Generation Of Oxygen Free Radicals Research Articles

Involvement of TRPM2 Channel on Hypoxia-Induced Oxidative Injury, Inflammation, and Cell Death in Retinal Pigment Epithelial Cells: Modulator Action of Selenium Nanoparticles.

Hypoxia (HYPX) in several eye diseases such as glaucoma and diabetic retinopathy causes oxidative cell death and inflammation. TRPM2 cation channel is activated by HYPX-induced ADP-ribose (ADPR) and oxidative stress. The protective role of selenium via inhibition of TRPM2 on the HYPX-induced oxidative cytotoxicity and inflammation values in the human kidney cell line was recently reported. However, the protective role of selenium nanoparticles (SeNP) on the values in the retinal pigment epithelial (ARPE-19) cells has not been clarified yet. In the current study, we investigated two subjects. First, we investigated the involvement of TRPM2 channel on the HYPX-induced oxidative injury, inflammation, and apoptosis in the ARPE-19 cells. Second, we investigated the protective role of SeNP via inhibition of TRPM2 channel on the HYPX-induced oxidative injury and apoptosis in the ARPE-19 cells. For the aims, the ARPE-19 cells were divided into four main groups as follows: Control (Ctr), SeNP (2.5 μg/ml for 24 h), HYPX (200 μM CoCl2 for 24 h), and HYPX+SeNP. The TRPM2 current density and Ca2+ fluorescence intensity with an increase of mitochondrial membrane depolarization and oxygen free radical (OFR) generations were increased in the ARPE-19 cells by the treatment of HYPX. There was no increase of Ca2+ fluorescence intensity in the pre-treated cells with PARP-1 inhibitors (DPQ and PJ34) or in the presence of Ca2+-free extracellular buffer. When HYPX-induced TRPM2 activity was treated by SeNP and TRPM2 (2-APB and ACA) blockers, the increases of OFR generation, cytokine (TNF-α and IL-1β) levels, TRPM2, and PARP-1 expressions were restored. In conclusion, the exposure of HYPX caused mitochondrial oxidative cell cytotoxicity and cell death via TRPM2-mediated Ca2+ signaling and may provide an avenue for treating HYPX-induced retinal diseases associated with the excessive OFR and Ca2+ influx.

Correlation of Glycated Haemoglobin with Protein Carbonyl Content as Biomarkers of Oxidative Stress in Type 2 Diabetes Mellitus

Introduction: Diabetes is chronic disease which is characterised by defect in insulin secretion and insulin action leading to hyperglycaemia. Aim: To detect protein carbonyl as oxidative stress marker in Type 2 Diabetes Mellitus (T2DM). Materials and Methods: The present cross-sectional study was conducted on 100 subjects (aged 40 to 70 years) out of which 50 were T2DM and 50 were normal individuals. Serum was tested for Fasting Blood Sugar (FBS) and Glycated Haemoglobin (HbA1c) and Protein Carbonyl Content (PCC). Serum PCC was measured by spectrophotometric DNPH (dinitrophenylhydrazone) method of Reznick AZ and Packer L. Results: The protein carbonyl content, Fasting blood sugar and HbA1c were observed as positively correlated in type 2 diabetes mellitus as the levels of PCC, FBS and HbA1c were raised in T2DM as compared to controls. Conclusion: Increased HbA1c may be associated with generation of oxygen free radicals in the form of protein carbonyls and decreased antioxidants in T2DM.

Melatonin ameliorates docetaxel-induced mitochondrial oxidative toxicity and cytokine generation in the laryngo-tracheal epithelial cell

A protective action of melatonin (MELAT) on docetaxel (DCT)-induced inflammation, apoptosis, and reactive free oxygen radical (fROS) generation values via blocking of TRPM2 calcium-permeable channel was investigated in different cells except for laryngo-tracheal epithelial (LT-Epi) cells. Hence, the protective action of MELAT on DCT-induced oxidative toxicity and inflammation in LT-Epi tissue and cells of mice were investigated in the current study. MELAT treatment ameliorated DCTinduced mitochondrial ROS in the LT-Epi cells by reducing the generation of fROS (cytosolic and mitochondrial), lipid peroxidation, and depolarization of the mitochondrial membrane, while increasing reduced glutathione (GSH), GSH peroxidase, and total antioxidant status. In addition, DCT-induced increases of cytokine (IL-1β, IL-6, and TNF-α) generations were also diminished in the LT-Epi tissue by MELAT treatment. Furthermore, MELAT treatment increased viability and count of the cells followed by decreasing levels of cell death, caspase -3, and -9. The TRPM2 activity was also reduced by MELAT and TRPM2 channel blocker (ACA) treatments. In conclusion, MELAT modulated the increase of DCT-induced LT-Epi cell death by inhibiting mitochondrial oxidative stress and TRPM2 channel activity. Hence, DCTcaused side cell death, oxidant, and inflammatory actions in the LT-Epi were diminished via the treatment of MELAT.

Toxic Hepatitis And Multiple Fecaliths Formation In Paraquat Poisoning

Cases of Paraquat poisoning are on the rise in countries like India, where it is not banned or restricted adequately for use. Paraquat at the molecular level generates oxygen free radicals in the lungs, causing respiratory failure and may also cause acute renal failure in hyper-acute poisoning. There are renal, hepatic and pulmonary manifestations of Paraquat toxicity. We report a case of Paraquat poisoning presenting with toxic hepatitis and multiple fecaliths formations. The clinical toxicologist needs to be wary of bowel-related complications in Paraquat poisoning. The role of paraquat in disturbing bowel mobility and creating a nidus for fecalith formation is of concern in managing the poisoning. Recommendations for proper bowel care in poisoning cases are discussed in this case report.

Antibacterial and antibiofilm potential of silver nanoparticles against antibiotic-sensitive and multidrug-resistant Pseudomonas aeruginosa strains.

Due to the severity of infections caused by P. aeruginosa and the limitations in treatment, it is necessary to find new therapeutic alternatives. Thus, the use of silver nanoparticles (AgNPs) is a viable alternative because of their potential actions in the combat of microorganisms, showing efficacy against Gram-positive and Gram-negative bacteria, including multidrug-resistant microorganisms (MDR). In this sense, the aim of this work was to conduct a literature review related to the antibacterial and antibiofilm activity of AgNPs against antibiotic-sensitive and multidrug-resistant Pseudomonas aeruginosa strains. The AgNPs are promising for future applications, which may match the clinical need for effective antibiotic therapy. The size of AgNPs is a crucial element to determine the therapeutic activity of nanoparticles, since smaller particles present a larger surface area of contact with the microorganism, affecting their vital functioning. AgNPs adhere to the cytoplasmic membrane and cell wall of microorganisms, causing disruption, penetrating the cell, interacting with cellular structures and biomolecules, and inducing the generation of reactive oxygen species and free radicals. Studies describe the antimicrobial activity of AgNPs at minimum inhibitory concentration (MIC) between 1 and 200μg/mL against susceptible and MDR P. aeruginosa strains. These studies have also shown antibiofilm activity through disruption of biofilm structure, and oxidative stress, inhibiting biofilm growth at concentrations between 1 and 600μg/mL of AgNPs. This study evidences the advance of AgNPs as an antibacterial and antibiofilm agent against Pseudomonas aeruginosa strains, demonstrating to be an extremely promising approach to the development of new antimicrobial systems.

Caloric restriction: implications for sarcopenia and potential mechanisms.

Sarcopenia is a potential risk factor for weakness, disability and death in elderly individuals. Therefore, seeking effective methods to delay and treat sarcopenia and to improve the quality of life of elderly individuals is a trending topic in geriatrics. Caloric restriction (CR) is currently recognized as an effective means to extend the lifespan and delay the decline in organ function caused by aging. In this review, we describe the effects of CR on improving muscle protein synthesis, delaying muscle atrophy, regulating muscle mitochondrial function, maintaining muscle strength, promoting muscle stem cell (MuSC) regeneration and differentiation, and thus protecting against sarcopenia. We also summarize the possible cellular mechanisms by which CR delays sarcopenia. CR can delay sarcopenia by reducing the generation of oxygen free radicals, reducing oxidative stress damage, enhancing mitochondrial function, improving protein homeostasis, reducing iron overload, increasing autophagy and apoptosis, and reducing inflammation. However, the relationships between CR and genetics, sex, animal strain, regimen duration and energy intake level are complex. Therefore, further study of the proper timing and application method of CR to prevent sarcopenia is highly important for the aging population.

A Supersmall Single-Cell Nanosensor for Intracellular K + Detection

Intracellular potassium ions (K+) play pivotal roles in many physiological processes. Several K+ sensors have been developed for probing cellular K+ fluctuations. Nevertheless, the existing solutio...

Effect of COVID-19 Infection on the Immune System and Risk of Developing Diabetes Complications: A Review

Coronavirus disease (COVID-19) is caused by SARS-COV2 and represents the causative agent of a potentially fatal disease that is of great global public health concern. The pandemic outbreak of COVID-19 is rapidly spreading all over the world. In this review, we try to summarize studies of the relationship between the alteration of immune system during COVID-19 infection and the risk of developing diabetes complications. The data were collected by searching Science Direct, Google Scholar, PubMed, Scopus, Springer and National Center for Biotechnology Information (NCBI). The Keywords used as search terms were “COVID-19”, “SARS-COV2 induced inflammatory reaction”, “ACE2 and COVID-19 infection”, “Diabetes and Oxidative stress” and “COVID-19 induced Diabetes complication”. The risk of COVID-19 infection in patients is due to the severity of the viral infection and also to the host's immune response. The risk of infection is one of the main complications of diabetics, as it has been suggested that diabetes inhibits the immune response which contributes to infection and progression to symptoms. Also, the evidence of generation of oxygen free radicals and oxidative stress is a key process in the onset of diabetes mellitus which participate in the development of the systemic inflammatory response syndrome. In addition, chronic hyperglycemia during COVID-19 infection may increase the release of inflammatory cytokines, a high ability to bind to the virus ACE2 glycosylated, worsen the ketoacidosis and vascular complications that may explain the severity of the SARS-CoV-2 infection in diabetic patients.

Salt stress triggers generation of oxygen free radicals and DNA breaks in Physcomitrella patens protonema

One of the early reactions of plants to high levels of NaCl is the generation of reactive oxygen species (ROS), which is critical for stress signaling, Na+ extrusion, oxidative damage and programmed cell death (PCD) under salt stress. Using moss Physcomitrella patens protonema as a model system, we have tested whether ROS generation and DNA degradation can be induced by salinity in Bryophyta. We have shown with dihydroethidium in vivo test that toxic NaCl concentrations significantly stimulate ROS production. The pharmacological analysis carried out using superoxide dismutase, catalase, dimethyl sulfoxide, thiourea and spermine outlines the superoxide and hydroxyl radicals as major NaCl-induced species. Using Comet assay, we have found that NaCl affects the DNA stability in ROS-dependent manner, increasing both single and double strand DNA breaks (SSBs and DSBs, respectively). Surprisingly, DSBs were induced by NaCl to a lesser extent than SSBs. This is indicative of an unexpected and sophisticated action of NaCl on moss genome including DSBs through PCD and SSBs caused by hydroxyl radical-induced DNA oxidation or transposon rearrangement. We also report a relatively high sensitivity of Physcomitrella patens protonema to NaCl compared to later developmental stages of this moss, suggesting that dividing cells are more sensitive to NaCl than other tissues.

Iron Metabolism in Obesity and Metabolic Syndrome.

Obesity is an excessive adipose tissue accumulation that may have detrimental effects on health. Particularly, childhood obesity has become one of the main public health problems in the 21st century, since its prevalence has widely increased in recent years. Childhood obesity is intimately related to the development of several comorbidities such as nonalcoholic fatty liver disease, dyslipidemia, type 2 diabetes mellitus, non-congenital cardiovascular disease, chronic inflammation and anemia, among others. Within this tangled interplay between these comorbidities and associated pathological conditions, obesity has been closely linked to important perturbations in iron metabolism. Iron is the second most abundant metal on Earth, but its bioavailability is hampered by its ability to form highly insoluble oxides, with iron deficiency being the most common nutritional disorder. Although every living organism requires iron, it may also cause toxic oxygen damage by generating oxygen free radicals through the Fenton reaction. Thus, iron homeostasis and metabolism must be tightly regulated in humans at every level (i.e., absorption, storage, transport, recycling). Dysregulation of any step involved in iron metabolism may lead to iron deficiencies and, eventually, to the anemic state related to obesity. In this review article, we summarize the existent evidence on the role of the most recently described components of iron metabolism and their alterations in obesity.

Iron solubility in fine particles associated with secondary acidic aerosols in east China

Soluble iron (FeS) in aerosols contributes to free oxygen radical generation with implications for human health, and potentially catalyzes sulfur dioxide oxidation. It is also an important external source of micronutrients for ocean ecosystems. However, factors controlling FeS concentration and its contribution to total iron (FeT) in aerosols remain poorly understand. Here, FeS and FeT in PM2.5 was studied at four urban sites in eastern China from 21 to 31 December, 2017. Average FeT (869–1490 ng m−3) and FeS (24–68 ng m−3) concentrations were higher in northern than southern China cities, but Fe solubility (%FeS, 2.7–5.0%) showed no spatial pattern. Correlation analyses suggested %FeS was strongly correlated with FeS and PM2.5 instead of FeT concentrations. Individual particle observations confirmed that more than 65% of nano-sized Fe-containing particles were internally mixed with sulfates and nitrates. Furthermore, there was a high correlation between sulfates or nitrates/FeT molar ratio and %FeS. We also found that the sulfates/nitrates had weaker effects on %FeS at RH < 50% than at RH > 50%, suggesting RH as indirect factor can influence %FeS in PM2.5. These results suggest an important role of chemical processing in enhancing %FeS in the polluted atmosphere.

Sensitivity of bees’ pathogenic bacteria to a sample of copper solution and silver citrate

The article presents the studies’ results of the experimental disinfectan’s antimicrobial effect on microorganisms of various morphological groups that currently cause bees’ enterobacteriosis. For work, we used cultures of bee enterobacteria: a pure microorganisms culture of the species Klebsiella pneumoniae and natural (mixed) strains of enterobacteria excreted from sick bee colonies at apiaries in the North-Western region of Ukraine. Sick bees’ families had similar clinical signs – the abdomen in sick bees was thickened, filled with fecal matter, the bees moved slowly, noted damage to the pupae among the sealed brood in the spring and summer, and the families took off in August-September. A solution of copper and silver citrate was used in the native state and in such concentrations – 1:2, 1:5, 1:10, diluted in sterile 0.9 % NaCl. The studies were conducted by the disk-diffuse method. The most active influence of a copper and silver citrate solution sample was recorded with native use on both studied cultures, and the enlightenment zone in the mixed culture was significantly greater (by 28.8 %) than in the pure culture of the species Klebsiella pneumoniae. A significant difference was noted between the two cultures of microorganisms (pure and mixed) with similar dilutions (1:2 and 1:10). Due to the presence of genes encoding adhesins, they determine the formation of a biofilm on the surface of the medium during cultivation of the studied microorganisms, we have a pronounced bacteriostatic effect of the native sample. Such changes are explained by the antimicrobial action of AgNPs associated with the mechanisms of AgNPs adhesion to the surface of the cell wall and membrane, penetration of AgNPs into the cell and damage to intracellular structures (mitochondria, vacuole, ribosomes) and biomolecules (proteins, lipids and DNA), induction of cellular toxicity and oxidative stress AgNPs caused by the generation of reactive oxygen species (ROS) and free radicals and modulation of the signal transduction pathways, which is part of the experimental sample. Silver nanoparticles, unlike copper, can be easily synthesized using physical, chemical, electrochemical and biological methods. Therefore, there is a growing demand for the development of effective and environmentally friendly disinfectants in beekeeping. Further research will be aimed at evaluation a toxic dose of LD50 AgNPs in bee gardens, followed by studying the effect of certain doses in hives in vivo, probably not only as an organic disinfectant, but also as an immunomodulator that stimulates the bee’s body, helps to suppress the development of pathogenic microorganisms in the hive.

Chrysin Reduces Oxidative Stress but Does Not Affect Polyol Pathway in the Lenses of Type 1 Diabetic Rats.

Prolonged hyperglycemia is one of the main causes of reactive oxygen species and free radicals generation in diabetes which may affect various organs, including the eye. Oxidative damage to proteins and lipids in the eye lens could lead to cataract formation. To cope with oxidative stress, the endogenous antioxidative system may be supported by the supplementation of exogenous antioxidants. The aim of this study was to evaluate the effect of chrysin, a natural flavonoid, on oxidative stress and polyol pathway-related markers in the lenses of streptozotocin-induced type 1 male diabetic rats. Chrysin at doses of 50 and 100 mg/kg was administered by gavage for 28 days. This treatment resulted in a decrease in antioxidative enzymes activity and oxidative stress index. Moreover, chrysin administration elevated the reduced glutathione level in the lenses. A decrease in the markers linked to oxidative damage to proteins and lipids in the lenses was noted, especially after treatment with 50 mg/kg of chrysin. Neither of the chrysin doses affected glycemia-related markers in the serum or altered parameters related to the polyol pathway and advanced glycation end-products level in the lenses of diabetic rats. Upon obtaining results, it can be concluded that chrysin reveals antioxidative activity in the lenses but shows no antihyperglycemic or antiglycation properties.

Iron Metabolism, Ferroptosis, and the Links With Alzheimer's Disease.

Iron is an essential transition metal for numerous biologic processes in mammals. Iron metabolism is regulated via several coordination mechanisms including absorption, utilization, recycling, and storage. Iron dyshomeostasis can result in intracellular iron retention, thereby damaging cells, tissues, and organs through free oxygen radical generation. Numerous studies have shown that brain iron overload is involved in the pathological mechanism of neurodegenerative disease including Alzheimer’s disease (AD). However, the underlying mechanisms have not been fully elucidated. Ferroptosis, a newly defined iron-dependent form of cell death, which is distinct from apoptosis, necrosis, autophagy, and other forms of cell death, may provide us a new viewpoint. Here, we set out to summarize the current knowledge of iron metabolism and ferroptosis, and review the contributions of iron and ferroptosis to AD.

Current Review on Herbal Pharmaceutical improve immune responses against COVID-19 infection

Coronavirus SARS-COV2 (COVID-19) represents the causative agent of a potentially fatal disease that is of great global public health concern. The pandemic outbreak of COVID-19 is rapidly spreading all over the world. This review aims to provide the role of Herbal Pharmaceutical in reducing the spread or complications of COVID-19 infection in the body of people. The evidence of generation of oxygen free radicals and oxidative stress is a key process in the onset of chronic disease which participate in the development of the systemic inflammatory response syndrome. Medicines of plant origin aroused a lot of interest due to their wide use, abundance, high efficacy and lack of secondary effects as an antioxidants and anti-inflammatory agents, antiviral efficacy or in their preventive efficacy of the immune system From it we suggest that the combination of conventional therapy and herbal medicine for patients infected with COVID-19 to reduce the complexities and development of the virus.

Evaluation of dyslipidemia and oxidative stress in type II diabetes patients

Background: Diabetes mellitus (DM) is a metabolic disorder characterized by the presence of chronic hyperglycemia associated with impairment in the metabolism of carbohydrate, lipids, and proteins. The most common endocrine and metabolic disease in the world is Type II DM. Elevated glucose levels characterize a complicated combination of genes and environmental influences, contributing to decreased insulin secretions or resistance. Materials and Methods: This observational, case-control study was conducted in the Department of Biochemistry, Santosh Medical College and Hospital, Ghaziabad in collaboration with the Department of Medicine during the period from November 2016 to July 2018. A total of 316 subjects between the age of 30 and 60 years were enrolled in the study and they were divided into two groups-Cases: One hundred and fifty eighty Type-II diabetic patients and Controls: One hundred and fifty eighty healthy adults volunteers. Results: The mean age of Type 2 diabetic subjects had higher 44.52 ± 8.17 years and in 40.20 ± 7.42 years for healthy controls. Similarly, the mean body mass index of the Type II Diabetes subjects was higher 25.28 ± 2.55 as compared to 23.07 ± 1.49 healthy controls. Large changes have been observed in fasting blood sugar, Glycated Haemoglobin (HbA1c), and total cholesterol (TC), along with triglycerides. Low-density lipoprotein cholesterol (LDL-C) was also elevated, along with very low-density lipoprotein cholesterol (VLDL-C) and Malondialdehyde (MDA). With TG, LDL-C, and VLDL-C, fasting blood glucose with TC shows a favorable correlation between MDA and negative interaction with high-density lipoprotein cholesterol. Good interaction of MDA with HbA1c. Conclusion: Increased blood glucose levels lead to the generation of oxygen free radicals and decreased levels of antioxidants, which causes erythrocyte fragility in type 2 diabetes. As a step for the prevention of vascular complications along with macrovascular problems in Type II Diabetes subjects, early detection of dyslipidemia and oxidative stress may be used.

Impact of copper in Xenopus laevis liver: Histological damages and atp7b downregulation.

Copper is an essential micronutrient but its excess in the dietary can be toxic. Both copper deficiency and abundance can occur in natural conditions and can lead to pathological dysfunctions. Many of the toxic effects of copper, such as increased lipid peroxidation in cell membranes and DNA damage, are due to its role in the generation of oxygen free radicals. Copper is released into the environment by both natural sources and human activities and it can damage organisms and ecosystems. In the present work the effects of copper has been studied on Xenopus laevis, an interesting model organism, after three weeks of exposure at 1 mg/L of CuCl, concentration allowed in the water for human use. The effects of this metal were analysed on the liver at light microscope by Hematoxylin-Eosin, Mallory, Pas and Perls stainings to evaluate the general histology, the glycogen metabolism and presence of hemosiderin. Moreover the number and area of melanomoacrophages, known as inflammation parameters, were assessment. Finally, we investigated the expression of atp7b gene and localization of respective ATP7B protein, the membrane protein involved in Cu detoxication. The achieved results showed that copper, even at a low concentration, causes serious histological alterations of liver. It induces an increase in the size and number of melanomacrophages and higher amount of hemosiderin in the treated than controls. Moreover, it alters the gene expression and localization of ATP7B protein. The data are indicative that an exposition at low and chronic concentration of copper in Xenopus laevis damages seriously the liver. For this reason it's important to consider this metal one of the pollutants involved in the decline of the amphibians and for its possible effects in other vertebrates including humans.

Hyperthermia and Controllable Free Radical Coenhanced Synergistic Therapy in Hypoxia Enabled by Near-Infrared-II Light Irradiation.

Tumor cell metabolism and tumor blood vessel proliferation are distinct from normal cells. The resulting tumor microenvironment presents a characteristic of hypoxia, which greatly limits the generation of oxygen free radicals and affects the therapeutic effect of photodynamic therapy. Here, we developed an oxygen-independent free radical generated nanosystem (CuFeSe2-AIPH@BSA) with dual-peak absorption in both near-infrared (NIR) regions and utilized it for imaging-guided synergistic treatment. The special absorption provides the nanosystem with high photothermal conversion efficiency and favorably matched photoactivity in both I and II NIR biological windows. Upon NIR light irradiation, the generated heat could prompt AIPH release and decompose to produce oxygen-independent free radicals for killing cancer cells effectively. The contrastive research results show that the enhanced therapeutic efficacy of NIR-II over NIR-I is principally due to its deeper tissue penetration and higher maximum permission exposure that benefits from a longer wavelength. Hyperthermia effect and the production of toxic free radicals upon NIR-II laser illumination are extremely effective in triggering apoptosis and death of cancer cells in the tumor hypoxia microenvironment. The high biocompatibility and excellent anticancer efficiency of CuFeSe2-AIPH@BSA allow it to be an ideal oxygen-independent nanosystem for imaging-guided and NIR-II-mediated synergistic therapy via systemic administration.

The correlation of whole brain apparent diffusion coefficient with neurological impairment, Hcy metabolism and oxygen free radical generation in patients with Alzheimer′s Disease

Objective To study the correlation of whole brain apparent diffusion coefficient (ADC) with neurological impairment, homocysteine (Hcy) metabolism and oxygen free radical generation in patients with Alzheimer′s disease (AD). Methods The patients diagnosed as AD in Xuanwu Hospital of Capital Medical University from March 2014 to December 2017 were selected as AD group and healthy persons as control group. The ADC of whole brain was calculated after magnetic resonance scanning. The degree of neurological impairment was evaluated by Montreal Cognitive Function Assessment Scale (MoCA). The levels of Hcy metabolic index and oxygen free radical production were measured after collecting serum. Results ADC values of AD group in parietal lobe, frontal lobe, temporal lobe and occipital lobe were not significantly different from those of control group (P>0.05). The ADC value of hippocampus as well as serum Hcy, malondialdehyde (MDA) and nitric oxide (NO) contents were significantly higher than those of control group, while MoCA score as well as folic acid (FA), vitamin B12 (VitB12), superoxide dismutase (SOD) and glutathione peroxidase (GSH) contents in serum were significantly lower than those of control group (P<0.05); ADC value of hippocampus in AD patients was negatively correlated with MoCA score as well as serum FA, VitB12, SOD and GSH contents, and positively correlated with serum Hcy, MDA and NO contents. Conclusions The increased ADC value of hippocampus in AD patients was related to the cognitive function injury, Hcy metabolism disorder and excessive generation of oxygen free radicals. Key words: Alzheimer disease; Diffusion tensor imaging; Cognitive dysfunction; Homocysteine; Reactive oxygen species

Agrobiological, chemical and antioxidant properties of saffron (Crocus sativus L.) exposed to TiO2 nanoparticles and ultraviolet-B stress

Saffron (Crocus sativus L.) is one of the most commonly known and expensive medicinal and aromatic plants in the world from which dried stigmas are consumed. Saffron includes 85 species and has a special place among industrial and export commodities. Ultraviolet-B (UV-B) radiation causes the generation of oxygen free radicals, which disrupt the balance of metabolism in cells. The present study aimed to explore the application of titanium dioxide nanoparticles (TiO2 NPs) on saffron exposed to harmful UV-B radiation, in order to evaluate their effect against photo – oxidative stress. Saffron plants were grown in the hydroponic system in a greenhouse for 45 days. After the three-leaf stage, they were exposed to UV-B radiation for 30 and 45 min on a daily basis for one month. TiO2 NPs were used at two concentrations of 25 and 50 mg/L as the foliar application before UV-B exposure every day. The plants were harvested 75 days later and their growth, chemical and antioxidant parameters were measured. The results showed that UV-B exposure was related to lower plant length, fresh and dry weight, and leaf number. The simultaneous UV-B exposure and TiO2 NPs application resulted in the loss of dissolved sugars and the increased content of total anthocyanins and malondialdehyde (MDA) in saffron leaves. Besides, content of UV-B absorbents (total phenolics and total flavonoids) and radical scavenging activity ((DPPH) in saffron stigmas were increased. The foliar application of TiO2 NPs counterbalanced some plant traits impaired by UV-B exposure as compared with plants only exposed to UV-B radiation. Due to the increased antioxidant activity of saffron stigmas, it could be assumed that the use of TiO2 NPs enhances the nutritive value of saffron.