Antioxidative stress-induced damage in cochlear explants

The imbalance of reactive oxygen species and antioxidants is considered to be an important factor in the cellular injury of the inner ear. At present, great attention has been placed on oxidative stress. However,little is known about fighting oxidative stress. In the current study, we evaluated antioxidant-induced cochlear damage by applying several different additional antioxidants. To determine whether excessive antioxidants can cause damage to cochlear cells, we treated cochlear explants with 50 m M M40403, a superoxide dismutase mimetic, 50 m M coenzyme Q-10, a vitamin-like antioxidant, or 50 m M d-methionine, an essential amino acid and the important antioxidant glutathione for 48 h. Control cochlear explants without the antioxidant treatment maintained their normal structures after incubation in the standard serum-free medium for 48 h, indicating the maintenance of the inherent oxidative and antioxidant balance in these cochlear explants. In contrast, M40403 and coenzyme Q-10-treated cochlear explants displayed significant hair cell damage together with slight damage to the auditory nerve fibers.Moreover, d-methiodine-treated explants exhibited severe damage to the surface structure of hair cells and the complete loss of the spiral ganglion neurons and their peripheral fibers. These results indicate that excessive antioxidants are detrimental to cochlear cells, suggesting that inappropriate dosages of antioxidant treatments can interrupt the balance of the inherent oxidative and antioxidant capacity in the cell.

Photosynthetic activity and antioxidative response of seagrass Thalassia hemprichii to trace metal stress

This study concerned the accumulation of trace metals in tissues of seagrass ( Thalassia hemprichii) exposed to various concentrations of Zn2+,Cd2+,Pb2+ and Cu2+ for 10 d,and the effect of excessive metals on quantum yield (△F/F′m),photosynthetic pigments and antioxidative enzymes like superoxide dismutase (SOD),guaiacol peroxidase (POD) were also examined.Cadmium was the most highly accumulated metal.Meanwhile,high metals levels led to a remarkable breakdown of photosynthetic parameters.Especially,△F/F′m,chlorophyll and carotenoid were significantly low during prolonged Cu exposure.Besides,△F/F′m was more severely depressed by Cu and Zn than Pb and Cd.However,T.hemprichii had positive response by increasing the activity of SOD and POD.The results indicate that T.hemprichii is the most sensitive to Cu,and the antioxidative protection mechanisms of T.hemprichii are more efficiently activated to avoid damage of Zn,Cd and Pb stress. Finally,due to the high Cd-accumulation and strong Cd-tolerance capacity,T.hemprichii can be used for phytoremediation in Cd-contaminated areas.

Oxidative Stress and Role of Natural Plant Derived Antioxidants in Animal Reproduction

The experimental knowledge on the role of oxidative stress,and beneficial and detrimental effects of plant derived antioxidants in male and female animal reproduction are reviewed in this article.Free radical-induced oxidative stress in animal reproduction causes great loss to livestock industry.Antioxidant therapy has been implicated to be effective in preventing diseases resulted from oxidative stress.Considering the advantages of lower side effects of natural antioxidants than those of synthetic antioxidants,plants or their extracts have been extensively utilized in animals.Although many advances have been gained on application of plant derived antioxidants in alleviating oxidative stress,debatable issues still exist.Because many opposite effects were observed even using plant extracts containing similar bioactive substances in the same animal species.Therefore,plant derived antioxidants,like free radicals,are ＂double-edged swords＂ in animal reproduction,representing that they may exhibit beneficial or detrimental effects in animal reproduction,including spermatogenesis,semen functions,estrous cycles,ovulation,ovary functions,endometrium,embryo development,and pregnancy.Besides dose-dependent manner as an explanation of plant extracts＇ dual function,future studies are needed to investigate the mechanism of double-edged actions of plant derived antioxidants in different animal reproduction systems.

Effects of chilling tolerance induced by spermidine pretreatment on antioxidative activity,endogenous hormones and ultrastructure of indica-japonica hybrid rice seedlings

Spermidine（Spd） is known to be involved in the regulation of plant responses to chilling stress and counteract the adverse effect of stress conditions.Antioxidant activities,endogenous hormones and ultrastructure change under chilling stress were investigated in indica-japonica hybrid rice seedlings.12-d-old seedlings were subjected to exogenous Spd（1 mmol L^（-1）） and then a chilling stress（6℃,4 d） was induced,followed by a subsequent recovery（25℃,4 d）.Results showed that malondialdehyde（MDA） and proline content were enhanced significantly,whereas shoot fresh and dry weights decreased during chilling stress and after recovery;chlorophyll content of chilling-stressed seedlings increased slightly but declined after recovery;additionally,total soluble sugar,sucrose,fructose and starch contents increased significantly during chilling stress,and only soluble sugar and fructose contents were observed in increase after recovery;chilling stress-induced increases in superoxide dismutase（SOD）,peroxidase（POD） and catalase（CAT） activities,but declined after recovery,and the level of ascorbate peroxidase was lower during chilling stress and after recovery;however,endogenous indole-3-acetic acid（IAA）,zeatin riboside（ZR）,gibberellic acid（GA_3）,and abscisic acid（ABA） levels were induced decreased compared with Spd pretreatment.The microscopic analysis revealed that chilling stress-induced destruction of the chloroplast envelope during chilling stress and increased the number of plastoglobuli along with aberrations in thylakoid membranes after recovery.In contrast,exogenous Spd protected rice seedlings from chilling-induced injuries in terms of lower malondialdehyde,proline and carbohydrates accumulation coupled with increased endogenous hormones metabolism.After recovery,Spd pretreatment chilling-exposed seedlings showed higher activities of antioxidant enzymes and normal physiological function of chloroplasts.These results suggest that Spd could promote effectively chilling tolerance which might be largely attributable to the integrity of cell structure and normal metabolism of endogenous hormones in indica-japonica hybrid rice seedlings.

The protective effects of α-ketoacids against oxidative stress on rat spermatozoa in vitro

The aim of this study was to determine the effects of antioxidants,including α-ketoacids （α-ketoglutarate and pyruvate）,lactate and glutamate/malate combination,against oxidative stress on rat spermatozoa. Our results showed that H2O2 （250 μmol L^-1）-induced damages,such as impaired motility,adenosine triphosphate （ATP） depletion,inhibition of sperm protein phosphorylation,reduced acrosome reaction and decreased viability,could be significantly prevented by incubation of the spermatozoa with α-ketoglutarate （4 mmol L^-1） or pyruvate （4 mmol L^-1）. Without exogenous H2O2 in the medium,the addition of pyruvate （4 mmol L^-1） significantly increased the superoxide anion （O2^-·） level in sperm suspension （P≤0.01）,whereas the addition of α-ketoglutarate （4 mmol L^-1） and lactate （4 mmol L^-1） significantly enhanced tyrosine-phosphorylated proteins with the size of 95 kDa （P≤0.04）. At the same time,α-ketoglutarate,pyruvate,lactate,glutamate and malate supplemented in media can be used as important energy sources and supply ATP for sperm motility. In conclusion,the present results show that α-ketoacids could be effective antioxidants for protecting rat spermatozoa from H2O2 attack and could be effective components to improve the antioxidant capacity ofBiggers,Whitten and Whittingham media.

Hyperbaric oxygen preconditioning improves postoperative cognitive dysfunction by reducing oxidant stress and inflammation

Postoperative cognitive dysfunction is a crucial public health issue that has been increasingly studied in efforts to reduce symptoms or prevent its occurrence. However, effective advances remain lacking. Hyperbaric oxygen preconditioning has proved to protect vital organs, such as the heart, liver, and brain. Recently, it has been introduced and widely studied in the prevention of postoperative cognitive dysfunction, with promising results. However, the neuroprotective mechanisms underlying this phenomenon remain controversial. This review summarizes and highlights the definition and application of hyperbaric oxygen preconditioning, the perniciousness and pathogenetic mechanism underlying postoperative cognitive dysfunction, and the effects that hyperbaric oxygen preconditioning has on postoperative cognitive dysfunction. Finally, we conclude that hyperbaric oxygen preconditioning is an effective and feasible method to prevent, alleviate, and improve postoperative cognitive dysfunction, and that its mechanism of action is very complex, involving the stimulation of endogenous antioxidant and anti-inflammation defense systems.

Antioxidant efficiency of lycopene on oxidative stress-induced damage in bovine spermatozoa

Background： Lycopene（LYC） is a natural carotenoid with powerful reactive oxygen species（ROS） scavenging activities. The aim of this study was to investigate if lycopene has the ability to reverse ROS-mediated alterations to the motility, viability and intracellular antioxidant profile of bovine spermatozoa subjected to ferrous ascorbate（Fe AA）. Spermatozoa were washed out of fresh bovine semen, suspended in 2.9 % sodium citrate and subjected to LYC treatment（0.25, 0.5, 1 or 2 mmol/L） in the presence or absence of Fe AA（150 μmol/L Fe SO4 and 750 μmol/L ascorbic acid） during a 6 h in vitro culture. Spermatozoa motion characteristics were assessed using the Sperm Vision？computer-aided sperm analysis（CASA） system. Cell viability was examined with the metabolic activity（MTT） assay,ROS generation was quantified via luminometry and the nitroblue-tetrazolium（NBT） test was applied to quantify the intracellular superoxide formation. Cell lysates were prepared at the end of the in vitro culture to investigate the intracellular activity of superoxide dismutase（SOD）, catalase（CAT）, glutathione peroxidase（GPx） as well as the concentrations of glutathione（GSH） and malondialdehyde（MDA）.Results： FeA A treatment led to a reduced spermatozoa motility（P 〈 0.001）, viability（P 〈 0.001） and a decline of the antioxidant capacity of spermatozoa（P 〈 0.001） but increased the ROS generation（P 〈 0.001）, superoxide production（P 〈 0.001） and lipid peroxidation（P 〈 0.001）. LYC administration resulted in a preservation of the spermatozoa motion parameters（P 〈 0.001）, mitochondrial activity（P 〈 0.001） and antioxidant characteristics（P 〈 0.001 with respect to SOD;P 〈 0.01 in relation to CAT; P 〈 0.05 as for GPx and GSH） with a concentration range of 1 and 2 mmol/L LYC revealed to be the most effective.Conclusions： Our results suggest that LYC exhibits significant ROS-scavenging and antioxidant properties which may prevent spermatozoa alterations caused by oxidative stress, and preserve the functionality of male reproductive cells.

Association between heat stress and oxidative stress in poultry;mitochondrial dysfunction and dietary interventions with phytochemicals

Heat as a stressor of poultry has been studied extensively for many decades; it affects poultry production on a worldwide basis and has significant impact on well-being and production. More recently, the involvement of heat stress in inducing oxidative stress has received much interest. Oxidative stress is defined as the presence of reactive species in excess of the available antioxidant capacity of animal cells. Reactive species can modify several biologically cellular macromolecules and can interfere with cell signaling pathways. Furthermore, during the last decade, there has been an ever-increasing interest in the use of a wide array of natural feed-delivered phytochemicals that have potential antioxidant properties for poultry. In light of this, the current review aims to（1） summarize the mechanisms through which heat stress triggers excessive superoxide radical production in the mitochondrion and progresses into oxidative stress,（2） illustrate that this pathophysiology is dependent on the intensity and duration of heat stress,（3） present different nutritional strategies for mitigation of mitochondrial dysfunction, with particular focus on antioxidant phytochemicals.Oxidative stress that occurs with heat exposure can be manifest in all parts of the body; however, mitochondrial dysfunction underlies oxidative stress. In the initial phase of acute heat stress, mitochondrial substrate oxidation and electron transport chain activity are increased resulting in excessive superoxide production. During the later stage of acute heat stress, down-regulation of avian uncoupling protein worsens the oxidative stress situation causing mitochondrial dysfunction and tissue damage. Typically, antioxidant enzyme activities are upregulated. Chronic heat stress, however, leads to downsizing of mitochondrial metabolic oxidative capacity, up-regulation of avian uncoupling protein, a clear alteration in the pattern of antioxidant enzyme activities, and depletion of antioxidant reserves.Some phytochemicals, such as various types of flavonoids and related compounds, were shown to be beneficial in chronic heat-stressed poultry, but were less or not effective in non-heat-stressed counterparts. This supports the contention that antioxidant phytochemicals have potential under challenging conditions. Though substantial progress has been made in our understanding of the association between heat stress and oxidative stress, the means by which phytochemicals can alleviate oxidative stress have been sparsely explored.

Protective effect of pomegranate juice on retinal oxidative stress in streptozotocin-induced diabetic rats

AIM： To investigate the effect of pomegranate juice（PJ） intake on overall oxidation status in retinas of diabetic rats.METHODS： Twenty-seven rats were divided into four groups as control（CO）, diabetic（DM）, control treated with PJ（CO-PJ）, and diabetic treated with PJ（DM-PJ）.The retina tissues were used to determine 8-hydroxy-2＇-deoxyguanosine（8 OHd G）, malondialdehyde（MDA）, reduced glutathione（GSH） levels, and the enzyme activities of superoxide dismutase（SOD） and glutathione peroxidase（GSH-Px）. RESULTS： The levels of 8 OHdG and MDA were significantly increased in the retina of DM group compared to CO group（P=0.001, P〈0.001 respectively）. Both 8 OHd G and MDA levels were decreased in PJ-DM group compared to DM group（P=0.004, P〈0.001 respectively）. The activities of antioxidant enzymes GSH, SOD, and GDH-Px were significantly decreased in the retina of DM group compared to CO group（P≤0.01）. GSH and GSH-Px activities were higher in PJ-DM group compared with DM group（P=0.010, P=0.042, respectively） but SOD activity was not statistically different（P=0.938）. CONCLUSION： PJ intake is found to be effective in decreasing oxidative end products, and in increasing the activities of antioxidant enzymes in diabetic retinas of rats, which suggests it may be effective against oxidative stress in diabetic retinas.

The effect of sunblock against oxidative stress in farmers：a pilot study

Farmers are frequently exposed to ultraviolet（UV） radiation which causes various diseases by inducing oxidative stress.This study aimed to assess the effects of sunblock on oxidative stress in the body.Eighty-seven farmers were divided into two groups：those who wore sunblock for five days and those who did not.The total antioxidant capacity（TAC） in urine,which is an antioxidant indicator,and 8-hydroxy-2-deoxyguanosine（8-OHdG） levels in urine,an oxidative stress indicator,were measured.The urinary TAC of sunblock users was significantly higher than that of non-users,but urinary 8-OHdG levels were not significantly different.Even after adjustment for potential confounders,urinary TAC was found to be markedly increased with sunblock usage.These results suggest that sunblock is effective in preventing oxidative stress among farmers.In addition,they show that urinary TAC can be used as a good effect marker of oxidative stress caused by UV exposure.

Effects of selenium and sulfur on antioxidants and physiological parameters of garlic plants during senescence

A hydroponic study was conducted to determine the effects of selenium（Se： 0, 3, 6 μmol L^-1） on senescence-related oxidative stress in garlic plants grown under two sulfur（S） levels. We evaluated the yields of plants harvested at 160 and 200 days after sowing. Plants grown under a low Se dose（0.3 μmol L^-1） at low S level showed higher yields（12.0% increase in fresh weight yield, 13.7% increase in dry weight yield） than the controls, despite a decrease in chlorophyll concentration. Compared with control plants, the Se-treated plants showed lower levels of lipid peroxidation. The Se-treated plants also showed higher activities of glut athione peroxidase and catalase, but lower superoxide dismutase activities. Changes in Fv/Fm values and proline contents were affected more strongly by S than by Se. On the basis of our results, we can conclude that Se plays a key role in the antioxidant systems in garlic seedlings. It delays senescence by alleviating the peroxide stress, but it can be toxic at high levels. A high S level may increase tolerance to high Se concentrations through reducing Se accumulation in plants.

Effects of melatonin on the oxidative damage and pancreatic antioxidant defenses in ceruleininduced acute pancreatitis in rats

BACKGROUND： Oxidative stress is recognized as a pivotal effector of several pathogenic processes, including acute pancreatitis. Reactive oxygen species not just cause damage on the main cellular components, but also influence the expression of antioxidant system genes. Antioxidant molecules, such as melatonin, could be good candidates for the treatment of this multidimensional disease. The present study was to evaluate the chemopreventive effect of melatonin in a rat model of ceruleininduced acute pancreatitis.METHODS： Four subcutaneous injections of cerulein（20 μg/kg body weight） were given to Wistar rats at two hours intervals;melatonin was injected intraperitoneally（25 mg/kg body weight）30 minutes before each injection of cerulein. Lipid peroxidation,protein oxidation（carbonyl groups）, total antioxidant status,and glutathione peroxidase activity were determined in pancreatic tissue using commercial kits.RESULTS： The chemopreventive administration of melatonin caused a reduction in lipid peroxidation and protein oxidation due to injections of cerulein. Additionally, melatonin treatment was also able to revert glutathione peroxidase activity and total antioxidant status near to control levels, suggesting that melatonin could prevent from oxidative phenomena in the pancreas, such as lipid peroxidation and protein oxidation,and could stimulate, directly or indirectly, the expression of antioxidant enzymes.CONCLUSION： Melatonin, a polyvalent antioxidant, protected the pancreatic damage via the decrease of oxidative stress andincrease of the activities of antioxidant enzymes in ceruleininduced acute pancreatitis.

Heijiangdan Ointment(黑绛丹膏)Relieves Oxidative Stress from Radiation Dermatitis Induced by ^(60)Co γ-Ray in Mice

Objective：To investigate the effects of Heijiangdan Ointment（黑绛丹膏,HJD） on oxidative stress in （60）Co γ-ray radiation-induced dermatitis in mice.Methods：Female Wistar mice with grade 4 radiation dermatitis induced by ^（60）Co γ-rays were randomly divided into four groups（n=12 per group）;the HJD-treated,recombinant human epidermal growth factor（rhEGF）-treated,Trolox-treated,and untreated groups,along with a negative control group.On the 11 th and 21 st days after treatment,6 mice in each group were chosen for evaluation.The levels of superoxide dismutase（SOD）,malondialdehyde（MDA）,and lactate dehydrogenase（LDH） were detected using spectrophotometric methods.The fibroblast mitochondria were observed by transmission electron microscopy（TEM）.The expressions of fibroblast growth factor 2（FGF-2） and transforming growth factor β1（TGF-β1） were analyzed by western blot.Results：Compared with the untreated group,the levels of SOD,MDA and LDH,on the 11 th and 21 st days after treatment showed significant difference（P〈0.05）.TEM analysis indicated that fibroblast mitochondria in the untreated group exhibited swelling and the cristae appeared fractured,while in the HJD group,the swelling of mitochondria was limited and the rough endoplasmic reticulum appeared more relaxed.The expressions of FGF-2 and TGF-β1 increased in the untreated group compared with the negative control group（P〈0.05）.After treatment,the expression of FGF-2,rhEGF and Trolox in the HJD group were significantly increased compared with the untreated group（P〈0.05）,or compared with the negative control group（P〈0.05）.The expression of TGF-β1 showed significant difference between untreated and negative control groups（P〈0.05）.HJD and Trolox increased the level of TGF-β1 and the difference was marked as compared with the untreated and negative control groups（P〈0.05）.Conclusion：HJD relieves oxidative stress-induced injury,increases the antioxidant activity,mitigates the fibroblast mitochondrial damage,up-regulates the expression of growth factor,and promotes mitochondrial repair in mice.

Oxygen metabolism-balanced engineered hydrogel microspheres promote the regeneration of the nucleus pulposus by inhibiting acid-sensitive complexes

Intervertebral disc degeneration(IVDD)is commonly caused by imbalanced oxygen metabolism-triggered inflammation.Overcoming the shortcomings of antioxidants in IVDD treatment,including instability and the lack of targeting,remains challenging.Microfluidic and surface modification technologies were combined to graft chitosan nanoparticles encapsulated with strong reductive black phosphorus quantum dots(BPQDs)onto GelMA microspheres via amide bonds to construct oxygen metabolism-balanced engineered hydrogel microspheres(GM@CS-BP),which attenuate extracellular acidosis in nucleus pulposus(NP),block the inflammatory cascade,reduce matrix metalloproteinase expression(MMP),and remodel the extracellular matrix(ECM)in intervertebral discs(IVDs).The GM@CS-BP microspheres reduce H_(2)O_(2) intensity by 229%.Chemical grafting and electrostatic attraction increase the encapsulation rate of BPQDs by 167%and maintain stable release for 21 days,demonstrating the antioxidant properties and sustained modulation of the BPQDs.After the GM@CS-BP treatment,western blotting revealed decreased acid-sensitive ion channel-3 and inflammatory factors.Histological staining in an 8-week IVDD model confirmed the regeneration of NP.GM@CS-BP microspheres therefore maintain a balance between ECM synthesis and degradation by regulating the positive feedback between imbalanced oxygen metabolism in IVDs and inflammation.This study provides an in-depth interpretation of the mechanisms underlying the antioxidation of BPQDs and a new approach for IVDD treatment.

Engineering hiPSC-CM and hiPSC-EC laden 3D nanofibrous splenic hydrogel for improving cardiac function through revascularization and remuscularization in infarcted heart

Cell therapy has been a promising strategy for cardiac repair after myocardial infarction(MI),but a poor ischemic environment and low cell delivery efficiency remain significant challenges.The spleen serves as a hematopoietic stem cell niche and secretes cardioprotective factors after MI,but it is unclear whether it could be used for human pluripotent stem cell(hiPSC)cultivation and provide a proper microenvironment for cell grafts against the ischemic environment.Herein,we developed a splenic extracellular matrix derived thermoresponsive hydrogel(SpGel).Proteomics analysis indicated that SpGel is enriched with proteins known to modulate the Wnt signaling pathway,cell-substrate adhesion,cardiac muscle contraction and oxidation-reduction processes.In vitro studies demonstrated that hiPSCs could be efficiently induced into endothelial cells(iECs)and cardiomyocytes(iCMs)with enhanced function on SpGel.The cytoprotective effect of SpGel on iECs/iCMs against oxidative stress damage was also proven.Furthermore,in vivo studies revealed that iEC/iCM-laden SpGel improved cardiac function and inhibited cardiac fibrosis of infarcted hearts by improving cell survival,revascularization and remuscularization.In conclusion,we successfully established a novel platform for the efficient generation and delivery of autologous cell grafts,which could be a promising clinical therapeutic strategy for cardiac repair and regeneration after MI.

Effects of Chinese medicine Tongxinluo on hyperglycemia and beta-cell damage in streptozotocin-induced diabetic rats

Background Oxidative stress has been implicated in the onset and progression of diabetes. Tongxinluo is a traditional Chinese medicine with potent antioxidant properties. The aim of this study was to test the hypothesis that pretreatment with Tongxinluo has similar effects as melatonin on preventing hyperglycemia and beta-cell damage in a rat model of streptozotocin （STZ）-induced diabetes. Methods Forty male Sprague Dawley rats were randomly assigned to four groups （n=10 each）： normal control （NC） group; STZ group （70 mg/kg, i.p.）; Tongxinluo （1.0 g-kg-^-d-1） pretreated （TXL＋STZ） group and melatonin （200 iJg-kg-~.d-1） pretreated （MLT＋STZ） group. Tongxinluo and melatonin were administered by gavage beginning 8 days before STZ injection and continuing until the end of the study （15 days after STZ administration）. Blood glucose levels and body weights, malondialdehyde （MDA）, and reduced glutathione （GSH） levels were measured, and immunofluorescence studies were performed in all of the groups. Results Pretreatment with Tongxinluo, as with melatonin, attenuated severe hyperglycemia and weight loss induced by STZ.. In pancreatic homogenates, MDA levels were significantly lower and GSH levels were significantly higher in Tongxinluo pretreated group and in melatonin pretreated group than those in STZ group. Values of insulin staining were significantly improved in Tongxinluo pretreated group and in melatonin pretreated group as compared with those in STZ group. Conclusions Tongxinluo, as melatonin, prevented hyperglycemia and beta-cell destruction induced by STZ in rats through reducing oxidative stress in pancreatic tissues. Tongxinluo may provide an alternative therapy for the prevention and treatment of diabetes.

Antioxidant activity of dichloromethane fraction of Dichrocephala integrifolia in Salmonella typhi-infected rats

Objective: Infectious diseases such as typhoid fever lead to the formation of free radicals which can damage the body. Many medicinal plants have antioxidant molecules that neutralize free radicals. The present work evaluated the antioxidant activity and histopathological effects of the dichloromethane fraction of Dichrocephala integrifolia in Salmonella typhi-infected rats.Methods: The S. typhi-infected rats concurrently received daily doses of D. integrifolia extract at doses of 25, 50 and 100 mg/kg body weight or ciprofloxacin(5 mg/kg body weight) for 15 days. Body temperature was measured daily during infection and treatment periods. At the end of treatment period, the animals were sacrificed and biological responses including hematological parameters, superoxide dismutase and catalase activities, and glutathione, malondialdehyde and nitric oxide concentrations were evaluated.Results: The elevated body temperature induced by infection was significantly decreased in animals treated with 25, 50 or 100 mg/kg of the extract. Platelet levels decreased slightly in infected rats, while treatment with the dichloromethane fraction of D. integrifolia significantly increased platelet levels;this response was greater than that elicited by ciprofloxacin. The doses of 50 and 100 mg/kg of the dichloromethane fraction of D. integrifolia notably decreased monocyte and neutrophil values. Activity of superoxide dismutase and catalase and levels of glutathione in the tissues of treated animals were increased significantly(P < 0.01), while malondialdehyde and nitric oxide levels were significantly decreased(P < 0.01), following treatment with the dichloromethane fraction of D. integrifolia.Conclusion: The results of this study show that the dichloromethane fraction of D. integrifolia has protective effects against a series of pathological conditions initiated by oxidation and tissue damage in the course of a S. typhi infection.

Induction of Antioxidant and Heat Shock Protein Responses During Torpor in the Gray Mouse Lemur, Microcebus murinus

A natural tolerance of various environmental stresses is typically supported by various cytoprotective mechanisms that protect macromolecules and promote extended viability. Among these are antioxidant defenses that help to limit damage from reactive oxygen species and chaperones that help to minimize protein misfolding or unfolding under stress conditions. To understand the molecular mechanisms that act to protect cells during primate torpor, the present study characterizes antioxidant and heat shock protein（HSP） responses in various organs of control（aroused）and torpid gray mouse lemurs, Microcebus murinus. Protein expression of HSP70 and HSP90 a was elevated to 1.26 and 1.49 fold, respectively, in brown adipose tissue during torpor as compared with control animals, whereas HSP60 in liver of torpid animals was 1.15 fold of that in control（P 〈 0.05）. Among antioxidant enzymes, protein levels of thioredoxin 1 were elevated to 2.19 fold in white adipose tissue during torpor, whereas Cu–Zn superoxide dismutase 1 levels rose to 1.1 fold in skeletal muscle（P 〈 0.05）. Additionally, total antioxidant capacity was increased to 1.6 fold in liver during torpor（P 〈 0.05）, while remaining unchanged in the five other tissues. Overall, our data suggest that antioxidant and HSP responses are modified in a tissue-specific manner during daily torpor in gray mouse lemurs. Furthermore, our data also show that cytoprotective strategies employed during primate torpor are distinct from the strategies in rodent hibernation as reported in previous studies.

Divergent asymmetric synthesis of azaarene-functionalized cyclic alcohols through stereocontrolled Beckwith-Enholm cyclizations

The first enantioselective Beckwith-Enholm cyclization reaction is reported herein.Under cooperative photoredox and chiral hydrogen-bonding catalysis mediated by visible light,cyclization of carbonyls with azaarene-based olefins as a new reaction system offers a general and divergent synthetic pathway to furnish a variety of highly valuable enantioenriched azaarenefunctionalized carbocyclic and heterocyclic alcohols,which bear adjacent 1,2-or nonadjacent 1,3-stereocentres on distinct cyclic frameworks,in high yields and enantio-and diastereoselectivities.The good compatibility of various azaarenes and carbonyls as well as the diversity of cyclic structures of the products underscores the generality of the catalysis platform.In addition to the ability to precisely introduce deuterium into molecules in an enantioselective manner,the considerable synthetic value of this method includes the excellent antioxidant stress potential of the products.In particular,molecule 29 was determined to be a promising lead compound for antioxidant stress drug design.

Evaluation of In Vitro Enzymatic and Non-Enzymatic Antioxidant Properites of Leaf Extract from Alpinia Purpurata(Vieill.) K. Schum.

Objective： To evaluate the enzymatic and non-enzymatic antioxidants of leaf extract from Alpinia purpurata. Methods： One gram of fresh leaf of Alpinia purpurata was grinded in 2 mL of 50% ethanol and centrifuged at 10,000×g at 4 ℃ for 10 min. The supernatant obtained was used within 4 h for various enzymatic antioxidants assays like superoxide dismutase（SOD）, catalase（CAT）, glutathione peroxidase（GPx）, glutathione S-transferase（GST）, ascorbate oxidase, peroxidase, polyphenol oxidase（PPO） and non-enzymatic antioxidants such as vitamin C, total reduced glutathione（TRG） and lipid peroxidation（LPO）. Results： The leaf extract of Alpinia purpurata possess antioxidants like vitamin C 472.92±6.80 μg/mg protein, GST 372.11±5.70 μmol of 1-chloro 2,4 dinitrobenzene（CDNB）-reduced glutathione（GSH） conjugate formed/min/mg protein, GPx 281.69±6.43 μg of glutathione oxidized/min/mg protein, peroxidases 173.12±9.40 μmol/g tissue, TRG 75.27±3.55 μg/mg protein, SOD 58.03±2.11 U/mg protein, CAT 46.70±2.35 μmol of H_2O_2 consumed/min/mg protein in high amount whereas ascorbate oxidase 17.41±2.46 U/g tissue, LPO 2.71±0.14 nmol/L of malondialdehyde formed/min/mg protein and PPO 1.14±0.11 μmol/g tissue in moderate amount. Conclusion： Alpinia purpurata has the potential to scavenge the free radicals and protect against oxidative stress causing diseases. In future, Alpinia purpurata may serve as a good pharmacotherapeutic agent.