This study investigated the effect of antioxidants on the grinding efficiency,magnetic powder characteristics,microstructure,and magnetic properties of 2:17 type SmCo permanent magnet materials.The results show that a...This study investigated the effect of antioxidants on the grinding efficiency,magnetic powder characteristics,microstructure,and magnetic properties of 2:17 type SmCo permanent magnet materials.The results show that adding antioxidants helps improve the dispersion among magnetic powders,leading to a 33.3%decrease in jet milling time and a 15.8%increase in magnet powder production yield.Additionally,adding antioxidants enhances the oxidation resistance of the magnetic powders.After being stored in a constant temperature air environment at 25C for 48 h,the O content in the powder decreased by 33%compared to samples without antioxidants.While in the magnet body,the O content decreased from 0.21 wt.%to 0.14 wt.%,which helps increase the effective Sm content and domain wall pinning uniformity in the magnet.Excellent magnetic properties were obtained in the magnet with added antioxidants:B_(r)=11.6 kGs,SF=79.6%,H_(cj)=16.8 kOe,and(BH)_(max)=32.5 MGOe.展开更多
Plant extracts from natural sources are an excellent choice for food additives and natural antioxidants.In this study,the active components of Tulipa edulis were extracted and analysed,and their antioxidant capacity w...Plant extracts from natural sources are an excellent choice for food additives and natural antioxidants.In this study,the active components of Tulipa edulis were extracted and analysed,and their antioxidant capacity was measured.Then,the crude extract mixture was separated and purified using a Sephadex LH-20 gel,and the antioxidant activity of the purified products was determined.Human umbilical vein endothelial human umbilical vein endothelial cells(HUVEC)cells were treated with 35 mmol/L glucose to construct a model of oxidative stress.Then,the cells were treated with the active component to observe whether the products of T.edulis could have a good protective effect on HUVEC cells induced by glucose.Transcriptome analysis was also performed on HUVEC cells after same treatment to explore the possible mechanism of the component F2 protecting HUVEC cells from oxidative stress induced by high glucose.The results showed that component F2 obtained from T.edulis has strong antioxidant activity.Moreover,F2 can play a strong antioxidant protective role in HUVEC cells.Meanwhile,the gene expression of heme oxygenase 1(HO-1),γ-glutamyl cysteine ligase catalytic subunit(GCLC)and NAD(P)H quinone oxidoreductase-1(NQO1)in HUVEC cells was up-regulated after treated with F2.This study provides reference value for the further development and application of T.edulis and the d evelopment of functional food.展开更多
BACKGROUND Premature ovarian insufficiency(POI)is a condition that causes secondary amenorrhea owing to ovarian hypofunction at an early stage.Early follicular depletion results in intractable infertility,thereby cons...BACKGROUND Premature ovarian insufficiency(POI)is a condition that causes secondary amenorrhea owing to ovarian hypofunction at an early stage.Early follicular depletion results in intractable infertility,thereby considerably reducing the quality of life of females.Given the continuum in weakened ovarian function,progressing from incipient ovarian failure(IOF)to transitional ovarian failure and further to POI,it is necessary to develop biomarkers for predicting POI.The oxidative stress states in IOF and POI were comprehensively evaluated via oxidative stress[diacron-reactive oxygen metabolites(d-ROMs)]test and anti-oxidant capacity[biological antioxidant potential(BAP)].METHODS Females presenting with secondary amenorrhea over 4 mo and a follicle stimulating hormone level of>40 mIU/mL were categorized into the POI group.Females presenting with a normal menstrual cycle and a follicle stimulating hormone level of>10.2 mIU/mL were categorized into the IOF group.Healthy females without ovarian hypofunction were categorized into the control group.Among females aged<40 years who visited our hospital from January 2021 to June 2022,we recruited 11 patients into both POI and IOF groups.For the potential antioxidant capacity,the relative oxidative stress index(BAP/d-ROMs×100)was calculated,and the oxidative stress defense system was comprehensively evaluated.RESULTS d-ROMs were significantly higher in the POI and IOF groups than in the control group,(478.2±58.7 U.CARR,434.5±60.6 U.CARR,and 341.1±35.1 U.CARR,respectively)(U.CARR is equivalent to 0.08 mg/dL of hydrogen peroxide).However,no significant difference was found between the POI and IOF groups.Regarding BAP,no significant difference was found between the control,IOF,and POI groups(2078.5±157.4μmol/L,2116.2±240.2μmol/L,and 2029.0±186.4μmol/L,respectively).The oxidative stress index was significantly higher in the POI and IOF groups than in the control group(23.7±3.3,20.7±3.6,and 16.5±2.1,respectively).However,no significant difference was found between the POI and IOF groups.CONCLUSION High levels of oxidative stress suggest that evaluating the oxidative stress state may be a useful indicator for the early detection of POI.展开更多
Objective:To determine how biochanin-A(BCA)affects high-fat diet and streptozotocin-induced pathological changes in lipid metabolism and antioxidant status in diabetic rats.Methods:Diabetic rats were orally administer...Objective:To determine how biochanin-A(BCA)affects high-fat diet and streptozotocin-induced pathological changes in lipid metabolism and antioxidant status in diabetic rats.Methods:Diabetic rats were orally administered BCA(10 mg/kg body weight)for 30 days to investigate its effects on lipid profiles and oxidative stress markers in the liver and kidney.In addition,the mRNA expression of antioxidant and lipid metabolism enzymes in the liver was examined.Results:BCA attenuated hyperlipidemia by regulating mRNA expressions of HMG-CoA reductase,fatty acid synthase,carnitine palmitoyl transferase,and acetyl-CoA carboxylase.Additionally,BCA reduced high-fat diet and streptozotocin-induced oxidative stress by suppressing lipid peroxidation,improving superoxide dismutase,catalase,and glutathione peroxidase levels,and upregulating mRNA expressions of these enzymes.Conclusions:BCA may be a promising nutraceutical for the treatment of dyslipidemia and oxidative stress associated with diabetes.展开更多
It is known that the pathogenicity of Plasmodium induces the breakdown of haemoglobin, which leads to the induction of oxidative stress. This study aimed to identify the possible effects of oxidative stress and antiox...It is known that the pathogenicity of Plasmodium induces the breakdown of haemoglobin, which leads to the induction of oxidative stress. This study aimed to identify the possible effects of oxidative stress and antioxidant defence systems in symptomatic and asymptomatic Plasmodium falciparum malaria infection in children (1 - 15 years old) in the Mount Cameroon vicinity. This cross-sectional study involved blood samples collected from 473 children and examined for malaria parasitaemia. Full blood counts were performed using an automated haemoanalyser. Serum oxidative stress status (malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and vitamin C (Vit C)) were each determined by colorimetric enzymatic assays. The prevalence of malaria parasite infection was 32.1% among the participants. Out of that, 62.5% of patients with parasitaemia were symptomatic. Anaemia prevalence increased significantly with parasite density. MDA levels were significantly higher in patients with malaria symptoms than in those without symptoms. A significant and positive correlation was detected between MDA (r = 0.831, P < 0.05), NO (r = 0.779, P < 0.05), and malaria parasite density while, a significant and negative relationship occurred between parasite density and GSH (r = ?0.763, P < 0.05) and Vit C (r = ?0.826, P < 0.05) levels, SOD (r = ?0.621, P < 0.05) and CAT (r = ?0.817, P < 0.05) activities. The SOD activity and GSH level significantly decreased (P < 0.05) with an increase in the MDA levels. These findings showed that MDA and nitric oxide levels increased both in malaria participants with or without symptoms. A similar decrease in the antioxidant defence system was observed in both symptomatic and asymptomatic patients. Therefore, there is a need to develop public health policies that encourage routine diagnosis and treatment of malaria in seemingly healthy people (asymptomatic cases), and this will play an essential role in controlling malaria in tropical countries.展开更多
BACKGROUND Type 2 diabetes mellitus(T2DM)is a metabolic disease of impaired glucose utilization.Imbalance in generation and elimination of free radicals generate oxidative stress which modulates glucose metabolism and...BACKGROUND Type 2 diabetes mellitus(T2DM)is a metabolic disease of impaired glucose utilization.Imbalance in generation and elimination of free radicals generate oxidative stress which modulates glucose metabolism and insulin regulation,resulting in the occurrence and progression of diabetes and associated complications.Antioxidant supplements in T2DM can be seen as a potential preventive and effective therapeutic strategy.AIM To compare randomized controlled trials(RCTs)in which antioxidants have been shown to have a therapeutic effect in T2DM patients.METHODS We systematically searched the electronic database PubMed by keywords.RCTs evaluating the effect of antioxidant therapy on glycaemic control as well as oxidant and antioxidant status as primary outcomes were included.The outcomes considered were:A reduction in blood glucose;changes in oxidative stress and antioxidant markers.Full-length papers of the shortlisted articles were assessed for the eligibility criteria and 17 RCTs were included.RESULTS The administration of fixed-dose antioxidants significantly reduces fasting blood sugar and glycated hemoglobin and is associated with decreased malondialdehyde,advanced oxidation protein products,and increased total antioxidant capacity.CONCLUSION Antioxidant supplements can be a beneficial approach for the treatment of T2DM.展开更多
Flavonoids have attracted considerable attention due to their health benefits. This study aimed to investigate the flavonoid profiles and antioxidant activity of Paeonia lactiflora petal flavonoid extract(PPF). The UH...Flavonoids have attracted considerable attention due to their health benefits. This study aimed to investigate the flavonoid profiles and antioxidant activity of Paeonia lactiflora petal flavonoid extract(PPF). The UHPLC-ESI-Q-Exactive HF MS/MS method was established for characterization, and 21 predominant flavonoid compounds were tentatively identified in PPF. Among them, isoscutellarein-7-(6’-acetylallosyl-(1->2)-glucoside) and scutellarin methylester were discovered in PPF for the first time. Pretreatment with PPF significantly reduced H2O2-induced cell damage, ROS accumulation, and malondialdehyde content and increased the activity of SOD, CAT, and GSH-Px in buffalo rat liver 3A(BRL3A) cells. Moreover, the expression of nuclear Factor E2-related factor(Nrf2) was upregulated by PPF, whose expression trend was consistent with that of heme oxygenase-1(HO-1), glutamate-cysteine ligase catalytic subunit(GCLC), and NAD(P)H quinone oxidoreductase-1(NQO1). These findings suggested that herbaceous peony flavonoids can be used as a natural bioactive agent to prevent oxidative stress.展开更多
Arsenic(As)contaminated food chains have emerged as a serious public concern for humans and animals and are known to affect the cultivation of edible crops throughout the world.Therefore,the present study was designed...Arsenic(As)contaminated food chains have emerged as a serious public concern for humans and animals and are known to affect the cultivation of edible crops throughout the world.Therefore,the present study was designed to investigate the individual as well as the combined effects of exogenous silicon(Si)and sodium nitroprusside(SNP),a nitric oxide(NO)donor,on plant growth,metabolites,and antioxidant defense systems of radish(Raphanus sativus L.)plants under three different concentrations of As stress,i.e.,0.3,0.5,and 0.7 mM in a pot experiment.The results showed that As stress reduced the growth parameters of radish plants by increasing the level of oxidative stress markers,i.e.,malondialdehyde and hydrogen peroxide.However,foliar application of Si(2 mM)and pretreatment with SNP(100μM)alone as well as in combination with Si improved the plant growth parameters,i.e.,root length,fresh and dry weight of plants under As stress.Furthermore,As stress also reduced protein,and metabolites contents(flavonoids,phenolic and anthocyanin).Activities of antioxidative enzymes such as catalase(CAT),ascorbate peroxidase(APX),guaiacol peroxidase(POD),and polyphenol oxidase(PPO),as well as the content of non-enzymatic antioxidants(glutathione and ascorbic acid)decreased under As stress.In most of the parameters in radish,As III concentration showed maximum reduction,as compared to As I and II concentrations.However,the individual and combined application of Si and NO significantly alleviated the As-mediated oxidative stress in radish plants by increasing the protein,and metabolites content.Enhancement in the activities of CAT,APX,POD and PPO enzymes were recorded.Contents of glutathione and ascorbic acid were also enhanced in response to co-application of Si and NO under As stress.Results obtained were more pronounced when Si and NO were applied in combination under As stress,as compared to their individual application.In short,the current study highlights that Si and NO synergistically regulate plant growth through lowering the As-mediated oxidative stress by upregulating the metabolites content,activity of antioxidative enzymes and non-enzymatic antioxidants in radish plants.展开更多
Aim： To examine the effects of melatonin treatment on lipid peroxidation （LPO） and the activities of antioxidant enzymes in the testicular tissue of streptozotocin （STZ）-induced diabetic rats. Methods： Twenty-si...Aim： To examine the effects of melatonin treatment on lipid peroxidation （LPO） and the activities of antioxidant enzymes in the testicular tissue of streptozotocin （STZ）-induced diabetic rats. Methods： Twenty-six male rats were randomly divided into three groups as follows： group Ⅰ, control, non-diabetic rats （n = 9）; group Ⅱ, STZ-induced, untreated diabetic rats （n = 8）; group Ⅲ, STZ-induced, melatonin-treated （dose of 10 mg/kg·day） diabetic rats （n = 9）. Following 8-week melatonin treatment, all rats were anaesthetized and then were killed to remove testes from the scrotum. Results： As compared to group Ⅰ, in rat testicular tissues of grouap Ⅱ, increased levels of malondialdehyde （MDA） （P 〈 0.01） and superoxide dismutase （SOD） （P 〈 0.01） as well as, decreased levels of catalase （CAT） （P 〈 0.01） and glutathione peroxidase （GSH-Px） （P 〉 0.05） were found. In contrast, as compared to group Ⅱ, in rat testicular tissues of group Ⅲ, levels of MDA decreased （but this decrease was not significant, P 〉 0.05） and SOD （P 〈 0.01） as well as CAT （P 〈 0.05） increased. GSH-Px was not influenced by any of the treatment. Melatonin did not significantly affect the elevated glucose concentration of diabetic group. At the end of the study, there was no significant difference between the melatonin-treated group and the untreated group by means of body and testicular weight. Conclusion： Diabetes mellitus increases oxidative stress and melatonin inhibits lipid peroxidation and might regulate the activities of antioxidant enzymes of diabetic rat testes.展开更多
Objective:To assess various antioxidative activities of Satureja khozestanica essential oil(SKE)and its effect on oxidation of low density lipoprotein(LDL)induced by CuSO_4 in vitro by monitoring the formation of conj...Objective:To assess various antioxidative activities of Satureja khozestanica essential oil(SKE)and its effect on oxidation of low density lipoprotein(LDL)induced by CuSO_4 in vitro by monitoring the formation of conjugated dienes and malondialdehyde(MDA).Methods:The formation of conjugated dienes,lag time and MDA were measured.Inhibition of this Cu-induced oxidation was studied in the presence of several concentrations of SKE.Also total antioxidant activity and free radical scavenging of SKE were determinated.Results:It was demonstrated that SKE was able to inhibit LDL oxidation and decrease the resistance of LDL against oxidation.The inhibitory effects of SKE on LDL oxidation were dose-dependent at concentrations ranging from 50 to 200μg/mL.Total antioxidant capacity of SKE was(3.20±0.40)nmol of ascorbic acid equivalents/g SKE.The SKE showed remarkable scavenging activity on 2,2-diphenyl-picrylhydrazyl,IC_(50)(5.30±0.11)ng/mL.Conclusions:This study shows that SKE is a source of potent antioxidants and prevents the oxidation of LDL in vitro and it may be suitable for use in food and pharmaceutical applications.展开更多
The advantages and disadvantages of organic antioxidant and inorganic salt on suppressing coal oxidation were analyzed on the basis of the theory that coal oxidation mechanisms can be attributed to the free radical ch...The advantages and disadvantages of organic antioxidant and inorganic salt on suppressing coal oxidation were analyzed on the basis of the theory that coal oxidation mechanisms can be attributed to the free radical chain-type reaction mechanism. The inhibition curves on suppressing coal oxidation of the different type and different concentration of organic antioxidant and inorganic salt were given through experimental study and data processing. Then some conclusions can be gained from the experimental study combining with theoretical analysis. First the inhibition mechanism of the organic antioxidant and inorganic salt is different. The former is that the chemical action is the dominant position. It can be called as the chain termination theory because the free radical is captured during coal oxidation. And the later is that the physical effect is the dominant position. It can be called as the decreasing-temperature theory because the liquid membrane which was formed by the inorganic salt can make coal body be the state of wetness and prevent oxygen from coal surface. Second the inhibition effect of the organic antioxidant is higher than the inorganic salt in the later period. But it is lower in the early period.展开更多
The present study aimed to investigate the effectiveness of the use of some antioxidants-<i>α</i>-tocopherol, n-octyl gallate, L-ascorbic acid 6-palmitate and matcha extract (green tea) as inhibitors of g...The present study aimed to investigate the effectiveness of the use of some antioxidants-<i>α</i>-tocopherol, n-octyl gallate, L-ascorbic acid 6-palmitate and matcha extract (green tea) as inhibitors of grape seeds, walnuts and corn germ oils oxidation. The oxidation was studied in a forced regime during 700 h, by the addition of hydrogen peroxide and Cu<sup>2+</sup> ions. The optimal conditions of the accelerated oxidation process in the analysed systems were established. The progress of lipid oxidation was evaluated by measuring the peroxide value (PV) and conjugated dienes and trienes (CD, CT). A series of secondary products of the lipid oxidation were identified: hexanal, octanal and hydroxy-nonadienal. The intensity of the formation of these compounds during oxidation was monitored. The results of this study showed that the oil samples with the addition of antioxidants showed considerably lower oxidation values compared to the control sample. More effective was the action of L-ascorbic acid 6-palmitate and n-octyl gallate, the optimum concentration <span>was 0.1%. An inhibitory effect of the oxidation process was noted for <i>α</i>-</span>tocopherol and matcha extract, the optimal addition concentration was 1%.展开更多
Background: Intravenous application of iron preparations which is a routine treatment of anemia in hemodialysis patients with end-stage renal disease can lead to iron overload in the body. Redox-active iron can cataly...Background: Intravenous application of iron preparations which is a routine treatment of anemia in hemodialysis patients with end-stage renal disease can lead to iron overload in the body. Redox-active iron can catalyze the formation of hydroxyl radicals and initiation of lipid peroxidation, increase oxidative stress and speed up the development of complications in these patients. Objective: In this study, we determined the markers of lipid peroxidation, protein oxidation and antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, glutathione S-transferase) in serum of patients with end-stage renal disease on hemodialysis, who had received repeated treatment of iron supplementation. Patients and Methods: The study included 29 patients undergoing regular hemodialysis treatment. These patients were divided into three groups according to the serum ferritin levels: group I (serum ferritin between 100 and 300 mg/L);group II (serum ferritin between 301 and 600 mg/L), and group III (serum ferritin above 601 mg/L). Results: The serum of patients with the highest concentration of serum ferritin and iron contained significantly higher level of lipid peroxidation products, total hydroperoxides and malondialdehyde and advanced oxidation protein products and the lowest concentration of sulfhydryl groups, reduced glutathione and total antioxidant capacity. Conclusion: Based on the obtained results, it can be concluded that iron supplementation in hemodialysis patients and consequently body iron overload of exacerbated oxidative stress have already been present in these patients.展开更多
In the current research study, an attempt is made to modification of polyvinyl chloride (PVC) by grafting with biologically based phenolic resin, namely, tannins. The reaction was carried out at 110°C in DMF ...In the current research study, an attempt is made to modification of polyvinyl chloride (PVC) by grafting with biologically based phenolic resin, namely, tannins. The reaction was carried out at 110°C in DMF solution. FTIR spectra show the presence of phenolic hydroxylic groups and other functional groups of tannins into the PVC-tannins derivative. Evaluation of the new PVC derivative as polymeric antioxidant for high density polyethylene (HDPE) was the main purpose of this study. Samples of HDPE containing (0.0, 0.5 and 2.0) %W/W from PVC-tannins and pure HDPE were exposed to thermal program by differential scanning calorimetry (DSC) by temperature sweep from 100°C to 350°C. DSC scans of the thermal oxidation process of pure HDPE as well as HDPE with PVC derivative show oxidation exothermic stage started at 195°C and continues to 285°C. The samples of polyethylene contain the PVC-tannins show more resistance to oxidation reactions until 215°C for HDPE sample stabilized with 0.5% and 221°C for HDPE stabilized with 2.0%. Faster initiation of degradation rate was observed when HDPE contained PVC-tannins. According to the DSC analysis, the PVC derivative can participate in stabilization mechanism of HDPE but at limited performance.展开更多
[Objective] The aim of the study was to determine whether phytotoxicity of TeA against Echinochloa crus-galli leaves was correlated with oxidative stress caused by generation of reactive oxygen and the changes of anti...[Objective] The aim of the study was to determine whether phytotoxicity of TeA against Echinochloa crus-galli leaves was correlated with oxidative stress caused by generation of reactive oxygen and the changes of antioxidant enzymes activity.[Method] The changes of malondialdehyde（MDA）content,hydrogen peroxide（H2O2）,and activities of superoxide dismutase（SOD）,glutathione reductase（GR）and catalase（CAT）were studied by leaf segment method in vitro.[Result] After the treatment of 500 μmol/L TeA,the content of MDA and H2O2 increased by 247.86% and 67.00%,respectively,indicating that the accumulation of MDA and H2O2 in E.crus-galli leaves was due to the reactive oxygen burst induced by TeA.TeA induced a significant increase in activities of SOD,GR and CAT.At 500 μmol/L TeA,activities of SOD,GR and CAT increased more than one fold compared with the control.[Conclusion] TeA could not only cause oxidative stress in leaves of E.crus-galli through the induction of reactive oxygen,but also induce the increasing of antioxidant enzyme activity.展开更多
[Objective] This study aimed to investigate the effect of chromium on ox- idative damage and antioxidant capacity of Ctenopharyngodon idellus （grass carp）. [Method] The grass carps were treated with hexavalent chrom...[Objective] This study aimed to investigate the effect of chromium on ox- idative damage and antioxidant capacity of Ctenopharyngodon idellus （grass carp）. [Method] The grass carps were treated with hexavalent chromium （Cr^6＋） solution at concentrations of 0, 7.23, 14.47, 28.94 mg/L, and then the content of malondialde- hyde （MDA）, the level of total antioxidative capacity （T-AOC） and the activity of gtu- tathione-S-transferase （GST） in the hepatopancreas of grass carp were determined after 96 hours in different treatment groups. [Result] The content of MDA presented increasing trend with the increase of exposure Cr^6＋ concentrations. The activity of T-AOC increased firstly, then decreased with the increasing Cr^6＋ exposure concentra- tions, showing that the level of T-AOC was induced in tow and medium concentrat ions （7.23 and 14.47 mg/L）, but inhibited in high concentrations （28.94 mg/L）. Among the exposure groups, the level of T-AOC in medium concentration group （14.47 mg/L） was significantly higher than the control （P〈0.05）. Except the low concentration groups （7.23 mg/L） of which the GST activity was slightly induced, the GST activities of the other groups all showed downward trend with increasing Cr^6＋ levels, and the activity of GST in 28.94 mg/L group was significantly lower than the control group （P〈0.05）. [Conclusion] Cr^6＋ could cause large oxidative damage in the hepatopancreas of grass carp, thus poisoning it, and Cr^6＋ may further damage the organizational structure and physiological function of grass carp.展开更多
MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, th...MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, the spontaneous oxidation of MXenes, which is critical to its processing and product lifespan, has gotten less attention due to its chemical complexity and poorly understood oxidation mechanism. This perspective focuses on the oxidation stability of MXenes and addresses the most recent advancements in understanding and the possible countermeasures to limit the spontaneous oxidation of MXenes. A section is dedicated to the presently accessible methods for monitoring oxidation, with a discussion on the debatable oxidation mechanism and coherently operating factors that contribute to the complexity of MXenes oxidation. The current potential solutions for mitigating MXenes oxidation and the existing challenges are also discussed with prospects to prolong MXene's shelf-life storage and expand their application scope.展开更多
Food provides abundant nutrients for human beings, but also has sensory functions and physiological regulation.Lipids are the main components of food as well as the important structural and functional components of ce...Food provides abundant nutrients for human beings, but also has sensory functions and physiological regulation.Lipids are the main components of food as well as the important structural and functional components of cells.Nevertheless, lipids are easily oxidized by different ways, such as thermal oxidation and air oxidation. Lipidoxidation has adverse effects on food quality and human health. Therefore, efforts should be made to reduce lipidoxidation and improve its stability. This review focuses on important knowledge about lipid oxidation, includingthe concept of lipids and lipid oxidation, the main pathways and mechanisms of lipid oxidation, factors affectinglipid oxidation, strategies to improve the stability of lipid oxidation, and the recent research progress of lipidoxidation in food science and nutritional health.展开更多
Antioxidants addition is believed as a facile and effective way to improve jet fuel thermal oxidation stability.However,amine antioxidants,as one of the most important antioxidants,have not received sufficient attenti...Antioxidants addition is believed as a facile and effective way to improve jet fuel thermal oxidation stability.However,amine antioxidants,as one of the most important antioxidants,have not received sufficient attention in the field of jet fuel autoxidation yet.Herein,the inhibition efficiency and mechanism of decane and exo-tetrahydrodicyclopentadiene(THDCPD)oxidation by di-4-tert-butylphenylamine(diarylamine)was experimentally and theoretically investigated.The results show that diarylamine can significantly inhibit decane oxidation but is less efficient for THDCPD oxidation,which is attributed to the higher energy barrier of retro-carbonyl-ene reaction(rate-determining step)in THDCPD than that in decane during diarylamine regeneration.However,the addition of diarylamine will cause undesirable color change after accelerated oxidation and produce slightly more deposits during high-temperature thermal oxidative stress for both decane and THDCPD.The results provide significant implications for the future design of effective antioxidant additives for high-performance jet fuel.展开更多
Objective:To evaluate the phytochemical constituents and antioxidant activities of aqueous extract of Scholia latifolia(S.latifolia)bark locally used for the treatment of oxidative stress-induced ailments in South Afr...Objective:To evaluate the phytochemical constituents and antioxidant activities of aqueous extract of Scholia latifolia(S.latifolia)bark locally used for the treatment of oxidative stress-induced ailments in South Africa.Methods:The antioxidant and free radical scavenging activity of aqueous extract of the plant was assessed against 1,1-diphenyl-2-pierylhydrazyl(DPPH),nitric oxide(NO),2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt(ABTS)and the ferric reducing agent.Total phenolics,flavonoids,flavonols and proanthocyanidins were also determined to assess their corresponding effect on the antioxidant activity of this plant.Results:The activities of plant extract against DPPH,ABTS and NO radicals were concentration dependent with IC_(50)value of 0.06,0.05 and 0.05 mg/mL,respectively.The reducing power of the extract was greater than that of butylated hydroxyl toluene(BHT)and ascorbic acid which were used as standard drugs in a concentration dependent manner.The total phenolics content of the aqueous bark extract was(193.33±0.03 TE/g),followed by flavonoids(72.70±0.01 QE/g),proanthocyanidins|48.76±0.00 CE/g)and flavonols(47.76±0.21 QE/g).Phytochemical analysis revealed the presence of percentage tannin(11.40±0.02),alkaloid(9.80±0.01),steroids(18.20±0.01),glycosides(29.80±0.01)and saponins(6.80±0.00).The results exhibited a positive linear correlation between these polyphenols and the free radical scavenging activities.Conclusions:Our findings provide evidence that the crude aqueous extract of S.latifolia is a potential source of natural antioxidants and this justifies its uses in folkloric medicines.展开更多
基金the National Key R&D Program of China(Grant No.2021YFB3803003)the Youth Innova-tion Promotion Association of Chinese Academy of Sciences(Grant No.2023311)+1 种基金Zhejiang Public Welfare Technology Application Research Project(Grant No.LGG22E010013)Class III Peak Discipline of Shanghai-Materials Science and Engineering(High-Energy Beam Intelligent Processing and Green Manufacturing).
文摘This study investigated the effect of antioxidants on the grinding efficiency,magnetic powder characteristics,microstructure,and magnetic properties of 2:17 type SmCo permanent magnet materials.The results show that adding antioxidants helps improve the dispersion among magnetic powders,leading to a 33.3%decrease in jet milling time and a 15.8%increase in magnet powder production yield.Additionally,adding antioxidants enhances the oxidation resistance of the magnetic powders.After being stored in a constant temperature air environment at 25C for 48 h,the O content in the powder decreased by 33%compared to samples without antioxidants.While in the magnet body,the O content decreased from 0.21 wt.%to 0.14 wt.%,which helps increase the effective Sm content and domain wall pinning uniformity in the magnet.Excellent magnetic properties were obtained in the magnet with added antioxidants:B_(r)=11.6 kGs,SF=79.6%,H_(cj)=16.8 kOe,and(BH)_(max)=32.5 MGOe.
基金supported by the Open Grant of Beijing Advanced Innovation Center for Food Nutrition and Human Health(20182024)National Natural Science Foundation of China(31370104)+4 种基金The Natural Science Foundation of Hunan Province,China(2021JJ30029)the Taishan Scholar Program of Shandong Province,China(tsqn201909168)“Double Hundred”Program for Foreign Experts of Shandong Province,China(WST2017004)Hunan Province Postgraduate Education Innovation Project and Professional Capacity Enhancement(CX20200297)Project the Fundamental Research Funds for the Central Universities of Central South University(2020zzts424,2020zzts422)。
文摘Plant extracts from natural sources are an excellent choice for food additives and natural antioxidants.In this study,the active components of Tulipa edulis were extracted and analysed,and their antioxidant capacity was measured.Then,the crude extract mixture was separated and purified using a Sephadex LH-20 gel,and the antioxidant activity of the purified products was determined.Human umbilical vein endothelial human umbilical vein endothelial cells(HUVEC)cells were treated with 35 mmol/L glucose to construct a model of oxidative stress.Then,the cells were treated with the active component to observe whether the products of T.edulis could have a good protective effect on HUVEC cells induced by glucose.Transcriptome analysis was also performed on HUVEC cells after same treatment to explore the possible mechanism of the component F2 protecting HUVEC cells from oxidative stress induced by high glucose.The results showed that component F2 obtained from T.edulis has strong antioxidant activity.Moreover,F2 can play a strong antioxidant protective role in HUVEC cells.Meanwhile,the gene expression of heme oxygenase 1(HO-1),γ-glutamyl cysteine ligase catalytic subunit(GCLC)and NAD(P)H quinone oxidoreductase-1(NQO1)in HUVEC cells was up-regulated after treated with F2.This study provides reference value for the further development and application of T.edulis and the d evelopment of functional food.
文摘BACKGROUND Premature ovarian insufficiency(POI)is a condition that causes secondary amenorrhea owing to ovarian hypofunction at an early stage.Early follicular depletion results in intractable infertility,thereby considerably reducing the quality of life of females.Given the continuum in weakened ovarian function,progressing from incipient ovarian failure(IOF)to transitional ovarian failure and further to POI,it is necessary to develop biomarkers for predicting POI.The oxidative stress states in IOF and POI were comprehensively evaluated via oxidative stress[diacron-reactive oxygen metabolites(d-ROMs)]test and anti-oxidant capacity[biological antioxidant potential(BAP)].METHODS Females presenting with secondary amenorrhea over 4 mo and a follicle stimulating hormone level of>40 mIU/mL were categorized into the POI group.Females presenting with a normal menstrual cycle and a follicle stimulating hormone level of>10.2 mIU/mL were categorized into the IOF group.Healthy females without ovarian hypofunction were categorized into the control group.Among females aged<40 years who visited our hospital from January 2021 to June 2022,we recruited 11 patients into both POI and IOF groups.For the potential antioxidant capacity,the relative oxidative stress index(BAP/d-ROMs×100)was calculated,and the oxidative stress defense system was comprehensively evaluated.RESULTS d-ROMs were significantly higher in the POI and IOF groups than in the control group,(478.2±58.7 U.CARR,434.5±60.6 U.CARR,and 341.1±35.1 U.CARR,respectively)(U.CARR is equivalent to 0.08 mg/dL of hydrogen peroxide).However,no significant difference was found between the POI and IOF groups.Regarding BAP,no significant difference was found between the control,IOF,and POI groups(2078.5±157.4μmol/L,2116.2±240.2μmol/L,and 2029.0±186.4μmol/L,respectively).The oxidative stress index was significantly higher in the POI and IOF groups than in the control group(23.7±3.3,20.7±3.6,and 16.5±2.1,respectively).However,no significant difference was found between the POI and IOF groups.CONCLUSION High levels of oxidative stress suggest that evaluating the oxidative stress state may be a useful indicator for the early detection of POI.
文摘Objective:To determine how biochanin-A(BCA)affects high-fat diet and streptozotocin-induced pathological changes in lipid metabolism and antioxidant status in diabetic rats.Methods:Diabetic rats were orally administered BCA(10 mg/kg body weight)for 30 days to investigate its effects on lipid profiles and oxidative stress markers in the liver and kidney.In addition,the mRNA expression of antioxidant and lipid metabolism enzymes in the liver was examined.Results:BCA attenuated hyperlipidemia by regulating mRNA expressions of HMG-CoA reductase,fatty acid synthase,carnitine palmitoyl transferase,and acetyl-CoA carboxylase.Additionally,BCA reduced high-fat diet and streptozotocin-induced oxidative stress by suppressing lipid peroxidation,improving superoxide dismutase,catalase,and glutathione peroxidase levels,and upregulating mRNA expressions of these enzymes.Conclusions:BCA may be a promising nutraceutical for the treatment of dyslipidemia and oxidative stress associated with diabetes.
文摘It is known that the pathogenicity of Plasmodium induces the breakdown of haemoglobin, which leads to the induction of oxidative stress. This study aimed to identify the possible effects of oxidative stress and antioxidant defence systems in symptomatic and asymptomatic Plasmodium falciparum malaria infection in children (1 - 15 years old) in the Mount Cameroon vicinity. This cross-sectional study involved blood samples collected from 473 children and examined for malaria parasitaemia. Full blood counts were performed using an automated haemoanalyser. Serum oxidative stress status (malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and vitamin C (Vit C)) were each determined by colorimetric enzymatic assays. The prevalence of malaria parasite infection was 32.1% among the participants. Out of that, 62.5% of patients with parasitaemia were symptomatic. Anaemia prevalence increased significantly with parasite density. MDA levels were significantly higher in patients with malaria symptoms than in those without symptoms. A significant and positive correlation was detected between MDA (r = 0.831, P < 0.05), NO (r = 0.779, P < 0.05), and malaria parasite density while, a significant and negative relationship occurred between parasite density and GSH (r = ?0.763, P < 0.05) and Vit C (r = ?0.826, P < 0.05) levels, SOD (r = ?0.621, P < 0.05) and CAT (r = ?0.817, P < 0.05) activities. The SOD activity and GSH level significantly decreased (P < 0.05) with an increase in the MDA levels. These findings showed that MDA and nitric oxide levels increased both in malaria participants with or without symptoms. A similar decrease in the antioxidant defence system was observed in both symptomatic and asymptomatic patients. Therefore, there is a need to develop public health policies that encourage routine diagnosis and treatment of malaria in seemingly healthy people (asymptomatic cases), and this will play an essential role in controlling malaria in tropical countries.
文摘BACKGROUND Type 2 diabetes mellitus(T2DM)is a metabolic disease of impaired glucose utilization.Imbalance in generation and elimination of free radicals generate oxidative stress which modulates glucose metabolism and insulin regulation,resulting in the occurrence and progression of diabetes and associated complications.Antioxidant supplements in T2DM can be seen as a potential preventive and effective therapeutic strategy.AIM To compare randomized controlled trials(RCTs)in which antioxidants have been shown to have a therapeutic effect in T2DM patients.METHODS We systematically searched the electronic database PubMed by keywords.RCTs evaluating the effect of antioxidant therapy on glycaemic control as well as oxidant and antioxidant status as primary outcomes were included.The outcomes considered were:A reduction in blood glucose;changes in oxidative stress and antioxidant markers.Full-length papers of the shortlisted articles were assessed for the eligibility criteria and 17 RCTs were included.RESULTS The administration of fixed-dose antioxidants significantly reduces fasting blood sugar and glycated hemoglobin and is associated with decreased malondialdehyde,advanced oxidation protein products,and increased total antioxidant capacity.CONCLUSION Antioxidant supplements can be a beneficial approach for the treatment of T2DM.
基金supported by the Agricultural Scientific and Technological Independent Innovation Fund Project of Jiangsu Province[Grant No.CX(20)2030]the Modern Agricultural(Flower)Industrial Technology System Construction Project of Jiangsu Province[Grant No.JATS[2021]489].
文摘Flavonoids have attracted considerable attention due to their health benefits. This study aimed to investigate the flavonoid profiles and antioxidant activity of Paeonia lactiflora petal flavonoid extract(PPF). The UHPLC-ESI-Q-Exactive HF MS/MS method was established for characterization, and 21 predominant flavonoid compounds were tentatively identified in PPF. Among them, isoscutellarein-7-(6’-acetylallosyl-(1->2)-glucoside) and scutellarin methylester were discovered in PPF for the first time. Pretreatment with PPF significantly reduced H2O2-induced cell damage, ROS accumulation, and malondialdehyde content and increased the activity of SOD, CAT, and GSH-Px in buffalo rat liver 3A(BRL3A) cells. Moreover, the expression of nuclear Factor E2-related factor(Nrf2) was upregulated by PPF, whose expression trend was consistent with that of heme oxygenase-1(HO-1), glutamate-cysteine ligase catalytic subunit(GCLC), and NAD(P)H quinone oxidoreductase-1(NQO1). These findings suggested that herbaceous peony flavonoids can be used as a natural bioactive agent to prevent oxidative stress.
文摘Arsenic(As)contaminated food chains have emerged as a serious public concern for humans and animals and are known to affect the cultivation of edible crops throughout the world.Therefore,the present study was designed to investigate the individual as well as the combined effects of exogenous silicon(Si)and sodium nitroprusside(SNP),a nitric oxide(NO)donor,on plant growth,metabolites,and antioxidant defense systems of radish(Raphanus sativus L.)plants under three different concentrations of As stress,i.e.,0.3,0.5,and 0.7 mM in a pot experiment.The results showed that As stress reduced the growth parameters of radish plants by increasing the level of oxidative stress markers,i.e.,malondialdehyde and hydrogen peroxide.However,foliar application of Si(2 mM)and pretreatment with SNP(100μM)alone as well as in combination with Si improved the plant growth parameters,i.e.,root length,fresh and dry weight of plants under As stress.Furthermore,As stress also reduced protein,and metabolites contents(flavonoids,phenolic and anthocyanin).Activities of antioxidative enzymes such as catalase(CAT),ascorbate peroxidase(APX),guaiacol peroxidase(POD),and polyphenol oxidase(PPO),as well as the content of non-enzymatic antioxidants(glutathione and ascorbic acid)decreased under As stress.In most of the parameters in radish,As III concentration showed maximum reduction,as compared to As I and II concentrations.However,the individual and combined application of Si and NO significantly alleviated the As-mediated oxidative stress in radish plants by increasing the protein,and metabolites content.Enhancement in the activities of CAT,APX,POD and PPO enzymes were recorded.Contents of glutathione and ascorbic acid were also enhanced in response to co-application of Si and NO under As stress.Results obtained were more pronounced when Si and NO were applied in combination under As stress,as compared to their individual application.In short,the current study highlights that Si and NO synergistically regulate plant growth through lowering the As-mediated oxidative stress by upregulating the metabolites content,activity of antioxidative enzymes and non-enzymatic antioxidants in radish plants.
文摘Aim： To examine the effects of melatonin treatment on lipid peroxidation （LPO） and the activities of antioxidant enzymes in the testicular tissue of streptozotocin （STZ）-induced diabetic rats. Methods： Twenty-six male rats were randomly divided into three groups as follows： group Ⅰ, control, non-diabetic rats （n = 9）; group Ⅱ, STZ-induced, untreated diabetic rats （n = 8）; group Ⅲ, STZ-induced, melatonin-treated （dose of 10 mg/kg·day） diabetic rats （n = 9）. Following 8-week melatonin treatment, all rats were anaesthetized and then were killed to remove testes from the scrotum. Results： As compared to group Ⅰ, in rat testicular tissues of grouap Ⅱ, increased levels of malondialdehyde （MDA） （P 〈 0.01） and superoxide dismutase （SOD） （P 〈 0.01） as well as, decreased levels of catalase （CAT） （P 〈 0.01） and glutathione peroxidase （GSH-Px） （P 〉 0.05） were found. In contrast, as compared to group Ⅱ, in rat testicular tissues of group Ⅲ, levels of MDA decreased （but this decrease was not significant, P 〉 0.05） and SOD （P 〈 0.01） as well as CAT （P 〈 0.05） increased. GSH-Px was not influenced by any of the treatment. Melatonin did not significantly affect the elevated glucose concentration of diabetic group. At the end of the study, there was no significant difference between the melatonin-treated group and the untreated group by means of body and testicular weight. Conclusion： Diabetes mellitus increases oxidative stress and melatonin inhibits lipid peroxidation and might regulate the activities of antioxidant enzymes of diabetic rat testes.
文摘Objective:To assess various antioxidative activities of Satureja khozestanica essential oil(SKE)and its effect on oxidation of low density lipoprotein(LDL)induced by CuSO_4 in vitro by monitoring the formation of conjugated dienes and malondialdehyde(MDA).Methods:The formation of conjugated dienes,lag time and MDA were measured.Inhibition of this Cu-induced oxidation was studied in the presence of several concentrations of SKE.Also total antioxidant activity and free radical scavenging of SKE were determinated.Results:It was demonstrated that SKE was able to inhibit LDL oxidation and decrease the resistance of LDL against oxidation.The inhibitory effects of SKE on LDL oxidation were dose-dependent at concentrations ranging from 50 to 200μg/mL.Total antioxidant capacity of SKE was(3.20±0.40)nmol of ascorbic acid equivalents/g SKE.The SKE showed remarkable scavenging activity on 2,2-diphenyl-picrylhydrazyl,IC_(50)(5.30±0.11)ng/mL.Conclusions:This study shows that SKE is a source of potent antioxidants and prevents the oxidation of LDL in vitro and it may be suitable for use in food and pharmaceutical applications.
文摘The advantages and disadvantages of organic antioxidant and inorganic salt on suppressing coal oxidation were analyzed on the basis of the theory that coal oxidation mechanisms can be attributed to the free radical chain-type reaction mechanism. The inhibition curves on suppressing coal oxidation of the different type and different concentration of organic antioxidant and inorganic salt were given through experimental study and data processing. Then some conclusions can be gained from the experimental study combining with theoretical analysis. First the inhibition mechanism of the organic antioxidant and inorganic salt is different. The former is that the chemical action is the dominant position. It can be called as the chain termination theory because the free radical is captured during coal oxidation. And the later is that the physical effect is the dominant position. It can be called as the decreasing-temperature theory because the liquid membrane which was formed by the inorganic salt can make coal body be the state of wetness and prevent oxygen from coal surface. Second the inhibition effect of the organic antioxidant is higher than the inorganic salt in the later period. But it is lower in the early period.
文摘The present study aimed to investigate the effectiveness of the use of some antioxidants-<i>α</i>-tocopherol, n-octyl gallate, L-ascorbic acid 6-palmitate and matcha extract (green tea) as inhibitors of grape seeds, walnuts and corn germ oils oxidation. The oxidation was studied in a forced regime during 700 h, by the addition of hydrogen peroxide and Cu<sup>2+</sup> ions. The optimal conditions of the accelerated oxidation process in the analysed systems were established. The progress of lipid oxidation was evaluated by measuring the peroxide value (PV) and conjugated dienes and trienes (CD, CT). A series of secondary products of the lipid oxidation were identified: hexanal, octanal and hydroxy-nonadienal. The intensity of the formation of these compounds during oxidation was monitored. The results of this study showed that the oil samples with the addition of antioxidants showed considerably lower oxidation values compared to the control sample. More effective was the action of L-ascorbic acid 6-palmitate and n-octyl gallate, the optimum concentration <span>was 0.1%. An inhibitory effect of the oxidation process was noted for <i>α</i>-</span>tocopherol and matcha extract, the optimal addition concentration was 1%.
文摘Background: Intravenous application of iron preparations which is a routine treatment of anemia in hemodialysis patients with end-stage renal disease can lead to iron overload in the body. Redox-active iron can catalyze the formation of hydroxyl radicals and initiation of lipid peroxidation, increase oxidative stress and speed up the development of complications in these patients. Objective: In this study, we determined the markers of lipid peroxidation, protein oxidation and antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, glutathione S-transferase) in serum of patients with end-stage renal disease on hemodialysis, who had received repeated treatment of iron supplementation. Patients and Methods: The study included 29 patients undergoing regular hemodialysis treatment. These patients were divided into three groups according to the serum ferritin levels: group I (serum ferritin between 100 and 300 mg/L);group II (serum ferritin between 301 and 600 mg/L), and group III (serum ferritin above 601 mg/L). Results: The serum of patients with the highest concentration of serum ferritin and iron contained significantly higher level of lipid peroxidation products, total hydroperoxides and malondialdehyde and advanced oxidation protein products and the lowest concentration of sulfhydryl groups, reduced glutathione and total antioxidant capacity. Conclusion: Based on the obtained results, it can be concluded that iron supplementation in hemodialysis patients and consequently body iron overload of exacerbated oxidative stress have already been present in these patients.
文摘In the current research study, an attempt is made to modification of polyvinyl chloride (PVC) by grafting with biologically based phenolic resin, namely, tannins. The reaction was carried out at 110°C in DMF solution. FTIR spectra show the presence of phenolic hydroxylic groups and other functional groups of tannins into the PVC-tannins derivative. Evaluation of the new PVC derivative as polymeric antioxidant for high density polyethylene (HDPE) was the main purpose of this study. Samples of HDPE containing (0.0, 0.5 and 2.0) %W/W from PVC-tannins and pure HDPE were exposed to thermal program by differential scanning calorimetry (DSC) by temperature sweep from 100°C to 350°C. DSC scans of the thermal oxidation process of pure HDPE as well as HDPE with PVC derivative show oxidation exothermic stage started at 195°C and continues to 285°C. The samples of polyethylene contain the PVC-tannins show more resistance to oxidation reactions until 215°C for HDPE sample stabilized with 0.5% and 221°C for HDPE stabilized with 2.0%. Faster initiation of degradation rate was observed when HDPE contained PVC-tannins. According to the DSC analysis, the PVC derivative can participate in stabilization mechanism of HDPE but at limited performance.
基金Supported by Scientific and Technological Project of Heilongjiang Province(GC05B205)Scientific and Technological Project of Heilongjiang Land Reclamation Bureau(HNKXV-03-04-06A)~~
文摘[Objective] The aim of the study was to determine whether phytotoxicity of TeA against Echinochloa crus-galli leaves was correlated with oxidative stress caused by generation of reactive oxygen and the changes of antioxidant enzymes activity.[Method] The changes of malondialdehyde（MDA）content,hydrogen peroxide（H2O2）,and activities of superoxide dismutase（SOD）,glutathione reductase（GR）and catalase（CAT）were studied by leaf segment method in vitro.[Result] After the treatment of 500 μmol/L TeA,the content of MDA and H2O2 increased by 247.86% and 67.00%,respectively,indicating that the accumulation of MDA and H2O2 in E.crus-galli leaves was due to the reactive oxygen burst induced by TeA.TeA induced a significant increase in activities of SOD,GR and CAT.At 500 μmol/L TeA,activities of SOD,GR and CAT increased more than one fold compared with the control.[Conclusion] TeA could not only cause oxidative stress in leaves of E.crus-galli through the induction of reactive oxygen,but also induce the increasing of antioxidant enzyme activity.
基金Supported by the National Program on Key Basic Research Project(2010CB134405)the Foundation for Doctors of Southwest University(SWU10903)the Project of China Three Gorges Corporation(CT-11-08-01)~~
文摘[Objective] This study aimed to investigate the effect of chromium on ox- idative damage and antioxidant capacity of Ctenopharyngodon idellus （grass carp）. [Method] The grass carps were treated with hexavalent chromium （Cr^6＋） solution at concentrations of 0, 7.23, 14.47, 28.94 mg/L, and then the content of malondialde- hyde （MDA）, the level of total antioxidative capacity （T-AOC） and the activity of gtu- tathione-S-transferase （GST） in the hepatopancreas of grass carp were determined after 96 hours in different treatment groups. [Result] The content of MDA presented increasing trend with the increase of exposure Cr^6＋ concentrations. The activity of T-AOC increased firstly, then decreased with the increasing Cr^6＋ exposure concentra- tions, showing that the level of T-AOC was induced in tow and medium concentrat ions （7.23 and 14.47 mg/L）, but inhibited in high concentrations （28.94 mg/L）. Among the exposure groups, the level of T-AOC in medium concentration group （14.47 mg/L） was significantly higher than the control （P〈0.05）. Except the low concentration groups （7.23 mg/L） of which the GST activity was slightly induced, the GST activities of the other groups all showed downward trend with increasing Cr^6＋ levels, and the activity of GST in 28.94 mg/L group was significantly lower than the control group （P〈0.05）. [Conclusion] Cr^6＋ could cause large oxidative damage in the hepatopancreas of grass carp, thus poisoning it, and Cr^6＋ may further damage the organizational structure and physiological function of grass carp.
基金financial support by the National Natural Science Foundation of China (Grant No. U2004212 and 51802012)。
文摘MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, the spontaneous oxidation of MXenes, which is critical to its processing and product lifespan, has gotten less attention due to its chemical complexity and poorly understood oxidation mechanism. This perspective focuses on the oxidation stability of MXenes and addresses the most recent advancements in understanding and the possible countermeasures to limit the spontaneous oxidation of MXenes. A section is dedicated to the presently accessible methods for monitoring oxidation, with a discussion on the debatable oxidation mechanism and coherently operating factors that contribute to the complexity of MXenes oxidation. The current potential solutions for mitigating MXenes oxidation and the existing challenges are also discussed with prospects to prolong MXene's shelf-life storage and expand their application scope.
基金funded by National Natural Science Foundation of China(Grant No.U21A20274)We also gratefully acknowledge the support of the National Key R&D Program Key Special Project(Grant No.2021YFD1600103)+1 种基金Technology Innovation Project of Hubei Province(Grant No.2021BEC021)Agricultural Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAASASTIP-2013-OCRI).
文摘Food provides abundant nutrients for human beings, but also has sensory functions and physiological regulation.Lipids are the main components of food as well as the important structural and functional components of cells.Nevertheless, lipids are easily oxidized by different ways, such as thermal oxidation and air oxidation. Lipidoxidation has adverse effects on food quality and human health. Therefore, efforts should be made to reduce lipidoxidation and improve its stability. This review focuses on important knowledge about lipid oxidation, includingthe concept of lipids and lipid oxidation, the main pathways and mechanisms of lipid oxidation, factors affectinglipid oxidation, strategies to improve the stability of lipid oxidation, and the recent research progress of lipidoxidation in food science and nutritional health.
基金the financial support from the Postdoctoral Science Foundation of China(2021M702810)the Haihe Laboratory of Sustainable Chemical Transformations(CYZC202103)the National Natural Science Foundation of China(21978200 and 22222808)。
文摘Antioxidants addition is believed as a facile and effective way to improve jet fuel thermal oxidation stability.However,amine antioxidants,as one of the most important antioxidants,have not received sufficient attention in the field of jet fuel autoxidation yet.Herein,the inhibition efficiency and mechanism of decane and exo-tetrahydrodicyclopentadiene(THDCPD)oxidation by di-4-tert-butylphenylamine(diarylamine)was experimentally and theoretically investigated.The results show that diarylamine can significantly inhibit decane oxidation but is less efficient for THDCPD oxidation,which is attributed to the higher energy barrier of retro-carbonyl-ene reaction(rate-determining step)in THDCPD than that in decane during diarylamine regeneration.However,the addition of diarylamine will cause undesirable color change after accelerated oxidation and produce slightly more deposits during high-temperature thermal oxidative stress for both decane and THDCPD.The results provide significant implications for the future design of effective antioxidant additives for high-performance jet fuel.
基金supported by Govan Mbeki Research Development Centre of the University of Fort Hare
文摘Objective:To evaluate the phytochemical constituents and antioxidant activities of aqueous extract of Scholia latifolia(S.latifolia)bark locally used for the treatment of oxidative stress-induced ailments in South Africa.Methods:The antioxidant and free radical scavenging activity of aqueous extract of the plant was assessed against 1,1-diphenyl-2-pierylhydrazyl(DPPH),nitric oxide(NO),2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt(ABTS)and the ferric reducing agent.Total phenolics,flavonoids,flavonols and proanthocyanidins were also determined to assess their corresponding effect on the antioxidant activity of this plant.Results:The activities of plant extract against DPPH,ABTS and NO radicals were concentration dependent with IC_(50)value of 0.06,0.05 and 0.05 mg/mL,respectively.The reducing power of the extract was greater than that of butylated hydroxyl toluene(BHT)and ascorbic acid which were used as standard drugs in a concentration dependent manner.The total phenolics content of the aqueous bark extract was(193.33±0.03 TE/g),followed by flavonoids(72.70±0.01 QE/g),proanthocyanidins|48.76±0.00 CE/g)and flavonols(47.76±0.21 QE/g).Phytochemical analysis revealed the presence of percentage tannin(11.40±0.02),alkaloid(9.80±0.01),steroids(18.20±0.01),glycosides(29.80±0.01)and saponins(6.80±0.00).The results exhibited a positive linear correlation between these polyphenols and the free radical scavenging activities.Conclusions:Our findings provide evidence that the crude aqueous extract of S.latifolia is a potential source of natural antioxidants and this justifies its uses in folkloric medicines.
