Investigation of the free radical scavenging ability of l-tryptophan and its derivatives using experimental methods and quantum chemical calculations.

The free radical scavenging ability of l-tryptophan (LP) and 5-hydroxy-l-tryptophan (HLP) was evaluated using experimental and theoretical methods. The impact of antioxidant concentration on the scavenging of DPPH˙ and ABTS˙ free radicals was assessed for both compounds. The results indicated that HLP exhibited superior scavenging ability, with IC values of 31.

A combination of experimental and theoretical methods in evaluating triazole derivatives' mild steel corrosion inhibition ability in an acidic solution.

A comprehensive study was conducted, both experimentally and theoretically, to evaluate the corrosion inhibition ability of 4-amino-5-phenyl-4-1,2,4-triazole-3-thiol (AT) and 4-amino-5-(pyridine-4-yl)-4-1,2,4-triazole-3-thiol (AP) on mild steel. The findings show that AT and AP are potential mixed-type inhibitors in hydrochloric acid solution. At 293 K and a concentration of 5 × 10 M, AT and AP have efficiencies of 93.

A Novel Fluorescent Sensor for Detecting Ag and Hg ions: A Combination of Theoretical and Experimental Studies.

A new fluorescent sensor based on diethylaminosalicylaldehyde-thiosemicarbazide (DST) was studied using a combination of density functional theory calculations and experimental investigations. DST was able to detect the metal ions Ag and Hg in the presence of various competing metal ions and anions, with detection limits of 0.45 and 0.

Advanced dual-atom catalysts on graphitic carbon nitride for enhanced hydrogen evolution water splitting.

In this comprehensive investigation, we explore the effectiveness of 55 dual-atom catalysts (DACs) supported on graphitic carbon nitride (gCN) for both alkaline and acidic hydrogen evolution reactions (HER). Employing density functional theory (DFT), we scrutinize the thermodynamic and kinetic profiles of these DACs, revealing their considerable potential across a diverse pH spectrum. For acidic HER, our results identify catalysts such as FePd-gCN, CrCr-gCN, and NiPd-gCN, displaying promising Δ values of 0.

Evaluation of Free Radical Scavenging Ability of Triazole-3-Thiol: A Combination of Experimental and Theoretical Approaches.

An assessment of the free radical scavenging potential of 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol (AT) and 4-amino-5-(4-pyridyl)-4H-1,2,4-triazole-3-thiol (AP) involved a combination of experimental methodologies and theoretical calculations. In the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, AT exhibited an heightened efficacy in scavenging DPPH radicals compared to AP. This was evidenced by the notably lower IC value observed for AT (1.

A Comprehensive Study of the Radical Scavenging Activity of Rosmarinic Acid.

Rosmarinic acid () is reported in separate studies to be either an inducer or reliever of oxidative stress, and this contradiction has not been resolved. In this study, we present a comprehensive examination of the radical scavenging activity of using density functional theory calculations in comparison with experimental data. In model physiological media, exhibited strong HO radical scavenging activity with overall rate constant values of 2.

Antiradical Activity of Lignans from : Theoretical Insights into the Mechanism, Kinetics, and Solvent Effects.

Sumatranus lignans () isolated from have demonstrated bioactivities, e.g., they were shown to exhibit immunosuppressive properties in previous research.

Exploring the Multitarget Activity of Wedelolactone against Alzheimer's Disease: Insights from Study.

In this study, Wedelolactone's multitarget activity against Alzheimer's disease was examined using density functional theory and molecular docking techniques. At physiological pH, the p and molar fractions have been estimated. The most likely relative rate constants of two radical scavenger mechanisms are formal hydrogen transfer in a lipid environment and single-electron transfer in a water solvent.

Insights into antiradical mechanism and pro-oxidant enzyme inhibitor activity of walterolactone A/B 6--gallate-β-d-pyranoglucoside originating from Champ. using study.

The ability of a new compound, Wal, (walterolactone A/B 6--gallate-β-d-pyranoglucoside) originating from Champ. as a hydroperoxyl radical scavenger and pro-oxidant enzyme inhibitor was studied . Different mechanisms, reaction locations, and chemical species of Wal in aqueous solution were taken into consideration.

Computational estimation of potential inhibitors from known drugs against the main protease of SARS-CoV-2.

The coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread worldwide recently, leading to global social and economic disruption. Although the emergently approved vaccine programs against SARS-CoV-2 have been rolled out globally, the number of COVID-19 daily cases and deaths has remained significantly high. Here, we attempt to computationally screen for possible medications for COVID-19 rapidly estimating the highly potential inhibitors from an FDA-approved drug database against the main protease (Mpro) of SARS-CoV-2.

Oxoberberine: a promising natural antioxidant in physiological environments.

Oxoberberine (OB, 2,10-dihydroxy-3,9-dimethoxy-8-oxo-protoberberine, artathomsonine), which was isolated from Artabotrys thomsonii, was shown to exhibit potent antioxidant activity , however that is the only reported evidence of the radical scavenging activity of this compound thus far. In the present study, thermodynamic and kinetic calculations were used to determine the free radical scavenging activity of OB against a range of biologically important species, under physiological conditions. In the first part the activity is calculated against the HOO˙ radical that is both biologically important and a reference radical for comparison.

Is natural fraxin an overlooked radical scavenger?

Fraxin (FX) (7-hydroxy-6-methoxycoumarin 8-glucoside) is a typical natural product of the coumarin family. This compound was shown to protect endothelial cells from oxidative stress; however, the nature of its antioxidant properties is still ambiguous. In this study, we report on a systematic evaluation of the radical scavenging activity of FX using a two-tier protocol based on thermodynamic and kinetic calculations.

Radical Scavenging Activity of Natural Anthraquinones: a Theoretical Insight.

Anthraquinones (ANQs) isolated from plants are known to have antidiarrheal, antitussive, anthelmintic, analgesic, anti-inflammatory, antihyperlipidemic, antihyperglycaemic, and antimicrobial activities. The antioxidant properties were also noted but not confirmed thus far. In this study, the superoxide and hydroperoxide radical scavenging activities of six ANQs were evaluated using a computational approach.

Binding of inhibitors to the monomeric and dimeric SARS-CoV-2 Mpro.

SARS-CoV-2 rapidly infects millions of people worldwide since December 2019. There is still no effective treatment for the virus, resulting in the death of more than one million patients. Inhibiting the activity of SARS-CoV-2 main protease (Mpro), 3C-like protease (3CLP), is able to block the viral replication and proliferation.

Theoretical and Experimental Studies of the Antioxidant and Antinitrosant Activity of Syringic Acid.

Syringic acid (SA) is a natural phenolic acid found in vegetables, fruits, and other plant-based foods. A range of biological activities were proposed for this compound including anticancer, antimicrobial, anti-inflammation, and anti-diabetic activities, as well as antioxidant and antinitrosant properties. In this study, the focus is on the latter two.

Pivotal Role of Heteroatoms in Improving the Corrosion Inhibition Ability of Thiourea Derivatives.

1,3-Diphenyl-2-thiourea (DPTU) and 1-phenyl-3-(2-pyridyl)-2-thiourea (PPTU) were selected as the researched subject for investigating the effect of heteroatoms on the low carbon steel corrosion inhibition ability. Results from the potentiodynamic polarization measurements (PPM) indicate that the addition of a nitrogen atom in the benzene ring increases the corrosion inhibition efficiency of PPTU (97.2%), being higher than that of DPTU (93.

Substituent Effects on the N-H Bond Dissociation Enthalpies, Ionization Energies, Acidities, and Radical Scavenging Behavior of 3,7-Disubstituted Phenoxazines and 3,7-Disubstituted Phenothiazines.

The substituent effects on the N-H bond dissociation enthalpies (BDE), ionization energies (IE), acidities (proton affinity, PA), and radical scavenging behavior of 3,7-disubstituted phenoxazines (PhozNHs) and 3,7-disubstituted phenothiazines (PhtzNHs) were determined using density functional theory, with the M05-2X functional in conjunction with the 6-311++G(d,p) basis set. These thermochemical parameters calculated in both gas phase and benzene solution with respect to the changes in several different substituents including halogen, electron-withdrawing, and electron-donating groups at both 3 and 7 positions in both PhozNHs and PhtzNHs systems were analyzed in terms of the inherent relationships between them with some quantitative substituent effect parameters. The kinetic rate constants of hydrogen-atom exchange reactions between PhozNH and PhtzNH derivatives with the HOO radical were also calculated, and the effects of the substituents on the kinetic behaviors of these reactions were thereby quantitatively evaluated.

A coumarin derivative-Cu complex-based fluorescent chemosensor for detection of biothiols.

Herein, a novel fluorescent sensor has been developed for the detection of biothiols based on theoretical calculations of the stability constant of the complex between a Cu ion and ()-3-((2-(benzo[]thiazol-2-yl)hydrazono)methyl)-7-(diethylamino) coumarin (BDC) as a fluorescent ligand. In this study, on the basis of density functional theory method, the Gibbs free energy of ligand-exchange reaction and the solvation model were carried out using thermodynamic cycles. The obtained results are in good agreement with the experimental data.

In Silico Evaluation of the Radical Scavenging Mechanism of Mactanamide.

Mactanamide () is a diketopiperazine isolated from marine fungi of the genus . This compound is known as a natural antioxidant from experimental studies, yet this activity has not been successfully modeled thus far. In this work, the hydroperoxyl radical scavenging activity of was evaluated in the gas phase and physiological environments by thermodynamic and kinetic calculations.

Coumarin-Based Dual Chemosensor for Colorimetric and Fluorescent Detection of Cu in Water Media.

A novel coumarin derivative () was synthesized and used as a colorimetric and fluorescent probe for selective detection of Cu ions in the presence of other metal ions, with the detection limits of 5.7 and 4.0 ppb, respectively.

A thermodynamic and kinetic study of the antioxidant activity of natural hydroanthraquinones.

Novel hydroanthraquinones isolated from marine algal-derived endophytic fungus EN-501 exhibited promising antioxidant properties in preliminary studies, raising the prospect of adapting these compounds for therapeutic use in diseases caused by oxidative stress. For medicinal applications it is beneficial to develop a full understanding of the antioxidant activity of these compounds. In this study, the hydroperoxide radical scavenging activity of five natural hydroanthraquinones was evaluated by kinetic and thermodynamic calculations.

Theoretical Study on the Antioxidant Activity of Natural Depsidones.

Depsidones are secondary metabolites in lichens with a range of potential health benefits. Among others, these compounds are believed to exhibit high hydroxyl radical and superoxide scavenging abilities, warranting a detailed investigation of their antioxidant properties. In this study, the radical scavenging activity of natural depsidones from lichenized fungi was investigated in silico.

Functionalization and antioxidant activity of polyaniline-fullerene hybrid nanomaterials: a theoretical investigation.

Functionalized fullerene is one of the most advantageous nanotechnologies to develop novel materials for potential biomedical applications. In this study, we applied the ONIOM-GD3 approach to explore the nucleophilic addition reaction mechanism between polyaniline (emeraldine and leucoemeraldine forms) and fullerene. Potential energy surfaces were also analyzed to predict the predominantly formed products of the functionalized reaction.