scholarly journals On the Importance of Water Molecules in the Theoretical Study of Polyphenols Reactivity toward Superoxide Anion

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Laure Lespade
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Anion ◽  
Fruits And Vegetables ◽  
Theoretical Study ◽  
Radical Scavenging ◽  
Aerobic Condition ◽  
Human Organism ◽  
Radical Scavenger ◽  
Water Molecules ◽  
Pathological State

Numerous studies have shown the benefits of a diet rich in fruits and vegetables. These benefits are partly due to the radical scavenging properties of polyphenols contained in fruits and vegetables since polyphenols can fight against an excess of radicals which goes along inflammation in a certain number of diseases. This pathological state, called oxidative stress, results from the aerobic condition of human organism when OH radical, hydrogen peroxide, superoxide anion, or peroxynitrite is produced in excess. If hydrogen peroxide is easily handled by human defense against radicals, the other radicals can cause damage to biological constituents like lipids, cell membranes, and other biomolecules. This paper is devoted to the theoretical study of the interaction of superoxide anion (O2•-) with a very potent radical scavenger, 1,2,4,6,8-pentahydroxynaphthalene. The importance of hydration of superoxide radical for the reactivity is analyzed. Potential energy surfaces (PES) are calculated for different number of water molecules around the radical and it is shown that the transition barrier vanishes when complete hydration with six water molecules is explicitly handled. The nature of the reactivity is determined by using the natural bond orbital (NBO) analysis.

Evaluation of antioxidant activity of Melothria maderaspatana in vitro

2010 ◽  
Vol 5 (2) ◽  
pp. 224-230 ◽  
Author(s):  
Boobalan Raja ◽  
Kodukkur Pugalendi
Keyword(s):  
Hydrogen Peroxide ◽  
Antioxidant Activity ◽  
Free Radical ◽  
Hydroxyl Radical ◽  
Superoxide Anion ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Free Radical Scavenging ◽  
Melothria Maderaspatana

AbstractIn this study, an aqueous extract of leaves from Melothria maderaspatana was tested for in vitro antioxidant activity. Free radical scavenging assays, such as hydroxyl radical, hydrogen peroxide, superoxide anion radical and 2,2-diphenyl-1-picryl hydrazyl (DPPH), 2,2’-azinobis-(3-ethyl-enzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, and reducing power assay, were studied. The extract effectively scavenged hydroxyl radical, hydrogen peroxide and superoxide anion radicals. It also scavenged DPPH and ABTS radicals. Furthermore, it was found to have reducing power. All concentrations of leaf extract exhibited free radical scavenging and antioxidant power, and the preventive effects were in a dose-dependent manner. The antioxidant activities of the above were compared to standard antioxidants such as butylated hydroxytoluene (BHT), ascorbic acid, and α-tocopherol. The results obtained in the present study indicate that the M. maderaspatana extract could be considered a potential source of natural antioxidant.

Arjunic Acid, a Strong Free Radical Scavenger from Terminalia arjuna

2008 ◽  
Vol 36 (01) ◽  
pp. 197-207 ◽  
Author(s):  
Fang-Yun Sun ◽  
Xiu-Ping Chen ◽  
Jin-Hua Wang ◽  
Hai-Lin Qin ◽  
Su-Rong Yang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Lipid Peroxidation ◽  
Ascorbic Acid ◽  
Free Radical ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Dpph Method ◽  
Significant Difference

This study was designed to investigate the antioxidant and free radical scavenging capacities of arjunic acid, an aglycone obtained from the fruit of medicine Terminalia Fruit. Liver microsomes, mitochondria, and red blood cells (RBCs) were prepared from Wistar rats. The antioxidant capacity was determined by the inhibitory effect on lipid peroxidation, hydrogen peroxide induced RBCs hemolysis, and RBCs autoxidative hemolysis. The free radical scavenging activity was tested by DPPH method and 2′,7′-dichlorodihydrofluoresc in diacetate (DCFH2-DA) assay. Ascorbic acid was chosen as the positive controls. Results showed that arjunic acid was a strong antioxidant and a free radical scavenger, more potent than ascorbic acid, in microsomes lipid peroxidation, DPPH, hydrogen peroxide induced RBCs hemolysis, and (DCFH2-DA) assay (p < 0.05). However, no significant difference was observed in the RBCs autoxidative hemolysis assay (p > 0.05).

Free Radical Scavengers and Antioxidants from Tagetes mendocina

2004 ◽  
Vol 59 (5-6) ◽  
pp. 345-353 ◽  
Author(s):  
Guillermo Schmeda-Hirschmann ◽  
Alejandro Tapia ◽  
Cristina Theoduloz ◽  
Jaime Rodríguez ◽  
Susana López ◽  
...  
Keyword(s):  
Free Radical ◽  
Superoxide Anion ◽  
Radical Scavenging ◽  
Lung Fibroblasts ◽  
Free Radical Scavengers ◽  
Total Phenolic ◽  
Antioxidant Compounds ◽  
Radical Scavenger ◽  
Radical Scavengers ◽  
Crude Drug

Tagetes mendocina (Asteraceae) is a medicinal plant widely used in the Andean provinces of Argentina. Preliminary assays showed free radical scavenging activity in the methanol extract of the aerial parts, measured by the decoloration of a methanolic solution of the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and scavenging of the superoxide anion. Assayguided isolation led to 4′-hydroxyacetophenone (1), protocatechuic acid (2), syringic acid (3), patuletin (4), quercetagetin 7-O-β-d-glucoside (5), patuletin 7-O-β-d-glucoside (6) and axillarin 7-O-β-d-glucoside (7) as the free radical scavengers and antioxidant compounds from Tagetes mendocina. On the basis of dry starting material, the total phenolic content of the crude drug was 3.00% with 0.372% of flavonoids. The content of compounds 1-7 in the crude drug was 0.008, 0.015, 0.010, 0.029, 0.238, 0.058 and 0.017%, respectively. Quercetagetin 7-O-β-d-glucoside proved to be the main free radical scavenger of the extracts measured by the DPPH decoloration test as well as for quenching the superoxide anion and inhibition of lipoperoxidation in erythrocytes. In the lipid peroxidation assay the percentual inhibition was related with the number of methoxy groups in the molecule, ranging from 86% for the quercetagetin glucoside to 67% for the monomethoxylated and 31% for the dimethoxylated derivative. The compounds showed low cytotoxicity towards human lung fibroblasts with IC50 > 1mᴍ for compounds 1-3 and 0.24 to 0.52 mm for the flavonoids 4-7.

Oxidation of hydrogen peroxide at the dropping mercury electrode

1984 ◽  
Vol 49 (10) ◽  
pp. 2320-2331 ◽  
Author(s):  
Miroslav Březina ◽  
Martin Wedell
Keyword(s):  
Hydrogen Peroxide ◽  
Superoxide Anion ◽  
Ph Value ◽  
Mercury Electrode ◽  
Electrode Process ◽  
Electrochemical Processes ◽  
Dropping Mercury Electrode ◽  
Oxidation Of Hydrogen ◽  
Decreasing Ph ◽  
Rate Controlling Step

Reduction of oxygen and oxidation of hydrogen peroxide at the dropping mercury electrode are electrochemical processes strongly influenced both by the pH value and the anions in solution. With decreasing pH, both processes become irreversible, especially in the presence of anions with a negative φ2 potential of the diffusion part of the double layer. In the case of irreversible oxygen reduction, the concept that the rate-controlling step of the electrode process is the acceptance of the first electron with the formation of the superoxide anion, O2-, was substantiated. Oxidation of hydrogen peroxide becomes irreversible at a lower pH value than the reduction of oxygen. The slowest, i.e. rate-controlling step of the electrode process in borate buffers at pH 9-10 is the transfer of the second electron, i.e. oxidation of superoxide to oxygen.

scholarly journals Comparative Metabolite Profile, Biological Activity and Overall Quality of Three Lettuce (Lactuca sativa L., Asteraceae) Cultivars in Response to Sulfur Nutrition

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 713
Author(s):  
Muna Ali Abdalla ◽  
Fengjie Li ◽  
Arlette Wenzel-Storjohann ◽  
Saad Sulieman ◽  
Deniz Tasdemir ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Plant Growth ◽  
Sesquiterpene Lactones ◽  
Critical Role ◽  
Soluble Sugars ◽  
Radical Scavenging ◽  
Metabolite Profile ◽  
Water Soluble ◽  
Radical Scavenger ◽  
Higher Plant

The main objective of the present study was to assess the effects of sulfur (S) nutrition on plant growth, overall quality, secondary metabolites, and antibacterial and radical scavenging activities of hydroponically grown lettuce cultivars. Three lettuce cultivars, namely, Pazmanea RZ (green butterhead, V1), Hawking RZ (green multi-leaf lettuce, V2), and Barlach RZ (red multi-leaf, V3) were subjected to two S-treatments in the form of magnesium sulfate (+S) or magnesium chloride (−S). Significant differences were observed under −S treatments, especially among V1 and V2 lettuce cultivars. These responses were reflected in the yield, levels of macro- and micro-nutrients, water-soluble sugars, and free inorganic anions. In comparison with the green cultivars (V1 and V2), the red-V3 cultivar revealed a greater acclimation to S starvation, as evidenced by relative higher plant growth. In contrast, the green cultivars showed higher capabilities in production and superior quality attributes under +S condition. As for secondary metabolites, sixteen compounds (e.g., sesquiterpene lactones, caffeoyl derivatives, caffeic acid hexose, 5-caffeoylquinic acid (5-OCQA), quercetin and luteolin glucoside derivatives) were annotated in all three cultivars with the aid of HPLC-DAD-MS-based untargeted metabolomics. Sesquiterpene lactone lactucin and anthocyanin cyanidin 3-O-galactoside were only detected in V1 and V3 cultivars, respectively. Based on the analyses, the V3 cultivar was the most potent radical scavenger, while V1 and V2 cultivars exhibited antibacterial activity against Staphylococcus aureus in response to S provision. Our study emphasizes the critical role of S nutrition in plant growth, acclimation, and nutritional quality. The judicious-S application can be adopted as a promising antimicrobial prototype for medical applications.

scholarly journals Hydroxycinnamic Acid Antioxidants: An Electrochemical Overview

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
José Teixeira ◽  
Alexandra Gaspar ◽  
E. Manuela Garrido ◽  
Jorge Garrido ◽  
Fernanda Borges
Keyword(s):  
Rational Design ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Phenoxyl Radical ◽  
Free Radical Scavenger ◽  
Hydroxycinnamic Acid ◽  
Hydroxycinnamic Acids ◽  
Radical Scavenger ◽  
Redox Potentials ◽  
Structure Property

Hydroxycinnamic acids (such as ferulic, caffeic, sinapic, andp-coumaric acids) are a group of compounds highly abundant in food that may account for about one-third of the phenolic compounds in our diet. Hydroxycinnamic acids have gained an increasing interest in health because they are known to be potent antioxidants. These compounds have been described as chain-breaking antioxidants acting through radical scavenging activity, that is related to their hydrogen or electron donating capacity and to the ability to delocalize/stabilize the resulting phenoxyl radical within their structure. The free radical scavenger ability of antioxidants can be predicted from standard one-electron potentials. Thus, voltammetric methods have often been applied to characterize a diversity of natural and synthetic antioxidants essentially to get an insight into their mechanism and also as an important tool for the rational design of new and potent antioxidants. The structure-property-activity relationships (SPARs) correlations already established for this type of compounds suggest that redox potentials could be considered a good measure of antioxidant activity and an accurate guideline on the drug discovery and development process. Due to its magnitude in the antioxidant field, the electrochemistry of hydroxycinnamic acid-based antioxidants is reviewed highlighting the structure-property-activity relationships (SPARs) obtained so far.

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