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.

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.

scholarly journals Antioxidant-Free Radical Scavenging of Some Euphorbiaceae Herbs

2011 ◽  
Vol 2 (1) ◽  
pp. 146
Author(s):  
Titik Sunarni ◽  
Fransiska Leviana
Keyword(s):  
Acetic Acid ◽  
Free Radical ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Radical Scavenger Activity ◽  
Ic50 Value ◽  
Scavenger Activity ◽  
Acetic Acid Water

In order to screen natural antioxidant, the research about antioxidant of some Euphobiaceae herbs, have been conducted. The air-dried herbs  of Euphorbia heterophylla L, Phyllanthus acidus (L.) Skeels, and Phyllanthus buxifolius Muell Arg were extracted with metanol. The obtained extract was concentrated and then suspended to produce n-hexane, ethyl acetat and aqueous fractions. Free radical scavenger activity against DPPH (1,1-diphenyl-2-pycrylhydrazyl) measured by spectrophotometric method  and the IC50 value was determined. The compounds of  active fraction had been identified by TLC method. All of the herbs showed activity as DPPH scavenger. Among these herbs, Euphorbia heterophylla L. and Phyllanthus buxifolius Muell, Arg. exhibited a strong free radical scavenging of ethyl acetat fraction with IC50 value 5,88 µg/ml and 4,64 µg/ml. The result of TLC by mobile phase n-buthanol-acetic acid-water (4:1:5) and acetic acid 15% showed flavonoid compound.Keywords: Euphorbiaceae herbs, antioxidant, DPPH, flavonoid

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.

scholarly journals Bergenin Content and Free Radical Scavenging Activity of Bergenia Extracts

2015 ◽  
Vol 10 (7) ◽  
pp. 1934578X1501000
Author(s):  
Helena Hendrychová ◽  
Jan Martin ◽  
Lenka Tůmová ◽  
Nina Kočevar-Glavač
Keyword(s):  
Free Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Hplc Method ◽  
Free Radical Scavenging ◽  
Free Radical Scavenging Activity ◽  
Free Radical Scavengers ◽  
Radical Scavenger ◽  
Scavenging Activity ◽  
Different Seasons

Our research was focused on the evaluation of bergenin content and free radical scavenging activity of extracts prepared from three different species of Bergenia - B. crassifolia (L.) Fritsch., B. ciliata (Haw.) Sternb. and B. x ornata Stein. collected during different seasons. Using an HPLC method, the highest total amount of bergenin was revealed in the leaves of B. x ornata and B. crassifolia (4.9 - 5.1 mg.g−1). Free radical scavenging power was determined by two methods - FRAP and NADH. The best free radical scavengers were B. crassifolia (FRAP: 6.7 - 15.9 mg GAE.100g−1; NADH: 20.3 - 50.9%) and B. ornata (FRAP: 13.7 - 15.2 mg GAE.100g−1; NADH: 29.3 - 31.1%). The lowest content of bergenin and the weakest radical scavenger was B. ciliata (bergenin: 3.1 mg.g−1; FRAP: 5.5 - 11.0 mg GAE.100g−1; NADH: 23.2 - 25.6%). The presence of a large percentage of bergenin is responsible for the radical scavenging activity, as shown by the results from the FRAP and NADH assays. Significant, positive correlation was found between bergenin content and radical scavenging activity in both methods.

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