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Handbook of Experimental Pharmacology 2021A number of diseases and conditions have been associated with prolonged or persistent exposure to non-physiological levels of reactive oxygen species (ROS). Similarly,... (Review)
Review
A number of diseases and conditions have been associated with prolonged or persistent exposure to non-physiological levels of reactive oxygen species (ROS). Similarly, ROS underproduction due to loss-of-function mutations in superoxide or hydrogen peroxide (HO)-generating enzymes is a risk factor or causative for certain diseases. However, ROS are required for basic cell functions; in particular the diffusible second messenger HO that serves as signaling molecule in redox processes. This activity sets HO apart from highly reactive oxygen radicals and influences the approach to drug discovery, clinical utility, and therapeutic intervention. Here we review the chemical and biological fundamentals of ROS with emphasis on HO as a signaling conduit and initiator of redox relays and propose an integrated view of physiological versus non-physiological reactive species. Therapeutic interventions that target persistently altered ROS levels should include both selective inhibition of a specific source of primary ROS and careful consideration of a targeted pro-oxidant approach, an avenue that is still underdeveloped. Both strategies require attention to redox dynamics in complex cellular systems, integration of the overall spatiotemporal cellular environment, and target validation to yield effective and safe therapeutics. The only professional primary ROS producers are NADPH oxidases (NOX1-5, DUOX1-2). Many other enzymes, e.g., xanthine oxidase (XO), monoamine oxidases (MAO), lysyl oxidases (LO), lipoxygenase (LOX), and cyclooxygenase (COX), produce superoxide and HO secondary to their primary metabolic function. Superoxide is too reactive to disseminate, but HO is diffusible, only limited by adjacent PRDXs or GPXs, and can be apically secreted and imported into cells through aquaporin (AQP) channels. HO redox signaling includes oxidation of the active site thiol in protein tyrosine phosphatases, which will inhibit their activity and thereby increase tyrosine phosphorylation on target proteins. Essential functions include the oxidative burst by NOX2 as antimicrobial innate immune response; gastrointestinal NOX1 and DUOX2 generating low HO concentrations sufficient to trigger antivirulence mechanisms; and thyroidal DUOX2 essential for providing HO reduced by TPO to oxidize iodide to an iodinating form which is then attached to tyrosyls in TG. Loss-of-function (LoF) variants in TPO or DUOX2 cause congenital hypothyroidism and LoF variants in the NOX2 complex chronic granulomatous disease.
Topics: Hydrogen Peroxide; NADPH Oxidases; Oxidants; Oxidation-Reduction; Physiological Phenomena; Reactive Oxygen Species
PubMed: 32767144
DOI: 10.1007/164_2020_380 -
Journal of Hazardous Materials Jun 2014Sulfamethoxazole (SMX), a typical sulfonamide antibiotic, has been widely detected in secondary wastewater effluents and surface waters. In this work we investigated the... (Comparative Study)
Comparative Study
Sulfamethoxazole (SMX), a typical sulfonamide antibiotic, has been widely detected in secondary wastewater effluents and surface waters. In this work we investigated the oxidative degradation of SMX by commonly used oxidants of chlorine, ozone and permanganate. Chlorine and ozone were shown to be more effective for the removal of SMX (0.05-5.0mg/L), as compared with permanganate. Higher pH enhanced the oxidation of SMX by ozone and permanganate, but decreased the removal by chlorine. Moreover, the ozonation of SMX was significantly influenced by the presence of humic acid (HA), which exhibited negligible influence on the oxidation by chlorine and permanganate. Fairly lower mineralization of SMX occurred during the oxidation reactions, with the highest dissolved organic carbon (DOC) removal of 13% (for ozone). By using LC-MS/MS, 7, 5 and 5 oxidation products were identified for chlorine, ozone and permanganate and possible transformation pathways were proposed. It was shown that different oxidants shared some common pathways, such as the cleavage of SN bond, the hydroxylation of the benzene ring, etc. On the other hand, each of the oxidants also exhibited exclusive degradation mechanisms, leading to the formation of different transformation products (TPs). This work may provide useful information for the selection of oxidants in water treatment processes.
Topics: Anti-Infective Agents; Chlorine; Humic Substances; Manganese Compounds; Oxidants; Oxidation-Reduction; Oxides; Ozone; Sulfamethoxazole; Water Pollutants, Chemical; Water Purification
PubMed: 24793298
DOI: 10.1016/j.jhazmat.2014.04.024 -
Scientific Reports Mar 2022The idea of applying ultrasound (US) as a green activation method in chemical transformations, especially in catalytic alcohol oxidations, technically and ecologically...
The idea of applying ultrasound (US) as a green activation method in chemical transformations, especially in catalytic alcohol oxidations, technically and ecologically appeals to chemists. In the present work, as an attempt to fulfill the idea of designing an eco-friendly system to oxidize alcoholic substrates into corresponding aldehydes, we developed multifunctional tungstate-decorated CQD base catalyst, A-CQDs/W, and examined its sonooxidation performance in presence of HO as a green oxidant in aqua media. By comparing the catalyst performance in oxidize benzyl alcohol as a testing model to benzaldehyde (BeOH) prior and after US irradiation-trace vs 93%- the key role of ultrasonic irradiation in achieving high yield is completely appreciated. Exceptional thermal and compression condition that is created as a result of acoustic waves is in charge of unparalleled yield results in this type of activation method. The immense degree of reagent interaction in this method, ensures the maximum yield in notably low time, which in turn leads to decrease in the number of unreacted reagents and by-products. Meanwhile, the need for using toxic organic solvents and hazardous oxidants, auxiliaries and phase transfer catalyst (PTC) is completely obviated.
Topics: Alcohols; Aldehydes; Catalysis; Hydrogen Peroxide; Oxidants; Tungsten Compounds
PubMed: 35233016
DOI: 10.1038/s41598-022-06874-5 -
Journal of Hazardous Materials Jul 2022Cr(VI) from oxidation of geogenic Cr(III) minerals is gradually becoming the primary source of Cr(VI) in soils and groundwater instead of direct emissions....
Cr(VI) from oxidation of geogenic Cr(III) minerals is gradually becoming the primary source of Cr(VI) in soils and groundwater instead of direct emissions. Thermodynamically, natural oxidants of Cr(III) are limited to O and Mn oxides. The oxidation of Cr(III) occurs commonly in oxic soils but the difference in the oxidative dissolution of Cr(III) by Mn oxides in different redox soils (especially under anoxic conditions) is not fully understood and field evidence is lacking. Here, the relationship between Cr(VI) and Mn oxides in basalt-origin soil profiles under three different redox conditions (anoxic, suboxic and oxic) was studied. The oxidative dissolution of chromite was validated by synthesising δ-MnO that was close to biogenic Mn oxides under anoxic and oxic conditions. In anoxic soils, high levels of Cr(VI) were detected in the same horizons as those where Cr(III)-minerals co-existed with Mn(III/IV) oxides, suggesting an exclusive pathway for Cr(VI) generation through oxidation by Mn oxides where there was a deficiency of other oxidants, such as O. In oxic soils, the highly abundant Fe oxides combined with Cr(III) to form Cr(III)-Fe(III) oxyhydroxides and Cr(VI) was generated mainly via slow oxidation by O. The chromite oxidation experiment results also indicated that a high abundance of Mn oxides could promote chromite oxidative dissolution to generate Cr(VI), even under anoxic conditions. Additionally, the form of Cr and the reactivity and abundance of Mn oxides and reducing agents controlled the net content of Cr(VI) in the soil. This study showed that, even under reducing conditions, Cr(III) is readily oxidised by Mn oxides to generate Cr(VI) in reductant-deficient and Mn-rich soils, which may lead to the continuous introduction of Cr(VI) into groundwater and agricultural soils.
Topics: Chromium; Ferric Compounds; Manganese Compounds; Minerals; Oxidants; Oxidation-Reduction; Oxides; Soil
PubMed: 35381512
DOI: 10.1016/j.jhazmat.2022.128805 -
The Journal of Organic Chemistry May 2022Second-generation chiral-substituted poly--vinylpyrrolidinones (CSPVPs) (-)- and (+)- were synthesized by free-radical polymerization of (3a,6a)- and...
Second-generation chiral-substituted poly--vinylpyrrolidinones (CSPVPs) (-)- and (+)- were synthesized by free-radical polymerization of (3a,6a)- and (3a,6a)-5-ethenyl-tetrahydro-2,2-dimethyl-4-1,3-dioxolo[4,5-]pyrrol-4-one, respectively, using thermal and photochemical reactions. They were produced from respective -isoascorbic acid and d-ribose. In addition, chiral polymer (-)- was also synthesized from the polymerization of ()-3-(methoxymethoxy)-1-vinylpyrrolidin-2-one. Molecular weights of these chiral polymers were measured using HRMS, and the polymer chain tacticity was studied using C NMR spectroscopy. Chiral polymers (-)-, (+)-, and (-)- along with poly--vinylpyrrolidinone (PVP, MW 40K) were separately used in the stabilization of Cu/Au or Pd/Au nanoclusters. CD spectra of the bimetallic nanoclusters stabilized by (-)- and (+)- showed close to mirror-imaged CD absorption bands at wavelengths 200-300 nm, revealing that bimetallic nanoclusters' chiroptical responses are derived from chiral polymer-encapsulated nanomaterials. Chemo-, regio-, and stereo-selectivity was found in the catalytic C-H group oxidation reactions of complex bioactive natural products, such as ambroxide, menthofuran, boldine, estrone, dehydroabietylamine, 9-allogibberic acid, and sclareolide, and substituted adamantane molecules, when catalyst Cu/Au (3:1) or Pd/Au (3:1) stabilized by CSPVPs or PVP and oxidant HO or -BuOOH were applied. Oxidation of (+)-boldine -oxide using NMO as an oxidant yielded 4,5-dehydroboldine , and oxidation of (-)-9-allogibberic acid yielded C6,15 lactone and C6-ketone .
Topics: Catalysis; Hydrogen Peroxide; Oxidants; Oxidation-Reduction; Polymers
PubMed: 35511477
DOI: 10.1021/acs.joc.2c00449 -
Free Radical Biology & Medicine Jan 2005Highly oxidized protein aggregates accumulating in the brain during neurodegenerative diseases are often surrounded by microglia. Most of the microglial cells...
Highly oxidized protein aggregates accumulating in the brain during neurodegenerative diseases are often surrounded by microglia. Most of the microglial cells surrounding these plaques are activated and release a high amount of oxidizing species. In order to develop their toxic effects numerous oxidizing species need iron. To prevent this iron-dependent oxidation an iron-sequestering apparatus exists, including the major iron storage protein ferritin. Microglial cells damage their own protein pool during activation and it is still unknown whether microglial cells are able to maintain their iron-sequestering function during oxidative stress. Therefore, we explored the microglial cell line RAW to test the maintenance of ferritin under oxidizing conditions. Our investigations revealed a half-life of both ferritin chains of 3-3.5 h and a reduced half-life due to oxidation. This was due to the removal of oxidized ferritin by the proteasomal system. Ferritin de novo synthesis was also severely affected by oxidation. This results in a decreased ferritin pool due to acute oxidative stress. These data let us conclude that microglial cells do not increase their ferritin amount after oxidative stress and an increase in the iron storage capacity in these cells after treatment might be achieved only by a high iron saturation of the existing ferritin molecules.
Topics: Animals; Cell Line; Chelating Agents; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Ferritins; Hydrogen Peroxide; Immunoblotting; Immunoprecipitation; Iron; Macrophages; Mice; Microglia; Oxidants; Oxidative Stress; Oxygen; Proteasome Endopeptidase Complex; Time Factors
PubMed: 15607911
DOI: 10.1016/j.freeradbiomed.2004.10.025 -
Water Research Aug 2023Sole O or HO oxidant hardly oxidize Sb(III) on a time scale of hours to days, but Sb(III) oxidation can simultaneously occur in Fe(II) oxidation by O and HO due to the...
Sole O or HO oxidant hardly oxidize Sb(III) on a time scale of hours to days, but Sb(III) oxidation can simultaneously occur in Fe(II) oxidation by O and HO due to the generation of reactive oxygen species (ROS). However, Sb(III) and Fe(II) co-oxidation mechanisms regarding the dominant ROS and effects of organic ligands require further elucidation. Herein, the co-oxidation of Sb(III) and Fe(II) by O and HO was studied in detail. The results indicated that increasing the pH significantly increased Sb(III) and Fe(II) oxidation rates during Fe(II) oxygenation, while the highest Sb(III) oxidation rate and oxidation efficiency was obtained at pH 3 with HO as the oxidant. HCO and HPOanions exerted different effects on Sb(III) oxidation in Fe(II) oxidation processes by O and HO. In addition, Fe(II) complexed with organic ligands could improve Sb(III) oxidation rates by 1 to 4 orders of magnitude mainly due to more ROS production. Moreover, quenching experiments combined with the PMSO probe demonstrated that OH was the main ROS at acidic pH, whereas Fe(IV) played a key role in Sb(III) oxidation at near-neutral pH. In particular, the steady-state concentration of Fe(IV) ([Fe(IV)]) and k were determined to be 1.66×10 M and 2.57×10 M s, respectively. Overall, these findings help to better understand the geochemical cycling and fate of Sb in Fe(II)- and DOM-rich subsurface environments undergoing redox fluctuations and are conductive to developing Fenton reactions for the in-situ remediation of Sb(III)-contaminated environments.
Topics: Hydrogen Peroxide; Reactive Oxygen Species; Oxygen; Ligands; Oxidation-Reduction; Oxidants; Ferrous Compounds; Ferric Compounds
PubMed: 37413752
DOI: 10.1016/j.watres.2023.120296 -
Journal of Hazardous Materials Feb 2023While extensive works focused on the enhancement of the activity of heterogeneous Fenton catalysts, little was paid attention to the inhibition of soil organic matter...
Insight on efficiently oriented oxidation of petroleum hydrocarbons by redistribution of oxidant through inactivation of soil organic matter coupled with passivation of manganese minerals.
While extensive works focused on the enhancement of the activity of heterogeneous Fenton catalysts, little was paid attention to the inhibition of soil organic matter (SOM) and Mn minerals in soil remediation. Here, the oxidation of petroleum hydrocarbons in soils (S1: 4.28 % SOM, S2: 6.04 % SOM, S3: 10.33 % SOM) with inactivated SOM and passivated Mn oxides regulating by calcium superphosphate (Ca(HPO)) was carried out. Oily sludge pyrolysis residue was used as precursors to prepare an oleophilic iron-supported solid catalyst (Fe-N @ PR). For regulated systems, under the optimal conditions of 1.8 mmol/g HO and 0.05 g/g Fe-N @ PR, 72 ∼ 91 % of total petroleum hydrocarbons (TPHs: 15,616.58 mg/kg) were oxidized, which was 38 ∼ 45 % higher than that of control systems. The mechanism of efficient oxidation was proposed that the passivated Mn minerals stabilized HO redistributing more HO to sustainably produce •OH, and the inactivated SOM improved the relative reactivity of •OH to TPHs. Additionally, the passivation of Mn oxides was mainly related to the binding of HPO, and the inactivation of SOM was realized by Ca combing with -OH and C-O-C to form stable complexes. This study brought us a new perspective on soil remediation through passivating Mn minerals and inactivating SOM.
Topics: Soil; Petroleum; Manganese; Soil Pollutants; Oxidants; Hydrogen Peroxide; Hydrocarbons; Oxidation-Reduction; Minerals; Oxides
PubMed: 36270191
DOI: 10.1016/j.jhazmat.2022.130192 -
Environmental Science & Technology Apr 2014Oxidation of arsenite (As(III)) is a critical yet often weak link in many current technologies for remediating contaminated groundwater. We report a novel, efficient...
Oxidation of arsenite (As(III)) is a critical yet often weak link in many current technologies for remediating contaminated groundwater. We report a novel, efficient oxidation reaction for As(III) conversion to As(V) using commercial available peroxymonosulfate (PMS). As(III) is rapidly oxidized by PMS with a utilization efficiency larger than 90%. Increasing PMS concentrations and pH accelerate oxidation of As(III), independent to the availability of dissolved oxygen. The addition of PMS enables As(III) to oxidize completely to As(V) within 24 h, even in the presence of high concentrations of radical scavengers. On the basis of these observations and theoretical calculations, a two-electron transfer (i.e., oxygen atom transfer) reaction pathway is proposed. Direct oxidation of As(III) by PMS avoids the formation of nonselective reactive radicals, thus minimizing the adverse impact of coexisting organic matter and maximizing the utilization efficiency of PMS. Therefore, this simple approach is considered a cost-effective water treatment method for the oxidation of As(III) to As(V).
Topics: Arsenites; Electrons; Free Radical Scavengers; Hydrogen-Ion Concentration; Ions; Iron; Methylene Blue; Oxidants; Oxidation-Reduction; Peroxides; Solutions; Thermodynamics
PubMed: 24580110
DOI: 10.1021/es405143u -
Chemosphere Apr 2002This paper describes a study of oxidation of diethylene glycol (DEG) by ozone and modified Fenton process (hydrogen peroxide and ferric salt mixture) in aqueous...
This paper describes a study of oxidation of diethylene glycol (DEG) by ozone and modified Fenton process (hydrogen peroxide and ferric salt mixture) in aqueous solution. Both oxidation processes were able to oxidize relatively high concentrations of DEG effectively. DEG reacted primarily through hydroxyl radical produced by decomposition of ozone, and about 3 mol of ozone were consumed per mole of DEG removed during the process. For modified Fenton oxidation, stepwise addition of hydrogen peroxide (H2O2) and ferric salt (Fe(III)) resulted in much higher removal of DEG than one-time pulse addition of the chemicals. The extent of DEG removal increased with increasing concentrations of both H2O2 and Fe(III). Oxidant consumption per mole of DEG oxidized was one order of magnitude higher for hydrogen peroxide than those observed for ozone. Overall, ozonation produced higher concentrations of aldehydes, and modified Fenton treatment produced higher concentrations of carboxylic acids for the same levels of DEG oxidation. The major products of ozonation were glycolaldehyde, glyoxal, formaldehyde, acetaldehyde, and acetic, formic, pyruvic, oxalic and glyoxalic acids. The major products of modified Fenton oxidation were formaldehyde, and formic and acetic acids.
Topics: Environmental Pollution; Ethylene Glycols; Hydrogen Peroxide; Iron; Oxidants; Oxidants, Photochemical; Oxidation-Reduction; Ozone
PubMed: 11996150
DOI: 10.1016/s0045-6535(01)00312-5