Theoretical studies on the antioxidant activity of viniferifuran

2019 ◽  
Vol 43 (39) ◽  
pp. 15736-15742 ◽  
Author(s):  
Yaxuan Shang ◽  
Huakang Zhou ◽  
Xiangzhou Li ◽  
Jun Zhou ◽  
Kai Chen
Keyword(s):  
Antioxidant Activity ◽  
Radical Scavenging ◽  
Theoretical Studies ◽  
Dft Studies ◽  
Thermodynamics And Kinetics ◽  
Kinetics Of

DFT studies reveal the thermodynamics and kinetics of radical scavenging reactions of a resveratrol dimer derivative – viniferifuran.

Chemical Reaction Dynamics at Liquid Interfaces: A Computational Approach

2002 ◽  
Vol 27 (2) ◽  
pp. 87-126 ◽  
Author(s):  
Ilan Benjamin
Keyword(s):  
Surface Roughness ◽  
Reaction Dynamics ◽  
Computational Approach ◽  
Theoretical Studies ◽  
Liquid Interfaces ◽  
Vapor Interface ◽  
Thermodynamics And Kinetics ◽  
Chemical Reaction Dynamics ◽  
Kinetics Of ◽  
Experimental And Theoretical Studies

Recent advances in experimental and theoretical studies of liquid interfaces provide remarkable evidence for the unique properties of these systems. In this review we examine how these properties affect the thermodynamics and kinetics of chemical reactions which take place at the liquid/vapor interface and at the liquid/liquid interface. We demonstrate how the rapidly varying density and viscosity, the marked changes in polarity and the surface roughness manifest themselves in isomerization, electron transfer and photodissociation reactions.

Thermal Kinetics of Gamma–Aminobutyric Acid and Antioxidant Activity in Germinated Red Jasmine Rice Milk using Arrhenius, Eyring-Polanyi and Ball Models

2021 ◽  
Vol 9 (2) ◽  
pp. 700-711
Author(s):  
Sani Jirasatid ◽  
Montira Nopharatana
Keyword(s):  
Antioxidant Activity ◽  
Heating Temperature ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Dpph Radical ◽  
Dpph Radical Scavenging Activity ◽  
Thermal Kinetics ◽  
Jasmine Rice ◽  
Kinetics Of ◽  
Dpph Radical Scavenging

The thermal kinetics of changes of –aminobutyric acid (GABA) and antioxidant activity (DPPH assay) in germinated red jasmine rice milk (GRJM) at heating temperatures of 80, 90, 100 and 121C using Arrhenius, Eyring–Polanyi and Ball models was examined in this study. Under isothermal conditions, the increasing of heating temperature from 80C to 121C resulted in the decreasing of GABA. However, DPPH radical scavenging activity increased under temperature range of 80–100C, but decreased at 121C. The highest residue of GABA was 94% after heating at 80C for 30 min, while the highest increasing of DPPH radical scavenging activity was 230% at 90C for 30 min. Thermal degradation of GABA followed a second–order reaction kinetic, while the increasing of antioxidant activity (80–100C) followed a first–order kinetic as well as the degradation of antioxidant activity (121C). The heating temperature dependence of rate constant for degradation of GABA and increasing of antioxidant activity were described by Arrhenius, Eyring–Polanyi and Ball models. Following the Arrhenius law, activation energies were 59.62 kJ/mol and 30.31 kJ/mol, respectively for degradation of GABA (80–121C) and increasing of antioxidant activity in GRJM (80–100C). Arrhenius, Eyring–Polanyi and Ball models could be used to predict accurately GABA content and antioxidant activity in GRJM during isothermal heat treatment.

scholarly journals Antioxidant activity coefficient, mechanism, and kinetics of different derivatives of flavones and flavanones towards superoxide radical

2012 ◽  
Vol 30 (No. 2) ◽  
pp. 153-163 ◽  
Author(s):  
S. Ahmed ◽  
F. Shakeel
Keyword(s):  
Antioxidant Activity ◽  
Activity Coefficient ◽  
Superoxide Radical ◽  
Linear Part ◽  
Radical Scavenging ◽  
Systematic Investigation ◽  
Strength Of Interaction ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Derivatives Of

A systematic investigation of the electrochemically generated superoxide radical (O<sub>2</sub><sup>●&ndash;</sup>) has been conducted in the presence of some flavonoids. Cyclic voltammetry was used to generate O<sub>2</sub><sup>●&ndash;</sup> by reducing the molecular oxygen in DMSO at room temperature. The scavenging of the radical was monitored by the decrease in anodic or/and cathodic currents while linearly increasing the concentration of the flavonoid. The strength of interaction was quantified in terms of the binding constant (K<sub>b</sub>)values ranging from 1 &times; 10<sup>2</sup> and 5 &times; 10<sup>3</sup>M<sup>&ndash;1</sup>. The antioxidant activity coefficient (K<sub>ao</sub>) was calculated from the linear part of the plot of &lsquo;current decrease vs. flavonoid concentration&rsquo;. Radical scavenging mechanism of the antioxidant was proposed and discussed in terms of the structure activity relationship. Nicholson-Shain method was employed to estimate the bimolecular homogeneous kinetics and on this basis control use of antioxidant is pointed out. &nbsp;

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

Evaluation of antioxidant and Anthelmintic activity of methanolic flower extract of Nyctanthes arbor-tristis

2018 ◽  
Vol 9 (1) ◽  
pp. 78
Author(s):  
Vijaya Jyothi M ◽  
Bhargav E ◽  
Pavan Kumar K ◽  
Praneeth Gowd K ◽  
Ram Pavan S
Keyword(s):  
Antioxidant Activity ◽  
Radical Scavenging Activity ◽  
Iridoid Glycosides ◽  
Radical Scavenging ◽  
Anthelmintic Activity ◽  
Total Phenolic ◽  
Standard Drug ◽  
Flower Extract ◽  
Reducing Ability ◽  
Total Flavonoids Content

Nyctanthes arbour-tristis is a shrub belongs to the family Oleaceae. The flowers of this plant are fragrant since the presence of flavonol glycosides. It has also been reported for the presence of β-sitosterol, iridoid glycosides, tannins etc., and known to have immunostimulant, hepatoprotective, antiviral and antifungal activities. In the present study an attempt is made to identify antioxidant capacity and anthelminthic potential of methanolic flower extract of Nyctanthes arbour-tristis. Antioxidant activity was evaluated by total phenolic content assay, total flavonoids content assay, free radical scavenging activity and reducing ability methods. Anthelmintic activity was evaluated on Perithima posthuma using Piperazine citrate as standard drug. The results obtained for the above activities reveals that Nyctanthes arbour-tristis shows considerable antioxidant activity for all the methods and anthelminthic potential at 300 mg/ml. Keywords: arbour-tristis; antioxidant activity; anthelminthic activity; Perithima posthuma; Piperazine citrate.

Assessment of antioxidant and antibacterial activities of crude extracts of verbena officinalis Linn root or Atuch (Amharic)

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Antioxidant Activity ◽  
Methanolic Extract ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Dry Weight ◽  
Antimicrobial Activities ◽  
Total Flavonoid ◽  
Root Extract ◽  
Antioxidant Power ◽  
Crude Extracts

Verbena officinalis Linn is a traditionally known medicinal plant which is used against a number of diseases including inflammatory conditions. In this study its antioxidant activity (reducing powers, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities), ferric reduction activity potential (FRAP), total flavonoid concentration and antimicrobial activities of 80%, 90%, 100% methanol and chloroform extracts of V. officinalis Linn root and 90% and100% methanol leaf extracts were determined. Its antioxidant activity increases with increase in amount of extract (10% to 40%v/v). Total flavonoid content (TFC) varied from 73.32±0.002 mgQE/100g of dry weight (90% methanol) to 42.39±0.032 mgQE/100g dry weight (chloroform), 2,2-diphenyl-1-picrylhydrazyl (DPPH), radical scavenging activity (%) was varied between 87.39% (90% methanol) to 45.57% (chloroform) while Ferric reducing antioxidant power was observed between 372.93±0.04 mgAAE/100 g extract (90% methanol) to 129.41±0.026 mgAAE/100 g chloroform in the root extract. The methanolic extract of the leaf showed less antioxidant activity than the methanolic extract of the root. Crude extracts of V. officinalis root showed various degree of antimicrobial activity towards drug resistance microbial pathogens. Growth inhibition tests against bacterial pathogens demonstrated concentration dependence. Moreover, gram positive bacteria were more susceptible to V. officinalis root extract when compared to gram negative bacteria. In general V. officinalis root and leave extracts possess strong antioxidant and antimicrobial activities.

Thermodynamics and kinetics of hydriding of the Zr(Ni0.75V0.25)2 laves phase

2004 ◽  
Vol 29 (2) ◽  
pp. 1-9
Author(s):  
Mustapha Boulghallat ◽  
Ahmed Jouaiti ◽  
Norbert Gérard
Keyword(s):  
Laves Phase ◽  
Thermodynamics And Kinetics ◽  
Kinetics Of
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