Search Results (171)

Endometriosis is a hormone-dependent gynecological disease manifested by cyclic pelvic pain and female infertility. Although many studies have shown that neoangiogenesis plays an essential role in the development of early endometriosis, the underlying pathophysiological mechanisms remain unclear. Recent evidence suggests that macrophages play an important role in the pathogenesis of endometriosis and that the hypoxia-inducible factor-1alpha (HIF-1α) may be involved, but when and how are largely unknown. Herein, we explore the role of macrophages in the early development of endometriosis using an in vivo subcutaneous implantation murine model. Upon depletion of macrophages, the subcutaneous injection of syngeneic endometrial material resulted in significant reduction in oxidative stress, endometriotic lesion size, and neovascularization. Likewise, inactivation of the lipid peroxidative gene Alox15 induced similar reduction in oxidative stress, lesion growth, and angiogenesis. Since HIF-1α is an important trigger of neoangiogenesis, we further administered a HIF-1α-specific inhibitor (PX-478) to our endometriotic model and further confirmed the same effects on the lesions. Taken together, these data suggest that an intact Alox15 pathway and HIF-1α signaling may play important roles in the macrophage-mediated oxidative stress and neovascularization of endometriosis in the early stages, suggesting anti-inflammation and antioxidation as potential therapeutic targets for the development of endometriosis. Full article

Endoperoxides constitute a distinctive class of highly oxygenated terpenoids defined by the presence of a cyclic peroxide (–O–O–) bond, a structural motif responsible for their pronounced chemical reactivity and diverse biological effects. Naturally occurring endoperoxide-containing terpenoids are broadly distributed across terrestrial and marine taxa, including higher plants, algae, fungi, and bryophytes, where they are believed to participate in chemical defense and ecological interactions. This review provides a comprehensive overview of naturally occurring endoperoxide terpenoids, focusing on their natural sources, structural diversity, and reported biological activities. Particular emphasis is placed on compounds exhibiting antiprotozoal and antitumor activities, exemplified by artemisinin and its derivatives, which remain cornerstone agents in antimalarial therapy and continue to attract interest for their anticancer potential. Structure–activity relationship (SAR) analysis, supported by computational prediction using the PASS (Prediction of Activity Spectra for Substances) platform, is employed to examine correlations between peroxide-containing frameworks and biological function. Comparative assessment of experimental data and predicted activity profiles identifies key structural features associated with antiprotozoal, antineoplastic, and anti-inflammatory effects. Collectively, this review highlights endoperoxides as a valuable and chemically distinctive class of bioactive natural products and discusses their promise and limitations as leads for further pharmacological development, particularly in light of their intrinsic reactivity and stability challenges. Full article

This study explores the efficacy of plasma-activated water (PAW), produced using a laboratory-made pin-hole air plasma jet, in the reduction of pesticide residues, including clothianidin, thiamethoxam, and propoxur. The physicochemical analysis indicated that PAW’s pH decreased significantly with longer discharge times, while oxidation–reduction potential (ORP) and electrical conductivity (EC) increased. Nitrogen and oxygen species in the plasma state were confirmed using optical emission spectroscopy. These results reflected the formation of rich reactive oxygen and nitrogen species (ROS and RNS), including hydroxyl radicals, hydrogen peroxide, and nitrate, contributing to its strong oxidative properties. The optimal PAW parameters for pesticide degradation were determined, and pesticide reduction was assessed using high-performance liquid chromatography (HPLC) and liquid chromatography–mass spectrometry (LC-MS). After 25 min of treatment, maximum reduction rates of 65%, 93%, and 88% were achieved for clothianidin, thiamethoxam, and propoxur, respectively. Only clothianidin yielded a single degradation product which is suggested to be formed by cyclic rearrangement following the loss of Cl and NO₂, while those of thiamethoxam and propoxur were not detected. PAW produced by atmospheric pin-hole air plasma jet demonstrated superior degradation efficiency with minimal toxic by-product formation. The findings contribute valuable insights into sustainable practices for environmental detoxification. Full article

This work presents a catalysis-based electrochemical biosensor to evaluate the peroxidase-like activity of methemoglobin (Hb-PLA) after exposure to cigarette smoke (CS) at different time intervals. The system consists of a microelectrode array coupled with a PDMS chamber containing a methemoglobin solution (biorecognition element). Hydrogen peroxide (H₂O₂) acts as the substrate, while 3,3′,5,5′-tetramethylbenzidine (TMB) functions as the chromogenic substrate for the Hb-PLA through its oxidation reaction. A spectrophotometric technique is used as a reference method to assess the catalytic activity of methemoglobin. Positive control samples exhibited higher absorbance, indicating strong catalytic activity, whereas CS-exposed samples showed a marked reduction, which was confirmed by the negative control. Cyclic voltammetry revealed significant alterations in the oxidation and reduction peaks of the CS-exposed samples. Therefore, chronoamperometry was employed to quantify the charge transfer as the electrochemical response associated with Hb-PLA, yielding a sensitivity of 0.86 ± 0.06 (%Hb-PLA/mC) and a limit of detection (LOD) of 0.23 (mC). The results demonstrate that cigarette smoke impairs the Hb-PLA in a time-dependent manner, with longer exposure reducing the activity by up to 25%. The proposed biosensor provides a rapid, sensitive, and straightforward strategy for detecting functional alterations in solutions of methemoglobin induced by environmental pollutants such as cigarette smoke. Full article

In this work, the effect of aqueous dispersions of graphene oxide (GO) and nanosized graphene oxide (nGO) on the enzymatic polymerization of polyaniline (PANI) was studied. The enzymatic polymerization of PANI was carried out in aqueous medium using toluenesulfonic acid (TSA) as the dopant, horseradish peroxidase (HRP) as the catalyst, and hydrogen peroxide (H₂O₂) as the oxidant, using 1.0, 2.5, and 5.0 wt% of GO and nGO. The morphology of PANI-GO/nGO composites was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further characterization was performed by thermogravimetric analysis (TGA) and spectroscopic techniques such as ultraviolet–visible (UV–Vis), Fourier-transform infrared (FTIR), Raman and X-ray photoelectronics (XPS). SEM images showed that during enzymatic polymerization, PANI completely covers the GO/nGO sheets. Furthermore, physicochemical results confirmed the production of a hybrid PANI-GO/nGO material with Van der Waals-type interactions between the oxygen-based functional groups of GO and the secondary amino bond (-NH-) of PANI. Also, cyclic voltammetry experiments were carried out in situ during the polymerization of PANI-GO/nGO films. The electrochemical response of PANI-GO/nGO composites reflects two broad oxidation peaks around 300 mV and 500 mV during anodic scanning, with reversible oxidation during cathodic scanning. Classical molecular dynamics simulations were used to understand the mechanism of the composite film’s growth. Full article

Recently, researchers have been focused on the recycling as well as transforming of bio-waste streams into a valuable resource. Banana peels are promising for such application, due to their wide availability. In this context, the integration of banana peel-derived biochar with environmentally benign magnetite has significantly broadened its potential applications as a solar photocatalyst compared to the conventional photocatalysts. The materials are mixed in varied proportions of Ban-Char500-Mag@-(0:1), Ban-Char500@Mag-(1:1) and Ban-Char500@Mag-(2:1) and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) augmented with dispersive X-ray spectroscopy (EDX). Such modification is leading to an improvement in its application as a solar photocatalyst using the photochemical solar collector facility. The study discusses the factors controlling acetaminophen removal from aqueous effluent within 30 min of solar illumination time. Furthermore, the highlighted optimum parameters are pH 3.0, using 10 mg/L of the Ban-Char500@Mag-(1:1) catalyst and 100 mg/L of the hydrogen peroxide as a Fenton combination system for removing a complete acetaminophen from wastewater (100% oxidation). Also, the temperature influence in the oxidation system is studied and the high temperature is unfavorable, which verifies that the reaction is exothermic in nature. The catalyst is signified as a sustainable (recoverable, recyclable and reusable) substance, and showed a 72% removal even though it was in the six cyclic uses. Further, the kinetic study is assessed, and the experimental results revealed the oxidation process is following the first-order kinetic reaction. Also, the kinetic–thermodynamic parameters of activation are investigated and it is confirmed that the oxidation is exothermic and non-spontaneous in nature. Full article

In the light reactions of photosynthesis, reactive oxygen species (ROS), such as superoxide anion radical (O₂^•−), hydrogen peroxide (H₂O₂), singlet oxygen (¹O₂*), and hydroxyl radical (OH^•), are continuously generated at basal levels and are kept in homeostasis by the antioxidative enzymatic and non-enzymatic systems. Nevertheless, under abiotic or biotic stress conditions, this balance between the creation and elimination of ROS is disrupted, and the increased ROS production leads to oxidative stress, which is involved in the growth retardation of plants. However, ROS are also beneficial, since they trigger the plant’s defense mechanisms for handling oxidative stress and are fundamental signaling molecules for the regulation of a range of physiological functions under optimum growth conditions or environmental stress circumstances, activating a plethora of acclimation responses. Gaining insight into the relationship between ROS generation, ROS scavenging, and the protective role of ROS will contribute to improving agricultural sustainability in the face of global climate change. Full article

Precision and real-time detection of hydrogen peroxide (H₂O₂) are essential in pharmaceutical, industrial, and defence sectors due to its strong oxidizing nature. In this study, silver (Ag)-doped CeO₂/Ag₂O-modified glassy carbon electrode (Ag-CeO₂/Ag₂O/GCE) has been developed as a non-enzymatic electrochemical sensor for the sensitive and selective detection of H₂O₂. The synthesized Ag-doped CeO₂/Ag₂O nanocomposite was characterized using various advanced techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). Their optical, magnetic, thermal, and chemical properties were further analyzed using UV–vis spectroscopy, electron paramagnetic resonance (EPR), thermogravimetric-differential thermal analysis (TG-DTA), and X-ray photoelectron spectroscopy (XPS). Electrochemical sensing performance was evaluated using cyclic voltammetry and amperometry. The Ag-CeO₂/Ag₂O/GCE exhibited superior electrocatalytic activity for H₂O₂, attributed to the increased number of active sites and enhanced electron transfer. The sensor displayed a high sensitivity of 2.728 µA cm⁻² µM⁻¹, significantly outperforming the undoped CeO₂/GCE (0.0404 µA cm⁻² µM⁻¹). The limit of detection (LOD) and limit of quantification (LOQ) were found to be 6.34 µM and 21.1 µM, respectively, within a broad linear detection range of 1 × 10⁻⁸ to 0.5 × 10⁻³ M. The sensor also demonstrated excellent selectivity with minimal interference from common analytes, along with outstanding storage stability, reproducibility, and repeatability. Owing to these attributes, the Ag-CeO₂/Ag₂O/GCE sensor proved effective for real sample analysis, showcasing its potential as a reliable, non-enzymatic platform for H₂O₂ detection. Full article

Parkinson’s disease (PD) is recognized as one of the most common neurodegenerative disorders globally. The primary factor contributing to this condition is the loss of dopaminergic neurons, which results in both motor and nonmotor symptoms. The etiology of neurodegeneration remains unclear. However, it is characterized by the elevated production of reactive oxygen species, which subsequently leads to oxidative stress, lipid peroxidation, mitochondrial dysfunction, and inflammation. The investigation of the applicability of natural compounds and their derivatives to various diseases is becoming increasingly important. The possible role of curcumin from Curcuma longa L. and its derivatives in the treatment of PD has been partially investigated, but there are no data on the action of synthetic cyclic C₅-curcuminoids and chalcones tested in a Parkinson’s model. Two chalcones and five synthetic cyclic C₅-curcuminoids with potential antioxidant properties were investigated in an in vitro model of 6-hydroxydopamine (6-OHDA)-induced neurodegeneration in differentiated SH-SY5Y cells. Reactive oxygen species (ROS) production, total antioxidant capacity, antioxidant enzyme activity, thiol and ATP levels, caspase-3 activity, and cytokine release were examined after treatment with the test compounds. Based on these results, one cyclic chalcone (compound 5) and three synthetic cyclic C₅-curcuminoids (compounds 9, 12, and 13) decreased oxidative stress and apoptosis in our in vitro model of neurodegeneration. Compounds 5 and 9 were also successful in decreasing the production of pro-inflammatory cytokines (IL-6, IL-8, and TNF-α), while promoting the release of anti-inflammatory cytokines (IL-4 and IL-10). These findings indicate that these two compounds exhibit potential antioxidant, anti-apoptotic, and anti-inflammatory properties, rendering them promising candidates for drug development. Full article

Psoriasis, a chronic inflammatory skin disorder, is driven by dysregulated immune responses and keratinocyte dysfunction. Here, we explore the therapeutic potential of Astilbin (AST), a flavonoid with potent anti-inflammatory properties, in modulating ferroptosis and the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway in IL-17-stimulated HaCaT keratinocytes. Our psoriatic cell model recapitulated key pathological features, including hyperproliferation, membrane integrity loss, mitochondrial dysfunction, and heightened oxidative stress, alongside elevated proinflammatory cytokine levels. Ferroptosis-related biomarkers were significantly altered, with increased malondialdehyde (MDA) accumulation, reduced glutathione (GSH) levels, iron overload (Fe²⁺), and enhanced lipid peroxidation (detected via C11-BODIPY). Mechanistically, mitochondrial damage triggered cytoplasmic leakage of mitochondrial DNA (mtDNA), activating the cGAS-STING pathway, as evidenced by upregulated pathway-associated protein expression. AST intervention effectively mitigated these pathological changes by suppressing ferroptosis and modulating cGAS-STING signaling. These findings reveal a dual-pathway regulatory mechanism, positioning AST as a promising therapeutic candidate for psoriasis. By elucidating the interplay between ferroptosis and the cGAS-STING pathway, this study provides new insights into psoriatic inflammation and offers a rationale for targeting these pathways in therapeutic strategies. Full article

With increasing energy demands, fuel cells are a popular avenue for portability and low waste emissions. Hydrogen fuel cells are popular due to their potential output power and clean waste. However, due to storage and transport concerns, hydrogen peroxide fuel cells are a promising alternative. Although they have a lower output potential compared to hydrogen fuel cells, peroxide can act as both the oxidizing and reducing agent, simplifying the structure of the cell. In addition to reducing the complexity, hydrogen peroxide is stable in liquid form and can be stored in less demanding methods. This paper investigates chelated metals as electrode material for hydrogen peroxide fuel cells. Chelated metal complexes are ring-like structures that form from binding organic or inorganic compounds with metal ions. They are used in medical imaging, water treatment, and as catalysts for reactions. Copper(II) phthalocyanine, phthalocyanine green, poly(copper phthalocyanine), bis(ethylenediamine)copper(II) hydroxide, iron(III) ferrocyanine, graphene oxide decorated with Fe₃O₄, zinc phthalocyanine, magnesium phthalocyanine, manganese(II) phthalocyanine, cobalt(II) phthalocyanine are investigated as electrode materials for peroxide fuel cells. In this study, the performance of these materials is evaluated using cyclic voltammetry. The voltammograms are compared, as well as observations are made during the materials’ use to measure their effectiveness as electrode material. There has been limited research comparing the use of these chelated metals in the context of hydrogen peroxide fuel cells. Through this research, the goal is to further the viability of hydrogen peroxide fuel cells. Poly(copper phthalocyanine) and graphene oxide doped with iron oxides had strong redox catalytic activity for use in acidic peroxide single-compartment fuel cells, where the poly(copper phthalocyanine) electrode compound generated the highest peak power density of 7.92 mW/cm² and cell output potential of 0.634 V. Full article

This work presents the development of a biosensing platform for hydrogen peroxide (H₂O₂) electrochemical reduction. The developed platform uses a multi-walled carbon nanotube paste (PMWCNT) and the enzyme cholesterol oxidase (ChOx). The supramolecular architecture of the PMWCNT/ChOx platform was characterized using cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry. The results indicated that the presence of ChOx enhances the sensitivity of electrochemical detection for H₂O₂ by 21 times compared to that without ChOx. The designed electrochemical sensing bio-platform for H₂O₂ shows a sensitivity of 26.15 µA/mM in the linear range from 0.4 to 4.0 mM, an LOD of 0.43 µM, and an LOQ of 1.31 µM. Furthermore, in silico studies (molecular dynamics simulations, molecular docking assays, and binding free energy calculations (ΔG_b)) were carried out to characterize and validate the molecular interaction between ChOx and H₂O₂. The computed data confirmed that the binding is spontaneous, and the type of labile interaction promotes a rapid electrochemical reduction of H₂O₂. Full article

Alumina is a well-known catalyst and catalyst support. The electrochemical properties of alumina have recently gained attention. The electrochemical response of alumina greatly depends on the type and number of surface groups present in different alumina types. The surfaces of two types of alumina, anhydrous (A) and trihydrate (T) alumina, were modified by copper through an ion-exchange procedure. The samples were characterized by diffuse reflectance UV–Vis spectroscopy. The obtained samples were used as modifiers of carbon paste electrodes. The electrochemical characterization of the samples was performed using cyclic voltammetry and two redox probes. The electrochemical behavior of samples was investigated in the alkaline and neutral media. The electroanalytical performance of the synthesized composites was tested on glutamate and hydrogen peroxide by linear sweep voltammetry. The functionalization of alumina with copper by ion exchange offered a fast and cost-effective procedure for obtaining a composite with enhanced electrochemical properties for sensing biologically important analytes. Full article

Changes in the environment have a significant impact on photosynthetic efficiency, which in turn influences plant growth and yield. Consequently, there is a greater focus on methods to enhance photosynthetic efficiency with the goal of raising plant productivity. In this study, the effects of titanium oxide nanoparticles (TiO₂ NPs) on pea plants (Pisum sativum L.) subjected to moderate salt stress by the addition of 100 mM NaCl to the nutrient solution were investigated. Two concentrations of NPs (50 mg/L and 100 mg/L) were applied through foliar spray on pea leaves. Data showed that NPs prevent salt-induced membrane damage, growth inhibition, and the increase in hydrogen peroxide and lipid peroxidation. An analysis of the chlorophyll fluorescence curves revealed that TiO₂ NPs decreased the effects of NaCl on the reduction in the open photosystem II centers (corresponding with qp) and their efficiency (Φexc), as well as the activity of the oxygen-evolving complex (Fv/Fo). The co-treatment with TiO₂ NPs and NaCl also improved the photochemical energy conversion of photosystem II (Φ_PSII), alleviated the interaction of Q_A⁻ with plastoquinone, and enhanced electron transport activity and the rate of photosynthesis, compared to the plants treated with NaCl only. Additionally, NPs application under salt stress stimulated cyclic electron transport around photosystem I, thus protecting its photochemical activity. These protective effects of NPs were more pronounced at a concentration of 100 mg/L. Full article

Low temperatures can significantly affect the growth of ornamental plants, emphasizing the importance of improving their cold tolerance. However, comparative studies on the photosynthetic responses of sun and shade plants to low temperatures remain limited. In this study, gas exchange, chlorophyll fluorescence in Photosystem II (PSII) and Photosystem I (PSI), the antioxidant system, the osmoregulator substance, and lipid peroxidation were investigated in the shade plant Helleborus viridis (Hv) and the sun plant Lupinus polyphyllus (Lp) during cold acclimation (CA) and the freezing–thaw recovery (FTR). The CA treatment significantly declined the net photosynthetic rate (Pn) and the maximum photochemical efficiency of PSII (Fv/Fm) in Hv and Lp, indicating the photoinhibition occurred in both species. However, Hv exhibited a much better photosynthetic stability to maintain Pn, Fv/Fm, and carboxylation efficiency (CE) than Lp during CA, suggesting that Hv had a greater photosynthetic resilience compared to Lp. Furthermore, Hv preferred to maintain Pn, Fv/Fm, the actual photosynthetic efficiency of PSII (Y(II)), and the actual photosynthetic efficiency of PSI (Y(I)) to consistently provide the necessary energy for the carbon assimilation process, while Lp tended to divert and dissipate excess energy by thermal dissipation and cyclic electron flow during CA. Moreover, there were higher soluble sugar contents in Hv in comparison to Lp. These traits allowed Hv to recover photosynthetic efficiency and maintain cellular integrity better than Lp after the freezing stress. In conclusion, CA significantly reduced the photosynthetic capacity and led to the divergent photosynthetic strategies of both species, which finally resulted in a different freezing tolerance after the freezing–thaw recovery. These findings provide insights into the divergent photoprotective strategies of sun and shade plants in response to cold temperatures. Full article