Role In Antioxidant Defense System Research Articles

CONSERVATION AND VARIABILITY OF THE ANTIOXIDANT PROTECTION SYSTEM OF THE RETINAL PIGMENT EPITHELIA IN VERTEBRATES

In the course of evolution and adaptation to life conditions, organisms have developed the strategies that allow to use of the reactive oxygen species (ROS) in regulation of physiological processes and in maintenance of homeostasis. Retinal pigment epithelium (RPE) is one of the prime examples of tissues with a high level of metabolism and intracellular ROS, that have the more risk of damage after oxidative stress (OS), under the influence of exogenous or endogenous stress factors. Vertebrate RPE cells, despite the conservatism of the eye tissue structures and their main functions, respond differently to OS are due to the taхon-species specificity of the components of signaling pathways that form the antioxidant defense system (AODS). Transcription factors, in particular, Nrf2 play a key role in AODS. AODS in RPE includes the several levels of regulation, interaction of which ensures the stability of morphofunctional state of the cells. Phylogenetic analysis of the key components of AODS in various vertebrates revealed not only conservation, but also variability in the protein domain organization. This may reflect the differences in functions, adaptability and regenerative potential. The identification of AODS mechanisms that ensure the morphofunctional stability of RPE cells is of fundamental importance and is aimed at finding tissue-specific targets for effective treatment of a spectrum of eye diseases.

Association between selenium intake and cognitive function among older adults in the US: National Health and Nutrition Examination Surveys 2011-2014.

Cognitive decline occurs commonly as people age. Despite the complexity of cellular mechanisms, oxidative stress is a critical contributor to age-associated cognitive impairment. Selenium plays an important role in antioxidant defense systems. The purpose of the present study was to assess the correlation between selenium intake and cognitive function among older adults. The participants were individuals ≥65 years old (n=1681) who participated in the 2011-2014 National Health and Nutrition Examination Survey (NHANES), a country-wide cross-sectional survey. Dietary selenium intake and adequacy were evaluated with 2 d of 24-h recalls and the estimated average requirement (EAR) cut-point method, respectively. Cognitive function was assessed with the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) score, which was significantly higher when selenium intake was adequate. After adjusting for energy intake, the association was no longer significant. Inadequate intake of selenium is rare in the US and dependent on caloric intake in older adults.

Effect of heat stress on oxidative damage and antioxidant defense system in white clover (Trifolium repens L.)

This study leads to advances in the field of heat tolerance among different plant species. We concluded that a coordinated, increased antioxidant defense system enabled white clover to reduce heat-induced oxidative damage. The rise in global ambient temperature has a wide range of effects on plant growth, and, therefore, on the activation of various molecular defenses before the appearance of heat damage. Elevated temperatures result in accelerated generation of reactive oxygen species (ROS), causing an imbalance between ROS production and the ability of scavenging systems to detoxify and remove the reactive intermediates. The aim of this study was to determine the role of antioxidant defense systems in the alleviation of heat stress (HS) consequences in white clover (Trifolium repens L.), which is cultivated worldwide. We evaluated how temperature and time parameters contribute to the thermotolerance of white clover at different growth stages. We revealed HS protection in white clover from 37 to 40°C, with 40°C providing the greatest protection of 3-day-old seedlings and 28-day-old adult plants. Heat-provoked oxidative stress in white clover was confirmed by substantial changes in electrolyte leakage, malondialdehyde (MDA), and chlorophyll content, as well as superoxide anion (O2·-) and hydrogen peroxide (H2O2) production. Furthermore, superoxide dismutase (SOD) and ascorbate peroxidase (APX) as well as a high level of GSH non-enzymatic antioxidant were the most responsive, and were associated with acquired thermotolerance through the regulation of ROS generation.We demonstrated, by studying protoplast transient gene expression, direct genetic evidence of endogenous antioxidant-related genes that confer HS tolerance in white clover. Our present study clearly establishes that oxidative stress ensues from HS, which triggers the induction of antioxidant defense systems for ROS scavenging in white clover.

Protective Effects of Anthocleista djalonensis Extracts against Pentylenetetrazole-Induced Epileptic Seizures and Neuronal Cell Loss: Role of Antioxidant Defense System.

Oxidative stress and neurodegeneration are involved in the initiation of epileptogenesis and progression of epileptic seizures. This study was aimed at investigating the anticonvulsant, antioxidant, and neuroprotective properties of active fractions isolated from Anthocleista djalonensis root barks in pentylenetetrazole mouse models of epileptic seizures. Bioactive-guided fractionation of Anthocleista djalonensis (AFAD) extracts using acute pentylenetetrazole (90 mg/kg) induced generalised tonic-clonic seizures, which afforded a potent anticonvulsant fraction (FPool 5). Further fractionation of AFAD was performed by high-performance liquid chromatography, which yielded fifteen subfractions, which were chemically characterised. In addition, AFAD was tested against convulsions or spontaneous kindled seizures induced, respectively, by acute (50 mg/kg) or subchronic (30 mg/kg) injection of pentylenetetrazole. Finally, oxidative stress markers, brain GABA content, and neuronal cell loss were evaluated in AFAD-treated pentylenetetrazole-kindled mice. Administration of AFAD significantly protected mice against acute pentylenetetrazole (90 mg/kg)-induced convulsions. In acute pentylenetetrazole (50 mg/kg)-induced hippocampal and cortical paroxysmal discharges, AFAD significantly decreased the number of crisis, the cumulative duration of crisis, and the mean duration of crisis. Additionally, AFAD significantly decreased the number of myoclonic jerks and improved the seizure score in subchronic pentylenetetrazole-induced kindled seizures. The pentylenetetrazole-induced alteration of oxidant-antioxidant balance, GABA concentration, and neuronal cells in the brain were attenuated by AFAD treatment. This study showed that AFAD protected mice against pentylenetetrazole-induced epileptic seizures possibly through the enhancement of antioxidant defence and GABAergic signalling. These events might be correlated with the amelioration of neuronal cell loss; hence, AFAD could be a potential candidate for the treatment of epilepsy.

Role of antioxidative defense system in amelioration of cadmium-induced phytotoxic effects in germinating seeds of maize (

Context Anthropogenic activities are increasing Cd concentration in soil and environment that limits seed germination capacity and causes poor seedling establishment. Aims The effect of different Cd concentrations on seed germination and seedling growth of two maize cultivars (C-20 and EV-1098) was tested in this study. Methods Maize seeds were sown in Petri dishes lined with double filter paper. The seedlings were grown in a growth chamber, applied with different Cd concentrations (0, 2, 4, 6, 8 and 10 μM), and harvested 12 days after germination. Key results Seeds applied with higher levels of Cd showed a significant decrease in seed germination percentage (GP), seed emergence index (EI) and germination energy (GE). A significant delay in seed germination was observed at the highest Cd treatment in terms of increased mean emergence time (MET), days to 50% germination (T 50) and coefficient of uniformity of emergence (CUE). A marked decline in leaf K, Ca, Na, and P was observed, whereas root K, Ca and P increased with an increase in external Cd concentration. The roots and leaves of maize C-20 showed greater activities of superoxide dismutase (SOD) than did those of EV-1098. In contrast, peroxidase (POD) activity was reasonably high in roots and leaves, whereas catalase (CAT) was high only in roots of EV-1098. Non-enzymatic antioxidants such as phenolics and ascorbicacid (AsA) also significantly increased, accompanied with substantially lowermalondialdehyde (MDA) contents in the roots and leaves of EV-1098 than of C-20. Conclusions The differential modulation of the activities of enzymatic and non-enzymaticanti-oxidative defense system in roots and leaves played a critical role intolerance of both cultivars to Cd stress. Implications The findings of this study are helpful in improving seed germination capacity and seedling growth of maize in Cd contaminated soils.

Supranutritional selenium level minimizes high concentrate diet-induced epithelial injury by alleviating oxidative stress and apoptosis in colon of goat

BackgroundHigh concentrate (HC) diet-induced oxidative stress causes gut epithelial damages associated with apoptosis. Selenium (Se) being an integral component of glutathione peroxidase (GSH-Px) plays an important role in antioxidant defense system. Therefore, increasing dietary Se level would alleviate HC diet-induced injuries in gut mucosa. The present study investigated eighteen cross-bred goats, randomly divided into three groups (n = 6/group) fed either low concentrate (LC, roughage: concentrate ratio 65:35), high concentrate (HC, 35:65) or HC plus Se (HC-SY) diets for 10 weeks. Se was supplemented at the dose rate of 0.5 mg Se kg− 1 diet in the form of selenium yeast. The background Se level in HC and LC diets were 0.15 and 0.035 mg.kg− 1 diet, respectively. The Se at the dose of 0.115 mg.kg− 1 diet was added in LC diet to make its concentration equivalent to HC diet and with the supplementation of 0.5 mg Se kg− 1, the goats in group HC-SY received total Se by 0.65 mg.kg− 1 diet.ResultsThe molar concentrations of individual and total short chain fatty acids (TSCFA) significantly increased (P < 0.05) with simultaneous decrease in pH of colonic fluid in goats of HC and HC-SY groups compared with LC goats. HC diet induced loss of epithelial integrity, inflammation and loss of goblet cells in colonic mucosa associated with higher lipopolysaccharide (LPS) concentrations in colonic fluid whereas, the addition of SY in HC diet alleviated such damaging changes. Compared with LC, the HC diet elevated malondialdehyde (MDA) level with concurrent decrease in GSH-Px and superoxide dismutase (SOD) activities, while SY supplementation attenuated these changes and improved antioxidant status in colonic epithelium. Moreover, epithelial injury and oxidative stress in colon of HC goats were associated with increased apoptosis as evidenced by downregulation of bcl2 and upregulation of bax, caspases 3 and 8 mRNA expressions compared with LC goats. On contrary, addition of SY in HC (HC-SY) diet alleviated these changes by modulating expression of apoptotic genes in colonic epithelium.ConclusionsOur data suggest that supranutritional level of Se attenuates HC diet-induced oxidative stress and apoptosis and thereby minimizes the epithelial injury in colon of goats.

Foliar Concentrations of Selected Elements, Assessment of Oxidative Stress Markers and Role of Antioxidant Defense System is Associated with Fly Ash Stress Tolerance in Withania somnifera

Increased dependence on thermal power has resulted in a significant increase in the generation of fly ash (FA), which exacerbates environmental pollution. In order to mitigate this source of pollution, we propose covering FA dumps with a layer of planted vegetation. Due to varying degrees of tolerance and their sessile nature, plants are themselves susceptible to stress from pollution. This suggests that an investigation to assess the role of wild growing plants for management of FA dumps, where selected wild plants could be grown to mitigate consequences of FA. The present study assesses oxidative damage and the foliar concentration of metals in Withania somnifera growing wild at the Badarpur Thermal Power Plant (BTPP) compared to those growing at a control site. Plants growing at the BTPP showed significantly higher foliar concentrations of Pb, Mn, and Fe, and low concentrations of Ni and Cd. The plants at the BTPP site showed signs of oxidative stress as indicated by enhanced levels of malondialdehyde and electrolyte leakage from cells. The CO2 assimilation rate, net photosynthetic rate, rate of transpiration, stomatal conductance decrease, while water use efficiency, and air pollution tolerance index increase. Among air pollution tolerance index parameters, relative water content showed a significant increase with FA pollution stress at the BTPP. A significant decrease was observed in leaf morphology single leaf area, leaf length, and leaf width and biochemical parameters (Chlorophyll a, Chlorophyll b, total chlorophyll, and carotenoids. Moreover, FA pollution stress induces oxidative stress in W. somnifera through a significant and enhanced production of reactive oxygen species (ROS). According to our observations, the ability of W. somnifera to effectively coordinate superoxide dismutase, ascorbate peroxidase, and glutathione reductase activities involved in the scavenging of ROS along with the enhanced increment of nonenzyme activities (total ascorbic acid, proline, and oxidized glutathione) could be related to FA stress tolerance in W. somnifera.

Isolation and Identification of Flavonoids from Arctiumlappa Stem and Study the Hepatoprotective Effecton Acetaminophen Induced Liver Damage

The present study investigate the hepatoprotective and antioxidant effect of crude extract of Arctiumlappastem(E-ALS) and isolated total flavonoids(ITF) from the stem, With qualitative and quantitative determination of flavonoids by HPLC.Twenty four local adult male rabbitswere used in this study which divided into four groups(6animal in each group), Control-1(C1) as control group, Control-2(C2):treated with 300mg/kgparacetamoladministrated for one week, Group 1(G1): 300mg/kg paracetamol administrated for one week +Orally 250mg/kg of E-ALSadministrated daily for 4 weeks, Group 2(G2): Orally 300mg/kg paracetamol administrated for one week +Orally 50mg/kg of ITFdministrated daily for 4 weeks. The results identified five types of flavonoids for the first time in plant stem (Rutin, Myricetin, Quercetin, Apigenin, Kaempferol) with quantified determination for the concentration of each type of flavonoids in E-ALS and also in ITF which identified the same five flavonoids. The hepatoprotective effect of E-ALS and ITF were observed by monitoring the antioxidant parameters and activity of liver enzymes. The results obtained from this study showed that the levels of glutathione-GSH, Glutathione peroxidase GPX and Glutathione-S-Transferase-GST were significantly (P ? 0.05) decreased in C2 treated with paracetamol as comparing with C1, with significant (P ? 0.05) elevation of alanine aminotransferase-ALT activity and non-significant effect on Aspartate aminotransferase-AST, while the level of GSH and GPX were significantly (P ? 0.05) elevated in G1 and G2 treated with E-ALS and ITF respectively as compared with C2, in which the levels of GSH and GPX are less than the levels in C1 and G1. Otherwise the levels of GST, ALT and AST significantly (P ? 0.05) decreased in G1 and G2 as compared with C2. These findings show the hepatoprotective properties of E-ALS and IFT against liver injury induced by paracetmol and also the protective role of anti-oxidative defense system of flavonoids in the two extracts.

Differential responses of a pi-class glutathione S-transferase (CnGSTp) expression and antioxidant status between golden and brown noble scallops under pathogenic stress

Glutathione S-transferases (GSTs) play important roles in immunity by protecting organisms against the damage of reactive oxygen species (ROS). In this study, a pi-class GST cDNA sequence was first cloned from noble scallop Chlamys nobilis (named CnGSTp). The full length cDNA of CnGSTp was 922 bp, encoding a cytosolic protein of 202 amino acids residues, with predicted molecular masses of 23.1 kDa. Then an acute Vibrio Parahaemolyticus challenge experiment was conducted by using the Golden and Brown noble scallops with different total carotenoids content (TCC), and CnGSTp expression level, TCC and ROS level was separately determined. The results showed that ROS and CnGSTp expression levels were significantly up-regulate under Vibrio Parahaemolyticus challenge than the control group (P < 0.05). The Golden scallops showed significantly higher CnGSTp expression level and lower ROS level in hemocytes than the Brown ones (P < 0.05). Moreover, there is a significantly positive correlation between TCC and ROS in the Golden scallops. The present results revealed that CnGSTp plays important roles in immune response and carotenoids play assistant roles in antioxidant defense system under pathogenic stress in the noble scallop.

ABTS radical-based single reagent assay for simultaneous determination of biologically important thiols and disulfides

Both the total amount of biothiols and thiol/disulfide ratio are wellness indicators of oxidative balance that play an important role in antioxidant defense system. Oxidized biothiols in disulfide form cannot be determined by conventional ABTS assay due to the biphasic kinetic pattern of the reaction between biothiols and ABTS radical cation (ABTS•+), necessitating the initial reduction of disulfides to thiols prior to measurement. In this study, direct simultaneous determination of biothiols (RSH) and their disulfides (RSSR) by using a single reagent of ABTS•+ was achieved without preliminary chemical reduction. Thus, conventional problems of preliminary operations arising from direct borohydride reduction of disulfides to thiols, followed by formaldehyde removal of borohydride excess and complications caused by formaldehyde-thiol reactions were effectively overcome with the use of a single reagent (ABTS•+). Box-Behnken statistical experimental design was employed to specify the optimal incubation temperature and time as 60 °C and 60 min, respectively. The detection limits (LOD) of the proposed assay for biothiols were compared to those of the widely used DTNB (Ellman) reference assay known to be nonresponsive to disulfides, and were found to be much lower (4–70 times). The proposed biothiol assay was successfully applied to some pharmaceutical samples and synthetic serum without preliminary treatment, and the results were highly compatible with the HPLC findings. The proposed assay was demonstrated to have superior features such as simplicity, rapidity and higher sensitivity over the widely applied Ellman thiols assay.

Chronic khat (Catha edulis) chewing and genotoxicity: The role of antioxidant defense system and oxidative damage of DNA

Background: Khat chewing is culturally endemic in the Southern areas of Saudi Arabia. Many health-related issues such as the incidence of carcinogenicity and comorbidities associated with the chewing of khat have been reported earlier. Objectives: Mainly, the objective of the study was to assess the risk of genotoxicity caused due to oxidative stress that may result from khat chewing among chronic chewers from Jazan Province of Saudi Arabia. Materials and Methods: Hundred and twenty-two adult males were recruited after signing informed consent. Ninety participants were chronic khat chewers (CKCs), while the control group consisted of 32 non-chewers of matched age and gender for the study group. A blood sample was collected from all participants and kept at 4°C until the time of assay. The activity of superoxide dismutase (SOD) and glutathione reductase (GR) were estimated in erythrocyte lysate as well as 8-hydroxydeoxyguanosine (8-OHdG) level in plasma. Results: There is a decreased SOD activity, which might be due to an increase in the endogenous production of reactive oxygen species resulted from the increase in lipid hydroperoxides. Furthermore, the significant elevation in GR activity was observed, reflecting the presence of highly toxic compounds. The 8-OHdG levels were higher in khat chewers group in comparison to the control, but this increase was statistically insignificant. Conclusion: CKCs will be at considerable risk of oxidative stress as a result of a significant reduction in antioxidant enzymes. This would be a good reason for them to quit chewing khat for health benefits.

Cortico-Hippocampal Memory Enhancing Activity of Hesperetin on Scopolamine-Induced Amnesia in Mice: Role of Antioxidant Defense Systems, Cholinergic Neurotransmission and Expression of BDNF

Alzheimer disease (AD) is an age related neurodegenerative disease causing severe cognitive and memory decline in elderly people. Flavonoids play neuroprotective role by inhibiting and/or modifying the self-assembly of the amyloid-β (Aβ) or tau peptide into oligomers and fibrils. This study sought to investigate the effect of hesperetin (HPT) on scopolamine-induced memory impairments in mice. Mice were orally pretreated with HPT (1, 5 or 50 mg/kg) or vehicle (normal saline; 10 ml/kg) for 3 consecutive days. One hour post-treatment on day 3, scopolamine (3 mg/kg, i.p.) was administered 5 min before locomotor activity (open field test) and memory function (novel object recognition test (NORT) for 2 consecutive days and Morris water maze task (MWM) for 5 consecutive days). Levels of oxidative stress markers / brain derived neurotrophic factors (BDNF) and acetylcholinesterase activity were determined in the hippocampus and prefrontal cortex after completion of MWM task. Scopolamine caused no significant change in mice exploration of the familiar or novel object in the test session whereas the HPT-treated mice spent more time exploring the novel object more than familiar object in NORT. Scopolamine also increased the escape latency in acquisition phase and decreases time spent in target quadrant in probe phase which were ameliorated by the pretreatment with HPT. Scopolamine-induced alteration of oxidant-antioxidant balance, acetylcholinesterase activity and neurogenesis in the hippocampus and prefrontal cortex were attenuated by HPT treatment. This study showed that HPT ameliorated non-spatial/spatial learning and memory impairment by scopolamine possibly through enhancement of antioxidant defense, cholinergic and BDNF signaling.

Diallyl phthalate-triggered oxidative stress in Spirodela polyrhiza L. Schleiden: physiological effects and role of antioxidant defence system

The present study was designed to investigate the manifestations of diallyl phthalate (DAP)-induced oxidative stress in Spirodela polyrhiza. Plants were exposed to varying concentrations of DAP, viz. 10, 20, 40, 80, 100, 200, 400 ppm for 7 days under in vitro conditions. Biochemical analysis after harvesting revealed various phytotoxic effects of DAP on S. polyrhiza which was quite evident from a significant decline in fresh weight and dry-to-fresh weight ratio with progressively increasing concentrations of DAP. Plants accumulated a significant amount of DAP (92.00 mg/kgfw) at 80 ppm concentration which led to alterations in photosynthetic pigments (chl a, chl b, total chlorophyll), increase in carotenoid and anthocyanin pigment, increase in lipid peroxidation, decrease in protein and carbohydrate content. Results also revealed significant effects of DAP on increased proline, phenols and electrolyte leakage. In response to this and to confer DAP tolerance in S. polyrhiza, activities of antioxidant enzymes (SOD, APX, CAT, POD and GR) elevated with proceeding concentrations. Moreover, toxicological implications in plants were confirmed by observing scanning electron micrographs and confocal micrographs of frond and root, respectively, implying oxidative damage faced by plant under DAP exposure. Considering all these results into account, it appeared that there are alarming consequences of DAP toxicity to S. polyrhiza and this plant exhibited better phthalate tolerance ability attributed to its efficient antioxidant machinery which may play a cardinal role in combating diallyl phthalate-mediated stress.

Cortico-hippocampal memory enhancing activity of hesperetin on scopolamine-induced amnesia in mice: role of antioxidant defense system, cholinergic neurotransmission and expression of BDNF.

Alzheimer disease (AD) is an age related neurodegenerative disease causing severe cognitive and memory decline in elderly people. Flavonoids play neuroprotective role by inhibiting and/or modifying the self-assembly of the amyloid-β (Aβ) or tau peptide into oligomers and fibrils. This study sought to investigate the effect of hesperetin (HPT) on scopolamine-induced memory impairments in mice. Mice were orally pretreated with HPT (1, 5 or 50mg/kg) or vehicle (normal saline; 10ml/kg) for 3 consecutive days. One hour post-treatment on day 3, scopolamine (3mg/kg, i.p.) was administered 5min before locomotor activity (open field test) and memory function (novel object recognition test (NORT) for 2 consecutive days and Morris water maze task (MWM) for 5 consecutive days). Levels of oxidative stress markers / brain derived neurotrophic factors (BDNF) and acetylcholinesterase activity were determined in the hippocampus and prefrontal cortex after completion of MWM task. Scopolamine caused no significant change in mice exploration of the familiar or novel object in the test session whereas the HPT-treated mice spent more time exploring the novel object more than familiar object in NORT. Scopolamine also increased the escape latency in acquisition phase and decreases time spent in target quadrant in probe phase which were ameliorated by the pretreatment with HPT. Scopolamine-induced alteration of oxidant-antioxidant balance, acetylcholinesterase activity and neurogenesis in the hippocampus and prefrontal cortex were attenuated by HPT treatment. This study showed that HPT ameliorated non-spatial/spatial learning and memory impairment by scopolamine possibly through enhancement of antioxidant defense, cholinergic and BDNF signaling.

Association between Serum Uric Acid and Oxidative Stress in Korean Adults.

BackgroundOxidative stress is implicated in the pathogenesis and development of lifestyle-related diseases. In the present study, we evaluated the correlation between the serum uric acid (UA) levels and oxidative status in Korean adults.MethodsThe subjects were 5,093 individuals (2,041 women and 3,052 men) who underwent a health checkup between June 2012 and December 2016. Oxidative stress levels (derivatives of reactive oxygen metabolites [d-ROMs]) and antioxidant potential (biological antioxidant potential [BAP]) were measured. Metabolic markers, including UA, were also examined.ResultsHigher serum UA levels were associated with decreased levels of d-ROMs (P<0.05). The UA levels were positively associated with BAP levels (P<0.001).ConclusionSerum UA is related to oxidative status, especially antioxidant capacity, in Korean adults; UA may play a role in antioxidant defense systems in humans.

Differential enzymatic defense mechanisms in leaves and roots of two true mangrove species under long- term salt stress

To elucidate the role of antioxidative defense system against salt stresses, the levels of antioxidative enzymes and lipid peroxidation were quantified in leaves and roots of 2-year old Kandelia candel and Rhizophora stylosa seedlings subjected to 0, 5, 15 and 30 parts per thousand (ppt) of salt concentrations during one and two months treatments (1MT and 2MT). The data revealed differential responses between the species to different salt concentrations, while no significant differences observed between the treatment periods.In leaves, higher salinity decreased superoxide dismutase (SOD) and monodehydroascorbate reductase (MDHAR) activities in both species and catalase (CAT) activity in K. candel, while ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) activities in both species and CAT in R. stylosa were increased. In roots, salt stresses increased the activities of most of the tested enzymes. Except for the roots K. candel, the malondialdehyde (MDA) contents were decreased significantly at higher salt concentrations.In K. candel leaves, moderate to strong negative correlations existed between APX, GPX and DHAR activities with MDA content, while SOD, CAT and MDHAR showed positive correlations. Contrarily, in R. stylosa leaves, CAT, APX and sometimes GPX and DHAR showed inverse correlations with respective MDA, while other enzymes showed reverse correlations. With few exceptions, all tested enzymes in roots showed negative correlations with MDA. These results suggested that most of the antioxidant enzymes in roots acted coordinately for effective stress mitigation, while leaf tissues might adopt many other mechanisms for salt tolerance of mangrove plants where antioxidant enzymes played minor role.

Role of antioxidant defence, renal toxicity markers and inflammatory cascade in disease progression of acute pyelonephritis in experimental rat model.

Urinary tract infections are the most common bacterial infections affecting millions of people each year worldwide. The animal model provides an excellent and suitable system for studying cystitis and pyelonephritis caused by Escherichia coli and other uropathogens. Using this established model, we evaluate the role of antioxidant defence system, renal injury markers, and blood parameters in the diseases progression during Escherichia coli infection on 0th day, 12h and 7th day. The antioxidant enzymes like SOD, CAT, GSH, GPx, GR levels were evaluated. The blood parameters like AST, ALT, ALP, Total protein, BUN, creatinine level were estimated in infection model. The relative organ weights, anti microbial status of kidney, CRP, WBC count were done for the evaluation of inflammatory response associated with the infection. The oxidative stress marker like MDA was also evaluated. Histopathological analysis of renal tissue provides direct vision to tissue damage. The antioxidant status of renal tissue was decreased during the 7th day of infection. Likewise, renal toxicity markers were significantly increased during bacterial infection. The inflammatory markers like CRP, WBC count and oxidative stress marker like MDA were significantly increased by the infection on 7th day. The histopathology of renal tissue also reveals the inflammation and tissue damage associated with acute pyelonephritis.

Oxidative Stress and Amyloid Toxicity: Insights From Yeast.

Alzheimer's disease is the most common neurodegenerative disorder. One of the factors that promotes neurodegeneration is the accumulation of senile plaques formed by Aβ peptide. In this paper, it was analyzed that if oxidative stress is cause or consequence of amyloid cascade and the role of antioxidant defense system in this process, using S. cerevisiae (with a multicopy plasmid containing the Aβ1-42 sequence) as experimental model. Cells grown on glycerol were more tolerant than when grown on glucose, strengthening the role of the antioxidant defense system against Aβ accumulation. Antioxidant defense deficiency did not change the pattern of amyloid aggregation. On the other hand, the presence of Aβ increased the level of intracellular oxidation and induced the activity of catalase, superoxide dismutase, and aconitase. Peroxissomal catalase deficient cells (Δcta1), were more sensitive to Aβ toxicity than the wild type strain, while mitochondrial superoxide dismutase (Sod2) deficient cells displayed the highest frequency of petites. Besides, Aβ alters the oxygen consumption and the activity of complex III and IV. Taken together, our results point out that the Aβ toxicity mechanism involves an oxidative stress induction by increasing ROS production into the mitochondria, where Cta1 and Sod2 play a crucial role in the regulation of the redox balance. J. Cell. Biochem. 118: 1442-1452, 2017. © 2016 Wiley Periodicals, Inc.

Functional Significance of NADPH-Thioredoxin Reductase C in the Antioxidant Defense System of Cyanobacterium Anabaena sp. PCC 7120.

The redox regulation system is widely accepted as a crucial mechanism for controlling the activities of various metabolic enzymes. In addition to thioredoxin reductase/thioredoxin cascades, NADPH-thioredoxin reductase C (NTRC), a hybrid protein formed by an NADPH-thioredoxin reductase domain and a thioredoxin (Trx) domain, is present in chloroplasts and in most cyanobacteria species. Although several target proteins and physiological functions of NTRC in chloroplasts have been characterized, little is known about NTRC functions in cyanobacteria. Therefore, we investigated the molecular basis and physiological significance of NTRC-dependent redox regulation in the filamentous heterocyst-forming nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120 (Anabaena 7120). Initially, we identified six candidate NTRC targets in Anabaena 7120 using NTRC affinity chromatography. Subsequently, we compared the efficiency of reducing-equivalent transfer from NTRC and Trx-m1 to the NTRC target protein 2-Cys peroxiredoxin. Biochemical analyses revealed that compared with Trx-m1, NTRC more efficiently transfers reducing equivalents to 2-Cys peroxiredoxin. Subsequently, we constructed and analyzed an ntrC knockout strain in Anabaena 7120. The mutant showed impaired growth under oxidative stress conditions and lower concentrations of reduced 2-Cys peroxiredoxin in cells. Taken together, the present in vitro and in vivo results indicate that NTRC is a significant electron donor for 2-Cys peroxiredoxin and plays a pivotal role in antioxidant defense systems in Anabaena 7120 cells.

Ameliorative effect of kolaviron, a biflavonoid complex from Garcinia kola seeds against scopolamine-induced memory impairment in rats: role of antioxidant defense system.

In Alzheimer's disease (AD) basal forebrain cholinergic neurons appear to be targeted primarily in early stages of the disease. Scopolamine (muscarinic receptor antagonist) has been used for decades to induce working and reference memory impairment in rodents. In this study, we evaluated the protective effect of kolaviron, a biflavonoid complex isolated from Garcinia kola seeds extract against scopolamine-induced memory impairment/oxidative stress. Rats were pretreated with kolaviron (25, 50 or 100mg/kg p.o.) for 3 consecutive days, scopolamine (3mg/kg, i.p.) was administered 1h post-treatment on day 3. Five minutes post-scopolamine injection, memory function was assessed using the Y-maze or Morris water maze tests (MWM) in rats. The rats were sacrificed and brains isolated on the 8th day after the MWM test for estimation of acetylcholinesterase activity and nitrosative/oxidative stress status. Scopolamine injection induced deficit (P<0.05) in percentage alternation behaviour in the Y-maze test indicating memory impairment which was ameliorated by kolaviron in a dose-dependent manner. Also, pre-training treatment with kolaviron significantly improved spatial learning evidenced in the session-dependent and more efficient localization of the hidden platform in the MWM test. Moreover, scopolamine injection induced significant increase in lipid peroxidation (prefrontal cortex), nitrite generation (striatum and hippocampus) and a decrease in glutathione (prefrontal cortex, striatum and hippocampus) and superoxide dismutase (striatum and hippocampus) level which was attenuated by kolaviron pre-treatment. These findings showed that kolaviron possesses cognition enhancing effect through enhancement of antioxidant defense and cholinergic systems.