Changes in Noradrenergic Synthesis and Dopamine Beta-Hydroxylase Activity in Response to Oxidative Stress after Iron-induced Brain Injury.

Noradrenaline (NA) levels are altered during the first hours and several days after cortical injury. NA modulates motor functional recovery. The present study investigated whether iron-induced cortical injury modulated noradrenergic synthesis and dopamine beta-hydroxylase (DBH) activity in response to oxidative stress in the brain cortex, pons and cerebellum of the rat. Seventy-eight rats were divided into two groups: (a) the sham group, which received an intracortical injection of a vehicle solution; and (b) the injured group, which received an intracortical injection of ferrous chloride. Motor deficits were evaluated for 20 days post-injury. On the 3rd and 20th days, the rats were euthanized to measure oxidative stress indicators (reactive oxygen species (ROS), reduced glutathione (GSH) and oxidized glutathione (GSSG)) and catecholamines (NA, dopamine (DA)), plus DBH mRNA and protein levels. Our results showed that iron-induced brain cortex injury increased noradrenergic synthesis and DBH activity in the brain cortex, pons and cerebellum at 3 days post-injury, predominantly on the ipsilateral side to the injury, in response to oxidative stress. A compensatory increase in contralateral noradrenergic activity was observed, but without changes in the DBH mRNA and protein levels in the cerebellum and pons. In conclusion, iron-induced cortical injury increased the noradrenergic response in the brain cortex, pons and cerebellum, particularly on the ipsilateral side, accompanied by a compensatory response on the contralateral side. The oxidative stress was countered by antioxidant activity, which favored functional recovery following motor deficits.

From balance to imbalance: disruption of plasma glutathione concentration in micropapillary thyroid carcinoma.

BACKGROUND: Despite the presence of evidence that establishes a strong correlation between oxidative stress and thyroid cancer, there exists a scarcity of research that investigates the specific role of glutathione as an important antioxidant in this particular context. The objective of this study was to assess the altered balance of oxidative stress in cases of thyroid cancer, which includes both papillary thyroid carcinoma (PTC) and micro PTC (mPTC), by examining and comparing the total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), reduced glutathione (GSH), oxidized glutathione (GSSG), and GSSG/GSH ratio with those of individuals diagnosed with multinodular goiter (MNG) as well as Healthy subjects. MATERIALS AND METHODS: Plasma samples were collected from 92 patients (23 mPTC, 23 PTC, 23 MNG, 23 Healthy). The levels of TAC, TOS, GSH, and GSSG were measured using a commercial assay kits, and the OSI and GSSG/GSH ratio were calculated for each sample. Statistical analyses were performed to compare the oxidative stress between the groups. RESULTS: The plasma levels of TOS were significantly higher in the mPTC, PTC, and MNG groups compared to the Healthy individuals (p < 0.05). The OSI in the mPTC and PTC groups showed a significant increase compared to the Healthy group (p < 0.05). The levels of GSH in mPTC and PTC were markedly lower compared to the Healthy subjects (p < 0.01). Interestingly, the concentration of GSH in mPTC was found to be considerably lower than in PTC and MNG patients (p < 0.01). CONCLUSION: These findings indicate that GSH may be a useful biomarker for evaluating oxidative stress and antioxidant system status in patients with PTC, especially mPTC. Low levels of GSH may indicate increased levels of oxidative stress, which may contribute to the development and progression of mPTC to PTC.

Oxidized glutathione reverts carbapenem resistance in blaNDM-1-carrying Escherichia coli.

The emergence of drug-resistant Enterobacteriaceae carrying plasmid-mediated ß-lactamase genes has become a significant threat to public health. Organisms in the Enterobacteriaceae family containing New Delhi metallo-ß-lactamase­1 (NDM-1) and its variants, which are capable of hydrolyzing nearly all ß-lactam antibacterial agents, including carbapenems, are referred to as superbugs and distributed worldwide. Despite efforts over the past decade, the discovery of an NDM-1 inhibitor that can reach the clinic remains a challenge. Here, we identified oxidized glutathione (GSSG) as a metabolic biomarker for blaNDM-1 using a non-targeted metabolomics approach and demonstrated that GSSG supplementation could restore carbapenem susceptibility in Escherichia coli carrying blaNDM-1 in vitro and in vivo. We showed that exogenous GSSG promotes the bactericidal effects of carbapenems by interfering with intracellular redox homeostasis and inhibiting the expression of NDM-1 in drug-resistant E. coli. This study establishes a metabolomics-based strategy to potentiate metabolism-dependent antibiotic efficacy for the treatment of antibiotic-resistant bacteria.

UHPLC-HRMS-Based Analysis of S-Hydroxymethyl-Glutathione, GSH, and GSSG in Human Cells.

Glutathione (GSH) is one of the main antioxidant molecules present in cells. It harbors a thiol group responsible for sustaining cellular redox homeostasis. This moiety can react with cellular electrophiles such as formaldehyde yielding the compound S-hydroxymethyl-GSH (HSMGSH). HSMGSH is the substrate of the enzyme alcohol dehydrogenase 5 (ADH5) and thus a key intermediate in formaldehyde metabolism. In this work, we describe a method for the chemical synthesis of HSMGSH and a pipeline to identify this compound in complex cell extracts by means of ultra-high-performance liquid chromatography coupled to high-resolution spectrometry (UHPLC-HRMS). This method also allows determining GSH and oxidized disulfide (GSSG) in the same samples, thus providing broad information about formaldehyde-GSH metabolism.

Quantitation of Glutathione and Oxidized Glutathione Ratios from Biological Matrices Using LC-MS/MS.

Oxidation of glutathione (GSH) to its disulfide dimer (GSSG) is the major mechanism by which cells balance reactive oxygen species (ROS) and mitigate oxidative stress. Thus, measuring the ratio of GSH/GSSG is an ideal way to assess oxidative stress within a cell. Quantitative mass spectrometry offers an ideal method to measure the GSH/GSSG ratio and can be applied to a variety of biological matrices and disease models. The following chapter details the design, optimization, and execution of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay to measure the GSH/GSSG ratio.

Assessment of Oxidant and Antioxidant Status in Prepubertal Children following Vegetarian and Omnivorous Diets.

Oxidant-antioxidant balance is crucial for maintaining one's health, and the diet is possibly one of the most important factors affecting this balance. Therefore, the aim of this study was to determine the oxidant-antioxidant balance in children on a lacto-ovo-vegetarian diet. The study was conducted between January 2020 and December 2021. The concentrations of total oxidant capacity (TOC), total antioxidant capacity (TAC), reduced (GSH), and oxidized (GSSG) glutathione, as well as C-reactive protein (CRP) and calprotectin were measured in serum samples of 72 healthy prepubertal children (32 vegetarians and 40 omnivores). The oxidative stress index (OSI) and the GSH/GSSG ratio (R-index) were calculated. Children on a vegetarian diet had significantly lower median values of TOC, GSH, and GSSG, and higher TAC compared with the omnivores. OSI was significantly lower in vegetarians, while R-index, as well as median values of CRP and calprotectin did not differ between both groups of children. Significant negative correlations were observed between TOC and TAC levels in the whole group of children and in vegetarians. GSH and GSSG levels correlated positively in the groups of vegetarians, omnivores, and in all the children. There were significant positive correlations between TOC and GSH, as well as GSSG levels in all the studied groups of children. Our study results suggest that the vegetarian model of nutrition allows to maintain the oxidant-antioxidant balance in the serum of prepubertal children.

Analysis of biochemical parameters in an experimental model of chronic pancreatitis in rats.

BACKGROUND: Despite advanced research and great progress in understanding the chronic pancreatitis (CP) pathogenesis, no current causal treatment for the condition is available. For preclinical studies, the existence of a well-characterized CP animal model is essential. The aim of the study was to assess the impact of chronic pancreatitis on the antioxidant enzymes activity in rat blood serum and on the level of glutathione (intracellular antioxidant) in rat pancreas. METHODS: The experiments were carried out on the Wistar Kyoto rats in two groups: control and study group (CP), in which chemical induction of pancreatitis with dibutyl dichloride was performed. Serum enzyme activities of amylase, lipase, catalase and superoxide dismutase were analyzed. The levels of the following biochemical parameters were also investigated: total protein, albumin, calcium, magnesium, and triglycerides. Levels of low-molecular-weight thiols: reduced (GSH) and oxidized (GSSG) glutathione, were determined in pancreatic homogenates. RESULTS: Histopathological imaging of rat pancreatic parenchyma with induced inflammation confirmed focal lymphocytic interstitial chronic pancreatitis with fibrosis features and mild parenchymal atrophy, as well as pancreatic islets degeneration. In the CP group, we observed a statistically significant decrease in serum amylase and lipase activities and in total protein/albumin levels. Also, the elevated catalase activity was registered. In CP rats' tissues, we observed a 15-fold reduction in GSH levels. The other examined parameters remained unchanged. Clinically relevant are hypoalbuminemia and a moderate decrease in lipase activity. The described changes are most probably indicative of the impaired exocrine pancreas function, however without organ failure features.

Time course of changes in inflammatory and oxidative biomarkers in lung tissue of mice induced by exposure to electronic cigarette aerosol.

Significance: Electronic cigarettes (e-cigarettes) have become a popular way to smoke all over the world. Chronic exposure to e-cigarette aerosol may influence lung health. This study uses an animal model to explore the time course of the effect of exposure to e-cigarette aerosols on the lung. Methods: Lung samples were collected after exposure of Balb/c mice to e-cigarette aerosols for 1 h/day (6 times/week) for 1, 2 and 4 weeks and compared to sham-exposed controls. Examined biomarkers including inflammatory cells, tumor necrosis factor α (TNFα), interleukin-6 (IL-6), interleukin-10 (IL-10), reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GPx), catalase, superoxide dismutase (SOD), and Thiobarbituric acid reactive substances (TBARS). Results: Exposure of animals to e-cigarette aerosols induced significant increases (P < 0.05) in total inflammatory cells, eosinophils, macrophages and TNFα in the lung tissue after 1, 2 and 4 weeks of exposure. Furthermore, level of IL-10 significantly decreased, whereas levels of neutrophils and basophils significantly increased (P < 0.05) after 1 week of exposure. Exposure of animals to e-cigarette aerosol also induced significant decreases (P < 0.05) in the GSH/GSSG ratio, and GPx levels after 2 and 4 weeks of exposures. The activity of catalase was also reduced (P < 0.05) after 4 weeks of exposure. Level of TBARS showed a trend of elevation with time and it reached a significant elevation after 4 weeks (P < 0.01). Conclusion: Current results indicate that inhalation of unflavored e-cigarette aerosol might be associated with inflammation in lung tissue that worsen as the duration of exposure increases. Further experiments including more time points, histopathology and pulmonary physiology experiments are needed to confirm the current results.

A new mouse model of radiation-induced liver disease reveals mitochondrial dysfunction as an underlying fibrotic stimulus.

Background & Aims: High-dose irradiation is an essential tool to help control the growth of hepatic tumors, but it can cause radiation-induced liver disease (RILD). This life-threatening complication manifests itself months following radiation therapy and is characterized by fibrosis of the pericentral sinusoids. In this study, we aimed to establish a mouse model of RILD to investigate the underlying mechanism of radiation-induced liver fibrosis. Methods: Using a small animal image-guided radiation therapy platform, an irradiation scheme delivering 50 Gy as a single dose to a focal point in mouse livers was designed. Tissues were analyzed 1 and 6 days, and 6 and 20 weeks post-irradiation. Irradiated livers were assessed by histology, immunohistochemistry, imaging mass cytometry and RNA sequencing. Mitochondrial function was assessed using high-resolution respirometry. Results: At 6 and 20 weeks post-irradiation, pericentral fibrosis was visible in highly irradiated areas together with immune cell infiltration and extravasation of red blood cells. RNA sequencing analysis showed gene signatures associated with acute DNA damage, p53 activation, senescence and its associated secretory phenotype and fibrosis. Moreover, gene profiles of mitochondrial damage and an increase in mitochondrial DNA heteroplasmy were detected. Respirometry measurements of hepatocytes in vitro confirmed irradiation-induced mitochondrial dysfunction. Finally, the highly irradiated fibrotic areas showed markers of reactive oxygen species such as decreased glutathione and increased lipid peroxides and a senescence-like phenotype. Conclusions: Based on our mouse model of RILD, we propose that irradiation-induced mitochondrial DNA instability contributes to the development of fibrosis via the generation of excessive reactive oxygen species, p53 pathway activation and a senescence-like phenotype. Lay summary: Irradiation is an efficient cancer therapy, however, its applicability to the liver is limited by life-threatening radiation-induced hepatic fibrosis. We have developed a new mouse model of radiation-induced liver fibrosis, that recapitulates the human disease. Our model highlights the role of mitochondrial DNA instability in the development of irradiation-induced liver fibrosis. This new model and subsequent findings will help increase our understanding of the hepatic reaction to irradiation and to find strategies that protect the liver, enabling the expanded use of radiotherapy to treat hepatic tumors.

Glutathione Modulation in PVYNTN Susceptible and Resistant Potato Plant Interactions.

Glutathione is a metabolite that plays an important role in plant response to biotic stress through its ability to remove reactive oxygen species, thereby limiting the degree of potential oxidative damage. It can couple changes in the intracellular redox state to the development, especially the defense responses, of plants. Several studies have focused on measuring glutathione levels in virus infected plants, but have not provided complete information. Therefore, we analyzed, for the first time, the content of glutathione as well as its ultrastructural distribution related to susceptible and hypersensitive potato-Potato virus Y NTN (PVYNTN) interaction, with an aim of providing new insight into interactive responses to PVYNTN stress. Our findings reported that the inoculation of PVYNTN caused a dynamic increase in the content of glutathione, not only in resistance but also in susceptible reaction, especially at the first steps of plant-virus interaction. Moreover, the increase in hypersensitive response was much more dynamic, and accompanied by a significant reduction in the content of PVYNTN. By contrast, in susceptible potato Irys, the content of glutathione decreased between 7 and 21 days after virus inoculation, which led to a significant increase in PVYNTN concentration. Additionally, our findings clearly indicated the steady induction of two selected potato glutathione S-transferase StGSTF1 and StGSTF2 genes after PVYNTN inoculation, regardless of the interaction type. However, the relative expression level of StGSTF1 did not significantly differ between resistant and susceptible plants, whereas the relative expression levels of StGSTF2 differed between susceptible and resistant reactions. Therefore, we proposed that StGSTF2 can act as a marker of the type of response to PVYNTN. Our observations indicated that glutathione is an important component of signaling as well as the regulatory network in the PVYNTN-potato pathosystem. In resistance responses to PVYNTN, this metabolite activates plant defenses by reducing potential damage to the host plant cell, causing a reduction in virus concentration, while it can also be involved in the development of PVYNTN elicited symptoms, as well as limiting oxidative stress, leading to systemic infection in susceptible potato plants.

Targeting glutamine utilization to block metabolic adaptation of tumor cells under the stress of carboxyamidotriazole-induced nutrients unavailability.

Tumor cells have unique metabolic programming that is biologically distinct from that of corresponding normal cells. Resetting tumor metabolic programming is a promising strategy to ameliorate drug resistance and improve the tumor microenvironment. Here, we show that carboxyamidotriazole (CAI), an anticancer drug, can function as a metabolic modulator that decreases glucose and lipid metabolism and increases the dependency of colon cancer cells on glutamine metabolism. CAI suppressed glucose and lipid metabolism utilization, causing inhibition of mitochondrial respiratory chain complex I, thus producing reactive oxygen species (ROS). In parallel, activation of the aryl hydrocarbon receptor (AhR) increased glutamine uptake via the transporter SLC1A5, which could activate the ROS-scavenging enzyme glutathione peroxidase. As a result, combined use of inhibitors of GLS/GDH1, CAI could effectively restrict colorectal cancer (CRC) energy metabolism. These data illuminate a new antitumor mechanism of CAI, suggesting a new strategy for CRC metabolic reprogramming treatment.

Extracellular Calcium Receptor as a Target for Glutathione and Its Derivatives.

Extracellular glutathione (GSH) and oxidized glutathione (GSSG) can modulate the function of the extracellular calcium sensing receptor (CaSR). The CaSR has a binding pocket in the extracellular domain of CaSR large enough to bind either GSH or GSSG, as well as the naturally occurring oxidized derivative L-cysteine glutathione disulfide (CySSG) and the compound cysteinyl glutathione (CysGSH). Modeling the binding energies (ΔG) of CySSG and CysGSH to CaSR reveals that both cysteine derivatives may have greater affinities for CaSR than either GSH or GSSG. GSH, CySSG, and GSSG are found in circulation in mammals and, among the three, CySSG is more affected by HIV/AIDs and aging than either GSH or GSSG. The beta-carbon linkage of cysteine in CysGSH may model a new class of calcimimetics, exemplified by etelcalcetide. Circulating glutathionergic compounds, particularly CySSG, may mediate calcium-regulatory responses via receptor-binding to CaSR in a variety of organs, including parathyroids, kidneys, and bones. Receptor-mediated actions of glutathionergics may thus complement their roles in redox regulation and detoxification. The glutathionergic binding site(s) on CaSR are suggested to be a target for development of drugs that can be used in treating kidney and other diseases whose mechanisms involve CaSR dysregulation.

Stability of glutathione added as a supplement to parenteral nutrition.

BACKGROUND: Most very premature newborns (<32 weeks of gestation) receive parenteral nutrition (PN) that is inherently contaminated with peroxides. Oxidative stress induced by PN is associated with bronchopulmonary dysplasia, a main pathological complication in these infants who have weak antioxidant capacity to detoxify peroxides because of their glutathione deficiency. In animals, glutathione supplementation of PN prevented oxidative stress and alveolar loss (the main characteristic of bronchopulmonary dysplasia). Of its two forms-oxidized glutathione (GSSG) and reduced glutathione (GSH)-GSSG was used because of its better stability. However, a 30% loss of GSSG in PN is observed. The potentially high therapeutic benefits of GSSG supplementation on the health of very premature infants make the study of its stability highly important. METHODS: GSSG was incubated in combination with the following components of PN: dextrose, multivitamins, Primene, and Travasol, and with cysteine, cystine, and peroxides, for 24 h. Total glutathione in these solutions was measured 0-24 h after the addition of GSSG. RESULTS: The combination of cysteine and multivitamins caused the maximum loss of glutathione. The stability of GSSG was not affected by multivitamins. The cysteine was responsible for ∼20% of the loss of GSSG; in the presence of multivitamins, the loss reached >70%. Removing the cysteine prevented the degradation of glutathione. CONCLUSION: GSSG reacts with cysteine to form cysteine-glutathione mixed disulfide, another suitable glutathione substrate for preterm neonates. The study confirms that GSSG added to PN can potentially provide a precursor to de novo synthesis of glutathione in vivo.

Naringin prevents cyclophosphamide-induced erythrocytotoxicity in rats by abrogating oxidative stress.

Earlier reports have shown that Cyclophosphamide (CYCP), an anti-malignant drug, elicited cytotoxicity; and that naringin has several beneficial potentials against oxidative stress and dyslipidaemias. We investigated the influence of naringin on free radical scavenging, cellular integrity, cellular ATP, antioxidants, oxidative stress, and lipid profiles in the CYCP-induced erythrocytotoxicity rat model. Rats were pretreated orally by gavage for fourteen consecutive days with three doses (50, 100, and 200 mg/kg) naringin before single CYCP (200 mg/kg, i.p.) administration. Afterwards, the rats were sacrificed. Naringin concentrations required for 50 % scavenging hydrogen peroxide and nitric oxide radical were 0.27 mg/mL and 0.28 mg/mL, respectively. Naringin pretreatment significantly (p < 0.05) protected erythrocytes plasma membrane architecture and integrity by abolishing CYCP-induced decrease in the activity of erythrocyte LDH (a marker of ATP). Pretreatment with naringin remarkably (p < 0.05) reversed CYCP-induced decreases in the erythrocytes glutathione levels, activities of glutathione-S-transferase, catalase, glutathione peroxidase, and glutathione reductase; attenuated CYCP-mediated increases in erythrocytes levels of malondialdehyde, nitric oxide, and major lipids (cholesterol, triacylglycerol, phospholipids, and non-esterified fatty acids). Taken together, different acute pretreatment doses of naringin might avert CYCP-mediated erythrocytes dysfunctions via its antioxidant, free-radical scavenging, and anti-dyslipidaemia properties.

8-Week Supplementation of 2S-Hesperidin Modulates Antioxidant and Inflammatory Status after Exercise until Exhaustion in Amateur Cyclists.

Both acute and chronic ingestion of 2S-hesperidin have shown antioxidant and anti-inflammatory effects in animal studies, but so far, no one has studied this effect of chronic ingestion in humans. The main objective was to evaluate whether an 8-week intake of 2S-hesperidin had the ability to modulate antioxidant-oxidant and inflammatory status in amateur cyclists. A parallel, randomized, double-blind, placebo-controlled trial study was carried out with two groups (500 mg/d 2S-hesperidin; n = 20 and 500 mg/d placebo; n = 20). An incremental test was performed to determine the working zones in a rectangular test, which was used to analyze for changes in antioxidant and inflammatory biomarkers. After 2S-hesperidin ingestion, we found in the rectangular test: (1) an increase in superoxide dismutase (SOD) after the exercise phase until exhaustion (p = 0.045) and the acute recovery phase (p = 0.004), (2) a decrease in the area under the oxidized glutathione curve (GSSG) (p = 0.016), and (3) a decrease in monocyte chemoattractant protein 1 (MCP1) after the acute recovery phase (p = 0.004), post-intervention. Chronic 2S-hesperidin supplementation increased endogenous antioxidant capacity (↑SOD) after maximal effort and decreased oxidative stress (↓AUC-GSSG) during the rectangular test, decreasing inflammation (↓MCP1) after the acute recovery phase.

The impact of glutathione metabolism in autism spectrum disorder.

This paper reviews the potential role of glutathione (GSH) in autism spectrum disorder (ASD). GSH plays a key role in the detoxification of xenobiotics and maintenance of balance in intracellular redox pathways. Recent data showed that imbalances in the GSH redox system are an important factor in the pathophysiology of ASD. Furthermore, ASD is accompanied by decreased concentrations of reduced GSH in part caused by oxidation of GSH into glutathione disulfide (GSSG). GSSG can react with protein sulfhydryl (SH) groups, thereby causing proteotoxic stress and other abnormalities in SH-containing enzymes in the brain and blood. Moreover, alterations in the GSH metabolism via its effects on redox-independent mechanisms are other processes associated with the pathophysiology of ASD. GSH-related regulation of glutamate receptors such as the N-methyl-D-aspartate receptor can contribute to glutamate excitotoxicity. Synergistic and antagonistic interactions between glutamate and GSH can result in neuronal dysfunction. These interactions can involve transcription factors of the immune pathway, such as activator protein 1 and nuclear factor (NF)-κB, thereby interacting with neuroinflammatory mechanisms, ultimately leading to neuronal damage. Neuronal apoptosis and mitochondrial dysfunction are recently outlined as significant factors linking GSH impairments with the pathophysiology of ASD. Moreover, GSH regulates the methylation of DNA and modulates epigenetics. Existing data support a protective role of the GSH system in ASD development. Future research should focus on the effects of GSH redox signaling in ASD and should explore new therapeutic approaches by targeting the GSH system.

Establishment of a cultivation method for leaf lettuce (Lactuca sativa var. crispa) and komatsuna (Brassica rapa var. perviridis) with high zinc content for patients with zinc deficiency and evaluation of its effectiveness.

BACKGROUND: Insufficient intake of zinc is associated with various diseases worldwide. To overcome this problem, we aimed to establish a method for cultivating leafy vegetables with high zinc content in hydroponics without inhibiting their growth. Furthermore, we evaluated the effectiveness of the cultivated leafy vegetables with high zinc content in zinc-deficient mice. RESULTS: By adjusting the zinc concentration in the hydroponic solution to 5 mg L-1 starting from 7 days before harvesting, the zinc content in leaf lettuce increased eight times of that in the control, without any inhibition of the growth. Furthermore, when oxidized glutathione (GSSG) was added simultaneously with zinc to the hydroponic solution, the zinc content further doubled (16 times of that in the control). Similar results were obtained with komatsuna and red leaf lettuce, although there was a difference in the effect of GSSG treatment. The effectiveness of leafy vegetables with high zinc content in ameliorating zinc deficiency was evaluated by feeding lettuce with high zinc content to zinc-deficient mice. High zinc content lettuce significantly increased the zinc content in the liver, kidneys, gastrocnemius, and tibia of these mice. CONCLUSION: We established a cultivation method for lettuce and komatsuna with high zinc content without inhibiting growth by adjusting the zinc concentration in the hydroponic solution at an appropriate concentration for an appropriate period. The result of feeding test indicates that the intake of leafy vegetables with high zinc content can ameliorate zinc deficiency and might be useful in protection from several diseases associated with this deficiency. © 2020 Society of Chemical Industry.

The Relationship between Choroidal Thickness and Intracellular Oxidised-reduced Glutathione and Extracellular Thiol-disulfide Homeostasis at Different Stages of Diabetic Retinopathy.

Purpose: To evaluate the relationship between diabetic retinopathy and oxidative damage by measuring intracellular and extracellular thiol levels, and to compare intracellular and extracellular thiol levels. Method: In this prospective, cross-sectional, and comparative study, 25 healthy control participants (group 1), a total of 25 diabetic macular edema (DME) patients with non-proliferative diabetic retinopathy (DRP) and without DME (group 2), and 25 DME patients with non-proliferative DRP and with DME (group 3) were included. Choroidal thickness (ChT) and central macular thickness (CMT) were measured by spectral domain optic coherence tomography. For the evaluation of antioxidant/oxidant balance, intracellular GSH (reduced glutathione) and GSSG (oxidized glutathione), extracellular SH (thiol) and SS (disulfide) levels were measured and recorded. Results: Comparing intracellular and extracellular thiol levels between groups, intracellular GSSG level and GSSG/GSH percent ratio, and extracellular disulfide and SS/SH percent ratio values were higher in diabetic patients than healthy participants. Choroidal thicknesses were significantly thinner in DRP groups compared to the healthy population. When the relationship between choroidal thicknesses and thiol levels was investigated, there were significant relationships between choroidal thicknesses and thiol levels in group 3. Conclusion: Oxidative stress and impaired intracellular GSH/GSSG and serum SH/SS balances were observed to have an effect on DRP and DME pathogenesis. In addition, in groups with and without DME, thinning in choroidal thicknesses and the relationship between these thicknesses and intra/extracellular oxidative stress indicators can also be explained.

The antioxidant system in Olea europaea to enhanced UV-B radiation also depends on flavonoids and secoiridoids.

The Mediterranean crop Olea europaea is often exposed to high UV-B irradiation conditions. To understand how this species modulates its enzymatic and non-enzymatic antioxidant system under high UV-B radiation, young O. europaea plants (cultivar "Galega Vulgar") were exposed, for five days, to UV-B radiation (6.5 kJ m-2 d-1 and 12.4 kJ m-2 d-1). Our data indicate that UV-doses slightly differ in the modulation of the antioxidant protective mechanisms. Particularly, superoxide dismutase (SOD), guaiacol peroxidase (GPox) and catalase (CAT) activities increased contributing to H2O2 homeostasis, being more solicited by higher UV-B doses. Also, glutathione reductase (Gr) activity, ascorbate (AsA) and reduced glutathione (GSH) pools increased particularly under the highest dose, suggesting a higher mobilization of the antioxidant system in this dose. The leaf metabolites' profile of this cultivar was analysed by UHPLC-MS. Interestingly, high levels of verbascoside were found, followed by oleuropein and luteolin-7-O-glucoside. Both UV-B treatments affected mostly less abundant flavonoids (decreasing 4'-methoxy luteolin and 4' or 3'-methoxy luteolin glucoside) and hydroxycinnamic acid derivatives (HCAds, increasing ß-hydroxyverbascoside). These changes show not only different mobilization with the UV-intensity, but also reinforce for the first time the protective roles of these minor compounds against UV-B, as reactive oxygen species (ROS) scavengers and UV-B shields, in complement with other antioxidant systems (e.g. AsA/GSH cycle), particularly for high UV-B doses. Secoiridoids also standout in the response to both UV-B doses, with decreases of oleuropein and increases 2''-methoxyoleuropein. Being oleuropein an abundant compound, data suggest that secoiridoids play a more important role than flavonoids and HCAds, in O. europaea protection against UV-B, possibly by acting as signalling molecules and ROS scavengers. This is the first report on the influence of UV-B radiation on the secoiridoid oleuropein, and provides a novel insight to the role of this compound in the O. europaea antioxidant defence mechanisms.

[Effect of the sulfur-containing compounds on the quinoid process of adrenaline autoxidation; potential neuroprotectors]. / Deistvie serosoderzhashchikh soedinenii na khinoidnyi protsess avtookisleniia adrenalina; potentsial'nye neiroprotektory.

The superoxide-generating reaction of adrenaline autoxidation in an alkaline medium, used in vitro to identify the antioxidant properties of various compounds, simulates the complex multistep process of quinoid oxidation of catecholamines (CA) in the body. Sulfur-containing cysteine (Cys) and reduced glutathione (GSH), as well as oxidized glutathione (GSSG), have been shown to inhibit this process. The studied substances were considered as inhibitors of quinoid oxidation and are evaluated as antioxidants. The IC50 values for Cys and GSH were close to 7.5 mM. Inhibition by GSSG was weaker; represented approximately 50-70% of Cys and GSH. Other sulfur-containing compounds that differ in chemical structure, the amino acids taurine and methionine were ineffective. The interest in this model and the search for effective compounds acting on this reaction is associated with one of the mechanisms of the etiopathogenesis of Parkinson's disease (PD) discussed in the literature, which occurs when the biochemical transformations of dopamine CA and its quinoid oxidation process are violated. Cys, GSH and GSSG in the model system inhibit quinoid oxidation of adrenaline, as a result of which the formation of superoxide (O2 ·-) is also inhibited. Experiments with the superoxide-generating enzymatic reaction xanthine xanthioxidase, the chemistry of which is different and not related to formation of quinoid metabolites, showed that the studied substances did not inhibit O2 ·- formation in this model. Thus, it was established that the biologically active sulfur-containing compounds Cys, GSH and GSSG are specific inhibitors of quinoid oxidation of CA, and are likely to be able to play the role of a neuroprotector. It is proposed to use these compounds in the treatment and prevention of PD by activating their biosynthesis in the body.