Synthesis, Antioxidant Activity, and Determination of Binding Parameters of Meso-Tetra-4-Actophenyl-Porphyrin and its Palladium (II) Complex with Superoxide Anion Radicals

2020 ◽  
Vol 16 (7) ◽  
pp. 1063-1071
Author(s):  
Amira Boutarfaia ◽  
Lazhar Bechki ◽  
Touhami Lanez ◽  
Elhafnaoui Lanez ◽  
Mohamed Kadri
Keyword(s):  
Antioxidant Activity ◽  
Superoxide Anion ◽  
Binding Free Energy ◽  
Electronic Spectroscopy ◽  
Binding Constants ◽  
Order Rate Constant ◽  
Binding Parameters ◽  
Free Energies ◽  
Peak Current Density ◽  
Anodic Peak Current

Background: Meso-tetra-4-actophenyl-porphyrin (TAcPPH2) was synthesized by reacting 4- acetyl-benzaldehyde with pyrrole in propionic acid, and used as a ligand for the synthesis of palladium (II) complex (PdTAcPP). The structure of the ligand and the complex were characterized by NMR and electronic spectroscopy. Methods: he antioxidant activity and the binding parameters of both the ligand and its complex with superoxide anion radical . (O2 -) were measured using cyclic voltammetry based assay. The assays were based on the measurement of the anodic peak current density of . O2− electrochemically generated by reduction of molecular oxygen in DMF. Results: The complex PdTAcPP showed the highest antioxidant activity (0.73 ± 0.01 mg/mL) which is four times higher than that of the standard antioxidant α-tocopherol (3.04 ± 0.03 mg/mL). Discussion: Binding parameters like binding constants, the ratio of binding constants and binding free energies were also measured. Conclusion: The value of the binding free energy ranging from -7.89 kJmol-1 for TAcPPH2 to -17.59 kJ.mol-1for PdTAcPP suggests an electrostatic interaction of . O2− with TAcPPH2 and PdTAcPP which has been found to be the dominant interaction mode. The kinetics of the interaction reaction of the ligand and complex was quantified having second-order rate constant values equal to 0.2 and 1.3 M-1 s-1, respectively.

Antioxidant Activities, Binding Parameters, and Electrochemical Behavior of Superoxide Anion Radicals Twords 1-Ferrocenylmethylthymine and 1-Ferrocenylmethylcytosine

2020 ◽  
Vol 10 (1) ◽  
pp. 10-22
Author(s):  
Elhafnaoui Lanez ◽  
Lazhar Bechki ◽  
Touhami Lanez
Keyword(s):  
Antioxidant Activity ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Antioxidant Activities ◽  
Binding Free Energy ◽  
Order Rate Constant ◽  
Superoxide Anion Radical ◽  
Binding Parameters ◽  
Ferrocene Derivatives ◽  
Peak Current Density

Background: An electrochemical method based on cyclic voltametry techniques was used to measure the antioxidant activity of two ferrocene-nucleobases. Objective: The present study aims to measure the antioxidant activity of two ferrocene derivatives bearing nucleobases; the technique is based on the reaction of the in-situ electrochemical generated superoxide anion radical with ferrocene-nucleobases. Methods: The decrease in the anodic peak current density of the O2 / O2 .− redox couple following the addition of ferrocene-nucleobases was used to measure the antioxidant activity and binding parameters of 1-ferrocenylmethylthymine and 1-ferrocenylmethylcytosine with superoxide anion radical. Conclusion: Both 1-Ferrocenylmethylthymine and 1-Ferrocenylmethylcytosine showed higher antioxidant activity (0.34 ± 0.03 and 0.045 ± 0.02 mg/mL respectively) than that of standard antioxidant α-tocopherol (3.04 ± 0.03 mg/mL). The value of the binding free energy ranging from -16.1 kJ.mol-1 for 1-ferrocenylmethylthymine to -21.8 kJ.mol-1 for 1- ferrocenylmethylcytosine suggests an electrostatic interaction of superoxide anion radical with both compounds which has been found to be the dominant interaction mode. The kinetics of the interaction reaction of the compounds was quantified having second-order rate constant values equal to 4.0 and 16.5 M-1 s-1 respectively.

scholarly journals Automation of absolute protein-ligand binding free energy calculations for docking refinement and compound evaluation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Germano Heinzelmann ◽  
Michael K. Gilson
Keyword(s):  
Free Energy ◽  
Early Stage ◽  
Binding Free Energy ◽  
Low Cost ◽  
Free Energy Calculations ◽  
Free Energies ◽  
Energy Calculations ◽  
Drug Candidates ◽  
Binding Free Energy Calculations ◽  
Binding Free Energies

AbstractAbsolute binding free energy calculations with explicit solvent molecular simulations can provide estimates of protein-ligand affinities, and thus reduce the time and costs needed to find new drug candidates. However, these calculations can be complex to implement and perform. Here, we introduce the software BAT.py, a Python tool that invokes the AMBER simulation package to automate the calculation of binding free energies for a protein with a series of ligands. The software supports the attach-pull-release (APR) and double decoupling (DD) binding free energy methods, as well as the simultaneous decoupling-recoupling (SDR) method, a variant of double decoupling that avoids numerical artifacts associated with charged ligands. We report encouraging initial test applications of this software both to re-rank docked poses and to estimate overall binding free energies. We also show that it is practical to carry out these calculations cheaply by using graphical processing units in common machines that can be built for this purpose. The combination of automation and low cost positions this procedure to be applied in a relatively high-throughput mode and thus stands to enable new applications in early-stage drug discovery.

scholarly journals New Mixed Ligand Cobalt(II), Nickel(II) and Copper(II) Complexes of 2,2'-Bipyridine-3,3'-Dicarboxylic acid (bpdc) with 2-Mercapto-5-Phenyl-1,3,4-Oxadiazole (phozSH) and Their Antioxidant activity

2020 ◽  
Vol 36 (05) ◽  
pp. 834-842
Author(s):  
Rezan Ali Saleh ◽  
Hikmat Ali Mohammad ◽  
Salim Najm Aldin Saber
Keyword(s):  
Antioxidant Activity ◽  
Metal Ions ◽  
Dicarboxylic Acid ◽  
Potassium Hydroxide ◽  
Electronic Spectroscopy ◽  
Conductivity Measurement ◽  
Mixed Ligand ◽  
Methanol Solution ◽  
Dpph Method ◽  
Colored Complexes

The mixing of one mole of 2,2'-bipyridine-3,3'-dicarboxylic acid (bpdc) with two mole of potassium hydroxide (KOH) in methanol were refluxed for (half hour), followed by addition of one mole methanol solution of MCl2.nH2O (where M=Co, Ni or Cu). The mixture was refluxed for (2 hours) to give colored complexes of the metal ions of [M(bpdc)(H2O)4]. The [M(bpdc)(H2O)4] were reacted with one mole of 2-Mercapto-5-phenyl-1,3,4-oxadiazole (phozSH) producing the colored mixed ligand complexes with general formula [M(bpdc)(phozSH)(H2O)3] in which the metal ions coordinated to the ligand through O-atoms of carboxyl group in (bpdc) and N-atom of (phozSH) ligand. The ligands and complexes are well identified by using Furrier transform infrared spectroscopy, 1H-NMR, 13C-NMR, Electronic spectroscopy, CHNS analysis, Melting point, conductivity measurement. The Antioxidant activity were screened for all the complexes by the use of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method.

scholarly journals Alchemical Absolute Protein-Ligand Binding Free Energies for Drug Design

2021 ◽  
Author(s):  
Yuriy Khalak ◽  
Gary Tresdern ◽  
Matteo Aldeghi ◽  
Hannah Magdalena Baumann ◽  
David L. Mobley ◽  
...  
Keyword(s):  
Free Energy ◽  
Drug Discovery ◽  
Drug Design ◽  
Ligand Binding ◽  
Binding Free Energy ◽  
Free Energy Calculations ◽  
Free Energies ◽  
Energy Calculations ◽  
Binding Free Energy Calculations ◽  
Binding Free Energies

The recent advances in relative protein-ligand binding free energy calculations have shown the value of alchemical methods in drug discovery. Accurately assessing absolute binding free energies, although highly desired, remains...

A Study of Antioxidant Activity about Seleno-Polysaccharide of Cordyceps militaris from Different Areas of China

2013 ◽  
Vol 807-809 ◽  
pp. 1984-1987 ◽  
Author(s):  
Qin Li ◽  
Chi Zhang
Keyword(s):  
Antioxidant Activity ◽  
Hydroxyl Radical ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Reducing Power ◽  
Cordyceps Militaris ◽  
Superoxide Anion Radical ◽  
Scavenging Capacity ◽  
Research Objects ◽  
Total Selenium

In this article,Cordyceps militaris,that from Hubei and Yunnan,were used as the research objects, to extract seleno-polysaccharide ,then the antioxidant activity of seleno-polysaccharide were determined by reducing power,the scavenging capacity on superoxide anion radical and hydroxyl radical.The results indicated that,the content of selenium in Hubei and Yunnan Cordyceps militaris samples were 210.0μg/g and 57.5μg/g,respectively;the share of Se-polysaccharide in total selenium were 11.086% and 26.713%,respectively,lower degree to turn the selenium organic in Hubei Cordyceps militaris.The reducing power of seleno-polysaccharide from Hubei and Yunnan Cordyceps militaris were 0.0253,0.0297,respectively;two kinds of Cordyceps militaris have certain ability to remove superoxide anion radical and different between them,the seleno-polysaccharide of Yunnan Cordyceps militaris has a better effect to remove superoxide anion radical under different sample amount.About hydroxyl radical,there were no ability to remove it.

Antioxidant and ROS inhibitory activities of heterocyclic 2-Aryl-4(3H)-quinazolinone derivatives

2021 ◽  
Vol 18 ◽  
Author(s):  
Shahida Perveen ◽  
Syed Muhammad Saad ◽  
Khalid Mohammed Khan ◽  
Muhammad Iqbal Choudhary
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activity ◽  
Free Radicals ◽  
Cell Line ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Radical Scavenging ◽  
Superoxide Anion Radical ◽  
Inhibitory Activities ◽  
Quinazolinone Derivatives

Background: Antioxidants are small molecules that prevent or delay the process of oxidations caused by highly reactive free radicals. These molecules are known for their ability to protect various cellular architecture and other biomolecules from oxidative stress and free radicals. Thus, antioxidants play a key role in the prevention of oxidative damages caused by highly reactive free radicals. Method: In the present study, a series of previously synthesized heterocyclic 2-aryl-4(3H)-quinazolinone derivatives 1-25 was screened for antioxidant activity by employing in vitro DPPH and superoxide anion radical scavenging activities. ROS inhibitory activities were also evaluated by serum-opsonized zymosan activated whole blood phagocytes and isolated neutrophils. Cytotoxicity studies were carried out by employing an MTT assay against the 3T3 cell line. Results: Most of the 2-aryl-4(3H)-quinazolinone derivatives showed potent antioxidant activities in superoxide anion radical scavenging assay with IC50 value ranging between 0.57 µM – 48.93 µM, as compared to positive control quercetin dihydrate (IC50 = 94.1± 1.1 µM ). Compounds 5, 6, and 14 showed excellent activity in DPPH assay. Compounds 5-8, 12-15, 17, and 20 showed promising activities in the ROS inhibition assay. All compounds were found to be non-cytotoxic against the 3T3 cell line. Structure antioxidant activity has been established. Conclusion: It can be concluded that most of the heterocyclic 2-aryl-4(3H)-quinazolinone derivatives 1-25 are identified as promising antioxidant agents that are capable of fighting against free radicals and oxidative stress. Thus, they can serve as a lead towards treating oxidative stress and related pathologies.

scholarly journals Hit-to-lead and lead optimization binding free energy calculations for G protein-coupled receptors

2020 ◽  
Vol 10 (6) ◽  
pp. 20190128 ◽  
Author(s):  
Shunzhou Wan ◽  
Andrew Potterton ◽  
Fouad S. Husseini ◽  
David W. Wright ◽  
Alexander Heifetz ◽  
...  
Keyword(s):  
G Protein ◽  
Binding Free Energy ◽  
Absolute Error ◽  
Free Energy Calculations ◽  
Lead Optimization ◽  
Receptor Protein ◽  
Enhanced Sampling ◽  
Free Energies ◽  
G Protein Coupled ◽  
Binding Free Energies

We apply the hit-to-lead ESMACS (enhanced sampling of molecular dynamics with approximation of continuum solvent) and lead-optimization TIES (thermodynamic integration with enhanced sampling) methods to compute the binding free energies of a series of ligands at the A 1 and A 2A adenosine receptors, members of a subclass of the GPCR (G protein-coupled receptor) superfamily. Our predicted binding free energies, calculated using ESMACS, show a good correlation with previously reported experimental values of the ligands studied. Relative binding free energies, calculated using TIES, accurately predict experimentally determined values within a mean absolute error of approximately 1 kcal mol −1 . Our methodology may be applied widely within the GPCR superfamily and to other small molecule–receptor protein systems.

Evaluation of antioxidant activity of Melothria maderaspatana in vitro

2010 ◽  
Vol 5 (2) ◽  
pp. 224-230 ◽  
Author(s):  
Boobalan Raja ◽  
Kodukkur Pugalendi
Keyword(s):  
Hydrogen Peroxide ◽  
Antioxidant Activity ◽  
Free Radical ◽  
Hydroxyl Radical ◽  
Superoxide Anion ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Free Radical Scavenging ◽  
Melothria Maderaspatana

AbstractIn this study, an aqueous extract of leaves from Melothria maderaspatana was tested for in vitro antioxidant activity. Free radical scavenging assays, such as hydroxyl radical, hydrogen peroxide, superoxide anion radical and 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2’-azinobis-(3-ethyl-enzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, and reducing power assay, were studied. The extract effectively scavenged hydroxyl radical, hydrogen peroxide and superoxide anion radicals. It also scavenged DPPH and ABTS radicals. Furthermore, it was found to have reducing power. All concentrations of leaf extract exhibited free radical scavenging and antioxidant power, and the preventive effects were in a dose-dependent manner. The antioxidant activities of the above were compared to standard antioxidants such as butylated hydroxytoluene (BHT), ascorbic acid, and α-tocopherol. The results obtained in the present study indicate that the M. maderaspatana extract could be considered a potential source of natural antioxidant.

Effect of Egyptian Propolis on the Susceptibility of LDL to Oxidative Modification and its Antiviral Activity with Special Emphasis on Chemical Composition

2007 ◽  
Vol 62 (9-10) ◽  
pp. 645-655 ◽  
Author(s):  
Faten K. Abd El-Hadya ◽  
Ahmed G. Hegazi ◽  
Eckhard Wollenweber
Keyword(s):  
Antioxidant Activity ◽  
Antiviral Activity ◽  
Disease Virus ◽  
Superoxide Anion ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Polyphenolic Compounds ◽  
Oxidative Modification ◽  
Aromatic Acids ◽  
Bursal Disease

The antioxidant activity of eight Egyptian propolis samples from different localities was evaluated by the antioxidative potential and capacity of the DPPH-ESR signal, superoxide anion generated in the xanthine-xanthine oxidase (XOD) system and low density lipoprotein (LDL) peroxidation assay. As, F, Is and D samples showed the highest antioxidative capacity and potential, respectively. The El, IsR, Is, D and So samples exhibited highly significant antioxidant activity in the XOD system and in LDL peroxidation assays. The antiviral activity of propolis samples was investigated. They showed variations in their activity; sample D induced the highest antiviral activity against Newcastle disease virus and infectious bursal disease virus. 42 Polyphenolic compounds were identified by HPLC; 13 aromatic acids, esters and alcohols were present, 29 flavonoids were identified, 6 of them being new to propolis.

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