scholarly journals The Analysis of Different Factors Affecting the Red Wines Antioxidant Content

2011 ◽  
Vol 39 (1) ◽  
pp. 159 ◽  
Author(s):  
Anamaria D. HOSU ◽  
Claudia CIMPOIU ◽  
Nastasia POP ◽  
Vasile MICLAUS ◽  
Sorana D. BOLBOACĂ ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance Spectroscopy ◽  
Pinot Noir ◽  
Resonance Spectroscopy ◽  
Protective Effects ◽  
Red Wines ◽  
Grape Variety ◽  
Paramagnetic Resonance ◽  
Factors Affecting ◽  
Antioxidant Content ◽  
Generalized Nonlinear Model

The benefits of moderate consumption of wines consist in the protective effects against cardiovascular diseases and anticarcinogenic is associated with their antioxidants content. There are plenty of analytical methods for assessing the antioxidant content of wines but unfortunately, there is not a standardized method. The antioxidant content of ‘Cabernet Sauvignon’, ‘Merlot’ and ‘Pinot Noir’ wines obtained from cultivated grapes varieties from Recas and Minis Romanian vineyard from different harvesting years were investigated. The electron paramagnetic resonance spectroscopy, using the 2,2,6,6-tetramethyl-4-hydroxypiperidine-N-oxyl (Tempol) free stable radical, was used to determine the antioxidant content of wines. Measurements were done in order to analyze the effects of the grape varieties, the harvesting year and the vineyard on the antioxidant content of wines. The obtained results revealed that the antioxidant content of studied red wines depends on the harvesting year of grape, the grape variety and on the vineyard. Using the observed values of the antioxidant content, a relationship was identified between the antioxidant content of wines and the harvesting year of grapes. Furthermore, the designed generalized nonlinear model revealed that the antioxidant content of wine depends on the combined effect of the grape variety and the vineyard, besides the year, the grape variety and the vineyard.

scholarly journals Tauroursodeoxycholic Acid (TUDCA)—Lipid Interactions and Antioxidant Properties of TUDCA Studied in Model of Photoreceptor Membranes

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 327
Author(s):  
Michał J. Sabat ◽  
Anna M. Wiśniewska-Becker ◽  
Michał Markiewicz ◽  
Katarzyna M. Marzec ◽  
Jakub Dybas ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Plasma Membranes ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Protective Action ◽  
Antioxidant Properties ◽  
Model Membranes ◽  
Dynamics Simulation ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Tauroursodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA), a hydrophilic bile acid containing taurine conjugated with the ursodeoxycholic acid (UDCA), has been known and used from ancient times as a therapeutic compound in traditional Chinese medicine. TUDCA has recently been gaining significant interest as a neuroprotective agent, also exploited in the visual disorders. Among several mechanisms of TUDCA’s protective action, its antioxidant activity and stabilizing effect on mitochondrial and plasma membranes are considered. In this work we investigated antioxidant activity of TUDCA and its impact on structural properties of model membranes of different composition using electron paramagnetic resonance spectroscopy and the spin labeling technique. Localization of TUDCA molecules in a pure POPC bilayer has been studied using a molecular dynamics simulation (MD). The obtained results indicate that TUDCA is not an efficient singlet oxygen (1O2 (1Δg)) quencher, and the determined rate constant of its interaction with 1O2 (1Δg) is only 1.9 × 105 M−1s−1. However, in lipid oxidation process induced by a Fenton reaction, TUDCA reveals substantial antioxidant activity significantly decreasing the rate of oxygen consumption in the system studied. In addition, TUDCA induces slight, but noticeable changes in the polarity and fluidity of the investigated model membranes. The results of performed MD simulation correspond very well with the experimental results.

scholarly journals Ambient base-free glycerol oxidation over bimetallic PdFe/SiO2 by in situ generated active oxygen species

2021 ◽  
Author(s):  
Ricci Underhill ◽  
Mark Douthwaite ◽  
Richard J. Lewis ◽  
Peter J. Miedziak ◽  
Robert D. Armstrong ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Bimetallic Catalyst ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Active Oxygen Species ◽  
Catalytic Performance ◽  
Resonance Spectroscopy ◽  
Oxygen Species ◽  
Paramagnetic Resonance ◽  
Temperature Oxidation

AbstractLow temperature oxidation of alcohols over heterogeneous catalysts is exceptionally challenging, particularly under neutral conditions. Herein, we report on an efficient, base-free method to oxidise glycerol over a 0.5%Pd-0.5%Fe/SiO2 catalyst at ambient temperature in the presence of gaseous H2 and O2. The exceptional catalytic performance was attributed to the in situ formation of highly reactive surface-bound oxygenated species, which promote the dehydrogenation on the alcohol. The PdFe bimetallic catalyst was determined to be significantly more active than corresponding monometallic analogues, highlighting the important role both metals have in this oxidative transformation. Fe leaching was confirmed to occur over the course of the reaction but sequestering experiments, involving the addition of bare carbon to the reactions, confirmed that the reaction was predominantly heterogeneous in nature. Investigations with electron paramagnetic resonance spectroscopy suggested that the reactivity in the early stages was mediated by surface-bound reactive oxygen species; no homogeneous radical species were observed in solution. This theory was further evidenced by a direct H2O2 synthesis study, which confirmed that the presence of Fe in the bimetallic catalyst neither improved the synthesis of H2O2 nor promoted its decomposition over the PdFe/SiO2 catalyst.

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