Examinando por Autor "Osorio, Edison"

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    Antioxidant activity and enzymatic of lichen substances: A study based on cyclic voltammetry and theoretical
    (2023-02) Yanez, Osvaldo; I.Osorio, Manuel; Osorio, Edison; Ruíz, Lina; Tiznado, William; García, Camilo; Orlando, Nagles,; Mario J, Simirgiotis,; Grover, Castañeta,; Olimpo, García-Beltrán,
    The antioxidant activity of nine lichen substances, including methylatrarate (1), methyl haematommate (2), lobaric acid (3), fumarprotocetraric acid (4), sphaerophorin (5), subsphaeric acid (6), diffractaic acid (7), barbatolic acid (8) and salazinic acid (9) has been determined through cyclic voltammetry. The compounds 1–4 presented slopes close to the Nernst constant of 0.059 V, indicating a 2H+/2e− relation between protons and electrons, as long as the compounds 5, 6, 7, 8, and 9 present slopes between 0.037 V and 0.032 V, indicating a 1H+/2e− relation between protons and electrons. These results show a high free radical scavenging activity by means of the release of H+, suggesting an important antioxidant capacity of these molecules. Theoretical calculations of hydrogen bond dissociation enthalpies (BDE), proton affinities (PA), and Proton Transfer (PT) mechanisms, at M06-2x/6-311+G(d,p) level complement the experimental results. Computations support that the best antioxidant activity is obtained for the molecules (3, 4, 5, 6, 7 and 8), that have a carboxylic acid group close to a phenolic hydroxyl group, through hydrogen atomic transfer (HAT) and sequential proton loss electron transfer (SPLET) mechanisms. Additional computations were performed for modelling binding affinity of the lichen substances with CYPs enzymes, mainly CYP1A2, CYP51, and CYP2C9*2 isoforms, showing strong affinity for all the compounds described in this study. © 2023 The Authors
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    In vitro and in silico analysis of galanthine from Zephyranthes carinata as an inhibitor of acetylcholinesterase
    (Elsevier Masson s.r.l., 2022-06) Sierra, Karina; de Andrade, Jean Paulo; R. Tallini, Luciana; Osorio, Edison H.; Yañéz, Osvaldo; Osorio, Manuel Isaías; Oleas, Nora H.; García-Beltrán, Olimpo; de S. Borges, Warley; Bastida, Jaume; Osorio, Edison; Cortes, Natalie
    Zephyranthes carinata Herb., a specie of the Amaryllidoideae subfamily, has been reported to have inhibitory activity against acetylcholinesterase. However, scientific evidence related to their bioactive alkaloids has been lacking. Thus, this study describes the isolation of the alkaloids of this plant, and their inhibition of the enzymes acetylcholinesterase (eeAChE) and butyrylcholinesterase (eqBuChE), being galanthine the main component. Additionally, haemanthamine, hamayne, lycoramine, lycorine, tazettine, trisphaeridine and vittatine/crinine were also isolated. The results showed that galanthine has significant activity at low micromolar concentrations for eeAChE (IC50 = 1.96 μg/mL). The in-silico study allowed to establish at a molecular level the high affinity and the way galanthine interacts with the active site of the TcAChE enzyme, information that corroborates the result of the experimental IC50. However, according to molecular dynamics (MD) analysis, it is also suggested that galanthine presents a different inhibition mode that the one observed for galanthamine, by presenting interaction with peripheral anionic binding site of the enzyme, which prevents the entrance and exit of molecules from the active site. Thus, in vitro screening assays plus rapid computer development play an essential role in the search for new cholinesterase inhibitors by identifying unknown bio-interactions between bioactive compounds and biological targets. © 2022 The Authors
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    Theobroma cacao L. compounds: Theoretical study and molecular modeling as inhibitors of main SARS-CoV-2 protease
    (Elsevier Masson s.r.l., 2021-05) Yañez, Osvaldo; Osorio, Manuel Isaías; Areche, Carlos; Vásquez-Espinal, Alejandro; Bravo, Jessica; Sandoval-Aldana, Angélica; Perez-Donoso, José; González -Nilo, Fernando; Joao-Matos, Maria; Osorio, Edison; García Beltrán, Olimpo; Tiznado, William
    Cocoa beans contain antioxidant molecules with the potential to inhibit type 2 coronavirus (SARS-CoV-2), which causes a severe acute respiratory syndrome (COVID-19). In particular, protease. Therefore, using in silico tests, 30 molecules obtained from cocoa were evaluated. Using molecular docking and quantum mechanics calculations, the chemical properties and binding efficiency of each ligand was evaluated, which allowed the selection of 5 compounds of this series. The ability of amentoflavone, isorhoifolin, nicotiflorin, naringin and rutin to bind to the main viral protease was studied by means of free energy calculations and structural analysis performed from molecular dynamics simulations of the enzyme/inhibitor complex. Isorhoifolin and rutin stand out, presenting a more negative binding ΔG than the reference inhibitor N-[(5-methylisoxazol-3-yl)carbonyl]alanyl-L-valyl-N~1~-((1R,2Z)−4-(benzyloxy)−4-oxo-1-{[(3R)−2-oxopyrrolidin-3-yl]methyl}but-2-enyl)-L-leucinamide (N3). These results are consistent with high affinities of these molecules for the major SARS-CoV-2. The results presented in this paper are a solid starting point for future in vitro and in vivo experiments aiming to validate these molecules and /or test similar substances as inhibitors of SARS-CoV-2 protease. © 2021 The Authors
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    Theoretical design of stable hydride clusters: isoelectronic transformation in the EnAl4−nH7+n− series
    (Royal Society of Chemistry, 2017) Giraldo, Carolina; Ferraro, Franklin; Hadad C.Z.; Riuz, Lina; Tiznado, William; Osorio, Edison
    New stable hydrogen-rich metallic hydrides are designed by systematic transformations of the stable known Al4H7− species, carried out by successive isoelectronic substitutions of one aluminum atom by one E-H unit at a time (where E = Be, Mg, Ca, Sr and Ba atoms). Searches on the potential energy surfaces (PESs) of EAl3H8−, E2Al2H9−, E3AlH10− and E4H11− systems indicate that structural analogues of Al4H7− become higher energy isomers as the number of E-H units increases. The electronic descriptors: Vertical Electron Affinity (VEA), Vertical Ionization Potential (VIP) and the HOMO-LUMO gap, suggest that the systems composed of EAl3H8−, E2Al2H9−, E3AlH10−, with E = Be and Mg, would be the most stable clusters. Additionally, for a practical application, we found that the Be-H and Mg-H substitutions increase the hydrogen weight percentage (wt%) in the clusters, compared with the isoelectronic analogue Al4H7−. The good capacity of beryllium and magnesium to stabilize the extra hydrogen atoms is supported by the increment of the bridge-like E-H-Al, 3center-2electron chemical bonds. Finally, explorations on the PESs of the neutral species (using Na+ as counterion) indicate that the NaBe2Al2H9, NaBe3AlH10 and NaMg3AlH10 minimum-energy structures retain the original geometric shapes of the anionic systems. This analysis supports the potential use of these species as building blocks for cluster-assembled hydrides in the gas phase. © The Royal Society of Chemistry.
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    Theoretical Study of the Antioxidant Activity of Quercetin Oxidation Products
    (Frontiers Media S.A., 2019-11) Vásquez-Espinal, Alejandro; Yañez, Osvaldo; Osorio, Edison; Areche, Carlos; García-Beltrán, Olimpo; Ruiz, Lina María; Cassels, Bruce K.; Tiznado, William
    It was recently shown that, when tested in cellular systems, quercetin oxidized products (Qox) have significantly better antioxidant activity than quercetin (Q) itself. The main Qox identified in the experiments are either 2,5,7,3′,4′-pentahydroxy-3,4-flavandione (Fl) or its tautomer, 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (Bf). We have now performed a theoretical evaluation of different physicochemical properties using density functional theory (DFT) calculations on Q and its main Qox species. The most stable structures (for Q and Qox) were identified after a structural search on their potential energy surface. Since proton affinities (PAs) are much lower than the bond dissociation enthalpies (BDEs) of phenolic hydrogens, we consider that direct antioxidant activity in these species is mainly due to the sequential proton loss electron transfer (SPLET) mechanism. Moreover, our kinetic studies, according to transition state theory, show that Q is more favored by this mechanism. However, Qox have lower PAs than Q, suggesting that antioxidant activity by the SPLET mechanism should be a result of a balance between proclivity to transfer protons (which favors Qox) and the reaction kinetics of the conjugated base in the sequential electron transfer mechanism (which favors Q). Therefore, our results support the idea that Q is a better direct antioxidant than its oxidized derivatives due to its kinetically favored SPLET reactions. Moreover, our molecular docking calculations indicate a stabilizing interaction between either Q or Qox and the kelch-like ECH-associated protein-1 (Keap1), in the nuclear factor erythroid 2-related factor 2 (Nrf2)-binding site. This should favor the release of the Nrf2 factor, the master regulator of anti-oxidative responses, promoting the expression of the antioxidant responsive element (ARE)-dependent genes. Interestingly, the computed Keap1-metabolite interaction energy is most favored for the Bf compound, which in turn is the most stable oxidized tautomer, according to their computed energies. These results provide further support for the hypothesis that Qox species may be better indirect antioxidants than Q, reducing reactive oxygen species in animal cells by activating endogenous antioxidants. © Copyright © 2019 Vásquez-Espinal, Yañez, Osorio, Areche, García-Beltrán, Ruiz, Cassels and Tiznado.
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    Theoretical Study of the Antioxidant Activity of Quercetin Oxidation Products
    (Frontiers Media S.A., 2019-11-27) Vásquez-Espinal, Alejandro; Yañez, Osvaldo; Osorio, Edison; Areche, Carlos; García-Beltrán, Olimpo; Ruiz, Lina María; Cassels, Bruce K.; Cassels B.K.; Tiznado, William
    It was recently shown that, when tested in cellular systems, quercetin oxidized products (Qox) have significantly better antioxidant activity than quercetin (Q) itself. The main Qox identified in the experiments are either 2,5,7,3′,4′-pentahydroxy-3,4-flavandione (Fl) or its tautomer, 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (Bf). We have now performed a theoretical evaluation of different physicochemical properties using density functional theory (DFT) calculations on Q and its main Qox species. The most stable structures (for Q and Qox) were identified after a structural search on their potential energy surface. Since proton affinities (PAs) are much lower than the bond dissociation enthalpies (BDEs) of phenolic hydrogens, we consider that direct antioxidant activity in these species is mainly due to the sequential proton loss electron transfer (SPLET) mechanism. Moreover, our kinetic studies, according to transition state theory, show that Q is more favored by this mechanism. However, Qox have lower PAs than Q, suggesting that antioxidant activity by the SPLET mechanism should be a result of a balance between proclivity to transfer protons (which favors Qox) and the reaction kinetics of the conjugated base in the sequential electron transfer mechanism (which favors Q). Therefore, our results support the idea that Q is a better direct antioxidant than its oxidized derivatives due to its kinetically favored SPLET reactions. Moreover, our molecular docking calculations indicate a stabilizing interaction between either Q or Qox and the kelch-like ECH-associated protein-1 (Keap1), in the nuclear factor erythroid 2-related factor 2 (Nrf2)-binding site. This should favor the release of the Nrf2 factor, the master regulator of anti-oxidative responses, promoting the expression of the antioxidant responsive element (ARE)-dependent genes. Interestingly, the computed Keap1-metabolite interaction energy is most favored for the Bf compound, which in turn is the most stable oxidized tautomer, according to their computed energies. These results provide further support for the hypothesis that Qox species may be better indirect antioxidants than Q, reducing reactive oxygen species in animal cells by activating endogenous antioxidants.