scholarly journals Free Radical–Mediated Cell Damage After Experimental Status Epilepticus in Hippocampal Slice Cultures

2002 ◽  
Vol 88 (6) ◽  
pp. 2909-2918 ◽  
Author(s):  
Richard Kovács ◽  
Sebastian Schuchmann ◽  
Siegrun Gabriel ◽  
Oliver Kann ◽  
Julianna Kardos ◽  
...  
Keyword(s):  
Free Radicals ◽  
Status Epilepticus ◽  
Free Radical ◽  
Hippocampal Slice ◽  
Cell Damage ◽  
Radical Scavenging ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Mitochondrial Depolarization ◽  
Hippocampal Slice Cultures

Generation of free radicals may have a key role in the nerve cell damage induced by prolonged or frequently recurring convulsions (status epilepticus). Mitochondrial function may also be altered due to production of free radicals during seizures. We therefore studied changes in field potentials (fp) together with measurements of extracellular, intracellular, and intramitochondrial calcium concentration ([Ca2+]e, [Ca2+]i, and [Ca2+]m, respectively), mitochondrial membrane potential (ΔΨ), NAD(P)H auto-fluorescence, and dihydroethidium (HEt) fluorescence in hippocampal slice cultures by means of simultaneous electrophysiological and microfluorimetric measurements. As reported previously, each seizure-like event (SLE) resulted in mitochondrial depolarization associated with a delayed rise in oxidation of HEt to ethidum, presumably indicating ROS production. We show here that repeated SLEs led to a decline in intracellular and intramitochondrial Ca2+ signals despite unaltered Ca2+ influx. Also, mitochondrial depolarization and the NAD(P)H signal became smaller during recurring SLEs. By contrast, the ethidium fluorescence rises remained constant or even increased from SLE to SLE. After about 15 SLEs, activity changed to continuous afterdischarges with steady depolarization of mitochondrial membranes. Staining with a cell death marker, propidium iodide, indicated widespread cell damage after 2 h of recurring SLEs. The free radical scavenger, α-tocopherol, protected the slice cultures against this damage and also reduced the ongoing impairment of NAD(P)H production. These findings suggest involvement of reactive oxygen species (ROS) of mitochondrial origin in the epileptic cell damage and that free radical scavenging may prevent status epilepticus–induced cell loss.

Interaction of cytokinins with lipid-associated oxy free radicals during senescence: a prospective mode of cytokinin action

1984 ◽  
Vol 62 (12) ◽  
pp. 2943-2949 ◽  
Author(s):  
Ya'acov Y. Leshem
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Xanthine Oxidase ◽  
Radical Scavenging ◽  
Free Radical Scavenger ◽  
Radical Formation ◽  
Radical Scavenger ◽  
Substrate Affinity ◽  
Xanthine Oxidase Inhibitors ◽  
Free Radical Formation

In senescence physiology, experimental data indicate causative relationships among cytokinin, lipoxygenation, anti-oxidation, and lipid-associated free radical scavenging. During both normal and induced senescence, there is a rise in lipoxygenase (LOX) which catalyzes the oxidation of polyunsaturated fatty acids containing the cis, cis-1,4-pentadiene configuration. These include linoleic and linolenic acids, which are of common occurrence in plants and inter alia may be situated in membranal phospholipids. Lipoxygenation causes the production of free radicals such as the superoxide, fatty acid, and peroxy species. Cytokinin (CK) lowers LOX and superoxide dismutase activities significantly in senescing foliage and is mimicked by the endogenous lipid antioxidant, α-tocopherol (vitamin E), in its chlorophyll-retaining and LOX-lowering effects. Further experimentation indicated that CK interaction with free radicals may occur in two ways, (i) CK may act as a direct free radical scavenger by virtue of the fact that the hydrogens of the α-carbon atom in the amine bond can be extracted, resulting in the formation of an amide: [Formula: see text][Formula: see text] (this mechanism may also, in part, explain polyamine effects), (ii) CK may serve as an incipient preventative of free radical formation by inhibiting oxidation of plant purine compounds, which at certain stages of breakdown release superoxide and hydroxyl free radicals. This effect is probably associated with a lowering of substrate affinity for xanthine oxidase. This assumption is further borne out by similar senescence-retarding effects of selective xanthine oxidase inhibitors such as allopurinol. These observations collectively indicate that prevention of free radical formation and (or) their direct scavenging should be included in the multifactorial antisencscence mode of action of cytokinin.

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).

DPPH Free Radical Scavenger Components from the Fruits of Alpinia rafflesiana Wall. ex. Bak. (Zingiberaceae)

2004 ◽  
Vol 59 (11-12) ◽  
pp. 811-815 ◽  
Author(s):  
Habsah Mohamad ◽  
Faridah Abas ◽  
Dharma Permana ◽  
Nordin H. Lajis ◽  
Abdul Manaf Ali ◽  
...  
Keyword(s):  
Free Radical ◽  
Methanol Extract ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Scavenging Activity ◽  
Colorimetric Analysis ◽  
Natural Sources

The methanol extract of the dried ripe fruits of Alpinia rafflesiana was investigated for its DPPH free radical scavenger constituents. 2′,3′,4′,6′-Tetrahydroxychalcone (7), which has never been isolated from natural sources was found to be most active as a DPPH free radical scavenger with the IC50 value of 55 μᴍ. Other known compounds isolated from this species include 5,6-dehydrokawain (1), flavokawin B (2), 1,7-diphenyl-5-hydroxy-6-hepten-3-one (3), (-)-pinocembrin (4), cardamonin (5) and (-)-pinostrobin (6). The DPPH free radical scavenger compounds were detected using TLC autographic analysis. The percentage inhibition of DPPH free radical scavenging activity was measured on isolates (5-7) using colorimetric analysis.

Oxygen Free Radicals and the Effect of a Free Radical Scavenger in Patients with Intermittent Claudication

2000 ◽  
Vol 34 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Emmanuel J. Diamantopoulos ◽  
Dionisios Charitos ◽  
Vassilios Georgopoulos ◽  
Emmanuel Economou ◽  
Michael Sfakianakis ◽  
...  
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Intermittent Claudication ◽  
Oxygen Free Radicals ◽  
Free Radical Scavenger ◽  
Radical Scavenger

scholarly journals Ilex khasiana - The silent holly species of Aquifoliaceae on its pharmacognostical importance as a free radical scavenger and antibacterial agent

2020 ◽  
Vol 11 (2) ◽  
pp. 2438-2444
Author(s):  
Charles Lalnunfela ◽  
Lalremsanga H.T. ◽  
Lalhriatpuii T.C. ◽  
Lalthanpuii P.B. ◽  
Kholhring Lalchhandama
Keyword(s):  
Free Radical ◽  
Medicinal Plant ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Northeast India ◽  
Free Radical Scavenger ◽  
Butylated Hydroxytoluene ◽  
Radical Scavenger ◽  
Endangered Medicinal Plant ◽  
Rare And Endangered

Ilex khasiana is a rare and endangered medicinal plant endemic to northeast India. Remaining largely unexplored,it is purported to have a range of medicinal values and may soon join the medicinal plant hall of fame.Extracts of the leaves were prepared using solvents of increasing polarity, namelypetroleum ether (IKP), chloroform (IKC) and methanol (IKM).The preliminary phytochemical screening indicated the presence of alkaloids, phytosterols, triterpenoids, saponins, reducing sugars, glycosides and carbohydrates. Free radical-scavenging activity was assessed using2,2-diphenyl-1-picrylhydrazyl(DPPH). IKC exhibited the highest activity with an IC50 of 17.22 ± 1.87, followed by IKM with an IC50 of 26.93 ± 5.14 and IKP with an IC50 of 37.16 ± 5.11. Butylated hydroxytoluene (BHT)was used as the standard DPPH scavenger and showed an IC50 of 8.31 ±0.72. IKM and IKC also showed positive antibacterial activity againstGram-negative bacteria such asEscherichia coli, Pseudomonas aeruginosa, andKlebsiella pneumoniae, and a Gram-positive bacteriaBacillus subtilis. IKP did not indicate any inhibition against the selected bacteria. Our findings substantiate the basis for further investigations on the medicinal potentials of the plant.  

MCI-186 (edaravone), a novel free radical scavenger, protects against acute autoimmune myocarditis in rats

2005 ◽  
Vol 289 (6) ◽  
pp. H2514-H2518 ◽  
Author(s):  
Masaomi Nimata ◽  
Taka-aki Okabe ◽  
Miki Hattori ◽  
Zuyi Yuan ◽  
Keisuke Shioji ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Free Radical ◽  
Hydroxyl Radicals ◽  
Radical Scavenging ◽  
Weight Ratio ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Cytotoxic Activities ◽  
Thiobarbituric Acid Reactive Substance ◽  
Autoimmune Myocarditis

In this study, we tested the hypothesis that MCI-186 (3-methyl-1-phenyl-2-pyrazolin-5-one; edaravone), a novel free radical scavenger, protects against acute experimental autoimmune myocarditis (EAM) in rats by the radical scavenging action associated with the suppression of cytotoxic myocardial injury. Recent evidence suggests that oxidative stress may play a role in myocarditis. We administered MCI-186 intraperitoneally at 1, 3, and 10 mg·kg−1·day−1 to rats with EAM for 3 wk. The results were compared with untreated rats with EAM. MCI-186 treatment did not affect hemodynamics. MCI-186 treatment (3 and 10 mg·kg−1·day−1) reduced the severity of myocarditis as assessed by comparing the heart-to-body weight ratio and pathological scores. Myocardial interleukin-1β (IL-1β)-positive cells and myocardial oxidative stress overload with DNA damage in rats with EAM given MCI-186 treatment were significantly less compared with those of the untreated rats with EAM. In addition, MCI-186 treatment decreased not only the myocardial protein carbonyl contents but also the myocardial thiobarbituric acid reactive substance products in rats with EAM. The formation of hydroxyl radicals in MCI-186-treated heart homogenates was decreased compared with untreated heart homogenates. Furthermore, cytotoxic activities of lymphocytes of rats with EAM treated with MCI-186 were significantly lower compared with those of the untreated rats with EAM. Hydroxyl radicals may be involved in the development of myocarditis. MCI-186 protects against acute EAM in rats associated with scavenging hydroxyl free radicals, resulting in the suppression of autoimmune-mediated myocardial damage associated with reduced oxidative stress state.

Control of Sonoluminescence in Carbon Dioxide Containing Di Water at near Neutral pH Conditions

2012 ◽  
Vol 187 ◽  
pp. 177-180 ◽  
Author(s):  
Sangita Kumari ◽  
Manish Keswani ◽  
Satish Kumar Singh ◽  
Mark Beck ◽  
Eric Liebscher ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Free Radical ◽  
Light Emission ◽  
Radical Scavenging ◽  
Inhibitory Effect ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Chemical Systems ◽  
Ph Conditions ◽  
Radical Scavenging Ability

Light emission in sound-irradiated liquids, known as Sonoluminescence (SL), is associated with the phenomenon of cavitation that affects wafer damage during megasonic processing of wafers. It has been shown that the intensity of SL can be substantially decreased through the dissolution of carbon dioxide in deionized water. However, such dissolution decreases the pH to roughly 4.0, which is not very desirable for the removal of contaminant particles. This paper reports two chemical systems that are capable of taking advantage of the effect of CO2 while allowing the use of slightly higher pH values. Specifically, NH4OH/CO2 and NH4HCO3/dilute HCl systems have been shown to be capable of well controlled reduction in SL at pH 5.7 or 7.0. In order to test whether the free radical scavenging ability of CO2 may be responsible for its strong SL-inhibitory effect, the effect of a well known free radical scavenger, dimethyl sulfoxide (DMSO), on SL produced in DI water has been investigated.

scholarly journals Hydroxy-Tyrosol as a Free Radical Scavenging Molecule in Polymeric Hydrogels Subjected to Gamma-Ray Irradiation

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 433
Author(s):  
Mauro Fiorini ◽  
Veronica Crognaletti ◽  
Omar Sabry ◽  
Lorenzo Scalise ◽  
Paolo Fattori
Keyword(s):  
Free Radical ◽  
Gamma Ray ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Free Radical Scavenger ◽  
Cross Linking ◽  
Radical Scavenger ◽  
Gamma Ray Irradiation ◽  
Anti Oxidant ◽  
Polymeric Hydrogels

Biomedical engineering is employing hydrogels with increasingly exciting possibilities for the treatment and regeneration of pathologically altered, degenerated, or traumatized tissues. Still, the sterilization processes may undesirably change the chemical and physical properties of hydrogels through cross-linking reactions. This work aims to characterize a new method of producing polyethylene oxide (PEO) hydrogels exploiting hydroxy-tyrosol (HT), an anti-oxidant molecule derived from olive leaf and olive oil, as a free radical scavenger to either prevent or limit gamma-ray-induced cross-linking. For this purpose, we produced hydrogels with PEO with two different buffer solutions (phosphate and citrate), varying HT concentration. We analyzed hydrogel preparations before and after gamma-ray irradiation, assessing the viscosity through rheological analysis and the chemical changes through IR analysis. We performed high-performance liquid chromatography (HPLC) analysis to measure residual HT in hydrogels after irradiation. The obtained results show that radiation-induced cross-linking and increase in viscosity of PEO hydrogels can be prevented by tailoring the concentration of HT as a free radical scavenging agent. Irradiation only consumes small amounts of HT; its presence in polymeric hydrogels can significantly impact biomedical applications by its anti-oxidant and anti-microbial activities.

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