Search results for "Peroxidase"
showing 10 items of 435 documents
A new dual inhibitor of arachidonate metabolism isolated from Helichrysum italicum.
2003
Six acetophenones (1-6) and one gamma-pyrone (7), previously isolated from Helichrysum italicum, were tested for their ability to inhibit enzymatic and non-enzymatic lipid peroxidation, the stable 1,1-diphenyl-2-pycryl-hydrazyl free radical, superoxide scavenging and arachidonic acid metabolism. In addition, they were studied in different experimental models such as the chronic inflammation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA), the phospholipase A(2)-induced mouse paw oedema test, the carrageenan-induced mouse paw oedema test, and the writhing induced by acetic acid in the mouse. Of the assayed compounds, only 1 inhibited enzymatic lipid peroxidation but had no effect on no…
Antioxidant and glutathione-related enzymatic activities in rat sciatic nerve
1990
Abstract The present work tries to establish the antioxidant capacity of the peripheral nervous tissue of the rat, in terms of the enzymatic activities present in this tissue that either prevent the formation of activated species as the semiquinone radical (DT-diaphorase), protect against activated oxygen species (superoxide dismutase, glutathione peroxidase), conjugate natural toxic products or xenobiotics (glutathione S-transferases, especially the activity conjugating 4-hydroxy-nonenal), or complete the glutathione system metabolism (glutathione disulfide reductase, γ-glutamyl transpeptidase). All the activities studied are lower in this tissue than they are in liver, except for γ-glutam…
Mechanism of interaction of betanin and indicaxanthin with human myeloperoxidase and hypochlorous acid.
2005
Hypochlorous acid (HOCl) is the most powerful oxidant produced by human neutrophils and contributes to the damage caused by these inflammatory cells. It is produced from H2O2 and chloride by the heme enzyme myeloperoxidase (MPO). Based on findings that betalains provide antioxidant and anti-inflammatory effects, we performed the present kinetic study on the interaction between the betalains, betanin and indicaxanthin, with the redox intermediates, compound I and compound II of MPO, and its major cytotoxic product HOCl. It is shown that both betalains are good peroxidase substrates for MPO and function as one-electron reductants of its redox intermediates, compound I and compound II. Compoun…
Effect of high levels of CO 2 on the electrochemical behavior and the enzymatic and non‐enzymatic antioxidant systems in black and white table grapes…
2019
[Bakghround]: In this study, we analyzed the effect of the application of high levels of CO2 (20 kPa CO2 + 20 kPa O2 + 60 kPa N2 ) for 3 days at low temperature on a white table-grape cultivar (Superior Seedless) in comparison with a black one (cv. Autumn Royal) in terms of quality parameters. We also used a solid-state voltammetry methodology to analyze the effect of the 3-day gaseous treatment in berry tissues from both cultivars in the first stage of storage. We determined the role of the non-enzymatic (total phenols, total anthocyanins, and antioxidant activity) and the enzymatic antioxidant (catalase (GCAT), ascorbate peroxidase (VcAPX) gene expression) systems in the behaviors of bo…
The SGLT2 Inhibitor Empagliflozin Ameliorates the Inflammatory Profile in Type 2 Diabetic Patients and Promotes an Antioxidant Response in Leukocytes
2019
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Assessment of the anti-inflammatory activity and free radical scavenger activity of tiliroside
2003
Three flavonoids, gnaphaliin, pinocembrin and tiliroside, isolated from Helichrysum italicum, were studied in vitro for their antioxidant and/or scavenger properties and in vivo in different models of inflammation. In vitro tests included lipid peroxidation in rat liver microsomes, superoxide radical generation in the xanthine/xanthine oxidase system and the reduction of the stable radical 1,1-diphenyl-2-pycryl-hydrazyl (DPPH). Acute inflammation was induced by application of 12-O-tetradecanoylphorbol 13-acetate (TPA) to the mouse ear or by subcutaneous injection of phospholipase A(2) or serotonin in the mouse paw. Eczema provoked on the mouse ear by repeated administration of TPA was selec…
Stevia rebaudiana Bertoni as a natural antioxidant/antimicrobial for high pressure processed fruit extract: Processing parameter optimization
2013
Response surface methodology was used to evaluate the optimal high pressure processing treatment (300-500 MPa, 5-15 min) combined with Stevia rebaudiana (Stevia) addition (0-2.5% (w/v)) to guarantee food safety while maintaining maximum retention of nutritional properties. A fruit extract matrix was selected and Listeria monocytogenes inactivation was followed from the food safety point of view while polyphenoloxidase (PPO) and peroxidase (POD) activities, total phenolic content (TPC) and antioxidant capacity (TEAC and ORAC) were studied from the food quality point of view. A combination of treatments achieved higher levels of inactivation of L. monocytogenes and of the oxidative enzymes, s…
Disturbance of antioxidant capacity produced by beauvericin in CHO-K1 cells
2014
Glutathione (GSH) levels, glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) as antioxidant defense system were evaluated in CHO-K1 cells after beauvericin (BEA) exposure. The effect of N-acetyl-cysteine (NAC) pre-treatment was assessed. GSH levels significantly decrease 18% and 29% after 5 μM of BEA in fresh medium and NAC pre-treatment, respectively compared to their controls. The GPx activity increased significantly from 35% to 66% in fresh medium and 20% in NAC pre-treatment. GR activity decreased after 5 μM of BEA up to 43% and 53% in fresh medium and NAC pre-treatment, respectively. The GST activity increased in fresh medium (from 61% to 89%) …
Betanin inhibits the myeloperoxidase/nitrite-induced oxidation of human low-density lipoproteins
2007
Production of nitrogen dioxide by the activity of myeloperoxidase (MPO) in the presence of nitrite is now considered a key step in the pathophysiology of low-density lipoprotein (LDL) oxidation. This study shows that betanin, a phytochemical of the betalain class, inhibits the production of lipid hydroperoxides in human LDL submitted to a MPO/nitrite-induced oxidation. Kinetic measurements including time-course of particle oxidation and betanin consumption, either in the presence or in the absence of nitrite, suggest that the antioxidant effect is possibly the result of various actions. Betanin scavenges the initiator radical nitrogen dioxide and can also act as a lipoperoxyl radical-scaven…
Reductive stress in young healthy individuals at risk of Alzheimer disease.
2013
Oxidative stress is a hallmark of Alzheimer disease (AD) but this has not been studied in young healthy persons at risk of the disease. Carrying an Apo e4 allele is the major genetic risk factor for AD. We have observed that lymphocytes from young, healthy persons carrying at least one Apo e4 allele suffer from reductive rather than oxidative stress, i.e., lower oxidized glutathione and P-p38 levels and higher expression of enzymes involved in antioxidant defense, such as glutamylcysteinyl ligase and glutathione peroxidase. In contrast, in the full-blown disease, the situation is reversed and oxidative stress occurs, probably because of the exhaustion of the antioxidant mechanisms just ment…