Mechanisms of Antioxidant Action: Rubber-Bound Antioxidants Based on Nitrones—I. Non-Sulphur Vulcanizates

1979 ◽  
Vol 52 (5) ◽  
pp. 949-961 ◽  
Author(s):  
G. Scott ◽  
K. V. Smith
Keyword(s):  
Solvent Extraction ◽  
Antioxidant Activities ◽  
Zinc Salt ◽  
Antioxidant Action ◽  
Before And After ◽  
Hindered Phenol

Abstract The antioxidant activities of a number of N-phenyl nitrones containing phenolic functions were compared with N-methyl nitrones and conventional antioxidants in peroxide and TMTD sulphurless vulcanizates. The N-phenyl nitrones were found to be effectively bound during vulcanization; whereas, the N-methyl nitrones were not. Unhindered phenols reacted to a higher degree and were relatively more effective than the typical hindered phenol antioxidant structures. A conventional bisphenol was effective in the sulphurless vulcanizate after solvent extraction, but this is considered to be due to the formation of an insoluble zinc salt. Synergism was observed in the TMTD sulphurless vulcanizate both before and after extraction.

scholarly journals Comparison of antioxidant activities of bovine whey proteins before and after simulated gastrointestinal digestion

2019 ◽  
Vol 102 (1) ◽  
pp. 54-67 ◽  
Author(s):  
Alberto R. Corrochano ◽  
Yunus Sariçay ◽  
Elena Arranz ◽  
Phil M. Kelly ◽  
Vitaly Buckin ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Whey Proteins ◽  
Gastrointestinal Digestion ◽  
Simulated Gastrointestinal Digestion ◽  
Before And After

Antioxidant Activities of Flavonoids from Canavalia maritime

2013 ◽  
Vol 834-836 ◽  
pp. 577-581
Author(s):  
Jian Chao Deng ◽  
Gai Gai Niu ◽  
Lai Hao Li ◽  
Xian Qing Yang ◽  
Yong Chuan Deng ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Hydroxyl Radical ◽  
High Speed ◽  
Superoxide Radical ◽  
Antioxidant Activities ◽  
Reducing Power ◽  
Dpph Radical ◽  
Inhibitory Effects ◽  
Counter Current

Flavonoids was isolated from canavalia maritime by accelerated solvent extraction (ASE) coupled with high-speed counter-current chromatography (HSCCC). The antioxidant activities of flavonoids were investigated in vitro and evaluated by IC50. The results indicated that flavonoids possessed obvious reducing power and significant inhibitory effects on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical and superoxide radical. These results suggest that canavalia maritime flavonoids could be a suitable natural antioxidant for humans.

scholarly journals Phenolic Compounds from An Algerian Endemic Species of Hypochaeris laevigata var. hipponensis and Investigation of Antioxidant Activities

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 514 ◽  
Author(s):  
Nabila Souilah ◽  
Zain Ullah ◽  
Hamdi Bendif ◽  
Kamel Medjroubi ◽  
Tahar Hazmoune ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Antioxidant Activities ◽  
Quinic Acid ◽  
Total Phenolic ◽  
Antioxidant Action ◽  
Endemic Plant ◽  
Aerial Parts ◽  
Phenolic Constituents ◽  
First Time ◽  
Phenolic And Flavonoid

Hypochaeris laevigata var. hipponensis (Asteraceae) is an endemic plant from Algeria. In the current study, we analyzed for the first time its chemical composition, especially phenolic constituents of dichloromethane (DCM), ethyl acetate (EA), and n-butanol (BuOH) fractionsof the aerial parts of Hypochaeris laevigata var. hipponensis by liquid chromatography-mass spectrometry (LC-MS/MS). The number of phenolic compounds detected in DCM, EA, and BuOH fractions were found to be 9, 20, and 15, respectively. More specifically, 12 phenolic acids were detected. Among them, quinic acid, chlorogenic acid, and caffeic acid were the most abundant ones. Meanwhile, only seven flavonoids were detected. Among them, rutin, apigetrin, and isoquercitrin were the major ones. We also determined the total phenolic and flavonoid contents, and fraction EA showed the highest values, followed by BuOH, and DCM fractions. Furthermore, the antioxidant action was dictated by five methods and the tested plant fractions demonstrated a noteworthy antioxidant action.

scholarly journals Effects of continuous UV-irradiation on the antioxidant activities of quercetin and rutin in solution in the presence of lecithin as the protective target

2011 ◽  
Vol 76 (7) ◽  
pp. 973-985 ◽  
Author(s):  
Dragan Cvetkovic ◽  
Dejan Markovic ◽  
Dragana Cvetkovic ◽  
Blaga Radovanovic
Keyword(s):  
Lipid Peroxidation ◽  
Uv Irradiation ◽  
Energy Input ◽  
Antioxidant Activities ◽  
Antioxidant Action ◽  
First Order ◽  
First Order Kinetics ◽  
Uv Photons ◽  
Uv C

The stabilities and antioxidant action of two selected flavonoids, quercetin and rutin, dissolved in methanol and water, toward continuous UV-irradiation from three different sub-ranges (UV-A, UV-B and UV-C) were studied. The flavonoids underwent degradation (bleaching) following first-order kinetics. The bleaching rates were highly dependent on the energy input of the involved UV-photons. The antioxidant activities of the two flavonoids on UV-induced lecithin lipid peroxidation were studied by the TBA-MDA test, and appeared to be also affected by the continuous UV irradiation. The energy input of the incident UV-photons again played a major governing role, but an impact of the flavonoids structures cannot be neglected.

scholarly journals Evaluation of Oxidative Stress in Patients with Fracture Admitted to Khatam Al-Anbia Hospital in Zahedan

2020 ◽  
Vol 18 (3) ◽  
Author(s):  
Mansour Karajibani ◽  
Farzaneh Montazerifar ◽  
Faezeh Kazemi ◽  
Ali Reza Dashipour
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activities ◽  
Control Group ◽  
Case Group ◽  
Cross Sectional ◽  
Stress Markers ◽  
Significant Difference ◽  
Before And After ◽  
Markers Of Oxidative Stress ◽  
The Mean

Background: Caused by an imbalance in the body’s oxidant and antioxidant status, oxidative stress can give rise to tissue damage and exacerbation of many diseases. Objectives: This study investigated the oxidative stress markers in patients with fractures and healthy subjects. Methods: In a cross-sectional case-control study, 40 patients with fractures admitted to an orthopedic ward and 40 healthy, non-fractured patients were selected using convenience sampling. Serum was analyzed for oxidant and antioxidant activities based on standard methods. P < 0.05 was considered statistically significant. Results: There was a significant difference in mean TAC between the case (748.2 ± 302.83 μmol/L) and control (984.90 ± 207.02 μmol/L) groups (P = 0.003). The mean MDA was 16.61 ± 4.16 µmol/L in the case group and 18.45 ± 5.43 µmol/L in the control group (P = 0.09). The mean SOD was 63.41 ± 16.67 U/g Hb in the case group and 58.54 ± 21.83 U/g Hb in the control group (P = 0.2). There was no significant difference between the two groups in terms of BMI and other variables. Conclusions: A significant difference existed in TAC between the two groups, which indicated increased oxidative stress in patients. However, oxidative stress could occur before and after undergoing fractures. The results suggested a slight, but not significant, difference between the two groups in the SOD and MDA scores. More conclusive results are required to determine the enzymatic and non-enzymatic markers of oxidative stress in larger sample sizes and during different stages of treatment.

scholarly journals Antioxidant Activities and Repair Effects on Oxidatively Damaged HK-2 Cells of Tea Polysaccharides with Different Molecular Weights

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Xin-Yuan Sun ◽  
Jian-Min Wang ◽  
Jian-Ming Ouyang ◽  
Li Kuang
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Cell Model ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Human Kidney ◽  
Molecular Weights ◽  
Before And After ◽  
Proximal Tubular Epithelial Cells

This study aims at investigating the antioxidant activity and repair effect of green tea polysaccharide (TPS) with different molecular weights (Mw) on damaged human kidney proximal tubular epithelial cells (HK-2). Scavenging activities on hydroxyl radical (⋅OH) and ABTS radical and reducing power of four kinds of TPS with Mw of 10.88 (TPS0), 8.16 (TPS1), 4.82 (TPS2), and 2.31 kDa (TPS3) were detected. A damaged cell model was established using 2.6 mmol/L oxalate to injure HK-2 cells. Then, different concentrations of TPSs were used to repair the damaged cells. Index changes of subcellular organelles of HK-2 cells were detected before and after repair. The four kinds of TPSs possessed radical scavenging activity and reducing power, wherein TPS2 with moderate Mw presented the strongest antioxidant activity. After repair by TPSs, cell morphology of damaged HK-2 cells was gradually restored to normal conditions. Reactive oxygen species production decreased, and mitochondrial membrane potential (Δψm) of repaired cells increased. Cells of G1 phase arrest were inhibited, and cell proportion in the S phase increased. Lysosome integrity improved, and cell apoptotic rates significantly reduced in the repaired group. The four kinds of TPSs with varying Mw displayed antioxidant activity and repair effect on the mitochondria, lysosomes, and intracellular DNA. TPS2, with moderate Mw, showed the strongest antioxidant activity and repair effect; it may become a potential drug for prevention and treatment of kidney stones.

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