Titre : |
Quantum Chemical Investigation for Exploring the Antioxidant Activity of Thiaflavan Compounds |
Type de document : |
texte imprimé |
Auteurs : |
Nour el houda AMRANE, Auteur ; Douniazed HANNACHI, Directeur de thèse |
Editeur : |
Setif:UFA |
Année de publication : |
2019 |
Importance : |
1 vol (60 f.) |
Format : |
29 |
Langues : |
Anglais (eng) |
Catégories : |
Thèses & Mémoires:Chimie
|
Mots-clés : |
Quantum
Chemical Investigation
Antioxidant Activity
Thiaflavan
Compounds |
Résumé : |
Conclusion
In this work, for the first time the antioxidative properties of thiaflavan and
thiaflavan-ferrocene in the gas, water and benzene phases were studied from
theoretical aspect.
The calculated molecular properties (chemical potential, hardness and
electrophilicity index) of DNA and thiaflavan compounds clearly confirm that the
thiaflavan mostly act as electron donners in their interaction with the DNA. Our
results showing that the thymine moiety in DNA is the primary target for the
thiaflavan drugs.
Based on the above result, three main antioxidant mechanisms, namely HAT,
SET-PT and SPLET were taken into account to analyze the antioxidative capacity
of thiaflavan compounds in the gas, water and benzene phases.
As for the HAT mechanism, from the magnitude of the lowest BDE values, in the
gas and solvent the two successive hydroxyl groups in the A or B ring (3- 4-
position in the A ring and 1-2- position in the B ring) have higher H-atom donation
ability than the single hydroxyl groups in A or in B ring. Our result indicates that
hydroxyl groups at A ring play the key role in scavenging radicals and exhibiting
antioxidant effectiveness.
As for SET-PT mechanism, in the studied environments, the antioxidant activity of
the investigated compounds reveal that PDE values of T13 to T15 (ferrocene
moiety at ring B) are higher than all the thiaflavans compounds.
In SPLET mechanism, in the in the studied medium, from the PA of the
investigated compounds can conclude that the rings B and C’ shows a strong
activity antioxidant than the all cases.
48
We can conclude that the HAT mechanism is the most favorable that the SPLET
and SET-PT.
From the calculated results, OH groups in A-ring contribute mainly to the
antioxidative activities of compared with B-ring. On the other hand, in thiaflavan,
the R3-dihydroxyl groups in ring A are the active site for trapping radicals than the
R4-dihydroxyl.
Our DFT calculations reveal that the better antioxidant is T25’ which have:
two successive hydroxyl groups in the A-ring (3 and 4- position), C'-ring and
ferrocene moiety at ring B.
This work provides an impetus and a benchmark to outlook experiments, for
a determination of the detailed properties of T25’and this compound being
attractive object for future studies of antioxidant properties. |
Note de contenu : |
Table of Contents
Abbreviations 3
Introduction 4
Reference 6
Chapter 1 :
Part I: Density Functional Theory
I.1. principals of modern theoretical chemistry 8
I.1.1. Introduction of DFT into chemistry 8
I.1.2. DFT work in the coordination chemistry lab 8
I.1.2.1.CAPABILITIES OF DFT 8
I.2. Theorical Basics of DFT 9
I.3.DFT tools available (Exchange Correlation Functional) 11
I.3.1. LOCAL DENSITY APPROXIMATION: 11
I.3.2.GENERALIZED-GRADIENT APPROXIMATION (GGA) 11
I.3.3.META-GGA DFS 12
I.3.4.HYBRID DFS 12
I.4.Jacob’s ladder 13
I.5. Gaussian bases 14
I.5.1. Polarization function 14
I.5.2. Diffuse function 15
Reference 16
Part II: Flavonoid
II .1. FLAVONOID DERIVATIVES 20
II.1.1. Introduction 20
II.1.2. Generalities about flavonoids 21
II.2. DNA 23
II.3. Antioxidant Activity 24
II.3.1. Methodology for the measurement of Antioxydant capacity 24
 ORAC method 24
 DPPH method 24
 ABTS method 24
 FRAP method 25
Reference 26
Chapter 2:
Results and discussion
1. Antioxidant reactions 29
2 .Thiaflavan 30
3.Ferrocene 32
4. Theory and computational details 32
4.1Theory 32
4.2. Computational details 33
5.Results and discussion 35
5.1 Reactivity 35
5 5. 2.Antioxidant activity 38
5. 2.1.The ionization potential 38
5. 2.1.Proton Affinities 41
5. 2.3.Bond dissociation enthalpy 41
5. 2.4.Proton Dissociation Enthalpies 42
5.5.Electron transfer enthalpy 43
5. 5.2.6.Spin density
5- 2. 7 Design of best thiaflavan antioxidant 44
Conclusion 47
Reference 49
Supporting information |
Côte titre : |
MACH/0098 |
En ligne : |
https://drive.google.com/file/d/1vqe-1-161CF2r-SAsDraR35qOPX1y9A5/view?usp=shari [...] |
Format de la ressource électronique : |
pdf |
Quantum Chemical Investigation for Exploring the Antioxidant Activity of Thiaflavan Compounds [texte imprimé] / Nour el houda AMRANE, Auteur ; Douniazed HANNACHI, Directeur de thèse . - [S.l.] : Setif:UFA, 2019 . - 1 vol (60 f.) ; 29. Langues : Anglais ( eng)
Catégories : |
Thèses & Mémoires:Chimie
|
Mots-clés : |
Quantum
Chemical Investigation
Antioxidant Activity
Thiaflavan
Compounds |
Résumé : |
Conclusion
In this work, for the first time the antioxidative properties of thiaflavan and
thiaflavan-ferrocene in the gas, water and benzene phases were studied from
theoretical aspect.
The calculated molecular properties (chemical potential, hardness and
electrophilicity index) of DNA and thiaflavan compounds clearly confirm that the
thiaflavan mostly act as electron donners in their interaction with the DNA. Our
results showing that the thymine moiety in DNA is the primary target for the
thiaflavan drugs.
Based on the above result, three main antioxidant mechanisms, namely HAT,
SET-PT and SPLET were taken into account to analyze the antioxidative capacity
of thiaflavan compounds in the gas, water and benzene phases.
As for the HAT mechanism, from the magnitude of the lowest BDE values, in the
gas and solvent the two successive hydroxyl groups in the A or B ring (3- 4-
position in the A ring and 1-2- position in the B ring) have higher H-atom donation
ability than the single hydroxyl groups in A or in B ring. Our result indicates that
hydroxyl groups at A ring play the key role in scavenging radicals and exhibiting
antioxidant effectiveness.
As for SET-PT mechanism, in the studied environments, the antioxidant activity of
the investigated compounds reveal that PDE values of T13 to T15 (ferrocene
moiety at ring B) are higher than all the thiaflavans compounds.
In SPLET mechanism, in the in the studied medium, from the PA of the
investigated compounds can conclude that the rings B and C’ shows a strong
activity antioxidant than the all cases.
48
We can conclude that the HAT mechanism is the most favorable that the SPLET
and SET-PT.
From the calculated results, OH groups in A-ring contribute mainly to the
antioxidative activities of compared with B-ring. On the other hand, in thiaflavan,
the R3-dihydroxyl groups in ring A are the active site for trapping radicals than the
R4-dihydroxyl.
Our DFT calculations reveal that the better antioxidant is T25’ which have:
two successive hydroxyl groups in the A-ring (3 and 4- position), C'-ring and
ferrocene moiety at ring B.
This work provides an impetus and a benchmark to outlook experiments, for
a determination of the detailed properties of T25’and this compound being
attractive object for future studies of antioxidant properties. |
Note de contenu : |
Table of Contents
Abbreviations 3
Introduction 4
Reference 6
Chapter 1 :
Part I: Density Functional Theory
I.1. principals of modern theoretical chemistry 8
I.1.1. Introduction of DFT into chemistry 8
I.1.2. DFT work in the coordination chemistry lab 8
I.1.2.1.CAPABILITIES OF DFT 8
I.2. Theorical Basics of DFT 9
I.3.DFT tools available (Exchange Correlation Functional) 11
I.3.1. LOCAL DENSITY APPROXIMATION: 11
I.3.2.GENERALIZED-GRADIENT APPROXIMATION (GGA) 11
I.3.3.META-GGA DFS 12
I.3.4.HYBRID DFS 12
I.4.Jacob’s ladder 13
I.5. Gaussian bases 14
I.5.1. Polarization function 14
I.5.2. Diffuse function 15
Reference 16
Part II: Flavonoid
II .1. FLAVONOID DERIVATIVES 20
II.1.1. Introduction 20
II.1.2. Generalities about flavonoids 21
II.2. DNA 23
II.3. Antioxidant Activity 24
II.3.1. Methodology for the measurement of Antioxydant capacity 24
 ORAC method 24
 DPPH method 24
 ABTS method 24
 FRAP method 25
Reference 26
Chapter 2:
Results and discussion
1. Antioxidant reactions 29
2 .Thiaflavan 30
3.Ferrocene 32
4. Theory and computational details 32
4.1Theory 32
4.2. Computational details 33
5.Results and discussion 35
5.1 Reactivity 35
5 5. 2.Antioxidant activity 38
5. 2.1.The ionization potential 38
5. 2.1.Proton Affinities 41
5. 2.3.Bond dissociation enthalpy 41
5. 2.4.Proton Dissociation Enthalpies 42
5.5.Electron transfer enthalpy 43
5. 5.2.6.Spin density
5- 2. 7 Design of best thiaflavan antioxidant 44
Conclusion 47
Reference 49
Supporting information |
Côte titre : |
MACH/0098 |
En ligne : |
https://drive.google.com/file/d/1vqe-1-161CF2r-SAsDraR35qOPX1y9A5/view?usp=shari [...] |
Format de la ressource électronique : |
pdf |
|