scholarly journals Natural Chain-Breaking Antioxidants and Their Synthetic Analogs as Modulators of Oxidative Stress

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 624
Author(s):  
Vessela D. Kancheva ◽  
Maria Antonietta Dettori ◽  
Davide Fabbri ◽  
Petko Alov ◽  
Silvia E. Angelova ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Free Radicals ◽  
Density Functional ◽  
Quantitative Structure Activity Relationship ◽  
Structure Activity Relationship ◽  
Oxidation Products ◽  
Activity Relationship ◽  
Phenolic Antioxidants ◽  
Structure Activity ◽  
Chain Breaking

Oxidative stress is associated with the increased production of reactive oxygen species or with a significant decrease in the effectiveness of antioxidant enzymes and nonenzymatic defense. The penetration of oxygen and free radicals in the hydrophobic interior of biological membranes initiates radical disintegration of the hydrocarbon “tails” of the lipids. This process is known as “lipid peroxidation”, and the accumulation of the oxidation products as peroxides and the aldehydes and acids derived from them are often used as a measure of oxidative stress levels. In total, 40 phenolic antioxidants were selected for a comparative study and analysis of their chain-breaking antioxidant activity, and thus as modulators of oxidative stress. This included natural and natural-like ortho-methoxy and ortho-hydroxy phenols, nine of them newly synthesized. Applied experimental and theoretical methods (bulk lipid autoxidation, chemiluminescence, in silico methods such as density functional theory (DFT) and quantitative structure–activity relationship ((Q)SAR) modeling) were used to clarify their structure–activity relationship. Kinetics of non-inhibited and inhibited lipid oxidation in close connection with inhibitor transformation under oxidative stress is considered. Special attention has been paid to chemical reactions resulting in the initiation of free radicals, a key stage of oxidative stress. Effects of substituents in the side chains and in the phenolic ring of hydroxylated phenols and biphenols, and the concentration were discussed.

scholarly journals STUDY ON ANTI-HIV ACTIVITY OF DIARYLANILINE DERIVATIVES USING QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP (QSAR)

2013 ◽  
Vol 13 (2) ◽  
pp. 129-135 ◽  
Author(s):  
Ihsanul Arief ◽  
Ria Armunanto ◽  
Bambang Setiaji
Keyword(s):  
Density Functional ◽  
Quantitative Structure Activity Relationship ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Quantitative Structure ◽  
Multilinear Regression ◽  
Dft Methods ◽  
Structure Activity ◽  
Parameterized Model ◽  
Anti Hiv

Study on anti-HIV activity of diarylaniline derivative compounds by using quantitative structure-activity relationship (QSAR) has been done. The compounds structure and their anti-HIV activities were obtained from literature. Molecular and electronic parameters were calculated by Austin Model 1 (AM1), Parameterized Model 3 (PM3), Hartree-Fock (HF), and density functional theory (DFT) methods. QSAR analysis was performed using multilinear regression method. The result shows that HF method can produce the best model as follows:log EC50 = 46.418 + (99.360 × qC4) - (67.189 × qC9) - (278.869 × qC15) + (782.466 × qC19) - (127.463 × qO7)n = 20; r2 = 0.815; SEE = 0.393; Fcal/Ftab = 4.185; PRESS = 2.160Those model can predict a good inhibitory activity (log EC50) value of -0.3359 to compound N1-(4′-Cyanophenyl)-5-(4″-cyanovinyl-2″,6″-dimethyl-phenoxy)-4-hydroxyethylbenzene-1,2-diamine).

scholarly journals Predictive Quantitative Structure–Activity Relationship Modeling of the Antifungal and Antibiotic Properties of Triazolothiadiazine Compounds

2020 ◽  
Vol 4 (1) ◽  
pp. 2
Author(s):  
Michael Appell ◽  
David L. Compton ◽  
Kervin O. Evans
Keyword(s):  
Density Functional Theory ◽  
Predictive Models ◽  
Density Functional ◽  
Quantitative Structure Activity Relationship ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Two Dimensional ◽  
Quantitative Structure ◽  
Functional Theory ◽  
Structure Activity

Predictive models were developed using two-dimensional quantitative structure activity relationship (QSAR) methods coupled with B3LYP/6-311+G** density functional theory modeling that describe the antimicrobial properties of twenty-four triazolothiadiazine compounds against Aspergillus niger, Aspergillus flavus and Penicillium sp., as well as the bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. B3LYP/6-311+G** density functional theory calculations indicated the triazolothiadiazine derivatives possess only modest variation between the frontier orbital properties. Genetic function approximation (GFA) analysis identified the topological and density functional theory derived descriptors for antimicrobial models using a population of 200 models with one to three descriptors that were crossed for 10,000 generations. Two or three descriptor models provided validated predictive models for antifungal and antibiotic properties with R2 values between 0.725 and 0.768 and no outliers. The best models to describe antimicrobial activities include descriptors related to connectivity, electronegativity, polarizability, and van der Waals properties. The reported method provided robust two-dimensional QSAR models with topological and density functional theory descriptors that explain a variety of antifungal and antibiotic activities for structurally related heterocyclic compounds.

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