dietr. submitted to herbivory by the beetle Monoplatus sp.
Experimental and theoretical study of possible correlation between the electrochemistry of canthin-6-one and the anti-proliferative activity against …
2015
Abstract This work presents an approach to study the performance of novel targets able to overcome cancer stem cell chemoresistance, based on the voltammetric data for microparticulate films of natural or synthetic alkaloids from the canthin-6-one series. A comparison of this voltammetric technique with conventional solution phase electrochemistry suggests the differences in the anti-proliferative activity of canthin-6-ones could be tentatively correlated to their different capacity to generate semiquinone radical anions. These data also match theoretical calculations.
Bone-Targeted Cisplatin-Complexed Poly(γ-benzyl-L-glutamate)-Poly(glutamic acid) Block Polymer Nanoparticles: An Electrochemical Approach
2015
The voltammetric response of different osteotropic multifunctional nanoparticles based on cisplatin-complexed poly(γ-benzyl-L-glutamate)–poly(glutamic acid) block polymer (CDDP-PBLG-b-PGlu) copolymer, with or without poly(γ-benzyl-L-glutamate)–poly(ethylene glycol) block polymer (PBLG-b-PEG), and having bone-targeting properties is studied at biologically relevant pH. Significant differences in the cisplatin-centered voltammetric signals allow monitoring of the association of cisplatin to nanoparticles as well as release kinetics from them, in agreement with atomic absorption spectroscopy data. Electrochemical studies reveal that the cisplatin association is significant only if the proporti…
Electrochemistry-based chemotaxonomy in plants using the voltammetry of microparticles methodology
2015
A methodology for characterizing vegetal taxonomic groups using microextraction-assisted voltammetry of microparticles is described. It is based on recording the voltammetric response of microparticulate films of polyphenolic compounds of leaf extracts using different organic solvents. As a result, characteristic voltammetric profiles, tentatively defining an electrochemolomic response, are obtained. Bivariant and multivariant chemometric evaluation of the voltammetric responses of such films allows characterizing vegetal families. Analysis of voltammetric responses for a set of species of the Rosales order suggests that electrochemical data can be correlated with phylogenetic trees.
Insight into the Mechanism of Action of Marine Cytotoxic Thiazinoquinones
2017
The electrochemical response of four natural cytotoxic thiazinoquinones isolated from the Aplidium species was studied using conventional solution-phase and solid-state techniques, based on the voltammetry of immobilized particles methodology. The interaction with O-2 and electrochemically generated reactive oxygen species (ROS) was electrochemically monitored. At the same time, a molecular modeling study including density functional theory (DFT) calculations was performed in order to analyze the conformational and electronic properties of the natural thiazinoquinones, as well as those of their reduced intermediates. The obtained electrochemical and computational results were analyzed and c…
Electrochemical monitoring of ROS generation by anticancer agents: the case of chartreusin
2017
Solution phase and solid-sate electrochemical techniques centered in the voltammetry of microparticles approach are applied for testing the cytotoxic activity of anticancer drugs. The possibility of electrochemical generation of reactive oxygen species (ROS) is exploited for evaluating their contribution to cellular damage. The described methodology is applied to the case of chartreusin (Ch) whose electrochemistry in non-aqueous solutions and in the solid state in contact with aqueous electrolytes is described in the absence (experimental data were confirmed by theoretical calculations) and in the presence of double-stranded DNA (dsDNA). In parallel, scanning electrochemical microscopy (SEC…
Harvesting canthinones: identification of the optimal seasonal point of harvest of Zanthoxylum chiloperone leaves as a source of 5-methoxycanthin-6-o…
2015
This article is focused on the seasonal variation in the contents of 5-methoxycanthin-6-one from the leaves of Zanthoxylum chiloperone (Rutaceae). Based on the pharmacological interest presented by 5-methoxycanthin-6-one, its seasonal variation in Z. chiloperone leaves was analysed in order to determine the best time for harvesting, optimising the 5-methoxycanthin-6-one content. The seasonal dynamics of canthinone alkaloids can be the key to improve the isolation from natural sustainable sources, such as leaves. Complementarily, this study describes the phytochemistry of leaf from this Ruraceae species.
Biosynthesis of heme O in intraerythrocytic stages of Plasmodium falciparum and potential inhibitors of this pathway
2019
A number of antimalarial drugs interfere with the electron transport chain and heme-related reactions; however, the biosynthesis of heme derivatives in Plasmodium parasites has not been fully elucidated. Here, we characterized the steps that lead to the farnesylation of heme. After the identification of a gene encoding heme O synthase, we identified heme O synthesis in blood stage parasites through the incorporation of radioactive precursors. The presence of heme O synthesis in intraerythrocytic stages of Plasmodium falciparum was confirmed by mass spectrometry. Inabenfide and uniconazole–P appeared to interfere in heme synthesis, accordingly, parasite growth was also affected by the additi…
Solid-State Electrochemical Assay of Heme-Binding Molecules for Screening of Drugs with Antimalarial Potential
2013
The interaction between heme and ligands is the basis for a variety of tests aimed at the discovery of antiplasmodial molecules. Two electrochemical methods for the screening of molecules with potential antimalarial activity through heme-binding mechanism are described. The first method is applicable to lipophilic environment, by using solution phase electrochemistry in DMSO solutions of Fe(III)-heme plus the tested compounds at carbon electrodes. This method provides well-defined voltammetric signals, characteristic of the heme-ligand (L) interaction. The second method involves aqueous media at biological pH and the use of voltammetry of immobilized particles, by means of microparticulate …
dsDNA, ssDNA, G-quadruplex DNA, and nucleosomal DNA electrochemical screening using canthin-6-one alkaloid-modified electrodes
2014
Abstract Microparticulate films of a canthin-6-one alkaloid ( L ), a natural β-carboline alkaloid presenting a characteristic naphtyridone motif, on glassy carbon electrodes yield different, separate voltammetric signals for dsDNA, ssDNA, G-quadruplex DNA, different degrees of DNA methylation and the biomimetic nucleosomal DNA with detection limit of 10 −5 M. This multiple-signal electrochemical behavior is in contrast with conventional use of DNA intercalators, only discriminating between different DNA forms by variations in the intensity of a unique signal. Complementary photochemical and scanning electrochemical microscopy (SECM) data suggest that the differences in the voltammetric res…
Transmembrane electrochemistry of erythrocytes: Direct electrochemical test for detecting hemolysis in whole blood
2016
A rapid method for detecting hemolysis in whole blood based on a direct electrochemical assay either in venous blood and finger blood, respectively at glassy carbon and screen-printed graphite electrodes is described. The presence of hemolysis is detected from characteristic voltammetric signatures associated to Fe-heme units in healthy and hemolyzed erythrocytes. The voltammetric response of blood was also investigated using scanning electrochemical microscopy (SECM) and scanning tunneling microscopy (STM) and involved transmembrane electrochemistry of erythrocytes superimposed to molecular electrochemistry of heme-containing proteins and heme fragments in the plasma. Voltammetric testing …
Bioelectrochemical monitoring of soluble guanylate cyclase inhibition by the natural β-carboline canthin-6-one
2017
Abstract The inhibition of soluble guanylate cyclase (sGC) by canthin-6-one alkaloid ( L1 ) is presented and the mechanism of deactivation is studied using solution phase and voltammetry of microparticles methodologies. Possible inhibition pathways: oxidation of Fe 2+ to Fe 3+ coupled to reduction of the naphthyridone motif present by the canthin-6-one and coordinating or reacting of L1 with cysteine units of sGC, are balanced.
Stabilization and detection of hydrophylloquinone as di-O-methyl derivative
2016
Phylloquinone is a redox active naphthoquinone involved in electron transport in plants. The function of this reduced form remains unclear due to its instability, which has precluded detection. Herein, a simple method that permits the stabilization of the reduced form of phylloquinone by di-O-methylation and HPLC detection is described. Fil: Sussmann, Rodrigo A. C.. Universidade de Sao Paulo; Brasil Fil: de Moraes, Marcilio M.. Universidade de Sao Paulo; Brasil Fil: Cebrián Torrejón, Gerardo. Universidad de Valencia; España. Universidade de Sao Paulo; Brasil Fil: Porta, Exequiel Oscar Jesús. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - …
"Sweet Chemistry": a Green Way for Obtaining Selenium Nanoparticles Active against Cancer Cells
2017
We present an environment friendly synthesis of selenium nanoparticles and the study of their cytotoxic activity against uterine sarcoma cancer and fibroblasts cells. Amorphous selenium (a-SeNPs) and trigonal selenium (t-SeNPs) were synthesized using D-fructose as the reducing agent and characterized by high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction analysis (XRD), inductively coupled plasma optical emission spectrometry (ICP OES), dynamic light scattering (DLS) to obtain zeta potential values and cyclic voltammetry (CV). Particularly, a-SeNPs presented high toxicity toward the resistant cancer cell line MES-SA/…
Phytoelectrochemical analysis ofZanthoxylum chiloperone
2016
Introduction An innovative application of the voltammetry of microparticles methodology to characterize the phytochemical composition of extracts of different parts of Zanthoxylum chiloperone var. angustifolium Engl. is described. Objective Characterize the phytochemical composition of extracts of different parts of plants by electrochemical methodologies. Methods The voltammetry of microparticles methodology was applied to alcoholic extracts from leaves, seeds, fruits, roots and stem bark of Zanthoxylum chiloperone. Results In contact with aqueous phosphate buffer, characteristic cathodic signals of its main natural products (canthin-6-one, 5-methoxycanthin-6-one and trans-avicennol) were …
Electrochemical characterization of mangrove sediments: A proposal of new proxies for organic matter oxidation
2019
Abstract The voltammetric response of microparticulate deposits resulting from solvent evaporation of ethanolic extracts of mangrove sediments in contact with aqueous acetate buffer is hereby described. Dated sediment cores sampled from the Peruvian mangrove system (“Manglares de Tumbes” National Sanctuary) presented voltammetric responses dominated by oxidative signals of organic components that exhibit significant variations depending on the depth. Voltammetric data allowed for the definition of electrochemical indexes representative of the electrochemically oxidable organic matter fraction. These electrochemical indexes were fEAOM (for the total amount of organic matter being electrochem…