scholarly journals Mechanism of Free Radical-Induced Hemolysis of Human Erythrocytes. II. Hemolysis by Lipid-Soluble Radical Initiator.

1998 ◽  
Vol 21 (3) ◽  
pp. 250-256 ◽  
Author(s):  
Yukio SATO ◽  
Sachiko KANAZAWA ◽  
Keiko SATO ◽  
Yasuo SUZUKI
Keyword(s):  
Free Radical ◽  
Human Erythrocytes ◽  
Radical Initiator

scholarly journals A Theoretical Antioxidant Mechanism for Cytoprotective Effect of p-AcetamideSalicylate Derivatives against Free Radical Initiator AAPH in Human Erythrocytes

2021 ◽  
Author(s):  
Valéria Barros ◽  
Glaécia Pereira ◽  
Sirlene Ota ◽  
Fernanda Melo ◽  
Ana Carolina de Jesus ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Free Radical ◽  
Molecular Mechanism ◽  
Positive Control ◽  
Human Erythrocytes ◽  
Water Soluble ◽  
Cytoprotective Effect ◽  
Potent Effect ◽  
Radical Initiator ◽  
Free Radical Initiator

The molecular mechanism of cytoprotective effect on human erythrocytes of aminophenol and salicylates associated derivatives was related to their antioxidant capacity. The oxidative hemolysis induced by water-soluble free-radical initiator 2,2’-azobis-(2-amidine-propane)-dihydrochloride (AAPH) was inhibited by drug candidates named benzaminophen (BZL), salicytamide or 5-acetamide-salicylic acid (ASL), and salibenzamide or 5-benzamide-salicylic acid (BSL) when compared to their parents salicylic acid (SAC) and acetaminophen (ACP). Trolox (TLX) was the most powerful compound and used as positive control. BZL showed a potent effect followed by ACP > BSL > ASL. SAC did not show protective effect in any evaluated concentrations. These results are in accordance with the molecular mechanism by using theoretical calculation of single electron transfers (SET), hydrogen atom transfers (HAT), and sequential proton loss electron transfer (SPLET) by means of DFT/B3LYP/6-31++G(d,p) level of theory. [1,5] Hydrogen shift between carboxyl and phenol moieties and electronic properties related to pKa and other physicalchemical properties can be involved. The molecular association approach provides protective compounds more effective than SAC.

Mechanism of Free Radical-Induced Hemolysis of Human Erythrocytes: Hemolysis by Water-Soluble Radical Initiator

Biochemistry ◽  
1995 ◽  
Vol 34 (28) ◽  
pp. 8940-8949 ◽  
Author(s):  
Yukio Sato ◽  
Shinya Kamo ◽  
Takeo Takahashi ◽  
Yasuo Suzuki
Keyword(s):  
Free Radical ◽  
Human Erythrocytes ◽  
Water Soluble ◽  
Radical Initiator

PNIPAM-based graft copolymers prepared using potassium persulfate as free-radical initiator: synthesis reproducibility

2016 ◽  
Vol 294 (6) ◽  
pp. 981-991 ◽  
Author(s):  
Nívia N. Marques ◽  
Bruna V. Lima ◽  
Valdelice R. Silveira ◽  
Bruna L. B. Lima ◽  
Ana M. S. Maia ◽  
...  
Keyword(s):  
Free Radical ◽  
Graft Copolymers ◽  
Potassium Persulfate ◽  
Radical Initiator ◽  
Free Radical Initiator

Polymerization of Diphenylbutadiyne Derivatives in Solution by Free Radical Initiator

2007 ◽  
Vol 44 (6) ◽  
pp. 605-611 ◽  
Author(s):  
Miriam F. Beristain ◽  
Eduardo Muñoz ◽  
Takeshi Ogawa
Keyword(s):  
Free Radical ◽  
Radical Initiator ◽  
Free Radical Initiator

1-(Trimethylsilyl)-1,2,4-triazene: A Novel Free Radical Initiator

2002 ◽  
Vol 177 (5) ◽  
pp. 1109-1116 ◽  
Author(s):  
S. Munavalli ◽  
D. K. Rohrbaugh ◽  
D. I. Rossman ◽  
H. D. Durst
Keyword(s):  
Free Radical ◽  
Radical Initiator ◽  
Free Radical Initiator

scholarly journals Effect of the Solvent on Propolis Phenolic Profile and its Antifungal, Antioxidant, and In Vitro Cytoprotective Activity in Human Erythrocytes Under Oxidative Stress

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4266
Author(s):  
Magdalena Woźniak ◽  
Lucyna Mrówczyńska ◽  
Patrycja Kwaśniewska-Sip ◽  
Agnieszka Waśkiewicz ◽  
Piotr Nowak ◽  
...  
Keyword(s):  
Free Radical ◽  
Antifungal Activity ◽  
Biological Effects ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Human Erythrocytes ◽  
Antioxidant Potential ◽  
Phenolic Profile ◽  
Cytoprotective Activity

Propolis is a natural bee product with various beneficial biological effects. The health-promoting properties of propolis depend on its chemical composition, particularly the presence of phenolic compounds. The aim of this study was to evaluate the relationship between extraction solvent (acetone 100%, ethanol 70% and 96%) and the antifungal, antioxidant, and cytoprotective activity of the extracts obtained from propolis. Concentrations of flavonoids and phenolic acids in the propolis extracts were determined using ultrahigh-performance liquid chromatography. The antioxidant potential of different extracts was assessed on the basis of 2,2-diphenyl-1-picrylhydrazyl (DPPH·) free-radical-scavenging activity, Fe3+-reducing power, and ferrous ion (Fe2+)-chelating activity assays. The ability of the extracts to protect human red blood cell membranes against free-radical-induced damage and their antifungal activity was also determined. The results showed that the concentration of flavonoids in the propolis extracts was dependent on the solvent used in the extraction process and pinocembrin, chrysin, galangin, and coumaric acid were the most abundant phenols. All extracts exhibited high antioxidant potential and significantly protected human erythrocytes against oxidative damage. On the other hand, the antifungal activity of the propolis extracts depended on the solvent used in extraction and the fungal strains tested. It needs to be stressed that, to the best of our knowledge, there is no study relating the effect of solvent used for extraction of Polish propolis to its phenolic profile, and its antifungal, antioxidant, and cytoprotective activity.

Evidence of Trolox and some gallates as synergistic protectors of erythrocytes against peroxyl radicals

1998 ◽  
Vol 76 (4) ◽  
pp. 661-664 ◽  
Author(s):  
J Wu ◽  
H Sugiyama ◽  
L -H Zeng ◽  
D Mickle ◽  
T -W Wu
Keyword(s):  
Antioxidant Activity ◽  
Vitamin E ◽  
Protective Effect ◽  
Propyl Gallate ◽  
Peroxyl Radical ◽  
Human Erythrocytes ◽  
Peroxyl Radicals ◽  
Methyl Ethyl ◽  
Radical Initiator ◽  
Individual Contributions

The peroxidation of human erythrocytes induced by peroxyl radical initiator and its inhibition by several gallate esters (e.g., propyl, methyl, ethyl) and Trolox (a more polar analogue of vitamin E) have been studied. The antioxidant activity was determined on erythrocytes against hemolysis generated by a thermal activator, 2,2prime-azobis-(2-amidinopropane)dihydrogenchloride. It was found that propyl gallate and its two analogues were more effective than Trolox in preventing cell lysis. However, the combination of gallate esters and Trolox produced a protective effect exceeding the arithmetic sum of their individual contributions. These perceived synergisms occur at more than one level of Trolox at a given level of a gallate ester.Key words: Trolox, gallates, synergism, peroxyl radicals.

scholarly journals Effect of Oxygen and Initiator Solubility on Admicellar Polymerization of Styrene on Silica Surfaces

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Pohlee Cheah ◽  
Caitlin N. Bhikha ◽  
John H. O’Haver ◽  
Adam E. Smith
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
Emulsion Polymerization ◽  
Water Soluble ◽  
Polymer Yield ◽  
Radical Initiator ◽  
Admicellar Polymerization ◽  
Molecular Weights ◽  
Precipitated Silica ◽  
Free Radical Initiator

Although admicellar polymerization has been termed the surface analog of emulsion polymerization, previous reports utilizing free radical-initiated admicellar polymerization relied on high levels of the free radical initiator when compared to emulsion polymerization, likely due to the presence of oxygen in the reported admicellar polymerization systems. Admicellar polymerizations of styrene on the surface of precipitated silica initiated by either a water-soluble or a water-insoluble initiator were studied to determine the effect of dissolved oxygen and free radical initiator solubility on the kinetics, yield, and molecular weight of the polymer formed. Results show that the presence of oxygen reduces the polymer yield and limits molecular weight. The solubility of the initiator also affected the polymer formed in the admicellar polymerization of styrene. While monomer conversions and polymer yield were similar, the molecular weights of polymerizations initiated by a water-soluble initiator were higher than comparable polymerizations initiated by a water-insoluble initiator.

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