Free Radical Generation Research Articles

Towards the Development of Novel, Point-of-Care Assays for Monitoring Different Forms of Antioxidant Activity: The RoXstaTM System

(1) Background: This study set out to develop a series of simple, novel, rapid methods for assessing different forms of antioxidant activity. (2) Methods: An ABTS platform was used to engineer: (i) an electrochemical post-activation assay to assess free radical scavenging activity; (ii) an electrochemical pre-activation strategy to assesses the suppression of free radical formation; (iii) a horseradish peroxidase-mediated oxidation system to monitor hydrogen peroxide scavenging activity and (iv) a cumene peroxide-hematin system to determine the ability of samples to scavenge the mixture of organic peroxides and peroxyl and alkoxyl radicals generated in the presence of these reagents. Each assay was assessed against a panel of candidate antioxidant compounds to determine their relative activities and specificities. In addition, human semen samples were analyzed to determine how the results of these antioxidant assays correlated with semen quality. (3) Results: All 4 assays revealed dose-dependent antioxidant activity on the part of vitamin C, N-acetyl cysteine, hypotaurine, BSA, melatonin, glutathione, resveratrol and epigallocatechin gallate. The other compounds tested either completely lacked antioxidant activity or were only active in one of the assays. Using unfractionated human semen as an exemplar of biological fluids rich in antioxidants, the outputs from the individual assays were found to reflect different aspects of semen quality. When the data from all 4 assays were combined, accurate predictions were generated reflecting the importance of oxidative stress in defining semen quality as reflected by sperm count, seminal lipid aldehyde content, sperm DNA damage and free radical generation by the sperm mitochondria. (4) Conclusions: The methodologies described in this paper constitute the basis for rapid, point-of-care assessments of oxidative stress.

Evaluate the effect of exercise core strength training on antioxidant enzyme activity in women from a biomechanical perspective

At present, the incidence rate of chronic diseases is increasing year by year. A variety of antioxidant enzymes in the human body, such as Superoxide Dismutase (SOD), Nitric Oxide Synthase (NOS), Glutathione Peroxidase (GSH Px), Malonic Dialdehyde (MDA) and Catalase (CAT), help to inhibit the generation of oxygen free radicals and play a certain role in preventing the occurrence of chronic diseases. The research on the activity of antioxidant enzymes and the delivery of antioxidant drugs has gradually become the focus of relevant scholars. The physical quality of women is lower than that of men, so it is of great practical significance to study the antioxidant enzyme activity of women. Therefore, this paper explores the influence of exercise core strength training on women’s antioxidant enzyme activity from a biomechanical perspective and concludes that core strength training can improve female students’ SOD content level by 2.58%, and can improve female students’ NOS content level, GSH-Px content level, and MDA content level. Sports core strength training has a positive impact on women’s antioxidant enzyme activity.

NMDA receptor blockade attenuates Japanese encephalitis virus infection-induced microglia activation

Neurodegeneration and neuroinflammation are key components in the pathogenesis of Japanese Encephalitis caused by Japanese Encephalitis Virus (JEV) infection. The N-methyl-D-aspartate (NMDA)-type glutamate receptor displays excitatory neurotoxic and pro-inflammatory properties in a cell context-dependent manner. Herein, potential roles of the NMDA receptor in excitatory neurotoxicity and neuroinflammation and effects of NMDA receptor blockade against JEV pathogenesis were investigated in rat microglia, neuron/glia, neuron cultures, and C57BL/6 mice. In microglia, JEV infection induced glutamate release and activated post-receptor NMDA signaling, leading to activation of Ca2+ mobilization and Calcium/Calmodulin-dependent Protein Kinase II (CaMKII), accompanied by pro-inflammatory NF-κB and AP-1 activation and cytokine expression. Additionally, increased Dynamin-Related Protein-1 protein phosphorylation, NAPDH Oxidase-2/4 expression, free radical generation, and Endoplasmic Reticulum stress paralleled with the reactive changes of microglia after JEV infection. JEV infection-induced biochemical and molecular changes contributed to microglia reactivity and pro-inflammatory cytokine expression. NMDA receptor antagonists MK801 and memantine alleviated intracellular signaling and pro-inflammatory cytokine expression in JEV-infected microglia. JEV infection induced neuronal cell death in neuron/glia culture associated with the concurrent production of pro-inflammatory cytokines. Conditioned media of JEV-infected microglia compromised neuron viability in neuron culture. JEV infection-associated neuronal cell death was alleviated by MK801 and memantine. Activation of NMDA receptor-related inflammatory changes, microglia activation, and neurodegeneration as well as reversal effects of memantine were revealed in the brains of JEV-infected mice. The current findings highlight a crucial role of the glutamate/NMDA receptor axis in linking excitotoxicity and neuroinflammation during the course of JEV pathogenesis, and proposes the anti-inflammatory and neuroprotective potential of NMDA receptor blockade.

Effect of calcination temperature on the presence pattern of calcium ions in slag-based geopolymer microspheres and visible light photocatalytic degradation of tetracycline hydrochloride

Tetracycline hydrochloride (TC) is currently treated mostly with photocatalysts that the preparation process is complicated and costly, limiting its large-scale application. In this study, slag-based geopolymer microspheres (SGMs) photocatalysts were prepared from low-cost slag as raw material using geopolymer technology, and excellent visible-light degradation properties for TC could be obtained by simple calcination. When the water addition was 4 g, the stirring speed was 1000 rpm and the calcination temperature was 800 °C for 3 h, the initial pH was 4.72 and the photocatalyst dosage was 0.4 g/L, SGMs showed excellent photocatalytic performance for TC with 94.76 % degradation in visible-light. Compared with the traditional powder materials, SGMs can achieve rapid separation with excellent settling performance (it can be completely settled within 1 min). With degradation rate remaining over 90 % after five cycles, it showed excellent cyclic stability. The degradation mechanism of SGMs on TC was as follows: firstly, TC adsorption takes place on the SGMs surface during the dark reaction stage; secondly, with Ca2+ in the SGMs enter the solution, it complexed with the TC, making it positively charged and accelerating the generation of free radicals, adsorption and degradation occurred simultaneously, with the order of active free radical action on TC degradation being ·O2- >·OH > h+. The SGMs prepared in this project has the benefits of being inexpensive, easy to operate, environmental protection, excellent visible-light photocatalyst performance, and potential industrial application prospects.

Synergistic effect of curcumin and Piperine loaded Niosomal nanoparticles on acute pulmonary toxicity induced by Paraquat in mice.

Paraquat (PQ), a widely used non-selective herbicide, induces severe lung toxicity by promoting cell death and tissue necrosis through the generation of reactive oxygen species (ROS) and free radicals. This study aimed to develop and evaluate novel niosomal nanoparticles (NPs) encapsulating curcumin and piperine to mitigate PQ-induced acute pulmonary toxicity in Balb/c mice. The NPs were prepared using non-ionic surfactants and cholesterol via the thin film hydration method. Characterization revealed high encapsulation efficiency (>85%), proper particle sizes (264-286nm), narrow polydispersity index (PDI) (0.19±0.04 to 0.23±0.02), and good stability over 90days. Thermal analysis confirmed successful encapsulation of curcumin and piperine within the niosomal NPs. In vivo studies showed that PQ exposure significantly elevated ROS, lipid peroxidation (LPO), and protein carbonylation (PC) levels, while reducing glutathione (GSH) levels and impairing mitochondrial function (P<0.001). However, co-treatment with curcumin- and piperine-loaded niosomal NPs effectively reversed these effects (P<0.001), improving mitochondrial function. The combined formulation of curcumin and piperine in niosomal NPs offers a promising therapeutic strategy for treating PQ-induced pulmonary toxicity, likely due to enhanced bioavailability and potent antioxidant activity.

Incretin-Based Therapies: A Promising Approach for Modulating Oxidative Stress and Insulin Resistance in Sarcopenia.

Recent studies have linked sarcopenia development to the hallmarks of diabetes, oxidative stress, and insulin resistance. The anti-oxidant and insulin sensitivityenhancing effects of incretin-based therapies may provide a promising option for the treatment of sarcopenia. This review aimed to unveil the role of oxidative stress and insulin resistance in the pathogenesis of sarcopenia and explore the potential benefits of incretin-based therapies in individuals with sarcopenia. PubMed, the Cochrane Library, and Google Scholar databases were searched by applying keywords relevant to the main topic, to identify articles that met our selection criteria. Incretin-based therapies manifested anti-oxidant effects by increasing the anti-oxidant defense system and decreasing free radical generation or by indirectly minimizing glucotoxicity, which was mainly achieved by improving insulin signaling and glucose homeostasis. Likewise, these drugs exhibit insulin-sensitizing activities by increasing insulin secretion, transduction, and β-cell function or by reducing inflammation and lipotoxicity. Incretin-based therapies, as modulators of oxidation and insulin resistance, may target the main pathophysiological factors of sarcopenia, thus providing a promising strategy for the treatment of this disease.

Oxidation of glyoxal with the Mo-oxime complex in a benzalkonium chloride interface: Raghavan and Srinivasan kinetic model

Gaining an understanding of the glucose oxidation product (glyoxal) interaction with the metal–organic complex in a biological environment is pivotal to its usage. Thus, the glyoxal (Gyx) oxidation with Mo-oxime complex (MC) is studied with the spectrophotometric method, following a pseudo-phase approach. The result highlights the inclusion of hydrolysis, ion catalysis, the neutral primary salt effect, and radical generation as the essential factors in Gyx oxidation, with the exclusion of intermediate species formation. The hydrolysis of Gxy is observed to actively engage MC without charge inhibition as charge-neutral reacting species are involved, thus, implicating neutral primary salt effect where the variation of ionic strength of the system keeps the redox rate unchanged. The involvement of charge-neutral specie at the rate controlling step encouraged electrostatic attraction when Mg2+ ion additive is incorporated into the system, leading to ion catalysis. The generation of free radical from Gxy aids the emergence of formic acid. The zero intercept of Michealis-Menten type plot and the non-appreciable shift in the maximum absorption wavelength of the reaction system and MC rule-out the presence of intermediate species. The contribution of thermodynamic enthalpy is instrumental in the redox process, leading to the formic acid product. The inclusion of benzalkonium chloride (BZC) hastens the Gxy oxidation, which is supported by Raghavan and Srinivasan’s model.

A mechanistic systems biology model of brain microvascular endothelial cell signaling reveals dynamic pathway-based therapeutic targets for brain ischemia

Ischemic stroke is a significant threat to human health. Currently, there is a lack of effective treatments for stroke, and progress in new neuron-centered drug target development is relatively slow. On the other hand, studies have demonstrated that brain microvascular endothelial cells (BMECs) are crucial components of the neurovascular unit and play pivotal roles in ischemic stroke progression. To better understand the complex multifaceted roles of BMECs in the regulation of ischemic stroke pathophysiology and facilitate BMEC-based drug target discovery, we utilized a transcriptomics-informed systems biology modeling approach and constructed a mechanism-based computational multipathway model to systematically investigate BMEC function and its modulatory potential. Extensive multilevel data regarding complex BMEC pathway signal transduction and biomarker expression under various pathophysiological conditions were used for quantitative model calibration and validation, and we generated dynamic BMEC phenotype maps in response to various stroke-related stimuli to identify potential determinants of BMEC fate under stress conditions. Through high-throughput model sensitivity analyses and virtual target perturbations in model-based single cells, our model predicted that targeting succinate could effectively reverse the detrimental cell phenotype of BMECs under oxygen and glucose deprivation/reoxygenation, a condition that mimics stroke pathogenesis, and we experimentally validated the utility of this new target in terms of regulating inflammatory factor production, free radical generation and tight junction protection in vitro and in vivo. Our work is the first that complementarily couples transcriptomic analysis with mechanistic systems-level pathway modeling in the study of BMEC function and endothelium-based therapeutic targets in ischemic stroke.

A Combined Stereolithography and A Pressureless Sintering Method to Prepare SiC Ceramics

The use of submicron silicon carbide powder as a raw material is crucial for preparing high-performance silicon carbide ceramics. However, its strong absorption of ultraviolet light makes stereolithography of submicron silicon carbide powder challenging. In this study, submicron SiC particles, photosensitive resin, and photoinitiator were used as raw materials to prepare SiC ceramics via stereolithography combined with a pressureless sintering method. The effects of ultraviolet wavelength, type, and content of photoinitiator on the curing properties of submicron SiC ceramic slurry were investigated. The results showed that the curing thickness of the SiC ceramic slurry significantly increased with the increasing ultraviolet wavelength. Compared to photoinitiators TPO and 396, photoinitiator 819 exhibited a better curing effect. Additionally, increasing the photoinitiator content facilitated the generation of more free radicals in the SiC ceramic slurry at low light intensity, thereby improving its ultraviolet absorption characteristics. When the dosage of photoinitiator 819 was 8.8%, the SiC slurry achieved the best curing performance, with a single-layer curing thickness of 50 μm and a sintering density of 95% for SiC ceramics.

A select thiosemicarbazone copper(II) complex induces apoptosis in gastric cancer and targets cancer stem cells reducing pluripotency markers

Copper(II)-based complexes are promising candidates as anti-cancer agents due to their ability to target cancer cells. Here we describe the synthesis and characterization of two copper(II) thiosemicarbazone complexes with the ligands 4-(dimethylamino)benzaldehyde N4-methylthiosemicarbazone (HL1) and 4-(dimethylamino)benzaldehyde N4-(4-(dimethylamino)phenylthiosemicarbazone (HL2) and general formula [Cu(L)2]. The complexes show stability in aqueous solution with 1 % of DMSO that allows to stablish its solution profile in biological buffers. Compound [Cu(L1)₂] lipophilicity was lower than [Cu(L2)₂], however, its solubility in biological buffer was not only better but also its DLS and ζ-potential data. In vitro studies demonstrate a higher cytotoxic effect of [Cu(L1)₂] on gastric cancer cells. The proposed mechanism of action consists in the generation of free radicals that induce DNA lesions, oxidative stress and ultimately autophagy deregulation and apoptosis. Additionally, [Cu(L1)₂] is equally active on gastric cancer stem cells and tumor cells resistant to cisplatin. More importantly, stem cells treated with [Cu(L1)₂] show a downregulation of pluripotency markers such as TWIST, NANOG and OCT4. Overall, our results with [Cu(L1)₂] prompt a significant advancement in the development of rational-designed pharmaceuticals for combating cancer.

Differential Cytoprotective Effect of Resveratrol and Its Derivatives: Focus on Antioxidant and Autophagy-Inducing Effects

Numerous beneficial effects of resveratrol were reported; however, its pharmacological profile is contradictious. Previously, we have demonstrated that resveratrol has a dose-dependent cytoprotective effect and the essential role of autophagy induction was demonstrated. Resveratrol suffers from unfavorable pharmacokinetics, hindering its clinical use. Our aim was to study the cytoprotective effect of resveratrol derivatives to better understand structure–activity relationships that may facilitate the development of compounds with better druglike characteristics. Serum-deprivation-induced caspase activation, free radical generation, mitochondrial membrane depolarization and autophagy were detected in the presence of resveratrol analogs with different oxidation states on mouse embryonal fibroblasts. Distinct cytoprotective mechanisms of the examined compounds were revealed. Monomethyl resveratrol had similar potency to resveratrol (EC50: 85.3 vs. 84.2 μM); however, autophagy induction was not essential for its cytoprotective effect. Oxyresveratrol was found to be a strong antioxidant that can induce direct cytoprotection rather than autophagy. Trimethyl-resveratrol, lacking free hydroxyl groups, induced damage that was too significant and hardly compensated by the activation of cytoprotective machineries, and caspase activation was reduced by only 24.5%. Based on our results, methylation of resveratrol reduces its antioxidant activity, while autophagy induction can still contribute to its cytoprotective effect. The introduction of an additional hydroxyl group, however, augments the antioxidant properties, inducing cytoprotection without autophagy induction.

Exploring the 3,5-Dibromo-4,6-dimethoxychalcones and Their Flavone Derivatives as Dual α-Glucosidase and α-Amylase Inhibitors with Antioxidant and Anticancer Potential.

The rising levels of type 2 diabetes mellitus (T2DM) and the poor medical effects of the commercially available antidiabetic drugs necessitate the development of potent analogs to treat this multifactorial metabolic disorder. It has been demonstrated that targeting two or more biochemical targets associated with the onset and progression of diabetes along with oxidative stress and/or cancer could be a significant strategy for treating complications related to this metabolic disorder. The 3,5-dibromo-4,6-dimethoxychalcones (2a-f) and the corresponding flavone derivatives (3a-f) were synthesized and characterized using spectroscopic (NMR, HR-MS and FT-IR) techniques. The inhibitory effect of both series of compounds against α-glucosidase and α-amylase was evaluated in vitro through enzymatic assays. Selected compounds were also evaluated for potential to activate or inhibit superoxide dismutase. Compound 3c was selected as a representative model for the flavone series and evaluated spectrophotometrically for potential to coordinate Cu(II) and/or Zn(II) ions implicated in the metal-catalyzed free radical generation. A plausible mechanism for metal-chelation of the test compounds is presented. Furthermore, the most active compounds from each series against the test carbohydrate-hydrolyzing enzymes were selected and evaluated for their antigrowth effect on the human breast (MCF-7) and lung (A549) cancer cell lines and for cytotoxicity against the African Green Monkey kidney (Vero) cell line. The parent chalcone 2a and flavone derivatives 3a, 3c and 3e exhibited relatively high inhibitory activity against the MCF-7 cells with IC50 values of 4.12 ± 0.55, 8.50 ± 0.82, 5.10 ± 0.61 and 6.96 ± 0.66 μM, respectively. The chalcones 2a and 2c exhibited significant cytotoxicity against the A549 cells with IC50 values of 7.40 ± 0.67 and 9.68 ± 0.80 μM, respectively. Only flavone 3c exhibited relatively strong and comparable cytotoxicity against the MCF-7 and A549 cell lines with IC50 values of 6.96 ± 0.66 and 6.42 ± 0.79 μM, respectively. Both series of compounds exhibited strong activity against the MCF-7 and A549 cell lines compared to the analogous quercetin (IC50 = 35.40 ± 1.78 and 35.38 ± 1.78 μM, respectively) though moderate compared to nintedanib (IC50 = 0.53 ± 0.11 and 0.74 ± 0.15 μM, respectively). The test compounds generally exhibited reduced cytotoxicity against the Vero cells compared to this anticancer drug. Molecular docking revealed strong alignment of the test compounds with the enzyme backbone to engage in hydrogen bonding interaction/s and hydrophobic contacts with the residues in the active sites of α-glucosidase and α-amylase. The test compounds possess favorable drug-likeness properties, supporting their potential as therapeutic candidates against T2DM.

Exfoliated Porous Carbon Nitride by Simultaneous Oxidation-Corrosion for Photocatalytic H2O2 Production and Organic Degradation.

Graphitic carbon nitride (g-C3N4) is a fascinating material with potential applications in photocatalysis due to its good chemical stability, high thermal stability, and relative ease of synthesis. In this work, ultrathin g-C3N4 is constructed using a hybridized method, which combines the advantages of thermal and liquid-phase stripping methods. This sample can improve performance in degrading organic pollutants several times, and the highest enhancement efficiency occurs in an alkaline environment. In addition, photocatalytic production of hydrogen peroxide can be increased to 2.6 times that of the bulk sample. These improved properties are due to the increase in specific surface area, the generation of free radicals, and adsorption capacity. This work presents a one-step exfoliation method for bulk g-C3N4 for more surface-active sites and strong redox capacity.

Numerical Study on the Explosion Reaction Mechanism of Multicomponent Combustible Gas in Coal Mines

Combustible gases, such as CO, CH4, and H2, are produced during spontaneous coal combustion in goaf, which may cause an explosion under the stimulation of an external fire source. It is of great significance to study the influence of combustible gases, such as CO and H2, on the characteristics of a gas explosion. In this study, CHEMKIN software (Version 17.0) and the GRI-Mech 3.0 reaction mechanism were used to study the influences of different concentration ratios between CO and H2 on the ignition delay time, free radical concentration, and key reaction step of a gas explosion. The results show that the increase in the initial CH4 and CO concentrations prolonged the ignition delay time, while the increase in the H2 concentration shortened the time and accelerated the explosion reaction. The addition of H2 promoted the generation of free radicals (H⸱, O⸱, ⸱OH) and accelerated the occurrence of the gas explosion. CO generated ⸱OH free radicals and dominated the methane consumption through the R119 and R156 reactions. As the concentrations of CO and H2 increased, the R38 reaction gradually became the main driving factor of the gas explosion.

Free radical detection in precision-cut mouse liver slices with diamond-based quantum sensing

Free radical generation plays a key role in many biological processes including cell communication, maturation, and aging. In addition, free radical generation is usually elevated in cells under stress as is the case for many different pathological conditions. In liver tissue, cells produce radicals when exposed to toxic substances but also, for instance, in cancer, alcoholic liver disease and liver cirrhosis. However, free radicals are small, short-lived, and occur in low abundance making them challenging to detect and especially to time resolve, leading to a lack of nanoscale information. Recently, our group has demonstrated that diamond-based quantum sensing offers a solution to measure free radical generation in single living cells. The method is based on defects in diamonds, the so-called nitrogen-vacancy centers, which change their optical properties based on their magnetic surrounding. As a result, this technique reveals magnetic resonance signals by optical means offering high sensitivity. However, compared to cells, there are several challenges that we resolved here: Tissues are more fragile, have a higher background fluorescence, have less particle uptake, and do not adhere to microscopy slides. Here, we overcame those challenges and adapted the method to perform measurements in living tissues. More specifically, we used precision-cut liver slices and were able to detect free radical generation during a stress response to ethanol, as well as the reduction in the radical load after adding an antioxidant.

Bioorthogonal Regulated Metabolic Balance for Promotion of Ferroptosis and Mild Photothermal Therapy.

The nanozyme with NADPH oxidase (NOX)-like activity can promote the consumption of NADPH and the generation of free radicals. In consideration of that the upregulation of glucose-6-phosphate dehydrogenase (G6PD) would accelerate the compensation production of NADPH, for inhibition of G6PD activity, our designed bioorthogonal nanozyme can in situ catalyze pro-DHEA to produce G6PD inhibitor and dehydroepiandrosterone (DHEA) drugs to inhibit G6PD activity. Therefore, the well-defined platform can disrupt NADPH homeostasis, leading to the collapse of the antioxidant defense system in the tumor cells. The enzyme-like activity of PdCuFe is further enhanced when irradiated by NIR-II light. The destruction of NADPH homeostasis can promote ferroptosis and, in turn, facilitate mild photothermal therapy. Our design can realize NADPH depletion and greatly improve the therapeutic effect through metabolic regulation, which may provide inspiration for the design of bioorthogonal catalysis.

Enhanced activation of peroxymonosulfate by nanomagnetic CoFe2O4-CeO2/g-C3N4 composites as a heterogeneous catalyst for metronidazole degradation

Antibiotic-induced catastrophic pollution has the potential to migrate over vast distances through water, thereby posing a detrimental effect on both humans and the environment. The construction of a highly robust catalyst to activate peroxymonosulfate (PMS) has become a fascinating approach for treating such types of wastewaters. In this study, we have developed CoFe2O4-CeO2/CN catalysts using an impregnation-hydrothermal and ultrasonication method to efficiently degrade metronidazole (MNZ). The synthesized catalyst materials were analyzed through multiple characterization techniques in order to correlate the material properties and the degradation performance. The degradation trials exhibited that MNZ underwent complete degradation within 40 min in the CoFe2O4-CeO2/CN-2/PMS system, with a rate constant of 0.1354 min−1, nearly 5.29 times faster than the CoFe2O4-CeO2/PMS (0.0235 min−1) under optimal conditions ([catalyst] = 0.5 g/L, [PMS] = 0.5 mM, [MNZ] = 20 mg/L, pH = 6.72). The increased abatement of MNZ in CoFe2O4-CeO2/CN-2/PMS system could be attributed to the higher surface area of the CoFe2O4-CeO2/CN-2 (75.96 m2/g) catalyst in comparison to the CoFe2O4-CeO2 (53.98 m2/g), which enhances the catalytically active sites and improves the PMS activation reaction. Besides, the impact of several operational variables and influencing anions on MNZ degradation was researched as well. The generation of free radicals was confirmed by radical scavenging analysis and authenticated using electron paramagnetic resonance analysis. The mechanistic analysis established that the activation of PMS was initiated by the transformations of Co3+/Co2+, Fe3+/Fe2+, and Ce4+/Ce3+. Briefly, this research provides valuable perspective for future research regarding heterogeneous catalysis leveraging PMS activation to alleviate toxic contaminants.

Square-wave pulsed potential driven electrocatalytic degradation of 4-chlorophenol using Fe-Ni/rGO/PPy@NF three dimensional electrode

To develop an energy-efficient system for the removal of chlorinated organic pollutants, Fe-Ni/reduced graphite oxide/polymerized polypyrrole@nickel foam was constructed as a catalytic cathode for pulsed electrocatalytic degradation, where cathode-catalyzed production of hydrogen radicals (H*) and hydroxyl radical (·OH) generated at the anode led to dechlorination of 4-chlorophenol (4-CP), and dechlorination products were mineralized and degraded under the action of·OH. When energy was continuously supplied to the reaction system in the constant potential mode, the 4-CP concentration near the electrode was insufficient, limiting the reaction rate. Conversely, in the square-wave pulsed potential mode, mass transfer limitations were mitigated, significantly enhancing reaction efficiency and reducing energy consumption. At −1.2 V (vs. Ag/AgCl), the 4-CP removal efficiency reached 93.79 % in the pulsed potential mode, surpassing the constant potential mode's performance of 81.40 %. The synergistic periodic oscillation of the potential, direct electron transfer, and catalytic generation of active free radicals in the pulsed potential mode reduced intermediate concentrations and increased 4-CP mineralization, while the degradation pathway remained unchanged. This research presents a method for the efficient treatment of chlorinated organic pollutants in water using pulsed electrocatalytic degradation.

In silico assessment of antioxidant activity and toxicity profiling of bioactive molecules from Murraya koenigii

The antioxidant activity of curry leaves is of interest because oxidative stress is implicated in a variety of diseases, including cancer, heart disease, and neurodegenerative disorders. By scavenging free radicals and inhibiting lipid peroxidation, antioxidants can help protect cells from damage and reduce the risk of these diseases. Overall, in-silico studies suggest that curry leaves and their bioactive compounds have potent antioxidant activity. The objective of the study was to assess the antioxidant activity of the bioactive molecules from Murraya koenigii and anticipate the toxicity by in-silico research. iGEMDOCK software was used to assess the antioxidant activity. ProTox II software was used to conduct the toxicity investigations. Osthol (− 81.4863, − 81.9046 kcal/mol), mukoenineA (− 81.0417, − 78.9941 kcal/mol), murrayone(− 80.0731, − 78.9453 kcal/mol), kaempferol (− 97.0774, − 89.3534 kcal/mol), and apigenin (− 89.5291, − 108.704 kcal/mol) were found to have the highest binding energies with SOD and GPx proteins, respectively, when compared with standard (ascorbic acid; − 81.132, − 98.917 kcal/mol). All the mentioned compounds have low levels of hepatotoxicity, carcinogenicity, immunotoxicity, mutagenicity, and cytotoxicity. The bioactive molecules of Murraya koenigii have a potent antioxidant effect and low level of toxicity that gives valuable insight for optimizing lead molecules to combat free radical generation or oxidation.

Cu‐Doped 0D Bi2WO6 Nanoparticles for Efficient Visible‐Light‐Driven Photocatalytic Tetracycline Degradation

AbstractBismuth‐based photocatalysts have been widely employed in the photocatalytic degradation of organic pollutants in wastewater. However, the lack of rational structural design and the slow generation of active free radicals have hindered its efficiency. Here, we stabilized Bi2WO6 nanoparticles by wrapping them with hydroxyl groups, introduced metal Cu doping, and underwent an annealing process to construct Cu‐BiNP nanocatalysts with exposed active sites. Under visible light irradiation, 0.03Cu‐BiNP achieved a 94.5% TC degradation efficiency, which is 15.8 times higher than the rate of bulk BiWO. The 0D structure endows Cu‐BiNP with ample opportunities for O2 adsorption and activation, and Cu atomic doping reduces the bandgap and increases the oxygen vacancy, promoting the generation of active oxygen species. This work demonstrates the rapid charge separation and activation of O2 to generate active oxygen species by 0D bismuth‐based nanocatalysts in photocatalytic oxidation reactions, providing a scalable nanocatalyst platform for TC photocatalytic degradation.