Peroxide Oxidation Research Articles

Nickel manganese oxide catalyst made in glycerol solvent via a tubular furnace in a batch reactor for the CWPO process of phenol oxidation

The process of catalytic wet peroxide oxidation (CWPO) of phenol has been investigated in a batch reactor employing (Al2O3/NiMnO3) made from nickel and manganese salts. The sol-gel method was utilized to create the nanocatalyst locally using Al(NO3)3 hydrate as the active ingredient and glycerol as the solvent. In addition to the standard FTIR, XRD, TEM, and SEM characteristics, nanocatalyst's surface area and adsorption capacity were measured. They then used a batch reactor running at various reaction temperatures (40, 50, 60, and 70 °C), concentrations of phenol (200, 300, 400, and 500 ppm), and batch times (60, 80, 100, and 120 min) to check for CWPO. The findings demonstrated that at the best reaction temperature (70°C), batch duration (120 min), and starting concentration (200 ppm), the greatest conversion was (98.37%) for the (8% Al2O3/NiMnO3). An effective ANN model is developed in this study using Python to predict the magnitude of this effect. Phenol removal studies in a wet catalytic peroxide oxidation batch reactor were used to validate the model's output and training data. The dataset is separated into three groups based on temperature, time, and concentration. Phenol was eliminated in order for the ANN model to forecast performance. The data nearly closely matched the projected yield values. 0.99 was the regression coefficient (R2).

Endothelial Dysfunction with Aging: Does Sex Matter?

Oxidative stress and inflammation accompany endothelial dysfunction that results from the excessive or uncontrolled production of reactive oxygen and nitrogen species (RONS) in older adults. This study was designed to assess the usefulness of serum oxi-inflammatory component combinations in vascular disease prediction and prevention with regard to sex. Women (n = 145) and men (n = 50) aged 72.2 ± 7.8 years participated in this project. The females demonstrated the elevated production of hydrogen peroxide (H2O2) and nitric oxide (NO) responsible for intravascular low-density lipoprotein oxidation. NO generation was enhanced in the women, but its bioavailability was reduced, which was expressed by a high 3-nitrotyrosine (3-NitroT) concentration. The relation of NO/3-NitroT (rs = 0.811, p < 0.001) in the women and NO/3-NitroT (rs = -0.611, p < 0.001) in the men showed that sex determines endothelial dysfunction. RONS generation in the women simultaneously promoted endothelial regeneration, as demonstrated by a ~1.5-fold increase in circulating progenitor cells. Inflammation-specific variables, such as the neutrophil-to-lymphocyte ratio, the systemic immune inflammation index, and the neutrophil-to-high-density lipoprotein (HDL) ratio, were reduced in the women and showed their diagnostic utility for clinical prognosis in vascular dysfunction, especially the C-reactive-protein-to-HDL ratio (AUC = 0.980, specificity 94.7%, sensitivity 93.3%, OR = 252, 95% CI 65-967, p < 0.001). This study is the first to have revealed sex-specific changes in the oxi-inflammatory response, which can generate the risk of cardiovascular events at an older age.

INDICATORS OF FREE RADICAL OXIDATION AND ANTIOXIDANT PROTECTION IN THE ORAL FLUID OF CHILDREN WITH CHRONIC CATARRHAL GINGIVITIS AND DIABETIS MELLITUS

Failure of antioxidant mechanisms leads to an increase in lipid peroxidation products in the body, resulting in a non-specific cascade of cellular membrane damage. Proteins play a crucial role in metabolic processes, but when lipid peroxidation intensifies, protein modifications occur, leading to fragmentation, denaturation, and loss of biological activity. This disruption impairs tissue regenerative processes. The objective of this study was to analyze indicators of free radical oxidation and antioxidant protection in the oral fluid of children with chronic catarrhal gingivitis and type I diabetes mellitus. Materials and methods. A total of 170 children aged 12 to 16 were observed, including 130 who were examined and treated at the Endocrinology Department of the Regional Municipal Non-Profit Institution “Chernivtsi Regional Pediatric Clinical Hospital” for type 1 diabetes mellitus. Among them, 74 children had a disease duration of less than 5 years, including 65 with chronic catarrhal gingivitis. Sixty five children had diabetes for more than 5 years, with 44 of them diagnosed to have chronic catarrhal gingivitis. The children with chronic catarrhal gingivitis were further divided into groups based on their level of glycemic control: 1 child with optimal glycemic control, 66 with suboptimal glycemic control, and 42 with glycemic control at a high risk to life. The control group included 40 practically healthy children: 22 of them had clinically healthy periodontal tissues, and 18 children were diagnosed to suffer from chronic catarrhal gingivitis. Results. The study performed found out that children with chronic catarrhal gingivitis present increased indicators of lipid peroxide oxidation (protein oxidative modification, diene conjugates, malondialdehyde) and decreased activity of the enzyme in the antioxidant protective system of the oral fluid (whole protein, НS-groups, ceruloplasmin, activity of supermutase and catalase) in comparison with indicators of children without dental pathology. The most considerable changes were found in patients with chronic catarrhal gingivitis and type 1 diabetes mellitus, especially when the disease lasted more than 5 years (р&lt;0,05).

Hepatoprotective effects of ethanolic extract of Corallocarpus epigaeus roots on nitrobenzene-induced liver injury in Wistar rats

ABSTRACT This study examined the potential of Corallocarpus epigaeus ethanolic root extract to combat free radicals using DPPH, FRAP, hydroxyl radical, hydrogen peroxide, and nitric oxide scavenging assays. Rats were initially exposed to a single oral dose of nitrobenzene (50 mg kg−1 body weight), followed by a 15-d oral regimen of the ethanolic root extract of C. epigaeus at 200 mg kg−1 body weight. The assessment of serum liver marker enzymes (AST, ALT, and ALP), lipid peroxidation levels, antioxidant enzyme activities, and histopathological examinations of liver tissues were carried out. The C. epigaeus ethanolic root extract demonstrated antioxidant properties and contained flavonoids, tannins, carotenoids, lycopene, and phenolic compounds. In Nitrobenzene-induced rats, elevated serum markers and increased liver lipid peroxidation were observed that were normalized by the extract. It also increased antioxidant enzyme activities, including superoxide dismutase, catalase, and glutathione peroxidase. Histopathological analysis confirmed the hepatoprotective effects of the extract.

Optimal carbofuran degradation via CWPO in NOM-doped water by a framework Cu-doped aluminate perovskite catalyst derived from aluminum saline slags

This study is the first to propose the synthesis of LayAl1–xCuxO3–δ perovskite catalysts using Al recovered from acid leaching of saline slags. The effect of parameters such as the La/Al molar ratio was explored during the synthetic process. A suite of characterization techniques—including XRF, XRD, N2 adsorption, H2-TPR, FTIR, TGA-DTA, TEM, SEM, EDX, and XPS—confirmed the successful synthesis of high-purity (up to 90 %) perovskites with La and O vacancies, and a high concentration of Cu(I) active sites dispersed within the perovskite lattice. The best catalyst was used to optimize the degradation of carbofuran (CBF) in water doped with synthetic dissolved natural organic matter (NOM) using the Fenton-like catalytic wet peroxide oxidation (CWPO) approach. The effects of catalyst concentration, H2O2 dose, and pH on catalytic performance were investigated. Degradation, mineralization (COD removal), and H2O2 consumption were maximized, while Cu leaching was minimized using a statistical desirability function for multiple responses. Optimal conditions were found to be a catalyst concentration (mg Cu/mg H2O2) of 0.234 (2.0 g L–1), an H2O2 dose of 73.3 % (0.73 times the stoichiometric dose for full COD mineralization), and a remarkable circumneutral pH of 6.2. Under these conditions, degradation reached 94.1 %, and COD mineralization was 51 % under room temperature. Notably, the perovskite catalyst exhibited remarkable stability during reuse in up to three cycles, as demonstrated by the low Cu leaching (<1.30 mg L–1).

A Piper nigrum based zinc oxide nanoparticles for anti-arthritic and antioxidant activity

Background: Zinc oxide nanoparticles (ZnONPs) are among the most effective metallic oxide nanoparticles for biological applications. They have potential anti-inflammatory and anti-oxidant properties, desirable biocompatibility, lower toxicity, and minimal cost. Methodology: Using diverse plant extracts for an ecologically friendly production of metallic nanoparticles is a better choice than conventional chemical synthesis techniques. The present study is decisive on the ZnONPs synthesis from a Piper nigrum extract (Pn-ZnONPs). Morphological characteristics of ZnONPs have been studied using UV-spectroscopy, DLS, SEM, and TEM. Further, it is analyzed for its anti-inflammatory (proteinase, collagenase, lipooxygenase, and elastase) and anti-oxidant properties (DPPH˙, SOD, NO, H2O2, and OH). Results and discussion: Synthesis of nanoparticles has been confirmed via visible spectroscopy with maximum absorbance of 350nm, having particle size and zeta potential of 80 nm and +7.4 mV, respectively. SEM and TEM analysis confirmed the nanoparticle's shape to be spherical and arranged compactly. Further, biogenic nanoparticles show desired anti-inflammatory properties by inhibiting the activity of collagenase (68.72%), elastase (65.16%), lipooxygenase (58.098%), and denaturation of protein (65.36%). It also exhibits the capability to suppress Superoxide radicals (64.87%), DPPH (65.46%), Hydrogen Peroxide (64.89%), Hydroxyl radical (68.45%), and Nitric oxide radicals (71.343%), which are responsible for the pathogenesis of many inflammatory disorders. Conclusion: This suggests that P. nigrum Zinc nanoparticles may be a promising agent in treating various inflammatory disorders, such as cancer, Rheumatoid Arthritis, Psoriasis, and others.

Shuttle HAT for mild alkene transfer hydrofunctionalization.

Hydrogen atom transfer (HAT) from a metal-hydride is a reliable and powerful method for functionalizing unsaturated C-C bonds in organic synthesis. Cobalt hydrides (Co-H) have garnered significant attention in this field, where the weak Co-H bonds are most commonly generated in a catalytic fashion through a mixture of stoichiometric amounts of peroxide oxidant and silane reductant. Here we show that the reverse process of HAT to an alkene, i.e. hydrogen atom abstraction of a C-H adjacent to a radical, can be leveraged to generate catalytically active Co-H species in an application of shuttle catalysis coined shuttle HAT. This method obviates the need for stoichiometric reductant/oxidant mixtures thereby greatly simplifying the generation of Co-H. To demonstrate the generality of this shuttle HAT platform, five different reaction manifolds are shown, and the reaction can easily be scaled up to 100 mmol.

Simultaneous degradation of cyanobacteria and cyanotoxins by catalytic wet peroxide oxidation: Impact of morphology and growth stage

The widespread proliferation of potentially toxic cyanobacteria in source waters for drinking water treatment plants (DWTPs) presents a pressing contemporary challenge. Although catalytic wet peroxide oxidation (CWPO) has been recognized as a highly effective and environmentally friendly technology for removing cyanotoxins from water, the simultaneous degradation of cyanobacteria and cyanotoxins has been scarcely investigated. Considering their great morphological diversity, in this work, the impact of the presence of pure strains of several species of toxic and non-toxic cyanobacteria on the degradation of relevant cyanotoxins has been evaluated considering also the main stages of their life cycle. In each studied scenario, achieving a full eradication of the cyanobacteria also led to the complete elimination of the cyanotoxin, including both intra and extracellular fractions. Morphological factors, including filament and cell sizes, play a crucial role in the efficiency of the process. Small cells and long filaments entail a higher presence of particulate organic matter, which consumes hydroxyl radicals considerably in competence with the cyanotoxin degradation. Moreover, the growth stage emerges as a pivotal factor in understanding the CWPO process performance, with cyanobacteria in their early life stages, exhibiting more pronounced interference compared to later stages, probably due to their higher cell viability and accelerated metabolism. All these understandings are essential for the successful implementation of the technology in treating surface waters affected by toxic cyanobacterial blooms.

Evaluating the Antioxidant Capacity, Phenolic Contents, and Anticancer Potential of Caralluma europaea Extracts

Background: Caralluma europaea (C. europaea) is a genus of shrubs in the Apocynaceae family, endemic to the Mediterranean region. Assessing the anticancer properties, total phenolic and flavonoid content, and antioxidant activity of different C. europaea extracts were the aim of this study.Methods: To determine antioxidant activity, we used three free radical scavenging assays: DPPH (2,2-Diphenyl-1-picrylhydrazyl), hydrogen peroxide (H2O2), and nitric oxide (NO) assays. Total phenolic and flavonoid contents were measured using colorimetric methods. The anti-important activity was evaluated by MTT assay.Results: Our findings showed that the efficacy of the extract in MCF7 cells decreased in the system containing chloroform, methanol, ethyl acetate, and water. The strength of the extract for U87 cells decreased according to methanolic, chloroform and water, where ethyl acetate was the strongest. The highest total phenolic and flavonoid content was found in methanol extract. All extracts showed a high scavenging activity of DPPH. Methanol extract showed the highest antioxidant activity in the NO assay of the solution, followed by ethyl acetate, chloroform, and aqueous extract. In the H2O2-based antioxidant activity assay, the methanol extract again showed the highest activity, followed by ethyl acetate, chloroform, and aqueous extracts.Conclusions: Extracts of C. europaea have shown great potential as natural antioxidants and anticancer agents in this study, suggesting that they deserve further investigation into the food and pharmaceutical fields.Keywords: Phenolic content; Flavonoid content; Antioxidant activity; Anti-cancer activity

Heteronuclear coordination polymers with imidazole ligand: Synthesis, characterization and alcohol oxidation activities

Two new heteronuclear Cd(II)/Pd(II) coordination polymers, [Cd2(µ-im)2(Him)4Pd(µ-CN)4]n (1) and [Cd(Him)2Pd(µ-CN)4]n (2) (Him: imidazole), have been synthesized under different conditions and characterized using elemental analysis, thermal analysis, FT-IR and Raman spectroscopy, single-crystal and powder X-ray diffraction techniques. In 1, the Cd(II) ions are bridged by imidazolate ligands to generate 1D chain structure. Neighbouring 1D chains were linked by [Pd(CN)4]2- ions to form 3D framework. In 2, the metal ions are bridged by cyanide ligands to generate 2D [Cd2Pd2(µ-CN)4]n network. Catalytic peroxidative oxidation activity of 1 and 2 was examined on the oxidation of benzyl alcohol using tertiary-butyl hydroperoxide (t-BuOOH) as the oxygen source. The compound 1 exhibited over 90 % product conversion at 80 °C in 24-hour reaction time. In addition, the catalyst exhibited high selectivity towards benzaldehyde and no over-oxidation product (benzoic acid) was detected.

Kolaviron: a Bioflavonoid from Seed Extract of Garcinia kola Attenuates Chromium (VI)-Induced Gut Dysfunction and Oxidative Damage in Drosophila melanogaster.

Hexavalent chromium [Cr(VI)] is of public health significance due to its toxicity and carcinogenic effects. Kolaviron, a bio-flavonoid fraction from Garcinia kola seed, has been reported to possess gastroprotective and antioxidative properties. We hypothesize that Kolaviron-fortified diet will attenuate chromium (VI)-induced gut dysfunction and oxidative damage in Drosophila melanogaster. We exposed D. melanogaster (Oregon strain of 1-3days old of both male and female) to a 1.0mg/kg diet of chromium (VI), with or without Kolaviron (100mg/kg diet) orally for 5days. We evaluated markers of oxidative stress (total peroxide and protein carbonyl), antioxidative status (total thiols (T-SH), non-protein thiols (NP-SH), and catalase), and inflammatory (nitric oxide (nitrite and nitrate) and gut's morphology. The data indicated that Kolaviron ameliorated chromium (VI)-induced reduction in the levels of T-SH, NP-SH, and catalase activity (p < 0.05). In addition, Kolaviron attenuated chromium (VI)-induced elevation of total peroxide, protein carbonyl, and nitric oxide (p < 0.05). Kolaviron offered a protective role in chromium VI-induced toxicity in the gut of D. melanogaster. This study provided further insights into the protective mechanisms of Kolaviron against chromium (VI)-induced toxicity in D. melanogaster by maintaining epithelial integrity of the gut and oxidative stress-antioxidant balance.

Synergistic catalytic degradation of Methotrexate using Ce-based high-entropy metal oxides: Insights from DFT calculations and CWPO performance

Methotrexate (MTX), a widely used anticancer drug, is a refractory organic pollutant posing serious threats to ecosystems and human health. This study focuses on the development of a novel catalyst composed of Ce-based high-entropy metal oxides (NHEMO) supported on nepheline for the catalytic wet peroxide oxidation (CWPO) process, targeting MTX degradation in simulated wastewater. The NHEMO catalyst exhibited a unique high-entropy structure that enhances catalytic performance by facilitating diverse electronic interactions, which was confirmed through X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses showing a well-defined crystal structure and uniform dispersion of metal oxides. Additionally, X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDS) revealed a stable metal composition and high oxidation states of active metal sites. At a reaction temperature of 160 °C, with a residence time of 150 s and an oxidation coefficient of 5, the catalyst achieved a MTX removal rate of 93.49 % and a chemical oxygen demand (COD) removal of 99.95 %. Density Functional Theory (DFT) calculations further demonstrated that H2O2 decomposes into both adsorbed (surface-bound) and free (solution-phase) hydroxyl radicals (·OH). These radicals synergistically degrade MTX through both radical and non-radical pathways, ensuring comprehensive pollutant breakdown. The catalyst also showed excellent stability and a very low metal dissolution rate during the reaction, maintaining high catalytic activity after repeated recycling. This catalyst offers high cost-effectiveness, activity, and stability, providing a promising solution for treating refractory organic pollutants in pharmaceutical wastewater.

Modern views on the etiology and role of microbial persistence in the development of inflammatory processes in the periodontal complex (review)

Alveolar tissue diseases cause the appearance of dentition defects, thereby reducing the patients' work capacity and quality of life. The purpose of this research was to investigate, modern views on the etiology of periodontitis and the role of microbial persistence in the development of inflammatory processes of periodontal complex basing on a review of literary sources. Literature review was conducted using PubMed, Web of Science, Scopus, Google Scholar from 2018 to March 2024. There were no restrictions on the date of publication or the language of scientific sources. Searches were conducted according to MeSH (Medical Subject Headings) with using the following search terms: "periodontitis", "oral mucosa", "gums", "dental plaque", "periodontium", "traumatic occlusion", "microorganisms". In total, during the initial analysis 82 literary sources were selected and processed, after further systematization of the selected information using general scientific methods, 70 of them remained. Used methods: bibliographic and analytical. Generalized perio­dontitis is a chronic inflammatory-dystrophic process that occurs as a result of various factors. In the pathogenesis of this disease, the key role is played by the inflammatory process, which is a complex interaction of microcirculatory, he­matological and connective tissue reactions to the lesion. Local (exogenic) and general (endogenic) causative factors are distinguished. The main factors that cause pathological changes in periodontium are bacterial biofilm, traumatic occlusion and various anatomical anomalies. Dental plaque occupies a special and main place among the causes of periodontitis. At present, leading pathogenetic links in the development of the inflammation in the periodontium, in par­ticular, the disruption of free radical oxidation, the processes of peroxide oxidation of lipids and proteins, the disorder of the functional state of the antioxidant system, the formation of oxidative stress, as well as the humoral link of adaptive immune protection and cytokinesis, have not been sufficiently studied. There is no doubt about the role of the microbial factor in the etiology of periodontal diseases, but the penetration of microbes into the periodontium does not always lead to the development of the disease, because the organism has a number of protective mechanisms that counteract the development of inflammation.

Ionising and ultraviolet radiation induce the secretion of melanin in Tetrahymena pyriformis

ABSTRACT The objective of this study was to determine the effect of ionising and ultraviolet radiation on stimulating melanin secretion in Tetrahymena pyriformis. Cell cultures were exposed to different doses of radiation for 48, 72 and 96 h. After incubation, melanin was extracted and analysed. Our results showed that melanin concentration increased with increasing irradiation dose and exposure duration. Melanin was insoluble in water and organic solvents but soluble in alkaline and acidic solutions. A linear correlation between the logarithm of melanin absorbance and wavelength ranging from 400 to 600 nm was observed. The HPLC chromatograms of melanin degradation products by the alkaline hydrogen peroxide oxidation method revealed the existence of four peaks. The natural melanin standard extracted from the cuttlefish Sepia officinalis was used as a reference compound of eumelanin markers. These markers were detected in control cells, irradiated cells and black human hair but with different intensities.

The role of exopolysaccharides Psl and Pel in resistance of Pseudomonas aeruginosa to the oxidative stressors sodium hypochlorite and hydrogen peroxide.

Biofilms are microbial communities of cells embedded in a self-produced polymeric matrix composed of polysaccharides, proteins, lipids, and extracellular DNA. Biofilm bacteria have been shown to possess unique characteristics, including increased stress resistance and higher antimicrobial tolerance, leading to failures in bacterial eradication during chronic infections or in technical settings, including drinking and wastewater industries. Previous studies have shown that in addition to conferring structure and stability to biofilms, the polysaccharides Psl and Pel are also involved in antibiotic resistance. This work provides evidence that these biofilm matrix components also contribute to the resistance of Pseudomonas aeruginosa to oxidative stressors including the widely used disinfectant NaOCl. Understanding the mechanisms by which bacteria escape antimicrobial agents, including strong oxidants, is urgently needed in the fight against antimicrobial resistance and will help in developing new strategies to eliminate resistant strains in any environmental, industrial, and clinical setting.

Non-radical oxidation driven by iron-based materials without energy assistance in wastewater treatment.

Chemical oxidation is extensively utilized to mitigate the impact of organic pollutants in wastewater. The non-radical oxidation driven by iron-based materials is noted for its environmental friendliness and resistance to wastewater matrix, and it is a promising approach for practical wastewater treatment. However, the complexity of heterogeneous systems and the diversity of evolutionary pathways make the mechanisms of non-radical oxidation driven by iron-based materials elusive. This work provides a systematic review of various non-radical oxidation systems driven by iron-based materials, including singlet oxygen (1O2), reactive iron species (RFeS), and interfacial electron transfer. The unique mechanisms by which iron-based materials activate different oxidants (ozone, hydrogen peroxide, persulfate, periodate, and peracetic acid) to produce non-radical oxidation are described. The roles of active sites and the unique structures of iron-based materials in facilitating non-radical oxidation are discussed. Commonly employed identification methods in wastewater treatment are compared, such as quenching, chemical probes, spectroscopy, mass spectrometry, and electrochemical testing. According to the process of iron-based materials driving non-radical oxidation to remove organic pollutants, the driving factors at different stages are summarized. Finally, challenges and countermeasures are proposed in terms of mechanism exploration, detection methods and practical applications of non-radical oxidation driven by iron-based materials. This work provides valuable insights for understanding and developing non-radical oxidation systems.

The Role of Inducible Nitric Oxide Synthase in Assessing the Functional Level of Coronary Artery Lesions in Chronic Coronary Syndrome.

Chronic coronary syndrome (CCS) is a long-term manifestation of coronary artery disease, marked by stable but recurring chest pain and myocardial ischemia due to the gradual buildup of atherosclerotic plaques in the coronary arteries. It is a metabolic disorder of coronary arteries characterized by oxidative stress, endothelial dysfunction, inflammation, and hyperlipidemia. The imbalance in oxidative-antioxidative status contributes to stable ischemic heart disease. Oxidative stress involves reactive oxygen and nitrogen species, leading to low-density lipoprotein (LDL) oxidation. Endothelial dysfunction, marked by reduced nitric oxide (NO) bioavailability, is an early onset of CCS, affecting vasodilation, cell proliferation, and inflammatory responses. Enzyme myeloperoxidase (MPO), traditionally considered protective, plays a dual role in initiating and progressing inflammatory diseases. MPO interacts with NO, modulating its catalytic activity. Elevated NO levels inhibit MPO through a reversible complex formation, preventing NO-induced inhibition by inducible nitric oxide synthase (iNOS). MPO also inactivates endothelial nitric oxide synthase (eNOS) and reacts with L-arginine, hindering NO synthesis. The interplay between MPO and NO significantly influences inflammation sites, impacting peroxidation rates and oxidation reactions. Peroxynitrite, a reactive species, contributes to nitration of tyrosine residues and lipid peroxidation. Mechanistic pathways suggest MPO enhances iNOS catalytic activity, influencing CCS development. iNOS, implicated in inflammation and atherosclerosis, is connected to NO regulation. This review analyzes the complex interplay of MPO, iNOS, and NO that affects plaque morphology, oxidative stress, and inflammation, contributing to atherosclerosis progression. Therefore, it is possible that the phenotypes of atherosclerotic plaques, focal and diffuse coronary artery disease, could be defined by the relationship between MPO and iNOS.

Measurement of Hydrogen Peroxide and Lipid Peroxide oxidants as Markers of Oxidative Stress and Activity of Antioxidant Enzymes Catalase and Superoxide Dismutase in Obese People

Measurement of Hydrogen Peroxide and Lipid Peroxide oxidants as Markers of Oxidative Stress and Activity of Antioxidant Enzymes Catalase and Superoxide Dismutase in Obese People

Nutmeg vs mace: Evaluation of functional, nutritional, antioxidant and antimicrobial traits to employ as a food preservative

Nutmeg and mace from Myristica fragrans Houtt. are renowned for their culinary significance and medicinal properties. This study was designed to analyze the functional properties, proximate and mineral composition of nutmeg and mace, phytochemical estimation, antioxidant and antimicrobial potential of nutmeg and mace essential oils and oleoresins. The study was further elaborated by testing their synergistic interaction with streptomycin and antibiofilm potential of the most effective treatment. Results revealed better functional properties, higher fiber (35.2%) and mineral (K, Mg, P, Ca, Mn, Zn) content in nutmeg than mace. Nutmeg and mace essential oils were isolated by hydrodistillation and their respective oleoresins were prepared by the Soxhlet extraction method. Phytochemical screening showed a greater phenolic content in mace oleoresin (43.85 mg GAE/g of dw) and terpenoid content in mace essential oil (75.4%). Among all the treatments, mace oleoresin revealed best antioxidant potential against mustard oil degradation during its accelerated oxidation at 70 °C when stored for 7–28 days with minimum increase in peroxide, anisidine, thiobarbituric acid and total oxidation values of mustard oil. Mace oleoresin also revealed the maximum antibacterial activity against Staphylococcus aureus, Bacillus spp., Escherichia coli and Yersinia enterocolitica (MIC values; 180–530 μg/ml). It also revealed synergistic interaction with streptomycin against all the test bacteria along with a notable decrease in biofilm formation (50% of MIC.) GC-MS studies of mace oleoresin showed the presence of terpenoids, phenylpropanoids, phenols and fatty acids and their esters. Hence, mace oleoresins may be used as a natural and safe food preservative.

Temperature Dependence of the Pre-Chromatographic ‘Lawrence’ Method for Bivalves Contaminated with Paralytic Shellfish Poisoning Toxins

Saxitoxins are potent neurotoxins originating the acute human neurological syndrome of paralytic shellfish poisoning (PSP) via bivalve vectors. The official testing method in the European Union, commonly known as the ‘Lawrence method’, involves pre-column oxidation steps. The Portuguese monitoring adopted the hydrogen peroxide oxidation screening approach for bivalves contaminated with Gymnodinium catenatum toxins, which can quantify chromatographically at once 6 out of 10 analogues commonly found in bivalves. Seasonal fluctuation in the fluorescence yield of calibration curves was observed across years in a consistent manner. It correlated with fluctuations in average monthly air temperature in Lisbon, highlighting the importance of recording the room temperature during the oxidation steps as a matter of routine practice. Incubation experiments also showed an increase in fluorescence yield with temperature, more pronounced for the 11-hydroxysulphate analogues (dcGTX2 + 3, C1 + 2, GTX2 + 3) than for the 11-H toxins (dcSTX, GTX5[B1], STX). Temperature can be exploited to increase fluorescence yield, assisting in spectral confirmation, but must not exceed 40–50 °C to avoid toxin decomposition or production of extra oxidation products.