Free Radicals from Purine Nucleosides after Hydroxyl Radical Attack

The reaction of the hydroxyl radical, generated by a Fenton system, with pyrimidine deoxyribonucleotides was investigated by using the e.s.r. technique of spin trapping. The spin trap t-nitrosobutane was employed to trap secondary radicals formed by the reaction of the hydroxyl radical with these nucleotides. The results presented here show that hydroxyl-radical attack on thymidine, 2-deoxycytidine 5-monophosphate and 2-deoxyuridine 5-monophosphate produced nucleotide-derived free radicals. The results indicate that .OH radical attack occurs predominantly at the carbon-carbon double bond of the pyrimidine base. The e.s.r. studies showed a good correlation with previous results obtained by authors who used x- or gamma-ray irradiation to generate the hydroxyl radical. A thiobarbituric acid assay was also used to monitor the damage produced to the nucleotides by the Fenton system. These results showed qualitative agreement with the spin-trapping studies.

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Titanium Dioxide Nanoparticle Photocatalysed Degradation of Ibuprofen and Naproxen in Water: Competing Hydroxyl Radical Attack and Oxidative Decarboxylation by Semiconductor Holes

ChemistrySelect ◽

10.1002/slct.201801953 ◽

2018 ◽

Vol 3 (39) ◽

pp. 10915-10924 ◽

Cited By ~ 9

Author(s):

Andreia Romeiro ◽

M. Emília Azenha ◽

Moisés Canle ◽

Victor H. N. Rodrigues ◽

José P. Da Silva ◽

...

Keyword(s):

Titanium Dioxide ◽

Hydroxyl Radical ◽

Oxidative Decarboxylation ◽

Titanium Dioxide Nanoparticle ◽

Radical Attack

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Myocardial alterations due to free-radical generation

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1984.246.6.h776 ◽

1984 ◽

Vol 246 (6) ◽

pp. H776-H783 ◽

Cited By ~ 17

Author(s):

K. P. Burton ◽

J. M. McCord ◽

G. Ghai

Keyword(s):

Endothelial Cells ◽

Free Radicals ◽

Hydroxyl Radical ◽

Cardiac Myocytes ◽

Hydroxyl Radicals ◽

Vascular Endothelial Cells ◽

Tissue Injury ◽

Myocardial Damage ◽

Vascular Endothelial ◽

Radical Generation

Oxygen-derived free radicals have been proposed as general mediators of tissue injury in a variety of disease states. Recent interest has focused on the possibility that free radicals may be involved in ischemic myocardial damage. However, the exact types of damage that result from myocardial exposure to free radicals remains to be established. The purpose of this study was to evaluate the effects of superoxide and hydroxyl radicals on myocardial structure and function in an isolated perfused rabbit interventricular septal preparation. Superoxide was generated by adding purine (2.3 mM) and xanthine oxidase (0.01 U/ml) to the physiological solutions perfusing the septa. Hydroxyl radical generation was catalyzed by the addition of 2.4 microM Fe3+-loaded transferrin to the system. Exposure of normal septa to superoxide-generating solutions resulted in the development of structural alterations in the vascular endothelium including the development of vacuoles. Membranous cellular debris was evident in the extracellular space and within the vessels. Cardiac myocytes showed evidence of mild alterations. Exposure of septa to solutions capable of generating hydroxyl radicals resulted in more extensive and severe damage. Vascular endothelial cells showed evidence of vacuoles or blebs and edema. Severe swelling of mitochondria was evident in cardiac myocytes and vascular endothelial cells. In addition, myocytes often showed blebbing of the basement membrane. Normal septa exposed to superoxide showed no significant decrease in developed tension, whereas hydroxyl radical exposure resulted in a significant decrease in myocardial function.(ABSTRACT TRUNCATED AT 250 WORDS)

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Pulse radiolytic study of the site of hydroxyl radical attack on aliphatic alcohols in aqueous solution

The Journal of Physical Chemistry ◽

10.1021/j100629a007 ◽

1973 ◽

Vol 77 (10) ◽

pp. 1218-1221 ◽

Cited By ~ 203

Author(s):

K. D. Asmus ◽

H. Moeckel ◽

A. Henglein

Keyword(s):

Aqueous Solution ◽

Hydroxyl Radical ◽

Aliphatic Alcohols ◽

Radical Attack

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Evidence for roles of radicals in protein oxidation in advanced human atherosclerotic plaque

Biochemical Journal ◽

10.1042/bj3330519 ◽

1998 ◽

Vol 333 (3) ◽

pp. 519-525 ◽

Cited By ~ 175

Author(s):

Shanlin FU ◽

Michael J. DAVIES ◽

Roland STOCKER ◽

Roger T. DEAN

Keyword(s):

Hydroxyl Radical ◽

Protein Modification ◽

Indirect Evidence ◽

Transition Metal Ions ◽

Oxidation Products ◽

Reaction Pathways ◽

Radical Attack ◽

Radical Damage ◽

Human Carotid

Oxidative damage might be important in atherogenesis. Oxidized lipids are present at significant concentrations in advanced human plaque, although tissue antioxidants are mostly present at normal concentrations. Indirect evidence of protein modification (notably derivatization of lysine) or oxidation has been obtained by immunochemical methods; the specificities of these antibodies are unclear. Here we present chemical determinations of six protein-bound oxidation products: dopa, o-tyrosine, m-tyrosine, dityrosine, hydroxyleucine and hydroxyvaline, some of which reflect particularly oxy-radical-mediated reaction pathways, which seem to involve mainly the participation of transition- metal ions. We compared the relative abundance of these oxidation products in normal intima, and in human carotid plaque samples with that observed after radiolytically generated hydroxyl radical attack on BSA in vitro. The close similarities in relative abundances in the latter two circumstances indicate that hydroxyl radical damage might occur in plaque. The relatively higher level of dityrosine in plaque than that observed after radiolysis suggests the additional involvement of HOCl-mediated reactions in advanced plaque.

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Glycoxidation, and protein and DNA oxidation in patients with diabetes mellitus

Clinical Science ◽

10.1042/cs0950331 ◽

1998 ◽

Vol 95 (3) ◽

pp. 331-337 ◽

Cited By ~ 16

Author(s):

K. KRAPFENBAUER ◽

R. BIRNBACHER ◽

H. VIERHAPPER ◽

K. HERKNER ◽

D. KAMPEL ◽

...

Keyword(s):

Oxidative Stress ◽

Diabetes Mellitus ◽

Hydroxyl Radical ◽

Protein Oxidation ◽

Type Ii Diabetes ◽

Dna Oxidation ◽

Type I ◽

Type Ii ◽

Patients With Diabetes ◽

Radical Attack

1.The role of oxidative stress in the pathogenesis of the diabetic state is being investigated extensively. Although oxidative stress has been reported in terms of glycoxidation, protein oxidation and DNA oxidation in diabetes mellitus, oxidation parameters have not been determined in parallel on the same study population. 2.We studied 24 patients with diabetes mellitus (14 patients with Type I diabetes with a mean age of 62.3±6.3 years and 10 patients with Type II diabetes aged 67.3±5.9 years) and compared them with age-matched non-diabetic controls. Urinary o-tyrosine, 8-hydroxy-2′-deoxyguanosine and pentosidine measurements by HPLC were made on two occasions (t1 and t2). 3.A clear statistical difference was found between diabetic patients and controls at t1 or t2 for 8-hydroxy-2′-deoxyguanosine and pentosidine, but not for o-tyrosine. No significant correlations were found between clinical and other laboratory parameters except high-density lipoprotein and uric acid. We revealed significantly increased glycoxidation and DNA oxidation in patients with Type I and Type II diabetes, but protein oxidation was not different from controls. 4.The finding of increased glycoxidation reflects increased oxidation of the carbohydrate moiety, whereas the increased levels of oxidized DNA may also be interpreted as due to increased DNA repair. The increased 8-hydroxy-2′-deoxyguanosine does not indicate the generation of an individual active oxygen species, but DNA could have been oxidized simply by alkenals from lipid peroxidation, as e.g. malondialdehyde. As no difference in protein oxidation (i.e. o-tyrosine) between diabetics and controls could be revealed, the oxidation of DNA by hydroxyl radical attack is unlikely, as o-tyrosine was proposed as a marker for hydroxyl radical attack. Therefore, the message is that increased glycoxidation can be confirmed, protein oxidation does not appear to take place and increased DNA oxidation is still not proven, as increased 8-hydroxy-2′-deoxyguanosine may simply reflect repair.

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Cephalexin Degradation Initiated by OH Radicals: Theoretical Prediction of the Mechanisms and the Toxicity of Byproducts

10.21203/rs.3.rs-1169649/v1 ◽

2021 ◽

Author(s):

R. Masmoudi ◽

S. Khettaf ◽

A. Soltani ◽

A. Dibi ◽

L. Messaadia ◽

...

Keyword(s):

Density Functional Theory ◽

Theoretical Prediction ◽

Hydroxyl Radical ◽

Density Functional ◽

Aquatic Organisms ◽

Addition Reactions ◽

Oh Radicals ◽

Functional Theory ◽

Radical Attack ◽

Mechanism Of The Reaction

Abstract In this work, density functional theory is used to study the local reactivity of cephalexin (CLX) to radical attack and explain the mechanism of the reaction between CLX and hydroxyl radical attack leading to degradation byproducts. The reaction between •OH and CLX is supposed to lead to either an addition of a hydroxyl radical or an abstraction of a hydrogen. The results showed that the affinity of cephalexin for addition reactions increases as it passes from the gas to the aqueous phase and decreases as it passes from the neutral to the ionized form. Thermodynamic data confirmed that OH addition radicals (Radd) are thermodynamically favored over H abstraction radicals (Rabs). The ecotoxicity assessments of CLX and its byproducts are estimated from the acute toxicities toward green algae, Daphnia and fish. The formation of byproducts is safe for aquatic organisms, and only one byproduct is harmful to Daphnia.

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