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1.
Orv Hetil ; 161(35): 1441-1448, 2020 08.
Artigo em Húngaro | MEDLINE | ID: mdl-32822322

RESUMO

Chronic liver disorders are the main leading cause of morbidity and mortality data. Viral infection, toxic injury, metabolic, autoimmun, storage disorders, in the case of ongoing presence of the etiological factors, could result in fibrotic remodelling in the liver. The process is complex, not fully understood in details; cells, cytokines, chemokines release, altered secretion of hepatokines, lipotoxicity, innate immun system, gut microbiom, metal ions and free radical reactions all have a role in it. Chronic liver disorders are often symptomless, diagnosed in the stage of fibrotic tissue accumulation, liver failure or hepatocellular carcinoma formation, when the prognosis is poor, treatment options are narrow. Noninvasive, properly sensitive and specific biomarkers are the targets of studies, with them the necessity of liver biopsies can be decreased, through the follow-up of processes, progression and treatment efficacy. Authors review the processes taking part in the progression of the most frequent chronic liver disorders, emphasizing the parameters of pro/antioxidant balance, and the necessity of a combined reliable biomarker. Orv Hetil. 2020; 161(35): 1441-1448.


Assuntos
Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Progressão da Doença , Radicais Livres , Humanos
2.
Orv Hetil ; 161(35): 1488-1496, 2020 08.
Artigo em Húngaro | MEDLINE | ID: mdl-32822328

RESUMO

Copper is an essential micronutrient for the human body, taking part in several metabolic processes. It is required for the terminal oxidation, the elimination of free radicals, the proper functioning of iron metabolism, the synthesis of hormones, neurotransmitters and the stabilization of the extracellular matrix. Copper is a two-faced element. Its significance in protein-bounded form is undeniable, but free copper causes severe cell damage mainly through free radical reactions, substituting other essential metals in protein structure, and it has various effects on cell signaling pathways. The amount of copper present in the human body is part of a delicate balance. Both its deficiency and excess can develop severe symptoms and diseases. The nutritional copper balance is rarely broken, because the average daily consumption excessively covers the needs, and the body's copper stores can tolerate the temporary differences. Genetic diseases (Menkes and Wilson disease) helped to understand the copper metabolism and understand the clinical symptoms of deficiency and excessive intake. The role of copper in the development of chronic diseases is receiving increasing attention. Recent studies show its significance in neurodegenerative and cancerous diseases, both in pathogenesis and as a therapeutic target. Orv Hetil. 2020; 161(35): 1488-1496.


Assuntos
Cobre/química , Cobre/metabolismo , Radicais Livres , Degeneração Hepatolenticular/genética , Humanos , Metais , Neoplasias/genética , Oligoelementos
3.
PLoS One ; 15(8): e0237031, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790698

RESUMO

Tomato is the most widespread vegetable crop in the world. In Italy, tomatoes are mainly cultivated in the South and in the Campania region, precisely in the area called Agro Nocerino-Sarnese. This flatland is affected by an extreme level of environmental degradation, especially related to the Sarno River, where concentrations of Potential Toxic Elements (PTEs) have been found to be higher than the maximum permitted level. The aim of this study was to determine the PTEs uptake by roots and their translocation to the aerial parts of the plants of two cultivars of tomatoes (Pomodoro Giallo and San Marzano Cirio 3). To the purpose, samples of the two cultivars were grown both in pots with experimentally contaminated soil containing: Cr or Cd or Pb at extremely high concentrations and in pots with uncontaminated soils (control). Additionally, the antioxidant properties of the cultivars selected grown on uncontaminated/contaminated soils were assessed. The results showed that Cd was the contaminant that most significantly interfered with the growth of both cultivars of tomato plants, whereas Pb caused lower phenotypical damage. Cd translocation from root to the organs of tomato plants was observed in both cultivars. Specifically, the total amount of Cd found in stems and leaves was higher in the Pomodoro Giallo (254.4 mg/kg dry weight) than in the San Marzano Cirio 3 (165.8 mg/kg dry weight). Cd was the only PTE found in the fruits of both cultivars, with values of 6.1 and 3.9 mg/kg dry weight of Pomodoro Giallo and San Marzano Cirio 3, respectively. The fruits of tomato plants grown in PTEs-contaminated soil showed inhibition or stimulations of the radical scavenging activity compared to the fruits grown in uncontaminated soil. This study highlighted that, despite the relatively high experimental concentrations of PTEs, their translocation to the edible part was comparatively low or absent.


Assuntos
Lycopersicon esculentum/metabolismo , Metais Pesados/farmacocinética , Poluentes do Solo/farmacocinética , Bioacumulação , Transporte Biológico Ativo , Cádmio/farmacocinética , Cádmio/toxicidade , Cromo/farmacocinética , Cromo/toxicidade , Depuradores de Radicais Livres/metabolismo , Radicais Livres/metabolismo , Itália , Chumbo/farmacocinética , Chumbo/toxicidade , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/crescimento & desenvolvimento , Metais Pesados/toxicidade , Poluentes do Solo/toxicidade , Distribuição Tecidual
4.
Food Chem ; 332: 127373, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619941

RESUMO

In the present study, effects of riboflavin (RF) and kelp polyphenol extracts (KPE) on mackerel (Scomberomorus Niphonius) myofibrillar protein (MP) gel were studied with or without ultraviolet A (UVA) irradiation treatment. The gel strength was increased with the addition of RF and KPE under UVA irradiation. Analysis of the proteins in the gel indicated that the carbonyl content increased, while the contents of total sulfhydryl and amino groups decreased. The proteins appeared to have no α-helix structures, and the endogenous tryptophan content appeared to decrease. The results of SDS-PAGE indicated that the RF and KPE treated samples under UVA irradiation showed massive MP cross-linking by covalent bonds. Electron spin resonance (ESR) results indicated that UVA irradiation generated free radicals in RF and KPE, which ultimately led to an improvement in MP gel properties. It also indicated that KPE could prevent the occurrence of peroxidation to improve the gel properties.


Assuntos
Proteínas de Peixes/química , Kelp/química , Perciformes , Polifenóis/química , Riboflavina/química , Raios Ultravioleta , Animais , Radicais Livres/química , Géis
5.
Chem Biol Interact ; 328: 109188, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32679048

RESUMO

We have reported that gestational exposure to hexavalent chromium (CrVI) represses androgen receptor (Ar) and follicle stimulating hormone receptor (Fshr) in Sertoli cells (SCs) of adult rats, while the mechanism underlying remains obscure. We tested the hypothesis "transient gestational exposure to CrVI during the critical embryonic windows of testicular differentiation and growth may have adverse impact on transcription factors controlling the expression of Ar and Fshr in SCs of the F1 progeny". CrVI (K2Cr2O7) was given through drinking water (50 ppm, 100 ppm and 200 ppm), to pregnant rats from gestational day 9-14 (testicular differentiation) and 15 to 21 (prenatal differentiation and proliferation of SC); male progenies were sacrificed on postnatal day 30 (Completion of postnatal SC maturation). A significant increase in free radicals and decrease in enzymatic and non-enzymatic antioxidants were observed in SCs of experimental rats. Real time PCR and western blot data showed decreased expression of Ar, Fshr, Inhibin B, Transferrin, Androgen binding protein, Claudin 11 and Occludin in SCs of experimental rats; concentrations of lactate, pyruvate and retinoic acid also decreased. Serum FSH, luteinizing hormone and estradiol increased, whereas testosterone and prolactin decreased in experimental rats. Western blot detection revealed decreased levels of transcription factors regulating Fshr viz., USF-1, USF-2, SF-1, c-fos, c-jun and GATA 1, and those of Ar viz., Sp-1, ARA54, SRC-1 and CBP in experimental rats, whereas the levels of cyclinD1 and p53, repressors of Ar increased. ChIP assay detected decreased USF-1 and USF-2 binding to Fshr promoter, and binding of Sp-1 to Ar promoter. We conclude that gestational exposure to CrVI affects SC structure and function in F1 progeny by inducing oxidative stress and diminishing the expression of Ar and Fshr through attenuation of their specific transcriptional regulators and their interaction with the respective promoter.


Assuntos
Cromo/toxicidade , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Receptores Androgênicos/metabolismo , Receptores do FSH/metabolismo , Células de Sertoli/metabolismo , Maturidade Sexual , Fatores de Transcrição/metabolismo , Animais , Antioxidantes/metabolismo , Disponibilidade Biológica , Feminino , Radicais Livres/metabolismo , Hormônios/sangue , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/sangue , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Ratos Wistar , Receptores Androgênicos/genética , Receptores do FSH/genética , Células de Sertoli/efeitos dos fármacos , Maturidade Sexual/efeitos dos fármacos , Proteínas de Junções Íntimas/metabolismo
6.
Rev. Asoc. Med. Bahía Blanca ; 30(1): 20-27, 20 de junio de 2020.
Artigo em Espanhol | LILACS, BINACIS | ID: biblio-1099865

RESUMO

Se evaluó la actividad gastroprotectora de la infusión proveniente de las hojas de Aloysia gratissima (Verbenaceae), especie nativa de interés medicinal que se desarrolla en el sudoeste bonaerense, utilizando un modelo de inducción de úlceras gástricas con etanol en ratones. Se realizó un tamizaje fitoquímico para detectar la presencia de compuestos que podrían ser responsables de la actividad gastroprotectora de la planta. Se determinó el contenido de fenoles totales y la capacidad atrapadora de radicales libres mediante el método del Folin-Ciocalteu y del 2,2'-difenil-1-picrilhidrazilo (DPPH), respectivamente. Los ensayos demostraron que la infusión de la planta, administrada por vía oral en dosis de 100, 500 y 1000 mg/kg, ejerció una gastroprotección significativa frente a la inducción de úlceras. Se detectó una actividad atrapadora de radicales libres de 47,5%, similar a la sustancia de referencia (BHT). El estudio fitoquímico detectó la presencia de flavonoides y otros polifenoles, sustancias con reconocida capacidad antioxidante. Estos metabolitos ejercen efectos protectores en diferentes modelos experimentales de inducción de úlceras mediante mecanismos que pueden involucrar la neutralización de radicales libres, lo que podría explicar la actividad gastroprotectora de la planta. Estos hallazgos requieren estudios adicionales de A. gratissima como una posible terapia frente a la úlcera gástrica. (AU)


The gastroprotective activity of the infusion from the leaves of Aloysia gratissima (Verbenaceae), a native species of medicinal interest growing in South West Buenos Aires, was evaluated in an ethanol-induced gastric ulcer model in mice. Phytochemical screening was carried out in order to determine the presence of compounds that could be responsible for the pharmacological effects of the plant. Total phenolic content and the free radical scavenging activity of the plant were determined using the Folin-Ciocalteu and the 2,2'-diphenyl1-picrylhydrazyl (DPPH) method, respectively. Assays demonstrated that the infusion, orally administered at 100, 500, and 1000 mg/kg doses, exerted a significant gastroprotection effect against ulcer induction (P<0,05). A free radical scavenging activity of 47.5% -similar to the reference substance (BHT)- was detected. Phytochemical screening revealed the presence of antioxidant compounds such as flavonoids and other phenolic compounds. These compounds exert protective effects in different experimental models of ulcer induction that could involve free radical neutralization, which could explain the gastroprotective activity of the plant. These promising results support additional studies of A. gratissima as a potential therapy against gastric ulcer. (AU)


Assuntos
Animais , Camundongos , Úlcera Gástrica/tratamento farmacológico , Verbenaceae/efeitos dos fármacos , Experiências Laboratoriais , Radicais Livres/farmacologia
7.
Nitric Oxide ; 102: 39-41, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32562746

RESUMO

COVID-19 is a severe pandemic which has caused a devastating amount of loss in lives around the world, and yet we still don't know how to appropriately treat this disease. We know very little about the pathogenesis of SARS-CoV-2, the virus which induces the COVID-19. However, COVID-19 does share many similar symptoms with SARS and influenza. Previous scientific discoveries learned from lab animal models and clinical practices shed light on possible pathogenic mechanisms in COVID-19. In the past decades, accumulated scientific findings confirmed the pathogenic role of free radicals damage in respiratory virus infection. Astonishingly very few medical professionals mention the crucial role of free radical damage in COVID-19. This hypothesis aims to summarize the crucial pathogenic role of free radical damage in respiratory virus induced pneumonia and suggest an antioxidative therapeutic strategy for COVID-19.


Assuntos
Betacoronavirus , Infecções por Coronavirus/metabolismo , Radicais Livres/metabolismo , Pandemias , Pneumonia Viral/metabolismo , Acetilcisteína/uso terapêutico , Animais , Antioxidantes/uso terapêutico , Ácido Ascórbico/uso terapêutico , Azitromicina/administração & dosagem , Azitromicina/farmacologia , Azitromicina/uso terapêutico , Ensaios Clínicos como Assunto , Infecções por Coronavirus/complicações , Infecções por Coronavirus/tratamento farmacológico , Síndrome da Liberação de Citocina/etiologia , Síndrome da Liberação de Citocina/metabolismo , Quimioterapia Combinada , Radicais Livres/antagonistas & inibidores , Glutationa/uso terapêutico , Humanos , Hidroxicloroquina/administração & dosagem , Hidroxicloroquina/farmacologia , Hidroxicloroquina/uso terapêutico , Camundongos , Insuficiência de Múltiplos Órgãos/etiologia , Insuficiência de Múltiplos Órgãos/prevenção & controle , Fator 2 Relacionado a NF-E2/agonistas , Óxido Nítrico/metabolismo , Infecções por Orthomyxoviridae/metabolismo , Estresse Oxidativo , Pneumonia Viral/complicações , Pneumonia Viral/tratamento farmacológico , Espécies Reativas de Oxigênio/metabolismo , Síndrome Respiratória Aguda Grave/tratamento farmacológico , Síndrome Respiratória Aguda Grave/metabolismo
8.
Chemosphere ; 258: 127306, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32540533

RESUMO

The threat of antibiotics in the environment causing antibiotics resistance is a global health concern. Enzymes catalyze pollutant transformations, and how commercially available enzymes like horseradish peroxidase (HRP), with or without a redox mediator, may be used to degrade antibiotics in water treatment is of great interest. This work demonstrates tetracycline transformation by HRP, and how it is significantly enhanced by free radicals created from the mediator 2,2-Azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Water temperature and pH strongly influence the tetracycline removal rate due to their correlation with the enzyme activity, abundance and stability of ABTS•+. Four transformation products were identified in the pure HRP system using a liquid chromatography tandem mass spectrometry hybrid quadrupole-orbitrap mass spectrometer system. Addition of 25 µmol L-1 ABTS not only accelerated the degradation of tetracycline, but also expanded the range of degradation pathways. Potential tetracycline transformation pathways are proposed based on these observations, which include a range of mechanisms such as hydroxylation, demethylation, dehydration, decarbonylation and secondary alcohol oxidation. Despite of decreased efficiency, the HRP/ABTS system was able to degrade tetracycline in a domestic wastewater treatment plant effluent matrix, which demonstrates the potential of the system to be utilized in wastewater treatment.


Assuntos
Peroxidase do Rábano Silvestre/química , Tetraciclina/química , Poluentes Químicos da Água/química , Antibacterianos , Benzotiazóis , Catálise , Cromatografia Líquida , Radicais Livres/química , Oxirredução , Ácidos Sulfônicos , Água , Purificação da Água/métodos
9.
Food Chem ; 331: 127314, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32590264

RESUMO

The formation of short-lived and stable radicals was investigated using electron paramagnetic resonance (EPR) spectroscopy and compared with hydroperoxides and hexanal in complex starch-protein-lipid model systems, as well as in corn extrudates. Stable radicals were detected directly in ground samples. Short-lived lipid radicals were measured ex situ in ethyl acetate extracts of model systems and extrudates by the use of the spin trap PBN. Significant adduct formation was found after 30 min at 50 °C. During storage, lipid radicals (PBN adducts) increased in model systems. Simulation of EPR spectra from bulk oil demonstrated that mainly alkoxyl radical adducts were detected, to which rapidly decomposing peroxyl radical adducts also contributed. Stable radicals in extrudates were attributed to protein radicals based on g-value of 2.00467 compared with 2.00474 found in model system prepared with zein. The signal intensity of the stable radical remained constant during storage, but increased during extrusion.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres/química , Lipídeos/química , Proteínas de Plantas/química , Amido/química , Zea mays/química
10.
AAPS PharmSciTech ; 21(5): 141, 2020 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-32419084

RESUMO

Current study is focused to enhance the solubility of poorly soluble drug olanzapine (OLZ) by nanogels drug delivery system, as improved solubility is one of the most important applications of nanosystems. Poor solubility is a major issue, and 40% of marketed and about 75% of new active pharmaceutical ingredients are poorly water soluble which significantly affect the bioavailability and therapeutic effects of these drugs. In this study, nanogels, a promising system for solubility enhancement, were developed by free-radical polymerization technique. Different formulations were synthesized in which poloxamer-407 was cross-linked with 2-acrylamido-2-methylpropane sulfonic acid (AMPS) with the help of cross-linker methylene bisacrylamide (MBA). The chemically cross-linked nanogels were characterized by Fourier transform infrared spectroscopy (FT-IR), thermos gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta size, swelling, sol-gel analysis, drug loading, solubility, and in vitro drug release studies. In order to determine the biocompatibility and cytotoxicity of nanogels to biological system, toxicity study on rabbits was also carried out. It was confirmed that the developed nanogels was thermally stable, safe, effective, and compatible to biological system, and the solubility of olanzapine (OLZ) was enhanced up to 38 folds as compared with reference product.


Assuntos
Antipsicóticos/administração & dosagem , Reagentes para Ligações Cruzadas , Nanogéis , Olanzapina/administração & dosagem , Poloxâmero/química , Acrilamidas , Animais , Antipsicóticos/química , Antipsicóticos/toxicidade , Disponibilidade Biológica , Liberação Controlada de Fármacos , Excipientes , Radicais Livres , Olanzapina/química , Olanzapina/toxicidade , Tamanho da Partícula , Coelhos , Solubilidade
11.
Nat Commun ; 11(1): 2315, 2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385229

RESUMO

As established nearly a century ago, mechanoradicals originate from homolytic bond scission in polymers. The existence, nature and biological relevance of mechanoradicals in proteins, instead, are unknown. We here show that mechanical stress on collagen produces radicals and subsequently reactive oxygen species, essential biological signaling molecules. Electron-paramagnetic resonance (EPR) spectroscopy of stretched rat tail tendon, atomistic molecular dynamics simulations and quantum-chemical calculations show that the radicals form by bond scission in the direct vicinity of crosslinks in collagen. Radicals migrate to adjacent clusters of aromatic residues and stabilize on oxidized tyrosyl radicals, giving rise to a distinct EPR spectrum consistent with a stable dihydroxyphenylalanine (DOPA) radical. The protein mechanoradicals, as a yet undiscovered source of oxidative stress, finally convert into hydrogen peroxide. Our study suggests collagen I to have evolved as a radical sponge against mechano-oxidative damage and proposes a mechanism for exercise-induced oxidative stress and redox-mediated pathophysiological processes.


Assuntos
Colágeno/química , Tendões/química , Animais , Materiais Biocompatíveis/química , Biopolímeros/química , Di-Hidroxifenilalanina/química , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres/química , Oxirredução , Estresse Oxidativo , Ratos , Espécies Reativas de Oxigênio/química
12.
Nat Commun ; 11(1): 2528, 2020 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-32433521

RESUMO

Arene dearomatization reactions are an important class of synthetic technologies for the rapid assembly of unique chemical architectures. Herein, we report a catalytic protocol to initiate a carboamination/dearomatization cascade that proceeds through transient sulfonamidyl radical intermediates formed from native sulfonamide N-H bonds leading to 1,4-cyclohexadiene-fused sultams. Importantly, this work demonstrates a facile approach to employ two-dimensional aromatic compounds as modular building blocks to generate richly substituted, three-dimensional compounds. These reactions occur at room temperature under visible light irradiation and are catalyzed by the combination of an iridium(III) photocatalyst and a dialkyl phosphate base. Reaction optimization, substrate scope, mechanistic features, and synthetic applications of this transformation are presented.


Assuntos
Radicais Livres/química , Irídio/química , Catálise/efeitos da radiação , Ligação de Hidrogênio , Luz , Estrutura Molecular , Fosfatos/química , Sulfonamidas/química
13.
Pol Merkur Lekarski ; 48(284): 124-127, 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32352946

RESUMO

Reactive oxygen species (ROS) are molecules capable of independent existence, containing at least one oxygen atom and one or more unpaired electrons. This group includes oxygen free radicals, e.g. superoxide anion radical, hydroxyl radical, hydroperoxyl radical, singlet oxygen, as well as free nitrogen radicals. Under physiological conditions, small quantities of ROS are formed during cell processes, such as aerobic respiration or inflammatory processes, mainly in hepatocytes and macrophages. Reactive oxygen species are primarily signalling molecules. In addition, they induce cell differentiation and apoptosis, thus contributing to the natural ageing process. They also participate in muscle contractions, regulation of vascular tone, and determine bactericidal and bacteriostatic activity. Increased production of free radicals is caused by excessive exposure to UV radiation, long-term stress conditions, intense physical exercise, improper diet and use of stimulants. Under physiological conditions, there is a balance between the generation and removal of free radicals from the body. The aim of the article was to review the current state of knowledge regarding oxidative stress, free radical function and free radical diseases. The search was performed using search engines such as PubMed and Google Scholar. The keywords used in the search included: oxygen radicals, oxidative stress, free radical-related diseases. Excessive formation of free radicals contributes to oxidative stress, causing damage at the molecular and cellular level. Reactive oxygen species in vitro cause chemical modifications as well as damaging effects to proteins (aggregation, denaturation), lipids (peroxidation), carbohydrates and nucleotides (changes in the DNA structure). These changes contribute to the development of many free radical-mediated diseases. Oxidative stress has a particularly adverse effect on the circulatory, respiratory and nervous systems.


Assuntos
Estresse Oxidativo , Oxigênio , Radicais Livres , Oxirredução , Espécies Reativas de Oxigênio
14.
Pol Merkur Lekarski ; 48(284): 128-132, 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32352947

RESUMO

Reactive oxygen species are molecules capable of independent existence, containing at least one oxygen atom and one or more unpaired electrons. Excessive formation of these molecules leads to oxidative stress. In recent years, there has been a growing interest in substances with antioxidant properties, reducing or preventing the harmful effects of free radicals. The compounds involved in antioxidant defence include endogenous and exogenous antioxidants, protecting body cells against the negative effects of oxygen radicals. The most important small-molecule non-enzymatic compounds found in food include ascorbic acid, retinol, ß-carotene, tocopherol and polyphenolic compounds. Products of plant origin may provide a valuable source of bioactive compounds with antioxidant properties. It is believed that a diet rich in antioxidants may reduce the risk of developing several nutrition-related conditions as well as delay the ageing process. The aim of this review was to elucidate this topic and the state of the art about the role of plant orgin substances in counteraction of free radical reactions in human body.


Assuntos
Antioxidantes , Ácido Ascórbico , Radicais Livres , Humanos , Estresse Oxidativo , Espécies Reativas de Oxigênio
15.
Chem Biol Interact ; 326: 109137, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32442417

RESUMO

In the present study eighteen inhibitors of the hydrolytic enzymes of the endocannabinoid system were investigated for antioxidant activity using lipid peroxidation (LP) method. Among the assayed compounds ten belong to carbamates with phenyl [1,1'-biphenyl]-3-ylcarbamate (6), reported for the first time, and eight are retro-amide derivatives of palmitamine. Interestingly, results indicated that most of the tested compounds have good antioxidant properties. In particular, 1,3-di([1,1'-biphenyl]-3-yl)urea (3) shows IC50 = 26 ± 6 µM comparable to ones obtained for standard antioxidants trolox and quercetin (IC50 = 22 ± 6 µM and 23 ± 6 µM, respectively). Compound 3 was investigated further by means of DFT calculations, to clarify a possible mechanism of the antioxidant action. In order to estimate the capability of 3 to act as radical scavenger the structure was optimized at B3LYP/6-311++G** level and the respective bond dissociation enthalpies were calculated. The calculations in non-polar medium predicted as favorable mechanism a donation of a hydrogen atom to the free radical and formation of N-centered radical, while in polar solvents the mechanism of free radical scavenging by SPLET dominates over HAT H-abstraction. The possible radical scavenging mechanisms of another compound with potent antioxidant properties (IC50 = 53 ± 12 µM), the retro-amide derivative of palmitamine (compound 18), was estimated computationally based on the reaction enthalpies of a model compound (structural analogue to 18). The computations indicated that the most favorable mechanisms are hydrogen atom transfer from the hydroxyl group in meta-position of the benzamide fragment in nonpolar medium, and proton transfer from the hydroxyl group in ortho-position of the benzamide fragment in polar medium.


Assuntos
Compostos de Bifenilo/química , Peroxidação de Lipídeos/efeitos dos fármacos , Ureia/química , Anilidas/química , Antioxidantes/química , Benzamidas/química , Ácidos Graxos/química , Depuradores de Radicais Livres/química , Radicais Livres/química , Hidrogênio/química , Ácidos Palmíticos/química , Solventes/química
16.
PLoS One ; 15(5): e0232360, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379772

RESUMO

The free radical nitric oxide (NO) is a powerful metabolic regulator in vertebrates and invertebrates. At cellular concentrations in the nanomolar range, and simultaneously reduced internal oxygen partial pressures (pO2), NO completely inhibits cytochrome-c-oxidase (CytOx) activity and hence mitochondrial- and whole-tissue respiration. The infaunal clam Arctica islandica regulates pO2 of hemolymph and mantle cavity water to mean values of <5 kPa, even in a completely oxygen-saturated environment of 21 kPa. These low internal pO2 values support a longer NO lifespan and NO accumulation in the body fluids and can thus trigger a depression of metabolic rate in the clams. Measurable amounts of NO formation were detected in hemocyte cells (~110 pmol NO 100-1 hemocytes h-1 at 6 kPa), which was not prevented in the presence of the NO synthase inhibitor L-NAME, and in the gill filaments of A. islandica. Adding a NO donor to intact gills and tissue homogenate significantly inhibited gill respiration and CytOx activity below 10 kPa. Meanwhile, the addition of the NO-oxidation product nitrite did not affect metabolic rates. The high nitrite levels found in the hemolymph of experimental mussels under anoxia do not indicate cellular NO production, but could be an indication of nitrate reduction by facultative anaerobic bacteria associated with tissue and/or hemolymph biofilms. Our results suggest that NO plays an important role in the initiation of metabolic depression during self-induced burrowing and shell closure of A. islandica. Furthermore, NO appears to reduce mitochondrial oxygen radical formation during surfacing and cellular reoxygenation after prolonged periods of hypoxia and anoxia.


Assuntos
Bivalves/metabolismo , Hipóxia/metabolismo , Óxido Nítrico/metabolismo , Animais , Antioxidantes/metabolismo , Bivalves/fisiologia , Respiração Celular , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Radicais Livres/metabolismo , Brânquias/metabolismo , Glutationa/metabolismo , Hemócitos/metabolismo , Hemolinfa/metabolismo , Longevidade/fisiologia , Mitocôndrias/metabolismo , Nitritos/metabolismo , Oxigênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo
17.
Chemosphere ; 255: 126910, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32402874

RESUMO

In particulate matter, organic precursors generate environmentally persistent free radicals (EPFRs) on metal oxides and attract worldwide attentions in health risk assessment and environmental protection. For the first time, we determined characteristics and formation processes of EPFRs evolved from different organic precursors on PbO particulate. As a result, phenol resulted in phenoxyl radical at 230 °C by releasing one H atom. One Cl atom was eliminated from monochlorobenzene and 1,2-dichlorobenzene, producing phenyl and chlorobenzene radicals, respectively. The decays of these radicals had an order of chlorobenzene radical (4 d) > phenyl radical (3 d) > phenoxyl radical (2 d). Density functional theory calculations indicated that the long decay of chlorobenzene radical was contributed to the high adsorption energy of 1,2-dichlorobenzene on PbO particulate. Furthermore, chlorobenzene radical produced more reactive oxygen species than the other two radicals in oxidative-stress investigations. Therefore, 1,2-dichlorobenzene creates more persistent EPFR, which will cause more dangerous health impact. The main results of this article provide a new insight into the health risk assessment of organic and oxide-containing particulate matter.


Assuntos
Poluentes Atmosféricos/análise , Teoria da Densidade Funcional , Material Particulado/análise , Adsorção , Clorobenzenos , Carvão Mineral , Poeira , Monitoramento Ambiental , Radicais Livres/análise , Minerais , Óxidos , Fenol , Espécies Reativas de Oxigênio
18.
Chemosphere ; 255: 126975, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32387909

RESUMO

Swine manure biochar (SBC) pyrolyzed at 300 °C, 600 °C and 900 °C were utilized to degrade sulfamethazine (SMT) in heterogeneous Fenton-like systems which achieved excellent degradation efficiency (over 85% in 30 min). Experiments results demonstrated that SBC possessed the poor SMT adsorption capacity but high catalytic performance. Electron Paramagnetic Resonance (EPR) and X-ray photoelectron spectroscopy (XPS) analysis revealed that there were oxygen-centered environmentally persistent free radicals (EPFRs) and carbon-centered EPFRs with an adjacent oxygen atom in SBC. The oxygen-centered EPFRs played a major role in the catalytic process which tended to convert to carbon-centered EPFRs after the reaction. Besides, the electron transfer pathways were the most likely catalytic mechanism of SBC and the contribution of OH was dominant through Electron capture experiments and Linear sweep voltammetry (LSV) measurements. The acidic or alkaline condition can promote the catalytic ability of SBC. The presence of dissolved salts (NaCl) inhibited the catalytic process but the inhibition was slightly weakened at high concentration of NaCl, which showed the high tolerance of Cl- in Fenton/Fenton-like systems. Moreover, real wastewater application suggested that SBC600/H2O2 system possessed excellent catalytic efficiency and good adaptability. This research provides a novel swine manure reuse process with high practicability and presents a more explicit perspective about the reaction mechanisms of EPFRs in biochar.


Assuntos
Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Radicais Livres/química , Peróxido de Hidrogênio/química , Sulfametazina/química , Adsorção , Animais , Catálise , Esterco , Suínos , Águas Residuárias/química
19.
Environ Sci Technol ; 54(9): 5710-5718, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32267684

RESUMO

In the current study, electron paramagnetic resonance (EPR) spectroscopy was employed to measure environmentally persistent free radicals (EPFRs) in the total particulate matter (TPM) of mainstream and sidestream TPM of conventional cigarettes and the TPM of e-cigarettes. Comparable concentrations of EPFRs were detected in both sidestream (8.05 ± 1.32) × 104 pmol/g and mainstream TPM (7.41 ± 0.85) × 104 pmol/g of conventional cigarettes. TPM exposure to air resulted in long-lived oxygen centered, secondary radicals with EPR g values of 2.0041 for mainstream and 2.0044 for sidestream. Surprisingly, despite no combustion process, the TPM from e-cigarettes (menthol flavor of NJOY and V2 brands) also contain EPFRs with g values of 2.0031-2.0033, characteristic of carbon centered radicals, while the radical signal in the vanilla flavor of V2 brand was remarkably similar to semiquinones in cigarette smoke with a higher g value (2.0063). The radical concentration in e-cigarettes was much lower as compared to tobacco TPM. Although the production of ROS generated by e-cigarettes is comparatively lower than ROS generated by conventional cigarettes, EPFRs in e-cigarettes appear to be more potent than those in tobacco TPM with respect to hydroxyl radical generation yield per unit EPFR. EPFRs in e-cigarette TPM may be a potential source of health impacts.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Produtos do Tabaco , Radicais Livres/análise , Material Particulado , Tabaco
20.
Ecotoxicol Environ Saf ; 196: 110571, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32276159

RESUMO

Environmentally persistent free radicals (EPFRs) was considered unrecognized composition of air pollutants and might help explain the long-standing medical mystery of why non-smokers develop tobacco-related diseases like lung cancer. EPFRs in airborne fine particulate matter (PM2.5) can induce oxidative and DNA damage when inhaled. We assessed the inhalation risk of EPFRs in PM2.5 and factors influencing this risk in Beijing as a large city with frequent haze events. The average concentration of EPFRs in PM2.5 was 6.00 × 1017 spins/m3 in spring, autumn, and winter; lower concentrations were recorded in the summer. To estimate the daily inhalation risk of EPFRs in PM2.5, we used the equivalent EPFRs in cigarette tar. The average daily inhalation exposure of EPFRs in PM2.5 was estimated to be the equivalent of 33.1 cigarette tar EPFRs per day (range: 0.53-226.9) during both haze and non-haze days. The major factors influencing EPFR concentrations in the atmosphere were precipitation and humidity, which reduced airborne concentrations. Levels of PM2.5 and carbon monoxide were positively correlated with EPFR concentrations. The health risks of inhaling airborne EPFRs could be significant and should be recognized and quantified.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Radicais Livres/análise , Exposição por Inalação/análise , Material Particulado/análise , Atmosfera/química , Pequim , Humanos , Oxirredução , Medição de Risco , Estações do Ano , Alcatrões/química
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