scholarly journals ANTIOXIDATIVE AND INHIBITION POTENCY OF CYNODONTIN

2020 ◽  
pp. 59-70
Author(s):  
Jelena Đorović ◽  
Marko Antonijević ◽  
Zoran Marković
Keyword(s):  
Electron Transfer ◽  
Density Functional ◽  
Human Leukocyte ◽  
Docking Study ◽  
Hydrogen Atom Transfer ◽  
Antioxidant Action ◽  
Molecular Docking Study ◽  
Leukocyte Elastase ◽  
Action Density ◽  
Inhibition Potency

The antioxidant activity of cynodontin was studied in the absence and the presence of free radical species. This in silico study was performed in water and benzene, with the aim to simulate polar and non-polar environment. To determine the most probable mechanism of antioxidant action, density functional theory (DFT) was employed. The change in reaction enthalpy of cynodontin with three different free radicals (hydroxyl, hydroperoxyl, and methyl peroxyl radical) were examined and presented. SET-PT (Single Electron Transfer – Proton Transfer) mechanism is not an operative mechanism of antioxidant action. The obtained results imply that the possible mechanism of antioxidant action in water is SPLET (Sequential Proton Loss Electron Transfer), while in benzene HAT (Hydrogen atom transfer) and SPLET are competitive mechanisms. The molecular docking study was performed in order to estimate the inhibition potency of the investigated compound toward human leukocyte elastase (HLE). The obtained results indicate that numerous interactions determine the inhibition activity towards the investigated protein.

scholarly journals COMPARATIVE ANTIRADICAL ACTIVITY AND MOLECULAR DOCKING STUDY OF BERGAPTOL AND XANTHOTOXOL

2020 ◽  
pp. 71-84
Author(s):  
Žiko Milanović ◽  
Marko Antonijević ◽  
Jelena Đorović ◽  
Dejan Milenković
Keyword(s):  
Antioxidant Activity ◽  
Electron Transfer ◽  
Molecular Docking ◽  
Free Radical ◽  
Hydrogen Atom ◽  
Antiradical Activity ◽  
Docking Study ◽  
Hydrogen Atom Transfer ◽  
Molecular Docking Study ◽  
Anionic Species

The antioxidant activity of bergaptol (4-hydroxyfuro[3,2-g]chromen-7-one, BER) and xanthotoxol (9-hydroxyfuro[3,2-g]chromen-7-one, XAN) was investigated in water and benzene, as solvents. For this purpose, the density functional theory (DFT) was used. The free radical scavenging potency of investigated compounds towards different reactive oxygen species (ROS) was performed. Antioxidative mechanism of investigated compounds – hydrogen atom transfer (HAT), single-electron transfer–proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET) were examined using M06-2X/6-311++G(d,p) theoretical model. The important thermodynamic parameters (BDE, IP, PDE, PA, ETE) and Gibbs free energies of reactions, were used to determine the most probable antioxidant mechanism of action. The obtained thermodynamic parameters suggested that Hydrogen Atom Transfer (HAT) is the most probable reaction pathway in benzene, while Sequential Proton Loss Electron Transfer (SPLET) was favorized in water. The obtained results indicate that the favorable mechanism of antiradical activity depends on the polarity of medium and the nature of free radical species. By comparing the antioxidant activity of investigated compounds, it can be concluded that bergaptol exhibits better antioxidant properties. Molecular docking study of neutral and anionic species of investigated compounds was performed according to Estrogen receptor alpha (ERα). In both cases, bergaptol showed better inhibitory potency. All the anionic species showed a higher inhibition constant, indicating lower inhibition potency than corresponding parent molecules.

Theoretical investigation and molecular docking approach on the antioxidant activity of Schiff bases and their tautomers

2017 ◽  
Vol 16 (01) ◽  
pp. 1750001 ◽  
Author(s):  
Ahmed Taki Eddine Ardjani ◽  
Sidi Mohamed Mekelleche
Keyword(s):  
Antioxidant Activity ◽  
Electron Transfer ◽  
Molecular Docking ◽  
Gas Phase ◽  
Great Influence ◽  
Docking Study ◽  
Hydrogen Atom Transfer ◽  
Molecular Docking Study ◽  
Antioxidant Power ◽  
Dissociation Enthalpy

A theoretical study of the antioxidant behavior of N[Formula: see text]-(2-hydroxy-3-methoxy-benzylidene)-4-tert-buty-lenzohydrazide (1), N[Formula: see text]-(5-bromo-2-hydroxy-benzylidene)-4-tert-butyl benzohydrazide (2) and N[Formula: see text]-(2-hydroxy-3-methoxybenzylidene)-4-methyl-benzene-sulfonohydrazide (3) and their tautomers 1 [Formula: see text] –3 [Formula: see text] have been carried out at B3LYP/6-31[Formula: see text]G(2d,2p). The numerical values of descriptors, namely, bond dissociation enthalpy, proton affinity (PA), electron transfer enthalpy (ETE), ionization potential, and proton dissociation enthalpy (PDE) have been calculated in gas phase and media solution (EtOH, DMSO and water). The obtained results show that the hydrogen atom transfer (HAT) mechanism is more favored thermodynamically in gas phase, whereas the sequential proton loss electron transfer (SPLET) mechanism is more preferred in solvents. Moreover, the couple (3,3[Formula: see text]) is found to be the most potent antioxidant as expected experimentally. Furthermore, the BDE values of compound 3 [Formula: see text] is much lower than that of ascorbic acid (AA), indicating that the tautomerization of compounds 1–3 has great influence on the antioxidant activity of these compounds. The antioxidant power of compounds (3.3[Formula: see text]) was also rationalized by the calculation of the atomic spin density. In addition, the molecular docking study of compounds 1–3 and 1[Formula: see text] –3[Formula: see text] on xanthine oxidase (XO) as the protein target revealed important interactions between active compounds and amino acids. Moreover, compound 3 is predicted to be a potential inhibitor with higher activity.

scholarly journals Comparative Study of Antioxidant Potential of Selected Dietary Vitamins; Computational Insights

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1646 ◽  
Author(s):  
Dinesh R. Pandithavidana ◽  
Samith B. Jayawardana
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom ◽  
Aqueous Phase ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Antioxidant Action ◽  
Polarized Continuum Model ◽  
Primary Antioxidant

Density functional theory (DFT) was used to explore the antioxidant properties of some naturally occurring dietary vitamins, and the reaction enthalpies related to various mechanisms of primary antioxidant action, i.e., hydrogen atom transfer, single electron transfer–proton transfer, and sequential proton loss–electron transfer were discussed in detail. B3LYP, M05-2X, and M06-2X functionals were utilized in this work. For aqueous phase studies, the integral equation formalism polarized continuum model (IEF–PCM) was employed. From the outcomes, hydrogen atom transfer (HAT) was the most probable mechanism for the antioxidant action of this class of compounds. Comparison of found results with experimental data (available in literature), vitamin C possesses the lowest enthalpy values for both proton affinity (PA) and bond dissociation energy (BDE)in the aqueous phase, suggesting it as the most promising candidate as an antioxidant. Accordingly, these computational insights encourage the design of structurally novel, simple vitamins which will be more economical and beneficial in the pharmaceutical industry.

scholarly journals Green One-Pot Synthesis of Coumarin-Hydroxybenzohydrazide Hybrids and Their Antioxidant Potency

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1106
Author(s):  
Marko R. Antonijević ◽  
Dušica M. Simijonović ◽  
Edina H. Avdović ◽  
Andrija Ćirić ◽  
Zorica D. Petrović ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Electron Transfer ◽  
Density Functional ◽  
Electron Transfer Reaction ◽  
Hydrogen Atom Transfer ◽  
Special Importance ◽  
Theory Approach ◽  
One Pot ◽  
Antioxidant Potency

Compounds from the plant world that possess antioxidant abilities are of special importance for the food and pharmaceutical industry. Coumarins are a large, widely distributed group of natural compounds, usually found in plants, often with good antioxidant capacity. The coumarin-hydroxybenzohydrazide derivatives were synthesized using a green, one-pot protocol. This procedure includes the use of an environmentally benign mixture (vinegar and ethanol) as a catalyst and solvent, as well as very easy isolation of the desired products. The obtained compounds were structurally characterized by IR and NMR spectroscopy. The purity of all compounds was determined by HPLC and by elemental microanalysis. In addition, these compounds were evaluated for their in vitro antioxidant activity. Mechanisms of antioxidative activity were theoretically investigated by the density functional theory approach and the calculated values of various thermodynamic parameters, such as bond dissociation enthalpy, proton affinity, frontier molecular orbitals, and ionization potential. In silico calculations indicated that hydrogen atom transfer and sequential proton loss–electron transfer reaction mechanisms are probable, in non-polar and polar solvents respectively. Additionally, it was found that the single-electron transfer followed by proton transfer was not an operative mechanism in either solvent. The conducted tests indicate the excellent antioxidant activity, as well as the low potential toxicity, of the investigated compounds, which makes them good candidates for potential use in food chemistry.

scholarly journals Flavones’ and Flavonols’ Antiradical Structure–Activity Relationship—A Quantum Chemical Study

Antioxidants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 461 ◽  
Author(s):  
Maciej Spiegel ◽  
Tadeusz Andruniów ◽  
Zbigniew Sroka
Keyword(s):  
Electron Transfer ◽  
Hydrogen Bonding ◽  
Density Functional ◽  
Hydrogen Abstraction ◽  
Quantum Chemical Study ◽  
Hydrogen Atom Transfer ◽  
Hydroxyl Group ◽  
Water Solvent ◽  
Intramolecular Hydrogen ◽  
Catechol Moiety

Flavonoids are known for their antiradical capacity, and this ability is strongly structure-dependent. In this research, the activity of flavones and flavonols in a water solvent was studied with the density functional theory methods. These included examination of flavonoids’ molecular and radical structures with natural bonding orbitals analysis, spin density analysis and frontier molecular orbitals theory. Calculations of determinants were performed: specific, for the three possible mechanisms of action—hydrogen atom transfer (HAT), electron transfer–proton transfer (ETPT) and sequential proton loss electron transfer (SPLET); and the unspecific—reorganization enthalpy (RE) and hydrogen abstraction enthalpy (HAE). Intramolecular hydrogen bonding, catechol moiety activity and the probability of electron density swap between rings were all established. Hydrogen bonding seems to be much more important than the conjugation effect, because some structures tends to form more intramolecular hydrogen bonds instead of being completely planar. The very first hydrogen abstraction mechanism in a water solvent is SPLET, and the most privileged abstraction site, indicated by HAE, can be associated with the C3 hydroxyl group of flavonols and C4’ hydroxyl group of flavones. For the catechol moiety, an intramolecular reorganization to an o-benzoquinone-like structure occurs, and the ETPT is favored as the second abstraction mechanism.

scholarly journals Molecular docking study of the phytol and its derivatives against COX-2 induced inflammation: A combined density functional study

2020 ◽  
pp. 1-5
Author(s):  
Muhammad Torequl Islam ◽  
Pranta Ray ◽  
Abul Bashar Ripon Khalipha ◽  
SM Hafiz Hassan ◽  
Md. Roich Khan ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Binding Energy ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Docking Study ◽  
Functional Study ◽  
Molecular Docking Study ◽  
Study Results ◽  
Homo And Lumo ◽  
Cox 2

This study aimed to determine the activity of PYT and its derivatives against COX-2, including 5IKR protein induced inflammation by using the computational tools. PYT and its derivatives have been designed by utilizing density functional theory (DFT) and the performance of the drugs was also evaluated by molecular docking study. Results suggest that the NH2 derivative of PYT (D-NH2) showed binding energy -6.4 (Kcal/mol) with protein 5IKR of COX-2 compared to the main drug (D) that showed binding energy -5.1 (Kcal/mol) with the same protein. HOMO and LUMO energy values were also calculated to determine the chemical reactivity of all the modified drugs. Non-covalent interactions of PYT and its derivatives were essential in improving the performance. In conclusion, D-NH2 showed better preference in inhibiting to the protein 5IKR of COX-2 compared to other modified drugs and it can be claimed that D-NH2 will be the best conformer for COX-2 induced inflammation.

scholarly journals Free Radical Scavenging Activity of Dihydrocaffeic Acid: A Quantum Chemical Approach

2021 ◽  
Vol 33 (4) ◽  
pp. 937-944
Author(s):  
K. Senthilkumar ◽  
S.S. Naina Mohammed ◽  
S. Kalaiselvan
Keyword(s):  
Electron Transfer ◽  
Quantum Chemical ◽  
Density Functional ◽  
Radical Scavenging ◽  
Hydrogen Atom Transfer ◽  
Basis Set ◽  
Published Data ◽  
Chemical Calculation ◽  
Neutral Radical ◽  
Donor And Acceptor

Based on density functional theory (DFT), to investigate relationships between the antioxidant activity and structure of dihydrocaffeic acid, quantum chemical calculation is used. The optimized structures of the neutral, radical and ionic forms have been carried out by DFT-B3LYP method with the 6-311G(d,p) basis set. Reaction enthalpies related with the hydrogen atom transfer (HAT), single electron transfer proton transfer (SET-PT) and sequential proton loss and electron transfer (SPLET) were calculated in gas and water phase. The HOMO-LUMO energy gap, electron affinity, electronegativity, ionization energy, hardness, chemical potential, global softness and global electrophilicity were calculated by using the same level of theory. Surfaces with a molecular electrostatic potential (MEP) were studied to determine the reactive sites of dihydrocaffeic acid. The difference in energy between the donor and acceptor as well as the stabilization energy was determined through the natural bond orbital (NBO) analysis. The Fukui index (FI) based on electron density was employed to predict reaction sites. Reaction enthalpies are compared with previously published data for phenol and 3,4-dihydroxycinnamic acid.

scholarly journals Molecular Docking Study on Several Benzoic Acid Derivatives against SARS-CoV-2

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5828
Author(s):  
Amalia Stefaniu ◽  
Lucia Pirvu ◽  
Bujor Albu ◽  
Lucia Pintilie
Keyword(s):  
Molecular Docking ◽  
Benzoic Acid ◽  
Density Functional ◽  
Chemical Reactivity ◽  
Principal Component ◽  
Docking Study ◽  
Docking Studies ◽  
Molecular Docking Study ◽  
Alkyl Gallates ◽  
Main Protease

Several derivatives of benzoic acid and semisynthetic alkyl gallates were investigated by an in silico approach to evaluate their potential antiviral activity against SARS-CoV-2 main protease. Molecular docking studies were used to predict their binding affinity and interactions with amino acids residues from the active binding site of SARS-CoV-2 main protease, compared to boceprevir. Deep structural insights and quantum chemical reactivity analysis according to Koopmans’ theorem, as a result of density functional theory (DFT) computations, are reported. Additionally, drug-likeness assessment in terms of Lipinski’s and Weber’s rules for pharmaceutical candidates, is provided. The outcomes of docking and key molecular descriptors and properties were forward analyzed by the statistical approach of principal component analysis (PCA) to identify the degree of their correlation. The obtained results suggest two promising candidates for future drug development to fight against the coronavirus infection.

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