Oxidative Conditions Research Articles

Cytoprotective Properties of Turmeric Oil (Curcuma longa L.) on Fibroblast Cells.

Senescence is a cellular physiological process involved in cell aging. One factor that increases senescence is oxidative stress, which can be induced by hydrogen peroxide. Active compounds in turmeric (Curcuma longa) are classified as volatile and non-volatile. Major non-volatile compounds in turmeric are curcumin, dimethoxy curcumin, and bisdemethoxycurcumin bioactivities that have been widely explored. However, turmeric rhizome oil (TO) has limited reports on its bioactivity and constituents. This study aims to determine the potency of TO as cytoprotective against oxidative stress induced by hydrogen peroxide using the fibroblast cell lines (NIH-3T3 and HDF). We evaluated the cytotoxicity of TO using MTT assay, then evaluated its effect on cell senescence using SA-β-gal assay. The cellular reactive oxygen species (ROS) level was observed using DCFDA staining through flow cytometry. The turmeric volatile oil which was obtained by steam-water distillation was analyzed with a gas chromatography-mass spectrophotometry (GC-MS) to determine the chemical profile. TO showed low cytotoxicity against HDF and NIH-3T3 cells, with IC50 values of over 100 µM. TO rescued cells from undergoing senescence and reduced ROS levels which were induced by hydrogen peroxide. The GC-MS spectra of the TO compound in positive ionization mode showed retention times of 23.56 and 26.20 minutes, corresponding to the ar-turmerone and turmerone compounds. These results indicated that TO has the potency as a cytoprotective agent in stress oxidative conditions.

Chemical characterization of activated carbon derived from Napier grass, rubber wood, bamboo, and hemp

This study examines the process and analysis of activated carbons that use H2SO4, H2O2, and NaOH as activating agents. The distinct chemical methods employed by each activator impacted the ash and carbon content, surface properties, and functional groups of the activated carbons, exhibiting notable disparities. The ash level varied from 6.86% to 37.08%. H2SO4-activated carbons had the lowest ash content, suggesting better elimination of inorganic contaminants. The iodine number, which serves as a measure of adsorption capacity, was consistent among all samples, with values ranging from 800 to 950 mg g-1. This indicates that the three activating agents effectively increased the surface area and porosity. The BET surface areas varied between 9.14 and 167.42 m2 g-1, whereas the BJH adsorption surface areas ranged from 9.68 to 28.89 m2 g-1. The pore volumes ranged from 0.0071 to 0.0595 cm2 g-1, while the sizes ranged from 0.51 to 8.2 nm. These measurements suggest the presence of both micropores and mesopores. The FTIR spectra exhibited comparable functional groups among all samples, such as OH, CH, C=C, and C-O. The SEM-EDX and XPS tests showed that there was a lot of carbon. The carbon content was highest in H2O2-activated carbons because they were exposed to less severe oxidative conditions. These activated carbons comply with the requirements set by IUPAC and ASTM. They are suitable for catalytic processes and liquid adsorption, such as water and wastewater treatment. Subsequent research should aim to improve activation conditions to get the highest possible carbon content and optimise surface characteristics.

Exploring the Role of Cuprotosis-Associated Genes in Cancer Progression and Therapy Resistance: A Comprehensive Analysis across Multiple Cancer Types

This review presents a comprehensive overview of the role of cuprotosis-associated genes in various cancer types, highlighting their significance in tumor progression and therapy resistance. In breast cancer and colorectal cancer (CRC), dysregulation of genes involved in mitochondrial function and copper metabolism, such as FDX1, LIAS, LIPT1, DLD, DLAT, and PDHA1/PDHB, promotes metabolic reprogramming and enhances cancer cell survival. Ovarian cancer exhibits unique dysregulations in genes like ATP7B, CCS, and COMMD1, influencing copper metabolism and redox signaling pathways, thereby contributing to chemoresistance and tumor growth. Head and neck cancer involves upregulation of MT1X, ATP7A, and CCS, potentially aiding cancer cell survival under oxidative stress conditions. Lung cancer is characterized by distinct dysregulation of genes like SLC31A1, ATOX1, and COMMD1, modulating copper homeostasis and redox signaling to support tumor proliferation. Liver cancer and kidney cancer each present unique sets of dysregulated cuprotosis-associated genes, such as SLC39A4, SCO2, and ATP7A, suggesting novel therapeutic targets specific to these cancer types. Pathway analysis reveals enrichment in mineral absorption pathways, emphasizing the importance of these genes in maintaining cellular mineral homeostasis. Understanding the intricate interplay between cuprotosis-associated genes and cancer biology offers insights into potential therapeutic strategies targeting copper metabolism for improved treatment outcomes across various cancer types.

Sodium Benzoate Induces Fat Accumulation and Reduces Lifespan via the SKN-1/Nrf2 Signaling Pathway: Evidence from the Caenorhabditis elegans Model.

Sodium benzoate (SB) is widely used in food products, cosmetics, and medical solutions due to its antimicrobial properties. While it is generally considered safe and has potential neuroprotective benefits, SB has also been linked to adverse effects, including hepatic oxidative stress and inflammation. However, the potential effects of SB on obesity and lifespan remain poorly understood. In this study, we investigated the effects of SB on fat accumulation and lifespan using the nematode Caenorhabditis elegans (C. elegans) as a model system. Wild-type worms were exposed to various SB concentrations (0%, 0.0004%, 0.0008%, 0.004%, and 0.1%) and 0.016% glucose as a positive control for 72 h in liquid or on NGM agar plates. Fat accumulation was assessed through the Oil Red O staining, which revealed that SB induced more fat accumulation compared to vehicle control, even at low concentrations, including the dosage of 0.0004%. Lifespan analysis also demonstrated that SB significantly reduced lifespan in wild-type worms, even at low concentrations. Further investigations found that SKN-1 (an Nrf2 homolog) is necessary for SB-induced fat accumulation and lifespan reduction. Moreover, SB inhibited the nuclear localization of SKN-1 under oxidative stress conditions. These findings suggest that SB may induce fat accumulation and reduce lifespan by inhibiting the oxidative stress-mediated SKN-1 signaling pathway.

Genistein Enhances the Beneficial Effects of Exercise on Antioxidant and Anti-Inflammatory Balance and Cardiomyopathy in Ovariectomized Diabetic Rats.

This study aimed to investigate the effects of genistein, swimming exercise, and their co-treatment on heart oxidative stress, inflammation, and cardiomyopathy in ovariectomized diabetic rats. It is well-established that diabetes is a major risk factor for cardiovascular disease in both young and postmenopausal women. Genistein is a natural phytoestrogen that has estrogenic effects. Studies have shown that genistein has a positive impact on menopause, cardiovascular dis-ease, and diabetes in women. However, the impact of genistein treatment alone and in combination with exercise training on the management of cardiac disease in diabetic women after ovarian hor-mone deprivation has not been fully explored. The objective of this study was to evaluate the effect of genistein alone or in combination with exercise training on the cardiac expression of oxidative/inflammation biomarkers (MDA, OSI, TOS, TNF- α, and NF-κB) and miRNA-133, IGF-1, and Bcl-2 in the diabetic ovariectomized rats. A group of Wistar rats were randomly divided into seven groups, with eight rats in each group. The groups were named control, sham, ovariectomized group (OVX), OVX +diabetes (OD), OD+ genistein (1 mg/kg, eight weeks; daily SC), OD+exercise (eight weeks), and OD+ genistein+exercise (eight weeks). The rats were given a high-fat diet and low-dose streptozotocin injection to induce diabetes. After eight weeks, the rats were anesthetized, and their hearts were removed. The study assessed the effects of treatment by measuring the expression of miRNA-133 using Real-time Polymerase Chain Reaction (PCR) and the protein levels of Bcl-2, Bax, and IGF-1 using Western blotting. The study also evaluated the levels of inflammation and oxidative stress markers using ELISA. Pathological changes were also assessed using periodic acid Schiff and he-matoxylin & eosin. After ovariectomy, the levels of cardiac miRNA-133, IGF-1, and Bcl-2 expression were down-regulated, and the levels of MDA, OSI, TOS, TNF-α, and NF-κB were increased, with a reduced total antioxidant capacity. Diabetes had an additive effect on these factors. Genistein was found to have a positive impact on oxidative and inflammation levels, and it also increased the expression of miRNA-133, Bcl-2, and IGF-1 in rats with OD. Furthermore, the combination of genistein and exercise had a positive effect on miRNA-133, Bcl-2, and IGF-1 expression in the heart, leading to a decrease in Bax levels. The combined intervention showed a noticeable improve-ment in oxidative and inflammation conditions. Histological examination revealed some abnormal-ities in cardiac tissue, which were found to be improved with genistein and/or exercise treatments. Genistein or/and exercise as a natural replacement therapy could improve diabetic-induced cardiac complications in ovariectomized rats' hearts.

Improving sunflower oil stability with propolis: A study on antioxidative effects of Turkish propolis during accelerated oxidation.

Propolis, a natural resinous substance collected by bees, is known for its potent antioxidant properties. This study investigates the antioxidant activities and total phenolic contents of propolis samples from 16 provinces of Türkiye and their effects on the oxidative stability of sunflower oil. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibition was in the range of 28.1%-92.5% in thirteen propolis samples, whereas this rate was 24.5% in butylated hydroxytoluene (BHT). Although 2,2'-azino-bis(3-ethylbenzotiazolin-6-sulfonic acid) (ABTS) value was 224µmol trolox/g in BHT, this value was in the range of 262-1370µmol trolox/g in propolis samples, except for one. Propolis methanol extracts 13 applied to sunflower oil at a concentration of 1000ppm were more efficient than BHT added at 200ppm for inhibiting the production of peroxide value (PV). Similarly, most propolis extracts (1000ppm) demonstrated antioxidant activity against the production of p-anisidine (p-AV) in sunflower oil under accelerated oxidation conditions. It was determined that Turkish propolis had strong antioxidant properties and delayed oxidation and may be utilized commercially in the food sector to delay the oxidation of fats and oils.

Mild and efficient approach to aromatic backbone cleavage using copper-lignosulfonate/hydrogen peroxide system

This study investigates the dual role of copper ions in catalysis and complexation during the oxidation of lignosulfonates with hydrogen peroxide (H2O2) under alkaline conditions. The presence of copper ions reduces partial oxidation by 86 % compared to H2O2 treatment alone, enhancing overall conversion efficiency to 63 % under increased oxidative conditions. Analyses reveal that copper-lignosulfonate complexes facilitate redox cycling and hydroxyl radical generation through interactions with H2O2, confirming copper’s dual functions. This mechanism mitigates the hindrance of sulfonic groups on hydroperoxide anions, leading to lignosulfonate degradation into dicarboxylic acids. These findings provide novel insights into the copper-lignosulfonate/H2O2 system, expanding the understanding of oxidative degradation mechanisms beyond traditional Fenton-like reactions. Furthermore, this system offers a simplified and efficient alternative for industrial applications, particularly in integration with the sulfite pretreatment process of woody biomass for producing valuable co-products.

Sodium Copper Chlorophyllin: A Sustainable Bioinspired Catalyst for the Aerobic Oxidative Synthesis of Nitrogen Heterocycles and the Oxidative Cyanation of Tertiary Amines

AbstractA remarkably simple and straightforward protocol has been reported showcasing sodium copper chlorophyllin (SCC) as an eco‐friendly, bioinspired catalyst for the aerobic oxidative synthesis of pharmaceutically prevalent nitrogen‐containing heterocycles, such as benzimidazoles and quinoxalines. This reaction was performed in green solvent water, using the green oxidant, molecular oxygen. SCC displayed exceptional efficiency, congruent with the prevailing metal/non‐metal‐based catalyst regime without requiring additives. The SCC catalyst exhibited excellent recyclability upto three cycles for the benzimidazole synthesis reaction. This benign strategy was successfully applied in synthesizing a bioactive quinoxaline i. e., Tyrphostin AG1296, a promising candidate for melanoma treatment. The catalytic activity of SCC was explored for the synthesis of another privileged moiety i. e., α‐aminonitriles, via the α‐cyanation of tertiary amines under oxidative conditions. This reaction progressed with a mild, easy‐to‐use, convenient cyanide source, such as ethyl cyanoformate, and a green and attractive solvent, such as methanol, precluding acidic media. SCC catalyst was efficiently recycled upto three cycles for the α‐aminonitriles synthesis. Overall, the utility of a biodegradable, robust catalyst such as SCC, eco‐friendly solvents such as water and methanol, green oxidants such as O2, and mild reaction conditions, devoid of acidic additives, renders the present work viable for academic and industrial research.

Quinic acid protects against the development of Huntington’s disease in Caenorhabditis elegans model

BackgroundQuinic acid (QA), a cyclitol and cyclohexanecarboxylic acid, is a natural product that is present and can be isolated from edible herbals like tea, coffee and several fruits and vegetables. It was previously reported that QA exerted antioxidant and neuroprotective activity against dementia. However, it was not tested for its neuroprotective potential against Huntington’s disease (HD). Since aging related disorders are greatly linked to oxidative stress conditions, we focused on testing the oxidative stress resistant activity and protective effect of QA against the development of HD by using the multicellular Caenorhabditis elegans (C. elegans) worm model.MethodsFirstly, QA was tested for its oxidative stress resistant properties. In survival assay, wild type and mutant skn-1 and daf-16 worms were exposed to oxidative stress conditions by using H2O2. Activation of SKN-1 pathway and expression of its downstream genes gcs-1 and gst-4 were also tested. Secondly, the effect of QA was evaluated on HD by testing its ability to decrease the formation of polyQ150 aggregates. Furthermore, its effect on the accumulation of polyglutamine (polyQ35 and polyQ40 aggregates) was tested.ResultsHere we report that QA could improve the survival of C. elegans after exposure to oxidative stress caused by H2O2 while also exerting antioxidant effects through the activation of SKN-1/Nrf2 pathway. Moreover, QA could be a potential candidate to protect against HD due to its effects on decreasing the formation of polyQ150, polyQ35 and polyQ40 aggregates.ConclusionsThis study highlights the importance of QA as a natural compound in defending against oxidative stress and the development of neurodegenerative diseases like HD.

A comparison of dry and wet grinding on gold-bearing sulphide ore flotation

This study investigates the hypothesis that dry grinding prior to flotation can mitigate the adverse effects of galvanic interactions, improve the selectivity of gold flotation compared to wet grinding, and offer additional benefits due to water scarcity concerns and high water treatment costs. The effects of dry and wet grinding on the flotation behavior of gold-bearing sulphide ore were studied comparatively in terms of flotation test results and pulp chemistry parameters (pH, Eh, and dissolved oxygen). In addition, flotation tests without conditioning were also conducted following dry grinding in an attempt to minimize water contact further. Results demonstrated that dry grinding increased pulp potentials and dissolved oxygen levels, implying more oxidative conditions. Despite a lower mass pull with dry grinding, flotation recoveries and grades of gold and chalcopyrite were comparable to wet grinding, while dry grinding enhanced pyrite flotation at the rougher stage. Notably, flotation without conditioning effectively rejected pyrite and achieved higher grades for gold and chalcopyrite, indicating selective flotation. Therefore, dry grinding before flotation emerges as a viable alternative for gold and chalcopyrite flotation due to its improved selectivity while carefully optimizing flotation strategies and reagents to maximize recoveries.

Monocytic mitochondrial dysfunction and impaired monocytic bioenergetic profile in patients with heart failure symptoms in post-COVID syndrome

Abstract Introduction/Purpose Approximately 35% of COVD-19 patients have persistent symptoms similar to congestive heart failure. The so called post-Covid syndrome, which includes symptoms such as dyspnea and angina pectoris, is presumably associated to cellular metabolism and oxidative stress, yet whether mitochondrial function is impaired in post-COVID patients is still unclear. We thus investigated the mitochondrial function in monocytes of symptomatic post-COVID patients compared to matched controls. Methods Patients with persisting cardiac symptoms in their daily activities and diagnosed with post-COVID syndrome (n=14) were recruited and matched with unaffected controls (n=10) for age, sex and cardiovascular risk factors. Structural heart disease was excluded through cardiac work-up (echocardiography, functional stress testing and when necessary coronary angiography). Primary monocytes were isolated using negative selection method. The bioenergetic status of the monocytes was assessed using the Agilent Seahorse XF Cell Mito Stress Test without and after modulation of reactive oxygen species (ROS) by buthionine sulfoximine (BSO). Results CD14++ monocytes isolated from post-COVID patients showed non-significantly increased basal proton leak (p=0.57), reduced maximal respiration, and reserved respiratory capacity (p=0.19) compared to controls. Induction of additional oxidative stress by ROS modulation revealed a significantly impaired bioenergetic profile of monocytes in terms of reduction of basal respiration (3-fold, p=0.0005), maximal respiration (4-fold, p=0.004) and spare respiratory capacity (5-fold, p=0.008). Conclusions We demonstrated an impaired bioenergetic profile of CD14++ monocytic mitochondria in patients suffering from heart failure symptoms following COVID-19 infection. Whether the findings provide a novel biomarker for measuring systemic oxidative stress conditions or whether there is a direct link between symptoms of post-COVID disease and monocytic function needs to be addressed in further studies.

Regulation of Catalase Expression and Activity by DhHog1 in the Halotolerant Yeast Debaryomyces hansenii Under Saline and Oxidative Conditions.

Efficient transcriptional regulation of the stress response is critical for microorganism survival. In yeast, stress-related gene expression, particularly for antioxidant enzymes like catalases, mitigates reactive oxygen species such as hydrogen peroxide (H2O2), preventing cell damage. The halotolerant yeast Debaryomyces hansenii shows oxidative stress tolerance, largely due to high catalase activity from DhCTA and DhCTT genes. This study evaluates D. hansenii's response to oxidative stress caused by H2O2 under saline conditions, focusing on cell viability, gene expression, and catalase activity. Chromatin organization in the promoter of DhCTA and DhCTT was analyzed, revealing low nucleosome occupancy in promoter regions, correlating with active gene expression. Stress-related motifs for transcription factors like Msn2/4 and Sko1 were found, suggesting regulation by the DhHog1 MAP kinase. Analysis of a Dhhog1Δ mutant showed DhHog1's role in DhCTA expression under H2O2 or NaCl conditions. These findings highlight DhHog1's critical role in regulating the stress response in D. hansenii, offering insights for enhancing stress tolerance in halotolerant yeasts, particularly for industrial applications in saline wastewater management.

Recent Advancements in Production and Extraction Methods of Phycobiliprotein C-phycocyanin by Arthrospira (Spirulina) platensis: A Mini Review.

Arthrospira platensis has been utilized as a food source since ancient times due to its rich nutrient profile. In recent years, its popularity as a dietary supplement has soared, especially due to the presence of a water-soluble phycobiliprotein, C-phycocyanin C (C-PC), which is abundant and notable for its fluorescent properties. C-PC contains the chromophore phycocyanobilin B (PCB-B), a tetrapyrrole molecule, that is why it plays a dual role as a food colorant and as nutraceutical. However, comprehensive studies have mostly evaluated C-PC's broader health-promoting properties, particularly its antioxidative and anti-inflammatory effects, which are linked to its ability to contrast oxidative stress and related pathological conditions. That is why this review explores recent advancements in optimizing culture conditions to enhance C-PC and PCB-B production, with a particular emphasis on novel extraction and purification techniques that increase yield and bioactivity. This focus on efficient production methods is crucial for expanding the commercial and therapeutic applications of C-PC, contributing to its growing relevance in the food and pharmaceutical industries.

Ultra-Performance Liquid Chromatography and Mass Spectrometry Characterization, and Antioxidant, Protective, and Anti-Inflammatory Activity, of the Polyphenolic Fraction from Ocimum basilicum.

Ocimum basilicum is a valuable plant widely consumed worldwide and considered a rich source of polyphenols. This study examined the impact of the polyphenolic fraction isolated from basil (ObF) on human normal colon epithelial cells and human colorectal adenocarcinoma cells, evaluating its anti-inflammatory and protective activity against oxidative stress. The phytochemical characterization of the fraction was performed using ultra-performance liquid chromatography (UPLC) with a photodiode detector (DAD) and mass spectrometry (MS). UPLC-DAD-MS revealed that ObF predominantly contains caffeic acid derivatives, with rosmarinic acid and chicoric acid being the most abundant. The fraction demonstrated high antioxidant potential, as shown by DPPH assays, along with significant reducing power (FRAP). Furthermore, it prevented the depletion of antioxidant enzymes, including superoxide dismutase and catalase, and decreased malonylodialdehyde (MDA) in induced oxidative stress condition. Additionally, it exhibited a significant protective effect against H2O2-induced cytotoxicity in human normal colon epithelial cells. Although it had no impact on the viability of adenocarcinoma cells, it significantly reduced IL-1β levels in the neoplastic microenvironment. Our study demonstrated that basil polyphenols provide significant health benefits due to their antioxidant and protective activities.

Refining habitat selection for sulfate-reducing bacteria: Evaluating suitability and adaptability for sulfate-metal wastewater treatment during anaerobic-to-aerobic transitions

Inoculating sulfate-reducing bacteria (SRB) habitats offers an eco-friendly method for treating sulfate-metal laden wastewater, characterized by high sulfate levels, low pH, and elevated heavy metals. This study optimizes source habitat selection of SRB by evaluating groundwater, sewage sludge, and lake sediment, focusing on their suitability and adaptability to aerobic-anaerobic transitions in industrial settings. Sewage sludge, with its slightly acidic pH, reducing environment, and high nutrient levels (Total organic carbon: 207.53 g kg−1, Total nitrogen: 47.12 g kg−1), provides robust SRB potential, as supported by its highest diversity index. However, heavy metals and polycyclic aromatic hydrocarbons pose application challenges. All habitats effectively reduced metal concentrations anaerobically, with Cu removal reaching 95%–99%, and groundwater achieved the highest chemical oxygen demand reduction (63.6%) aerobically. Sludge and sediment showed high biomass and extracellular polymeric substances (EPS) accumulation, while groundwater's nucleic acid-rich EPS enhanced metal immobilization, resulting in stable residual metal forms but with potential remobilization under oxidative conditions. Microbial analysis revealed that Proteobacteria and Firmicutes were key players during transitions, with the highest SRB abundance in groundwater. SRB composition varied across habitats, with Sedimentibacter (13.04%), Desulfovibrio (6.33%), and Desulfomonile (8.1%) dominating in groundwater, sludge, and sediment, respectively, during the anaerobic stage. Functional analysis highlighted sludge's persistence in sulfate reduction under aerobic conditions, while groundwater's limited nitrogen cycle involvement indicated broader biogeochemical limitations. Collectively, these findings highlight strengths and limitations of each habitat as SRB inoculum source, emphasizing the importance of tailored anaerobic-to-aerobic strategies for effective wastewater management.

Thioredoxin-1 protein interactions in neuronal survival and neurodegeneration

Neuronal cell death remains the principal pathophysiologic hallmark of neurodegenerative diseases and the main challenge for treatment strategies. Thioredoxin1 (Trx1) is a major cytoplasmic thiol oxidoreductase protein involved in redox signaling, hence a crucial player in maintaining neuronal health. Trx1 levels are notably reduced in neurodegenerative diseases including Alzheimer's and Parkinson's diseases, however, the impact of this decrease on neuronal physiology remains largely unexplored. This is mainly due to the nature of Trx1 redox regulatory role which is afforded by a rapid electron transfer to its oxidized protein substrates. During this reaction, Trx1 forms a transient bond with the oxidized disulfide bond in the substrate. This is a highly fast reaction which makes the identification of Trx1 substrates a technically challenging task. In this project, we utilized a transgenic mouse model expressing a Flag-tagged mutant form of Trx1 that can form stable disulfide bonds with its substrates, hence allowing identification of the Trx1 target proteins. Autophagy is a vital housekeeping process in neurons that is critical for degradation of damaged proteins under oxidative stress conditions and is interrupted in neurodegenerative diseases. Given Trx1's suggested involvement in autophagy, we aimed to identify potential Trx1 substrates following pharmacologic induction of autophagy in primary cortical neurons. Treatment with rapamycin, an autophagy inducer, significantly reduced neurite outgrowth and caused cytoskeletal alterations. Using immunoprecipitation and mass spectrometry, we have identified 77 Trx1 target proteins associated with a wide range of cellular functions including cytoskeletal organization and neurodegenerative diseases. Focusing on neuronal cytoskeleton organization, we identified a novel interaction between Trx1 and RhoB which was confirmed in genetic models of Trx1 downregulation in primary neuronal cultures and HT22 mouse immortalized hippocampal neurons. The applicability of these findings was also tested against the publicly available proteomic data from Alzheimer's patients. Our study uncovers a novel role for Trx1 in regulating neuronal cytoskeleton organization and provides a mechanistic explanation for its multifaceted role in the physiology and pathology of the nervous system, offering new insights into the molecular mechanisms underlying neurodegeneration.

Efficient Biomimetic Total Synthesis, Characterization, and Antioxidant Activity of Ommatins.

Ommatins, natural colorants found in cephalopods and arthropods, are biosynthesized from tryptophan with uncyclized xanthommatin (Uc-Xa) as the key biosynthetic precursor. These pigments change color under oxidative or reductive conditions. Xanthommatin (Xa) and dihydro-xanthommatin (H2-Xa), as well as decarboxylated xanthommatin (Dc-Xa) and decarboxylated-dihydro-xanthommatin (Dc-H2-Xa), are some of the most common and well-studied ommatins. Herein, we describe the biomimetic total synthesis of Xa/H2-Xa on a gram scale by using the Mannich reaction and oxidative dimerization as the key steps. The 7-step linear synthetic sequence achieved an overall yield of 27%. Dc-Xa/Dc-H2-Xa and protected Uc-Xa/Uc-H2-Xa were also synthesized from the common intermediate-protected 3-hydroxykynurenine (3-OHK). The synthesized ommatins underwent thorough characterization using various spectroscopic techniques, including NMR, UV-vis, FTIR, HRMS, and LC-MS. Their optoelectronic properties were studied using spectrophotometry and electrochemical analysis. Furthermore, the antioxidant activity of the synthesized ommatins was evaluated using an oxygen radical antioxidant capacity activity assay. The results indicated that Dc-Xa exhibited the highest antioxidant activity, followed by Xa, while Uc-Xa showed the lowest activity.

Thermal Conversion of Ultrathin Nickel Hydroxide for Wide Band Gap 2D Nickel Oxides.

Wide band gap (WBG) semiconductors (E g > 2.0 eV) are integral to the advancement of next-generation electronics, optoelectronics, and power industries owing to their capability for high-temperature operation, high breakdown voltage, and efficient light emission. Enhanced power efficiency and functional performance can be attained through miniaturization, specifically via the integration of device fabrication into a two-dimensional (2D) structure enabled by WBG 2D semiconductors. However, as an essential subgroup of WBG semiconductors, 2D transition metal oxides (TMOs) remain largely underexplored in terms of physical properties and applications in 2D optoelectronic devices, primarily due to the scarcity of sufficiently large 2D crystals. Thus, our goal is to develop synthesis pathways for 2D TMOs possessing large crystal domains (e.g., >10 μm), expanding the 2D TMO family and providing insights for future engineering of 2D TMOs. Here, we demonstrate the synthesis of WBG 2D nickel oxide (NiO) (E g > 2.7 eV) thermally converted from 2D nickel hydroxide (Ni(OH)2) with a lateral domain size larger than 10 μm. Moreover, the conversion process is investigated using various microscopic techniques, such as atomic force microscopy, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, providing significant insights into morphology and structural variations under different oxidative conditions. The electronic structure of the converted Ni x O y is further investigated using multiple soft X-ray spectroscopies, such as X-ray absorption and emission spectroscopies.

The Paradoxical Influence of Hydrothermally Treated Zeolites on the Hydrocarbon Pool Mechanism.

Understanding the mechanistic intricacies of hydrothermally treated zeolite is crucial for valorizing any oxygen-containing renewable feedstocks (e.g., methanol, carbon dioxide, biomass). Additionally, the regeneration of deactivated zeolite catalysts under oxidative conditions, akin to hydrothermal treatment, is essential in industrial processes. While research in this area has predominantly focused on characterizing steaming-induced physicochemical changes in zeolite, their ultimate impact on the organic reaction mechanism governed by the hydrocarbon pool dual-cycle mechanism remains unclear. To bridge this knowledge gap, this study investigates the effect of steamed zeolite on the organic reaction mechanism during the industrially significant methanol-to-hydrocarbons process. We achieved this objective by strategically integrating catalytic and control experiments over the pristine and steamed zeolites and their advanced characterization, including under operando conditions, XRD structural refinement, and using "mobility-dependent" solid-state NMR spectroscopy. This multimodal characterization approach was instrumental in elucidating elusive mechanistic information in the dual-cycle mechanism, shedding light on phenomena such as the unchanged ethylene selectivity despite decreasing aromatics selectivity, while ethylene could solely be derived from arene-based reaction intermediates. This study could improve the process efficiency in zeolite catalysis by connecting steaming-induced changes in the organic reaction mechanisms with inorganic material aspects.

The Paradoxical Influence of Hydrothermally Treated Zeolites on the Hydrocarbon Pool Mechanism

Understanding the mechanistic intricacies of hydrothermally treated zeolite is crucial for valorizing any oxygen‐containing renewable feedstocks (e.g., methanol, carbon dioxide, biomass). Additionally, the regeneration of deactivated zeolite catalysts under oxidative conditions, akin to hydrothermal treatment, is essential in industrial processes. While research in this area has predominantly focused on characterizing steaming‐induced physicochemical changes in zeolite, their ultimate impact on the organic reaction mechanism governed by the hydrocarbon pool dual‐cycle mechanism remains unclear. To bridge this knowledge gap, this study investigates the effect of steamed zeolite on the organic reaction mechanism during the industrially significant methanol‐to‐hydrocarbons process. We achieved this objective by strategically integrating catalytic and control experiments over the pristine and steamed zeolites and their advanced characterization, including under operando conditions, XRD structural refinement, and using “mobility‐dependent” solid‐state NMR spectroscopy. This multimodal characterization approach was instrumental in elucidating elusive mechanistic information in the dual‐cycle mechanism, shedding light on phenomena such as the unchanged ethylene selectivity despite decreasing aromatics selectivity, while ethylene could solely be derived from arene‐based reaction intermediates. This study could improve the process efficiency in zeolite catalysis by connecting steaming‐induced changes in the organic reaction mechanisms with inorganic material aspects.