scholarly journals DFT Studies on the Antioxidant Activity of Naringenin and Its Derivatives: Effects of the Substituents at C3

2019 ◽  
Vol 20 (6) ◽  
pp. 1450 ◽  
Author(s):  
Yan-Zhen Zheng ◽  
Geng Deng ◽  
Rui Guo ◽  
Da-Fu Chen ◽  
Zhong-Min Fu
Keyword(s):  
Antioxidant Activity ◽  
Density Functional ◽  
Radical Scavenging Activity ◽  
Resonance Effect ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Dft Method ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Selection Of

The radical scavenging activity of a flavonoid is largely influenced by its structure. The effects of the substituents at C3 position on the antioxidant activity of naringenin were carried out using the density functional theory (DFT) method. The reaction enthalpies related with the three well-established mechanisms were analyzed. Excellent correlations were found between the reaction enthalpies and Hammett sigma constants. Equations obtained from the linear regression can be helpful in the selection of suitable candidates for the synthesis of novel naringenin derivatives with enhanced antioxidant properties. In the gas and benzene phases, the antioxidant activity of naringenin was enhanced by the electron-donating substituents via weakening the bond dissociation enthalpy (BDE). In the water phase, it was strengthened by electron-withdrawing groups—via lowering the proton affinity (PA). The electronic effect of the substituent on the BDE of naringenin is mainly governed by the resonance effect, while that on the ionization potential (IP) and PA of naringenin is mainly controlled by the field/inductive effect.

scholarly journals A Theoretical Elucidation of the Radical-Scavenging Power of Cyanidin

2006 ◽  
Vol 1 (3) ◽  
pp. 1934578X0600100
Author(s):  
Hong-Fang Ji ◽  
Hong-Yu Zhang ◽  
Liang Shen
Keyword(s):  
Density Functional ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Dft Method ◽  
Radical Scavenger ◽  
High Potency ◽  
Functional Theory ◽  
Antioxidant Power ◽  
Proton Dissociation ◽  
Scavenging Efficiency

Cyanidin (CY), one of the most common anthocyanins, has a high radical-scavenging efficiency that can be compared with that of the flavone, quercetin (QU). Owing to the oxonium ion, CY exhibits diverse structures (isomers) in different (pH) environments. In this paper, to elucidate the high potency of CY as a radical scavenger, a combined density functional theory (DFT) method, labeled as (RO)B3LYP/6-311+G(2d,2p)//AM1/AM1, was employed to calculate the O-H bond dissociation enthalpies (BDEs), proton dissociation enthalpies (PDEs) and ionization potentials (IPs) of various CY isomers in acetonitrile and then the parameters were compared with those of QU. The comparable BDEs, PDEs and IPs of CY (in various forms) and QU account well for CY's high radical-scavenging activity in different environments. In addition, through estimating the contribution of each group to the BDEs and IP of the CY cation, some deeper insights into the antioxidant power of CY were obtained.

scholarly journals DFT study of the radical scavenging activity of isoxanthohumol, humulones (α-acids) and iso-α-acids from beer

2021 ◽  
Author(s):  
Ilija N. Cvijetić ◽  
Miljan Bigović ◽  
Petar Ristivojević ◽  
Maja Vitorović-Todorović ◽  
Mire Zloh ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Density Functional ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Natural Antioxidants ◽  
Dft Method ◽  
Hydrogen Atom Transfer ◽  
Antioxidant Mechanism ◽  
Intramolecular Hydrogen ◽  
Cis And Trans

Abstract Humulones and iso-humulones are potent natural antioxidants found in beer. In this study, density functional theory (DFT) method was applied for elucidating the structure-antioxidant activity relationship and molecular mechanism of antioxidant activity of eight bioactive humulones previously identified in different beer samples: isoxanthohumol, ( R )- and ( S )-adhumulone, cis - and trans -iso-adhumulone, cis - and trans -iso-n-humulone, and desdimetyhyl-octahydro-iso-cohumulone. The calculated bond dissociation enthalpies (BDEs) suggest that desdimethyl-octahydro-iso-cohumulone was the most potent compound with BDEs 5.1 and 23.9 kJ/mol lower compared to the values for resveratrol in gas phase and water, respectively. The enolic –OH is the most reactive site for hydrogen atom transfer (HAT). The presence of β-keto group with respect to enolic –OH diminishes the HAT potency via the formation of a strong intramolecular hydrogen bond. Another common antioxidant mechanism, single electron transfer followed by proton transfer (SET-PT), is only feasible for isoxanthohumol. The results of this study indicate a strong correlation between the increased antioxidant activity of beer products and the higher content of reduced iso-α-acids.

scholarly journals Reactivity Indexes and O-H Bond Dissociation Energies of a Large Series of Polyphenols: Implications for their Free Radical Scavenging Activity

2017 ◽  
Vol 56 (3) ◽  
Author(s):  
Adriana Pérez-González ◽  
Aida Mariana Rebollar-Zepeda ◽  
Jorge Rafael León-Carmona ◽  
Annia Galano
Keyword(s):  
Free Radicals ◽  
Density Functional ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Functional Theory ◽  
Electron Transfer Mechanism ◽  
Dissociation Energies ◽  
The Density Functional Theory ◽  
Reactivity Indexes ◽  
Chemical Descriptors

Several chemical descriptors have been evaluated for thirty polyphenols within the frame of the Density Functional Theory (DFT). They were used to investigate the donor and accepting electron capabilities, the fractional charge transfer feasibility, and the H transfer ability of these compounds. It was found that for deactivating free radicals Myricetin has the highest activity via H transfer, while Galangin and piceatannol are the best scavengers through the single electron transfer mechanism for nucleophilic and electrophilic free radicals, respectively.

Antioxidant activity of cookiessupplemented with sugarbeet dietary fiber

2011 ◽  
pp. 151-157 ◽  
Author(s):  
Marijana B. Saka ◽  
Julianna F. Gyura ◽  
Aleksandra Mišan ◽  
Zita I. Šereš ◽  
Biljana S. Pajin ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Shelf Life ◽  
Dietary Fiber ◽  
Wheat Flour ◽  
Room Temperature ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Functional Characteristics

The antioxidant activity of cookies prepared by the addition of sugarbeet dietary fibers was investigated in order to estimate their influence on functional characteristics and shelf-life of cookies. Treated fiber (TF) was obtained from sugarbeet by extraction with sulfurous acid (75 °C at pH = 5.7during 60 min) and treatment with hydrogen peroxide (20 g/LH2O2 at pH = 11 during 24 h). The fiber obtained was dried (80 °C), ground and sieved. TF was investigated in comparison with commercially available Fibrex®. The cookies were prepared by the addition of 0, 7, 9 and 11% of sugarbeet dietary fiber as a substitute for wheat flour in the formulation of cookies. The antioxidant properties of cookies were tested every 7 days using a DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity test during 6 weeks of storage at room temperature (23 ± 1 ºC). The obtained results indicated that substitution of wheat flour with Fibrex® in the formulation of cookies upgraded the antioxidant activity, i.e. the functional characteristics of Fibrex®-enriched cookies and could prolong their shelf-life. In contrast, TF did not increase the antioxidant activity of TF-enriched cookies. The better antioxidant activities of Fibrex®-enriched cookies could be attributed to the presence of ferulic acid.

scholarly journals Study on the interaction between catechin and cholesterol by the density functional theory

2020 ◽  
Vol 18 (1) ◽  
pp. 357-368
Author(s):  
Kaiwen Zheng ◽  
Kai Guo ◽  
Jing Xu ◽  
Wei Liu ◽  
Junlang Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Charge Transfer ◽  
Density Functional ◽  
Antioxidant Properties ◽  
Micelle Formation ◽  
Aromatic Rings ◽  
Hydrogen Bond Interaction ◽  
Functional Theory ◽  
The Density Functional Theory

AbstractCatechin – a natural polyphenol substance – has excellent antioxidant properties for the treatment of diseases, especially for cholesterol lowering. Catechin can reduce cholesterol content in micelles by forming insoluble precipitation with cholesterol, thereby reducing the absorption of cholesterol in the intestine. In this study, to better understand the molecular mechanism of catechin and cholesterol, we studied the interaction between typical catechins and cholesterol by the density functional theory. Results show that the adsorption energies between the four catechins and cholesterol are obviously stronger than that of cholesterol themselves, indicating that catechin has an advantage in reducing cholesterol micelle formation. Moreover, it is found that the molecular interactions of the complexes are mainly due to charge transfer of the aromatic rings of the catechins as well as the hydrogen bond interactions. Unlike the intuitive understanding of a complex formed by hydrogen bond interaction, which is positively correlated with the number of hydrogen bonds, the most stable complexes (epicatechin–cholesterol or epigallocatechin–cholesterol) have only one but stronger hydrogen bond, due to charge transfer of the aromatic rings of catechins.

Aktywność przeciwutleniająca i przeciwbakteryjna miodu, propolisu oraz pyłku kwiatowego

2020 ◽  
Vol 21 (3) ◽  
Author(s):  
Magdalena Woźniak ◽  
Lucyna Mrówczyńska ◽  
Anna Sip ◽  
Marta Babicka ◽  
Tomasz Rogoziński ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Pathogenic Bacteria ◽  
Radical Scavenging Activity ◽  
Colorimetric Method ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Total Content ◽  
Diffusion Method ◽  
Bacterial Strains

Introduction. Honey, propolis and pollen belong to bee products that have beneficial biological properties. These products exhibit e.g. antibacterial, antifungal and antioxidant properties. Due to biological activity and natural origin, bee products are used, e.g. in the food industry, cosmetology and pharmacy. Aim. The aim of the study was to compare the antioxidant and antibacterial activity of honey, propolis and pollen from an apiary located in Wielkopolska Province. Material and methods. Honey, propolis and pollen used in this study came from the same apiary located in Wielkopolska Province. The antioxidant potential of bee products was evaluated applying DPPH· free radical scavenging activity assay. The antimicrobial activity of the tested bee products was determined by the point-diffusion method against 13 strains of pathogenic and potentially pathogenic bacteria. In addition, the total content of phenolic compounds in honey, propolis and pollen was determined by the colorimetric method. Results. Propolis exhibited higher antioxidant activity, in comparison to honey and pollen. The antiradical activity of propolis was equal to 80% approx. activity of Trolox, the standard antioxidant. Among tested bee products, propolis was characterized by the highest total phenols content. In addition, honey, propolis and pollen showed antagonistic activity against tested bacterial strains. Conclusions. The obtained results indicate that among the tested bee products of native origin, i.e. honey, propolis and pollen, propolis characterized by the highest antioxidant activity and the total content of phenolic compounds. In addition, all bee products showed bactericidal activity against the tested bacterial strains.

First principles analysis of oxygen vacancy formation and migration in Sr2BMoO6 (B = Mg, Co, Ni)

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 31968-31975 ◽  
Author(s):  
Shuai Zhao ◽  
Liguo Gao ◽  
Chunfeng Lan ◽  
Shyam S. Pandey ◽  
Shuzi Hayase ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Oxygen Vacancy ◽  
First Principles ◽  
Density Functional ◽  
Dft Method ◽  
Double Perovskites ◽  
Functional Theory ◽  
Oxygen Vacancy Formation ◽  
The Density Functional Theory ◽  
And Migration

In this work, we present a detailed first-principles investigation on the stoichiometric and oxygen-deficient structures of double perovskites, Sr2BMoO6 (B = Mg, Co and Ni), using the density functional theory (DFT) method.

scholarly journals Vibrational Study and Force Field of the Citric Acid Dimer Based on the SQM Methodology

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Laura Cecilia Bichara ◽  
Hernán Enrique Lanús ◽  
Evelina Gloria Ferrer ◽  
Mónica Beatriz Gramajo ◽  
Silvia Antonia Brandán
Keyword(s):  
Citric Acid ◽  
Force Field ◽  
Density Functional ◽  
Solid Phase ◽  
Dft Method ◽  
Electronic Charge ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Atoms In Molecules Theory ◽  
Best Fit

We have carried out a structural and vibrational theoretical study for the citric acid dimer. The Density Functional Theory (DFT) method with the B3LYP/6-31G∗ and B3LYP/6-311++ methods have been used to study its structure and vibrational properties. Then, in order to get a good assignment of the IR and Raman spectra in solid phase of dimer, the best fit possible between the calculated and recorded frequencies was carry out and the force fields were scaled using the Scaled Quantum Mechanic Force Field (SQMFF) methodology. An assignment of the observed spectral features is proposed. A band of medium intensity at 1242  together with a group of weak bands, previously not assigned to the monomer, was in this case assigned to the dimer. Furthermore, the analysis of the Natural Bond Orbitals (NBOs) and the topological properties of electronic charge density by employing Bader's Atoms in Molecules theory (AIM) for the dimer were carried out to study the charge transference interactions of the compound.

scholarly journals RELATIONSHIP BETWEEN ANTIOXIDANT PROPERTIES AND NUTRITIONAL COMPOSITION OF SOME GALACTOPOIETICS HERBS USED IN INDONESIA: A COMPARATIVE STUDY

2016 ◽  
Vol 8 (12) ◽  
pp. 236 ◽  
Author(s):  
Ade Chandra Iwansyah ◽  
Rizal M. Damanik ◽  
Lilik Kustiyah ◽  
Muhammad Hanafi
Keyword(s):  
Antioxidant Activity ◽  
Chemical Composition ◽  
Total Phenolics ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Nutritional Composition ◽  
Total Flavonoids ◽  
Wide Range ◽  
Phenolics Content

<p><strong>Objective: </strong>The objectives of this research were to evaluate and compare the antioxidant activity; phenolics and flavonoids contents; and chemical composition of some galactopoietic herbs used in Indonesia and to find a possible relationship between antioxidant activity; phenolics, flavonoids and chemical composition of these plants.</p><p><strong>Methods: </strong>A wide range of analytical parameters was studied, including yield; pH; water activity (a<sub>w</sub>); total color difference; phenolics and flavonoids content; moisture; ash; protein; fat; carbohydrate; fiber; calcium; zinc; magnesium; potassium; iron content; and the data were analyzed by partial least squares (PLS) regression analysis and principal component analysis (PCA) to evaluate the correlation between the parameters and classification of the plants. Folin–cioceltaeu assay, aluminum chloride assay and DPPH scavenging assay were used to evaluate of total phenolics content and free radical scavenging activity of the ethanolic extract of galactopoietic herbs.</p><p><strong>Results: </strong>All of the galactagogue herbs, <em>viz</em>. <em>Plectranthus amboinicus </em>(Lour.) (PA), <em>Sauropus androgynus</em> (SA), <em>Moringa oleifera</em> (MO), and <em>Carica papaya</em> leaves (CP) exhibited good results of TPC, TFC and antioxidant activity. MO contained the highest average of total phenolics content (53.89 mg GAE/g). SA with a ratio of total flavonoids to total phenolics (TF/TP) which is 1.59 contained the highest average of total flavonoids and antioxidant activity (IC<sub>50</sub>), 43.63 mg QE/g and 126.13 μg/ml, respectively, followed by MO&gt;CA&gt;PA. Based on PLS and PCA analysis, antioxidant activity correlated with fat, protein, phenolics content, flavonoids content and pH, but only the total flavonoids content correlated strongly with antioxidant activity.<strong></strong></p><p><strong>Conclusion: </strong>This provides useful data about the studied relationships and chemical patterns in some galactopoietic herbs used and provides a helpful tool for understanding much more about the interpretation of results from the experiments and the mechanism of biosynthesis in plants.</p>

scholarly journals Effects of solvent extraction system on antioxidant activity of Lamium purpureum L.

2017 ◽  
Vol 71 (5) ◽  
pp. 361-370
Author(s):  
Slavica Grujic ◽  
Ana Dzamic ◽  
Violeta Mitic ◽  
Vesna Stankov-Jovanovic ◽  
P.D. Marin ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Methanol Extract ◽  
Phenolic Content ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Total Phenolic ◽  
Radical Scavenger ◽  
Scavenging Activity

Antioxidant and free radical scavenging activity of methanol, ethanol, ethyl acetate and chloroform extracts of aerial parts of Lamium purpureum L. was determined by DPPH, ABTS, FRAP and TRP assays. Contents of flavonoids and phenols were also investigated. The total phenolic content in the extracts, determined using Folin?Ciocalteu assay, ranged between 8.57 to 128.00 mg GAE/g d.e. while concentrations of flavonoids in the extracts varied from 24.20 to 39.80 mg QuE/g d.e. The highest phenolic content was found in methanol extract (128.00 mg GAE/g d.e.). The highest content of total flavonoids was identified in the methanol extract (39.80 mg QuE/g d.e.) and the lowest was in the chloroform (24.30 mg QuE/g d.e.). DPPH scavenging of the extracts was determined and obtained IC50 values ranged from 0.12 to 3.12 mg/mL of solution. The values of ABTS radical scavenging activity ranged from 0.35 to 1.80 mg AA/g. The highest ABTS antiradical activity was registered for methanol extract. The FRAP value was found within the range 0.08 to 1.04 ?mol Fe/mg. The best radical scavenger was methanol (1.04 ?mol Fe/mg). In reducing power assay different extracts of L. purpureum showed increasing of activity with increased concentration, and all extracts possessed substantial dose dependent antioxidant activity. The best reducing capacity was obtained with methanol extract of L. purpureum (0.0132 mg AA/mL). The results in this study confirmed that L. purpureum possesses moderate antioxidant properties.

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