scholarly journals The mechanism of Fe2+-initiated lipid peroxidation in liposomes: the dual function of ferrous ions, the roles of the pre-existing lipid peroxides and the lipid peroxyl radical

2000 ◽  
Vol 352 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Lixia TANG ◽  
Yong ZHANG ◽  
Zhongming QIAN ◽  
Xun SHEN
Keyword(s):  
Lipid Peroxidation ◽  
Latent Period ◽  
Time Lag ◽  
Lipid Peroxides ◽  
Peroxyl Radicals ◽  
Dual Function ◽  
Critical Ratio ◽  
Ferrous Ions ◽  
Liposomal System ◽  
Lipid Peroxyl Radicals

The mechanism of Fe2+-initiated lipid peroxidation in a liposomal system was studied. It was found that a second addition of ferrous ions within the latent period lengthened the time lag before lipid peroxidation started. The apparent time lag depended on the total dose of Fe2+ whenever the second dose of Fe2+ was added, which indicates that Fe2+ has a dual function: to initiate lipid peroxidation on one hand and suppress the species responsible for the initiation of the peroxidation on the other. When the pre-existing lipid peroxides (LOOH) were removed by incorporating triphenylphosphine into liposomes, Fe2+ could no longer initiate lipid peroxidation and the acceleration of Fe2+ oxidation by the liposomes disappeared. However, when extra LOOH were introduced into liposomes, both enhancement of the lipid peroxidation and shortening of the latent period were observed. When the scavenger of lipid peroxyl radicals (LOOP), N,N´-diphenyl-p-phenylene-diamine, was incorporated into liposomes, neither initiation of the lipid peroxidation nor acceleration of the Fe2+ oxidation could be detected. The results may suggest that both the pre-existing LOOH and LOOP are necessary for the initiation of lipid peroxidation. The latter comes initially from the decomposition of the pre-existing LOOH by Fe2+ and can be scavenged by its reaction with Fe2+. Only when Fe2+ is oxidized to such a degree that LOOP is no longer effectively suppressed does lipid peroxidation start. It seems that by taking the reactions of Fe2+ with LOOH and LOOP into account, the basic chemistry in lipid peroxidation can explain fairly well the controversial phenomena observed in Fe2+-initiated lipid peroxidation, such as the existence of a latent period, the critical ratio of Fe2+ to lipid and the required oxidation of Fe2+.

scholarly journals Drugs Repurposed as Antiferroptosis Agents Suppress Organ Damage, Including AKI, by Functioning as Lipid Peroxyl Radical Scavengers

2019 ◽  
Vol 31 (2) ◽  
pp. 280-296 ◽  
Author(s):  
Eikan Mishima ◽  
Emiko Sato ◽  
Junya Ito ◽  
Ken-ichi Yamada ◽  
Chitose Suzuki ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Cell Death ◽  
Cytochrome P450 ◽  
Liver Injury ◽  
Peroxyl Radical ◽  
Organ Damage ◽  
Peroxyl Radicals ◽  
Radical Scavengers ◽  
Lipid Peroxyl Radicals ◽  
Elevated Lipid

BackgroundFerroptosis, nonapoptotic cell death mediated by free radical reactions and driven by the oxidative degradation of lipids, is a therapeutic target because of its role in organ damage, including AKI. Ferroptosis-causing radicals that are targeted by ferroptosis suppressors have not been unequivocally identified. Because certain cytochrome P450 substrate drugs can prevent lipid peroxidation via obscure mechanisms, we evaluated their antiferroptotic potential and used them to identify ferroptosis-causing radicals.MethodsUsing a cell-based assay, we screened cytochrome P450 substrate compounds to identify drugs with antiferroptotic activity and investigated the underlying mechanism. To evaluate radical-scavenging activity, we used electron paramagnetic resonance–spin trapping methods and a fluorescence probe for lipid radicals, NBD-Pen, that we had developed. We then assessed the therapeutic potency of these drugs in mouse models of cisplatin-induced AKI and LPS/galactosamine-induced liver injury.ResultsWe identified various US Food and Drug Administration–approved drugs and hormones that have antiferroptotic properties, including rifampicin, promethazine, omeprazole, indole-3-carbinol, carvedilol, propranolol, estradiol, and thyroid hormones. The antiferroptotic drug effects were closely associated with the scavenging of lipid peroxyl radicals but not significantly related to interactions with other radicals. The elevated lipid peroxyl radical levels were associated with ferroptosis onset, and known ferroptosis suppressors, such as ferrostatin-1, also functioned as lipid peroxyl radical scavengers. The drugs exerted antiferroptotic activities in various cell types, including tubules, podocytes, and renal fibroblasts. Moreover, in mice, the drugs ameliorated AKI and liver injury, with suppression of tissue lipid peroxidation and decreased cell death.ConclusionsAlthough elevated lipid peroxyl radical levels can trigger ferroptosis onset, some drugs that scavenge lipid peroxyl radicals can help control ferroptosis-related disorders, including AKI.

scholarly journals Nitric Oxide Reaction with Lipid Peroxyl Radicals Spares α-Tocopherol during Lipid Peroxidation

2000 ◽  
Vol 275 (15) ◽  
pp. 10812-10818 ◽  
Author(s):  
Homero Rubbo ◽  
Rafael Radi ◽  
Daniel Anselmi ◽  
Marion Kirk ◽  
Stephen Barnes ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Lipid Peroxidation ◽  
Peroxyl Radicals ◽  
Lipid Peroxyl Radicals

scholarly journals Promethazine inhibits the formation of aldehydic products of lipid peroxidation but not covalent binding resulting from the exposure of rat liver fractions to CCl4

1989 ◽  
Vol 264 (2) ◽  
pp. 527-532 ◽  
Author(s):  
G Poli ◽  
K H Cheeseman ◽  
F Biasi ◽  
E Chiarpotto ◽  
M U Dianzani ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Free Radical ◽  
Covalent Binding ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Isolated Hepatocytes ◽  
Peroxyl Radicals ◽  
Liver Necrosis ◽  
Lipid Peroxyl Radicals ◽  
Carbonyl Products

Promethazine is known to have protective activity in relation to CCl4-induced liver necrosis. This hepatoprotective property has been investigated with regard to the free radical scavenging and antioxidant properties of promethazine using isolated hepatocytes and microsomal suspensions. CCl4 is activated in both systems to free radical metabolites that bind covalently to lipid and protein, and initiate lipid peroxidation. A large number of carbonyl products is produced during CCl4-induced lipid peroxidation; promethazine strongly inhibits the production of all classes of carbonyl compounds in both microsomal suspensions and isolated hepatocytes. In contrast, promethazine is a very weak inhibitor of the covalent binding of metabolites of CCl4. We conclude that promethazine acts by scavenging the trichloromethylperoxyl radical and lipid peroxyl radicals, and is a weak scavenger of the trichloromethyl radical. These data, when considered together with the hepatoprotective effects of promethazine, suggest that lipid peroxidation is of relatively more importance than covalent binding in the pathogenesis of CCl4-induced liver necrosis.

Nitric Oxide Inhibition of Lipid Peroxidation:  Kinetics of Reaction with Lipid Peroxyl Radicals and Comparison with α-Tocopherol†

Biochemistry ◽  
1997 ◽  
Vol 36 (49) ◽  
pp. 15216-15223 ◽  
Author(s):  
Valerie B. O'Donnell ◽  
Phillip H. Chumley ◽  
Neil Hogg ◽  
Allison Bloodsworth ◽  
Victor M. Darley-Usmar ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Lipid Peroxidation ◽  
Peroxyl Radicals ◽  
Nitric Oxide Inhibition ◽  
Kinetics Of Reaction ◽  
Lipid Peroxyl Radicals ◽  
Kinetics Of ◽  
Oxide Inhibition

scholarly journals Evaluation of antioxidant, antimutagenic, and lipid peroxidation inhibitory activities of selected fractions of Holarrhena floribunda (G. Don) leaves.

2013 ◽  
Vol 60 (3) ◽  
Author(s):  
Jelili A Badmus ◽  
Oyeronke A Odunola ◽  
Taofeek A Yekeen ◽  
Adedapo M Gbadegesin ◽  
John O Fatoki ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Ethyl Acetate ◽  
Mitotic Index ◽  
Allium Cepa ◽  
Lipid Peroxides ◽  
Egg Yolk ◽  
Ethyl Acetate Fraction ◽  
Peroxyl Radicals ◽  
Antimutagenic Activity ◽  
Inhibitory Activities

Exposure to environmental pollutants often leads to an upsurge in the production of reactive oxygen species (ROS). ROS oxidize cellular fatty acids to produce lipid peroxyl radicals, subsequently transformed into lipid peroxides, which decrease membrane fluidity and increase the activity of various enzymes implicated in degenerative diseases and cancer formation. Edible plants that contain exogenous compounds like curcumeroid, β-carotene, turmeric, and so on, protect the aerobic cells from oxidation of free radicals. This study thus evaluates antioxidant and antimutagenic activities of ethyl acetate, aqueous and methanolic fractions of Holarrhena floribunda leaves. Inhibitory activities of the ethyl acetate fraction on Fe(2+)-induced lipid peroxidation in hen egg yolk; rat liver and brain tissues were also evaluated. The Allium cepa root assay was used to evaluate antimutagenic activity. Results showed that the ethyl acetate scavenged DPPH, OH•, and •O2(-) much stronger than other fractions, as evidenced by its lowest respective IC50 values. All the fractions displayed antimutagenic activities against cyclophosphamide-induced chromosomal aberrations. Likewise, all the fractions induced a reduction in mitotic index, a hallmark of cytotoxicity in the root meristem of Allium cepa. The decrease in mitotic index was most profound for the ethyl acetate fraction, which also demonstrated a significant lipid peroxidation inhibitory activity in the liver and brain homogenates, but not in egg yolk, compared with the ascorbic acid standard. In general, the results suggest that the ethyl acetate fraction might contain beneficial phytochemicals that should be explored as novel candidates for preclinical drug development.

Plant polyphenols: free radical scavengers or chain-breaking antioxidants?

1995 ◽  
Vol 61 ◽  
pp. 103-116 ◽  
Author(s):  
Catherine Rice-Evans
Keyword(s):  
Biological Effects ◽  
Relative Effectiveness ◽  
Antioxidant Properties ◽  
Peroxyl Radicals ◽  
Free Radical Scavengers ◽  
Dietary Polyphenols ◽  
Chain Breaking ◽  
Lipid Peroxyl Radicals

There is increasing interest in the biological effects of tea- and wine-derived polyphenols and many studies in vitro and in vivo are demonstrating their antioxidant properties. Tea is a major source of dietary polyphenols and an even richer source of the flavanols, the catechins and catechin/gallate esters. Although there are limited studies on the bioavailability of the polyphenols, the absorption of flavanols in humans has been shown. The studies described in this chapter discuss the relative antioxidant potentials of the polyphenolic flavonoids in vitro against radicals generated in the aqueous phase in comparison with their relative effectiveness as antioxidants against propagating lipid peroxyl radicals, and how their activity influences that of α-tocopherol in low-density lipoproteins exposed to oxidative stress.

scholarly journals APR-246 induces early cell death by ferroptosis in acute myeloid leukemia.

Haematologica ◽  
2021 ◽  
Author(s):  
Rudy Birsen ◽  
Clement Larrue ◽  
Justine Decroocq ◽  
Natacha Johnson ◽  
Nathan Guiraud ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Cell Death ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Ex Vivo ◽  
Lipid Peroxides ◽  
Death Process ◽  
Glutathione Biosynthesis ◽  
Acute Myeloid

APR-246 is a promising new therapeutic agent that targets p53 mutated proteins in myelodysplastic syndromes and in acute myeloid leukemia. APR-246 reactivates the transcriptional activity of p53 mutants by facilitating their binding to DNA target sites. Recent studies in solid cancers have found that APR-246 can also induce p53-independent cell death. In this study, we demonstrate that AML cell death occurring early after APR-246 exposure is suppressed by iron chelators, lipophilic antioxidants and inhibitors of lipid peroxidation, and correlates with the accumulation of markers of lipid peroxidation, thus fulfilling the definition of ferroptosis, a recently described cell death process. The capacity of AML cells to detoxify lipid peroxides by increasing their cystine uptake to maintain major antioxidant molecule glutathione biosynthesis after exposure to APR-246 may be a key determinant of sensitivity to this compound. The association of APR-246 with induction of ferroptosis (either by pharmacological compounds, or genetic inactivation of SLC7A11 or GPX4) had a synergistic effect on the promotion of cell death, both in vivo and ex vivo.

Prevention of lipid peroxidation does not prevent oxidant-induced myocardial contractile dysfunction

1994 ◽  
Vol 267 (6) ◽  
pp. H2371-H2377 ◽  
Author(s):  
Y. Kong ◽  
E. J. Lesnefsky ◽  
J. Ye ◽  
L. D. Horwitz
Keyword(s):  
Lipid Peroxidation ◽  
Coronary Flow ◽  
Systolic Function ◽  
Lipid Peroxide ◽  
Left Ventricular Pressure ◽  
Lipid Peroxides ◽  
Left Ventricular ◽  
Contractile Dysfunction ◽  
Myocardial Contractile ◽  
Generating System

We tested whether, with exposure to an extraneous iron-catalyzed free radical-generating system, prevention of lipid peroxidation with U74006F, a 21-aminosteroid, could also prevent myocardial contractile dysfunction. Rabbits received either U74006F (10 mg/kg iv) or vehicle (V). Thirty minutes later the hearts were excised and perfused by a non-recirculating Langendorff technique. Six U74006F- and six V-treated hearts were exposed for 7.5 min to a .OH-generating system (H2O2 and Fe(2+)-ADP chelate). Myocardial lipid peroxides were measured by glutathione peroxidase-catalyzed oxidation of exogenous glutathione. With exposure to .OH, cytosolic lipid peroxide levels were increased threefold in V-treated hearts, but there was no increase in U74006F-treated hearts. After 30 min of recovery, developed pressure and maximum first derivative of left ventricular pressure were greater in U74006F-treated hearts than in V-treated hearts but were still 50 and 44% of levels in saline hearts, respectively. Coronary flow was markedly reduced after exposure to free radicals and was only slightly less depressed when U74006F was administered. When coronary flow following oxidant exposure was increased by nitroglycerin, U74006F again only modestly improved systolic function. Thus, although U74006F blocked lipid peroxidation, it only slightly improved the ventricular dysfunction caused by .OH. Therefore, factors other than lipid peroxidation play a major role in oxidant-induced myocardial stunning.

Overexpression of metallothionein decreases sensitivity of pulmonary endothelial cells to oxidant injury

1997 ◽  
Vol 273 (4) ◽  
pp. L856-L865 ◽  
Author(s):  
Bruce R. Pitt ◽  
Margaret Schwarz ◽  
Elizabeth S. Woo ◽  
Emily Yee ◽  
Karla Wasserloos ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Endothelial Cells ◽  
Pulmonary Artery ◽  
Metal Binding ◽  
High Performance ◽  
Binding Capacity ◽  
Peroxyl Radicals ◽  
Intact Cells ◽  
Tert Butyl Hydroperoxide ◽  
Liquid Chromatography Separation

Metallothionein (MT) is a low-molecular-weight cysteine-rich protein with extensive metal binding capacity and potential nonenzymatic antioxidant activity. Despite the sensitivity of vascular endothelium to either heavy metal toxicity or oxidative stress, little is known regarding the role of MT in endothelial cells. Accordingly, we determined the sensitivity of cultured sheep pulmonary artery endothelial cells (SPAEC) that overexpressed MT to tert-butyl hydroperoxide ( t-BOOH), hyperoxia, or 2,2′-azobis(2,4-dimethylvaleronitrile) (AMVN; peroxyl radical generator). Nontoxic doses of 10 μM Cd increased MT levels from 0.21 ± 0.03 to 2.07 ± 0.24 μg/mg and resulted in resistance to t-BOOH and hyperoxia as determined by reduction of Alamar blue or [3H]serotonin transport, respectively. SPAEC stably transfected with plasmids containing either mouse or human cDNA for MT were resistant to both t-BOOH and hyperoxia. In addition, we examined transition metal-independent, noncytotoxic AMVN-induced lipid peroxidation after metabolic incorporation of the oxidant-sensitive fluorescent fatty acid cis-parinaric acid into phospholipids and high-performance liquid chromatography separation. SPAEC that overexpressed MT after gene transfer completely inhibited peroxyl oxidation of phosphatidylserine, phosphatidylcholine, and sphingomyelin (but not phosphatidylethanolamine) noted in wild-type SPAEC. These data show for the first time that MT can 1) protect pulmonary artery endothelium against a diverse array of prooxidant stimuli and 2) directly intercept peroxyl radicals in a metal-independent fashion, thereby preventing lipid peroxidation in intact cells.

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