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A Study on Anti-oxidative Activity of Soybean Peptideswith Linoleic Acid Peroxidation Systems 被引量:13
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作者 XU Li LI Hong-mei +3 位作者 HUANG Yi-bing WANG Hua NIE Guang-jun ZHANG Xue-zhong 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2006年第2期205-208,共4页
Soybean bioactive peptides(SBPs) were prepared from the isolated soybean protein by proteolysis with an alkaline protease, alcalase, at 50℃ and pH = 8.0. The dependence of hydrolysis time on hydrolysis degree and m... Soybean bioactive peptides(SBPs) were prepared from the isolated soybean protein by proteolysis with an alkaline protease, alcalase, at 50℃ and pH = 8.0. The dependence of hydrolysis time on hydrolysis degree and molecular weight distribution were examined. The hydrolysate was fractionated on a Sephadex G-25 column and the anti-oxidative activities of the fractions were detected by the method of pyrogallol auto-oxidation. The average chain length of soybean peptides that have anti-oxidative activity was estimated to be about 7. The anti-oxidative properties of the soy- bean peptide were also studied by using linoleic acid peroxidation systems. The optimal condition of the peroxidation system was set up, Vc/Cu^2 + as the inducer at pH = 7.4 and 25 ℃. In addition, soybean peptides show higher antioxidative activity compared with GSH. 展开更多
关键词 Soybean bioactive peptides Anti-oxidative activity Linoleic acid peroxidation system
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The Relationship Between Senescence and Ca^(2+)-ATPase Activity of Microsomal Membrane and Lipid Peroxidation in Harvested Peach Fruit 被引量:2
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作者 GUAN Jun-feng FAN Xiu-cai +2 位作者 DOU Shi-juan ZHANG Ji-shu LI Guang-min 《Agricultural Sciences in China》 CAS CSCD 2006年第8期609-614,共6页
Peach fruit easily soften and have a short storage time at normal temperature. In this study, peach fruit (Prunus persica sieb et Zucc cv. Yingqing) were picked and stored at 25 and 4℃ to investigate the senescence... Peach fruit easily soften and have a short storage time at normal temperature. In this study, peach fruit (Prunus persica sieb et Zucc cv. Yingqing) were picked and stored at 25 and 4℃ to investigate the senescence in correlation with Ca^2+- ATPase activity of microsomal membrane and lipid peroxidation during ripening and senescence. In comparison with that stored at 25~C, the fruit stored at 4℃ exhibited a higher flesh firmness, lower respiration rate, and generated the late bigger peak value of Ca^2+-ATPase activity as well as maintained the higher activity of the enzyme. Meanwhile, the lower levels of super oxygen radical (O2^-.) production and content of malondialdehyde (MDA), a product of membrane lipid peroxidation were observed. Sodium orthovanadate (SO) and erythrosin B (EB), as Ca^2+-ATPase inhibitors, could stimulate the respiration rate. The results suggested that the slower senescence rate of peach fruit was closely related to the higher peak value and longer duration of Ca^2+-ATPase activity in microsomal membrane, with the slighter membrane lipid peroxidation and lower O2^-. production rate. 展开更多
关键词 peach fruit Ca^2+-ATPase active oxygen lipid peroxidation SENESCENCE
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Effects of Water Stress on the Protective Enzyme Activities and Lipid Peroxidation in Roots and Leaves of Summer Maize 被引量:26
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作者 GE Ti-da SUI Fang-gong +2 位作者 BAI Li-ping LU Yin-yan ZHOU Guang-sheng 《Agricultural Sciences in China》 CAS CSCD 2006年第4期291-298,共8页
A systematic study was conducted to determine the effects of water stress on the activities of protective enzymes and lipid peroxidation in maize. The results showed that, under water stress, the activities of superox... A systematic study was conducted to determine the effects of water stress on the activities of protective enzymes and lipid peroxidation in maize. The results showed that, under water stress, the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in leaves and roots increased sharply at prophase and metaphase growth stages, such as, male tetrad stage, but then declined towards the physiological maturity. The protective enzyme activities in roots were lower than those in leaves. The content of malondialdehyde (MDA) increased according to the severity of water stress. The content of MDA in roots was lower than that in leaves. The activities of protective enzymes and lipid peroxidation in roots were positively related to that in leaves with most of the correlation coefficients being significant. The content of soluble proteins in roots and leaves decreased with increasing drought stress. The ear characteristics deteriorated and the economic yields of maize decreased significantly under water stress. The main factors that caused reduction of yields were the decrease in the number of ear kernels and 100-kernel weight. 展开更多
关键词 MAIZE water stress protective enzyme activities lipid peroxidation
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Antioxidant Activity of Pigment Extracted from Green-Wheat-Bran 被引量:11
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作者 TANG Xiao-zhen DONG Yu-xiu +2 位作者 WEI Si-qing ZHANG Xian-sheng YIN Yan-ping 《Agricultural Sciences in China》 CAS CSCD 2010年第6期825-832,共8页
The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity ... The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity (TAA),superoxide anion radical scavenging activity (SARSA),active oxygen scavenging activity (AOSA),and DPPH (1,1-diphenyl-2 picrylhydrazyl free radical) radical scavenging activity.The results showed that the pigment had higher antioxidant activity and TAA,SARSA,AOSA and DPPH.scavenging activities at a certain concentration than Vc (antiscorbutic vitamin,vitamin C),and the capacity increased with the increase of pigment concentration.Its TAA was 51.06 U mL-1,1.73 times of Vc,and SARSA 18 025.21 U mL-1,2.26% higher than Vc,and AOSA 3 776.31 U mL-1,1.24 times of Vc.As to the DPPH.scavenging activity of the pigment,there was a trend that higher concentration performed higher activity significantly improved with the company of Vc.The pigment showed significant antioxidant activities evaluated by different assays.Results will provide a better understanding on antioxidant activity of green wheat and allow the screening or breeding of green wheat varieties with higher antioxidant activity for food processing. 展开更多
关键词 pigment from green-wheat-bran anti-lipid peroxidation total antioxidant superoxide anion radical scavenging active oxygen scavenging DPPH.scavenging
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Impact of dietary oils and fats on lipid peroxidation in liver and blood of albino rats 被引量:2
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作者 Mohammad El-Sayed Yassin El-Sayed Haggag Rafaat Mohamed Elsanhoty Mohamed Fawzy Ramadan 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2014年第1期52-58,共7页
Objective:To investigate the effects of different dietary fat and oils(differing in their degree of saturation and unsaturation)on lipid peroxidation in liver and blood of rats.Methods:The study was conducted on SO al... Objective:To investigate the effects of different dietary fat and oils(differing in their degree of saturation and unsaturation)on lipid peroxidation in liver and blood of rats.Methods:The study was conducted on SO albino rats that were randomly divided into 5 groups of 10 animals.The groups were fed on dietary butter(Group I),margarine(Croup II),olive oil(Group III),sunflower oil(Group IV)and com oil(Group V)for 7 weeks.After 12 h of diet removal,livers were excised and blood was collected to measure malondialdehyde(MDA)levels in the supernatant of liver homogenate and in blood.Blood superoxide dismutase activity(SOD),glutathione peroxidase activity(GPx),serum vitamin E and total antioxidant capacity(TAC)levels were also measured to determine the effects of fats and oils on lipid peroxidation.Results:The results indicated that no significant differences were observed in SOD activity,vitamin E and TAC levels between the five groups.However,there was significant decrease of GPx activity in groups IV and V when compared with otlier groups.The results indicated that feeding corn oil caused significant increases in liver and blood MDA levels as compared with other oils and fats.There were positive correlations between SOD and GPx,vitamin E and TAC as well as between GPx and TAC(r:0.743;P<0.001)and between blood MDA and liver MDA(r:0.897;P<0.00l).The results showed also negative correlations between blood MDA on one hand and SOD,GPx,vitamin E and TAC on the other hand.Conclusions:The results demonstrated that feeding oils rich in polyunsaturated fatly acids(PUFA)increases lipid peroxidation significantly and may raise the susceptibility of tissues to free radical oxidative damage. 展开更多
关键词 Vegetable oils BUTTER MARGARINE Polyunsaturated fatty acids(PUFA) Lipid peroxidation Malondialdehyde(MDA) Superoxide DISMUTASE activity(SOD) Glutathione peroxidase activity(CPX
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Determination of reactive oxygen generated from natural medicines and their antibacterial activity 被引量:8
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作者 Noriko Tajima Makiko Takasaki +3 位作者 Haruka Fukamachi Takeshi Igarashi Yoshijiro Nakajima Hidetoshi Arakawa 《Journal of Pharmaceutical Analysis》 SCIE CAS 2016年第4期214-218,共5页
Extracts of 16 natural medicine powders {Galla chinensis,Malloti cortex,Cassiae semen,Sophorae radix,Myricae cortex,Crataegi fructus,Gambit,Mume fructus,Geranii herba,Phellodendri cortex,Coptidis rhizoma,Swertiae herb... Extracts of 16 natural medicine powders {Galla chinensis,Malloti cortex,Cassiae semen,Sophorae radix,Myricae cortex,Crataegi fructus,Gambit,Mume fructus,Geranii herba,Phellodendri cortex,Coptidis rhizoma,Swertiae herba,and Cinnamomi cortex) were assayed for reactive oxygen concentrations using the peroxyoxalate chemiluminescent detection system.High luminescence intensity was observed in Galla chinensis,Geranii herba,Malloti cortex,Myricae cortex,and Cinnamomi cortex.Additional experiments identified the reactive oxygen species as hydrogen peroxide.Galla chinensis generated 2.4 × 10^(-4) mol/L hydrogen peroxide from a 1 mg/mL solution.In bacterial growth tests,Galla chinensis extract had antibacterial activity against Escherichia coli.Staphylococcus aureus,Bacteroides thetaiotaomicron,Campylobacter sputorum biovar sputorum.Streptococcus salivarius thermophilus,Lactobacillus casei,and Bifidobacterium longum infantis.This antibacterial activity was decreased by the addition of catalase.It revealed that hydrogen peroxide which Galla chinensis produced participated in antibacterial activity. 展开更多
关键词 Galla Chinensis Natural medicines Hydrogen peroxide Antibacterial activity
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Radical scavenging and antibacterial activity of Arnebia benthamii methanol extract 被引量:1
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作者 Showkat A Ganie Asima Jan +3 位作者 Sabeera Muzaffar Bilal A Zargar Rabia Hamid M Afzal Zargar 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2012年第10期766-772,共7页
Objective:To evaluate in vitro antioxidant and antibacterial activity of methanolic extract of Arnebia benthamii(A.benthamii) whole plant.Methods:Plasmid damage was analyzed by agarose gell electrophoresis.Calf thym... Objective:To evaluate in vitro antioxidant and antibacterial activity of methanolic extract of Arnebia benthamii(A.benthamii) whole plant.Methods:Plasmid damage was analyzed by agarose gell electrophoresis.Calf thymus DNA was monitored by TBARS formation.DPPH, reducing power and lipid peroxidation was evaluated by using standard procedures.Antibacterial assay was monitored by disc diffusion method.Results:DPPH radical scavenging and hydroxyl radical scavenging potential of the plant revealed that the extract to be active radical scavenger.Reducing(Fe<sup>3+</sup>-Fe<sup>2+</sup>) power and lipid peroxidation inhibition efficiency(TBARS assay) of the extract was also evaluated and the extract showed promising activity in preventing lipid peroxidation and might prevent oxidative damages to biomolecules.The extract offered a significant protection against plasmid and calf thymus UNA damage induced by hydroxyl radicals. The extract was also evaluated on different bacterial strains and the maximum antibacterial activity was exhibited against Escherichia coli(E.coli) when compared with standard drug. Conclusions:These findings demonstrate that the methanol extract of A.benthamii has excellent anti-oxidant activities and could be considered as a potential source of lead molecules for pharmaceutical industries. 展开更多
关键词 Free RADICALS LIPID peroxidation DPPH TBARS DNA damage ANTIBACTERIAL activity Arnebia benthamii
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Osmolyte modulated enhanced rice leaf catalase activity under salt-stress 被引量:1
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作者 Sushmita Sahu Priyanka Das +1 位作者 Mamata Ray Surendra Chandra Sabat 《Advances in Bioscience and Biotechnology》 2010年第1期39-46,共8页
Change in catalase activity was examined in leaves of rice plant exposed to salinity. Depending on the method of preparation of crude protein extract from leaf and the constituents of the assay medium, a significant d... Change in catalase activity was examined in leaves of rice plant exposed to salinity. Depending on the method of preparation of crude protein extract from leaf and the constituents of the assay medium, a significant difference in enzyme activity was recorded. Inclusion of sorbitol or mannitol or sucrose in the extraction and enzyme assay medium enhanced the enzyme activity in salt-stressed samples by nearly 1.5-1.8 fold, compared to the activity found in un- stressed plants, which otherwise showed a 50% declined activity in leaf extract prepared in buffer solution and assayed in a medium depleted of these sugars. In view of the accumulation of osmolytes under saline condition, these observations suggest that the catalase activity is modulated by the osmolytes and maintains a high rate of hydrogen peroxide scavenging property in vivo and serves as the major antioxidant enzyme to scavenge the salt-induced formation of peroxide. Therefore, the salt-stress induced appearance of low activity of the enzyme under normal buffer extraction and assay conditions, as reported in literature may represent an apparent than for its real in vivo activity. 展开更多
关键词 CATALASE activity Hydrogen peroxidE OSMOLYTE Rice SALT-STRESS
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Protective Effects of Extracts, Isolated Compounds from <i>Desmodium uncinatum</i>and Semi-Synthetic Isovitexin Derivatives against Lipid Peroxidation of Hepatocyte’s Membranes 被引量:1
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作者 Borice T. Tsafack Cyrille L. K. Bomgning +8 位作者 Jonas Kühlborn Romuald T. Fouedjou Beaudelaire K. Ponou Remy B. Teponno Agathe L. Fotio Luciano Barboni Till Opatz Télesphore B. Nguelefack Léon A. Tapondjou 《Advances in Biological Chemistry》 2018年第6期101-120,共20页
Lipid peroxidation plays a pivotal role in the pathogenicity and maintenance of hepatitis. Thus, substances protecting hepatocyte membranes from lipid peroxidation are of great importance in the management of hepatoto... Lipid peroxidation plays a pivotal role in the pathogenicity and maintenance of hepatitis. Thus, substances protecting hepatocyte membranes from lipid peroxidation are of great importance in the management of hepatotoxicity and hepatitis. The present work deals with the in vitro hepatoprotective activity of the methanol extract of Desmodium uncinatum, its sub-fractions, the major isolated compounds and some of their semi-synthetic derivatives in order to study structure activity relationships. Using hydrogen peroxide (H2O2)-induced lipid peroxidation of hepatocyte membranes as a model, the hepatoprotective-guided phytochemical survey of the methanol extract of aerial parts of D. uncinatum was carried out by successive column chromatography. One of the most active compounds (Isovitexin) was chemically transformed to yield new semi-synthetic. The identification of isolated and semi-synthetic compounds was performed using NMR techniques, mass spectrometry and by comparison of their data with those reported in the literature. The n-butanol fraction was the most effective (IC50: 22.9 μg/mL) compared to the crude methanol extract (IC50: 43.6 μg/mL) and other fractions. The n-butanol sub-fractions FA (containing non-phenolic compounds) and FB (mainly containing phenolic compounds) exhibited respective IC50 of 14.36 and 128.2 μg/ml. Purification of FA yielded 3-O-β-D-glucopyranosyl-β-sitosterol (1), 3-O-β-D- 2-acetyl-amino-2-deoxyglucopyranoxyloleanoic acid (2), (2S, 3S, 4R, 7R, 8Z)-1-O-β-D-glucopyranosyl-2-[(R)-2'-hydroxyarachidoylamino]-docosan-8-ene-3,4,7-triol (4), spiraeamide (5), mannitol (6), while FB afforded essentially three C-glycosylflavonoids namely isovitexin (7), vitexin (8) and vicenin-3 (9). Chemical transformations (methylation, allylation and prenylation) of isovitexin afforded five new semi-synthetic derivatives: 4',5,7-O- trimethyli-sovitexin (10), 4'-O-allylisovitexin (11), 4',7-O-diallylisovitexin (12), 4'-O-prenylisovitexin (13) and 8-C-prenyl-4',7-O-diprenylisovitexin (14). The screening of these derivatives revealed that allylation did not significantly affect the hepatoprotective activity while methylation, prenylation, number and position of sugar moieties on the A ring of flavonoids significantly reduced it. Results demonstrated that the n-butanol fraction obtained from the methanol extract of Desmdium uncinatum may possess hepatoprotective activity due to its content in C-glycosylflavonoids and cerebrosides. Hydroxyl groups in C-glycosylflavonoids are important for their lipid peroxidation inhibitory activity. 展开更多
关键词 DESMODIUM uncinatum HEPATOPROTECTIVE activity Lipid peroxidation HEPATOCYTE Membranes C-glycosylflavonoids
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Honey:its medicinal property and antibacterial activity 被引量:26
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作者 Manisha Deb Mandal Shyamapada Mandal 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2011年第2期154-160,共7页
Indeed,medicinal importance of honey has been documented in the world's oldest medical literatures,and since the ancient times,it has been known to possess antimicrobial property as well as wound-healing activity.... Indeed,medicinal importance of honey has been documented in the world's oldest medical literatures,and since the ancient times,it has been known to possess antimicrobial property as well as wound-healing activity.The healing property of honey is due to the fact that it offers antibacterial activity,maintains a moist wound condition,and its high viscosity helps to provide a protective barrier to prevent infection.Its immunomodulatory property is relevant to wound repair too.The antimicrobial activity in most honeys is due to the enzymatic production of hydrogen peroxide.However,another kind of honey,called non-peroxide honey(viz.,manuka honey),displays significant antibacterial effects even when the hydrogen peroxide activity is blocked.Its mechanism may be related to the low pH level of honey and its high sugar content(high osmolality) that is enough to hinder the growth of microbes.The medical grade honeys have potent in vitro bactericidal activity against antibiotic-resistant bacteria causing several life-threatening infections to humans. But,there is a large variation in the antimicrobial activity of some natural honeys,which is due to spatial and temporal variation in sources of nectar.Thus,identification and characterization of the active principle(s) may provide valuable information on the quality and possible therapeutic potential of honeys(against several health disorders of humans),and hence we discussed the medicinal property of honeys with emphasis on their antibacterial activities. 展开更多
关键词 HONEY Antibacterial activity Wound healing PROPERTY Glucose OXIDASE Non-peroxide effect Medical-grade HONEY ANTIMICROBIAL agents MEDICINAL PROPERTY ANTIMICROBIAL PROPERTY IMMUNOMODULATORY PROPERTY
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Plasma activation towards oxidized nanocarbons for efficient electrochemical synthesis of hydrogen peroxide
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作者 蔡伟 王燕 +2 位作者 肖长山 吴浩斌 遇鑫遥 《Plasma Science and Technology》 SCIE EI CAS CSCD 2021年第2期38-46,共9页
Oxidized nanocarbons(ONCs)have been regarded as efficient electrocatalysts for H2O2 production.However,wet chemical procedures involving large volumes of strong acid and long synthetic time are usually needed to obtai... Oxidized nanocarbons(ONCs)have been regarded as efficient electrocatalysts for H2O2 production.However,wet chemical procedures involving large volumes of strong acid and long synthetic time are usually needed to obtain these ONCs.Herein,a plasma activation strategy is developed as a rapid and environmentally benign approach to obtain various ONCs,including oxidized multiwalled carbon nanotubes,single-walled carbon nanotube,graphene,and super P carbon black.After a few minutes of plasma activation,oxygen-containing functional groups and defects can be effectively introduced onto the surface of nanocarbons.Enhanced electrocatalytic activity and selectivity are demonstrated by the plasma-ONCs for H2O2 production.Taking oxidized multiwalled carbon nanotubes as an example,high selectivity(up to 95%)and activity(0.75 V at 1 mA cm^(−2))can be achieved in alkaline solution.Moreover,ex situ x-ray photoelectron spectroscopy and in situ Raman measurements reveal that C–O,C=O,edge defect,and sp2 basal planar defect are probably the active sites. 展开更多
关键词 plasma activation hydrogen peroxide NANOCARBON DEFECT oxygen functional groups
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The Antioxidant Activity of Barley Malt Rootlet Extracts in Heated Corn Oil at Frying Temperature
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作者 Sravanthi Budaraju P. Kumar Mallikarjunan A. Saari Csallany 《Food and Nutrition Sciences》 2021年第9期899-914,共16页
In this study the antioxidant activity of barley malt rootlet (BMR) extracts w</span><span style="font-family:"">as</span><span style="font-family:""> evaluated in... In this study the antioxidant activity of barley malt rootlet (BMR) extracts w</span><span style="font-family:"">as</span><span style="font-family:""> evaluated in heat treated corn oil up to 5 hours at 185</span><span style="font-family:"">&deg;</span><span style="font-family:"">C frying temperature. The antioxidant activity </span><span style="font-family:"">of </span><span style="font-family:"">BMR extracts was measured at 25, 50, 100 and 150 ppm concentrations. The free and bound antioxidant phenolics were extracted from BMR using three different extraction methods. Conventional solvent extraction (CSE), microwave assisted extraction (MAE) and autoclave assisted pretreated solvent extraction (APSE). In the present experiment, the total phenolic content and antioxidant activity of the various extracts w</span><span style="font-family:"">ere</span><span style="font-family:""> measured. Thiobarbituric acid reactive substances (TBARS) assay was used to evaluate the ability of the BMR to protect lipid peroxidation in corn oil at 185</span><span style="font-family:"">&deg;</span><span style="font-family:"">C frying temperature. The formation of TBARS at 5 hours of heat treated corn oil ha</span><span style="font-family:"">s</span><span style="font-family:""> shown similar antioxidant levels in 150 ppm butylated hydroxytoluene (BHT) or MAE free phenolic extract added to corn oil. TBARS value for BHT was 1.896 ± 0.013 μg/mL of corn oil and for MAE was 1.896 ± 0.034 μg/mL of corn oil. The highest level of antioxidant activity was found for the free phenolic extracts. The order of inhibition of oxidation was found to be for free phenolics as follows: BHT (100 ppm) > APSE (50 ppm) > MAE (100 ppm) > CSE (100 ppm). 展开更多
关键词 Antioxidant activity Autoclave Treatment Barley Malt Rootlets BHT Bound and Free Phenolics Corn Oil Lipid peroxidation Microwave Assisted Extraction Secondary Oxidation Products Solvent Extraction
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Platelet-activating factor mediates hydrogen peroxide induced endothelial-leukocyte adhesion
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作者 丁自强 李少华 吴中立 《Journal of Medical Colleges of PLA(China)》 CAS 1992年第3期236-241,共6页
The effects of hydrogen peroxide(H<sub>2</sub>O<sub>2</sub>)on endothelial-polymorphonuclear leuko-cyte(EC-PMN)adhesion and their mechanisms were studied in cultured bovine pulmonaryartery ... The effects of hydrogen peroxide(H<sub>2</sub>O<sub>2</sub>)on endothelial-polymorphonuclear leuko-cyte(EC-PMN)adhesion and their mechanisms were studied in cultured bovine pulmonaryartery endothelial monolayers in vitro.H<sub>2</sub>O<sub>2</sub> at various concentrations(10<sup>-3</sup>,10<sup>-2</sup>,10<sup>-1</sup>mol/Lrespectively)stimulated EC-dependent PMN adhesion,of which 10<sup>-2</sup>mol/L H<sub>2</sub>O<sub>2</sub> was the mostpotent one,increasing adhesion to 2.3 times that of the control.Pretreatment of PMNs with SRI63-441,a platelet-activating factor(PAF)receptor antagonist,had no inhibition effect on H<sub>2</sub>O<sub>2</sub>induced EC-PMN adhesion.Pretreatment of ECs with SRI 63-441 before H<sub>2</sub>O<sub>2</sub> exposure signifi-cantly decreased PMN adherence to ECs.Pretreatment of ECs with phospholipase A<sub>2</sub> inhibitorp-bromophenacyl-bromide or calmodulin antagonist chlorpromazine and calcium ion chelate EG-TA obviously decreased H<sub>2</sub>O<sub>2</sub> induced increment of EC-PMN adhesion.These results suggestthat H<sub>2</sub>O<sub>2</sub> may activate ECs,causing the inflow of extracellular calcium or the release of calciumfrom intracellular deposits.Increased intracellar Ca<sup>2+</sup>may bind with calmodulin to activate phos-pholipase A<sub>2</sub>,thus initiating PAF synthesis and promoting EC-PMN adhesion. 展开更多
关键词 ENDOTHELIAL cells vascular hydrogen peroxidE platelet-activating factor LEUKOCYTE adhesion PHOSPHOLIPASE A BOVINE
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Efficient hydrogen peroxide production enabled by exploring layered metal telluride as two electron oxygen reduction reaction electrocatalyst
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作者 Yingming Wang Hongyuan Yang +6 位作者 Zhiwei Liu Kui Yin Zhaowu Wang Hui Huang Yang Liu Zhenhui Kang Ziliang Chen 《Journal of Energy Chemistry》 SCIE EI CSCD 2023年第12期247-255,I0007,共10页
It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) wi... It is of great interest to develop the novel transition metal-based electrocatalysts with high selectivity and activity for two electron oxygen reduction reaction(2e^(-) ORR).Herein,the nickel ditelluride(NiTe_(2)) with layered structure was explored as the 2e^(-) ORR electrocatalyst,which not only showed the highest 2e^(-) selectivity more than 97%,but also delivered a slight activity decay after 5000 cycles in alkaline media.Moreover,when NiTe_(2) was assembled as the electrocatalyst in H-type electrolyzer,the on-site yield of H_(2)O_(2) could reach up to 672 mmol h^(-1)g^(-1) under 0.45 V vs.RHE.Further in situ Raman spectra,theoretical calculation and post microstructural analysis synergistically unveiled that such a good 2e^(-) ORR performance could be credited to the intrinsic layered crystal structure,the high compositional stability,as well as the electron modulation on the active site Ni atoms by neighboring Te atoms,leading to the exposure of active sites as well as the optimized adsorption free energy of Ni to –OOH.More inspiringly,such telluride electrocatalyst has also been demonstrated to exhibit high activity and selectivity towards 2e^(-) ORR in neutral media. 展开更多
关键词 Transition metal telluride Oxygen reduction reaction Charge polarization activity and selectivity Hydrogen peroxide
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Structure-activity relationships regarding the antioxidant effects of the flavonoids on human erythrocytes
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作者 Yousif Y. Bilto Sanaa Suboh +1 位作者 Talal Aburjai Shtywy Abdalla 《Natural Science》 2012年第9期740-747,共8页
The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The followin... The effects of eleven flavonoids on lipid peroxidation, protein degradation, deformability and osmotic fragility of human erythrocytes exposed in vitro to 10 mM H2O2 for 60 min at 37 oC have been studied. The following flavonoids;quercetin, rutin and morin significantly protected eryt-hrocytes against lipid peroxidation caused by H2O2. This inhibition of lipid peroxidation could be explained by the presence of at least two hydroxyl groups in ring B of the flavonoid structure, regardless of their positions. However, the flavonoids;quercetin, 3,5,7-trihy- droxy-4'-methoxy flavone-7-rutinoside and 3- hydroxy flavone significantly protected eryt-hrocytes against protein degradation. This inhibition could also be explained by the presence of a hydroxyl group at C-3 in ring C of the flavonoid structure. Quercetin and 3,5,7-trihydroxy-4'- methoxy flvone-7-rutinoside significantly protected erythrocytes against loss of deformability and increased osmotic fragility, indicating that the loss of erythrocyte deformability and the increase in osmotic fragility of erythrocytes exposed to H2O2 are related to protein degradation rather than to lipid peroxidation. The other flavonoids (chrysin, 2-carboxy ethyl dihydroxy flavone, apigenin, cirsimaritin, α-naphto flavone and flavanone) failed to protect erythrocytes against the observed oxidative damages. The results demonstrate the importance of the chemical groups substituted on the basic skeleton of the flavonoids in dictating the type of antioxidant activity, and also demonstrate the hemorheological potentials of flavonoids that have particular protein-antioxidant activities. 展开更多
关键词 ERYTHROCYTE DEFORMABILITY LIPID peroxidation Protein Degradation Oxidative Stress H2O2 FLAVONOIDS STRUCTURE-activity Relationships
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CATALYTIC WET PEROXIDE OXIDATION OF HYDROQUINONE WITH Co(II)/ACTIVE CARBON CATALYST LOADED IN STATIC BED
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作者 LI Chunxiang YAN Yongsheng XU Wanzhen 《Chinese Journal of Reactive Polymers》 2008年第1期42-47,共6页
Catalysts based on Co(II) supported on active carbon were prepared and loaded in static bed. The hydroquinone would be degraded completely after treated by Catalytic wet peroxide oxidation method with Co(II)/active ca... Catalysts based on Co(II) supported on active carbon were prepared and loaded in static bed. The hydroquinone would be degraded completely after treated by Catalytic wet peroxide oxidation method with Co(II)/active carbon catalyst. After activate treatment, the active carbon was immerged in cobaltous nitrate solution, then put into a drying oven, Co(II) could be loaded on the micro-surface of carbon. Taking the static bed as the equipment, the absorption of active carbon and catalysis of Co(II) was used to reduce activation energy of hydroquinone. Thus hydroquinone could be drastically degraded and the effluent can be drained under the standard. Referring to Fenton reaction mechanism, experiment had been done to study the heterogeneous catalyzed oxidation mechanism of Co(II). The degradation rate of hydroquinone effluent could be achieved to 92% when treated in four columns at H2O2 concentration 10%, reaction temperature 40℃ , pH 5 and reaction time 2.5h. 展开更多
关键词 接触反应 过氧化物 氧化作用 氢醌 活性炭
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纯棉无纺布低温近中性练漂体系构建及其工艺优化
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作者 卢润 肖鑫 +2 位作者 姜会钰 徐操林 李青 《印染》 北大核心 2024年第1期15-20,共6页
纯棉无纺布练漂在高温强碱中进行,能耗高、排污大、纤维损伤严重。针对该问题,试验构建了三种低温近中性练漂体系,通过对比三者练漂无纺布的颜色特征值、亲水性能和机械性能,选出最优体系;采用XRD、FT-IR、SEM分析体系对棉纤维微观结构... 纯棉无纺布练漂在高温强碱中进行,能耗高、排污大、纤维损伤严重。针对该问题,试验构建了三种低温近中性练漂体系,通过对比三者练漂无纺布的颜色特征值、亲水性能和机械性能,选出最优体系;采用XRD、FT-IR、SEM分析体系对棉纤维微观结构与形貌的影响;通过中心复合设计(CCD)优化该体系漂白工艺,并寻求影响织物白度(WI)的关键因素。研究表明:四乙酰乙二胺/过氧化氢(TAED/H2O2)体系练漂织物WI最高,亲水性优良,强力损伤最小(<20%);练漂体系对棉纤维晶型结构与官能团无影响,能有效去除纤维表面杂质,保护纤维不受损伤。CCD结果显示,温度对WI影响最显著,其次是H2O2浓度与NaHCO3浓度;在最优条件下,得到的理论最优WI为90.38,比原布WI高39.32%。 展开更多
关键词 低温练漂 纯棉无纺布 过氧化氢活化剂 中心复合设计
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Protective effects of organic extracts of Alpinia oxyphylla against hydrogen peroxide-induced cvtotoxicitv in PC12 cells 被引量:4
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作者 Li-Hong Duan Meng Li +10 位作者 Chun-Bao Wang Qing-Mei Wang Quan-Quan Liu Wan-Feng Shang Ya-Jin Shen Zhuo-Hua Lin Tong-Yang Sun Zheng-Zhi Wu Ying-Hong Li Yu-Long Wang Xun Luo 《Neural Regeneration Research》 SCIE CAS CSCD 2020年第4期682-689,共8页
Alpinia oxyphylla,a traditional herb,is widely used for its neuroprotective,antioxidant and memory-improving effects.However,the neuroprotective mechanisms of action of its active ingredients are unclear.In this study... Alpinia oxyphylla,a traditional herb,is widely used for its neuroprotective,antioxidant and memory-improving effects.However,the neuroprotective mechanisms of action of its active ingredients are unclear.In this study,we investigated the neuroprotective effects of various organic extracts of Alpinia oxyphylla on PC12 cells exposed to hydrogen peroxide-induced oxidative injury in vitro.Alpinia oxyphylla was extracted three times with 95%ethanol(representing extracts 1–3).The third 95%ethanol extract was dried and resuspended in water,and then extracted successively with petroleum ether,ethyl acetate and n-butanol(representing extracts 4–6).The cell counting kit-8 assay and microscopy were used to evaluate cell viability and observe the morphology of PC12 cells.The protective effect of the three ethanol extracts(at tested concentrations of 50,100 and 200μg/mL)against cytotoxicity to PC12 cells increased in a concentration-dependent manner.The ethyl acetate,petroleum ether and n-butanol extracts(each tested at 100,150 and 200μg/mL)had neuroprotective effects as well.The optimum effective concentration ranged from 50–200μg/mL,and the protective effect of the ethyl acetate extract was comparatively robust.These results demonstrate that organic extracts of Alpinia oxyphylla protect PC12 cells against apoptosis induced by hydrogen peroxide.Our findings should help identify the bioactive neuroprotective components in Alpinia oxyphylla. 展开更多
关键词 active INGREDIENTS ALPINIA oxyphylla apoptosis ethanol CRUDE extract fraction hydrogen peroxidE nerve regeneration NEUROPROTECTIVE agent NEUROPROTECTIVE effects PC12 cells traditional HERB
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A new acyclic peroxide from Aspergillus nidulans SD-531,a fungus obtained from deep-sea sediment of cold spring in the South China Sea 被引量:4
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作者 LÜFengyi LI Xiaoming +2 位作者 CHI Luping MENG Linghong WANG Bingui 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2020年第4期1225-1232,I0031-I0039,共17页
A new acyclic peroxide derivative asperoxide A(1),along with 13 known compounds,namely,microperfuranone(2),9-hydroxymicroperfuranone(3),gibellulin A(4),lecanoric acid(5),terrequinone A(6),sterigmatocystin(7),isosecost... A new acyclic peroxide derivative asperoxide A(1),along with 13 known compounds,namely,microperfuranone(2),9-hydroxymicroperfuranone(3),gibellulin A(4),lecanoric acid(5),terrequinone A(6),sterigmatocystin(7),isosecosterigmatocystin(8),arugosin C(9),curvularin(10),3,3'-diindolylmethane(11),austinol(12),austin(13),and dehydroaustin(14),were isolated and identified from the culture extract of Aspergillus nidulans SD-531,a fungus obtained from the deep-sea sediment of cold spring in the South China Sea.Their structures were determined based on detailed interpretation of nuclear magnetic resonance(NMR)spectroscopic and mass spectrometry data analysis.All the isolated compounds were evaluated for antimicrobial activities against human and aquatic bacteria as well as plant pathogenic fungi.Compounds 1–8,10,and 11 exhibited antimicrobial activities against some of the tested strains with minimum inhibitory concentration(MIC)values ranging from^2 to 64μg/mL.Compounds 4 and 6 displayed strongest activities among the tested samples and might be used as promising molecules for the development of natural antimicrobial agents. 展开更多
关键词 acyclic peroxide Aspergillus nidulans cold spring fungus antimicrobial activity
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Recent progress on electrochemical production of hydrogen peroxide 被引量:1
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作者 Aniqa Sehrish Romana Manzoor +2 位作者 Kai Dong Yuanyuan Jiang Yizhong Lu 《Chemical Reports》 2019年第2期81-101,共21页
Hydrogen peroxide (H2O2), first synthesized in 1818 through the acidification of barium peroxide (BaO2) with nitric acid, is a clear and colorless liquid which is entirely miscible with water and variety of organic so... Hydrogen peroxide (H2O2), first synthesized in 1818 through the acidification of barium peroxide (BaO2) with nitric acid, is a clear and colorless liquid which is entirely miscible with water and variety of organic solvents such as carboxylic acid and esters. Anthraquinone process (an old production process of H2O2), a batch process carried out in large facilities is an energy demanding process that requires large facilities, and involves oxidation of anthraquinone molecules and sequential hydrogenation. Moreover, the direct synthesis method enables production in a continuous mode as well as it permits small scale, decentralized production. Many drawbacks associated with these processes such as, energetic inefficiency and inherent disadvantages have motivated researchers, industry and academia to find out alternative for synthesis of H2O2. Electrochemical route based on catalyst selectively reduce oxygen to hydrogen peroxide. O2 is cathodically reduced to produce H2O2 via 2-electron pathway or 4-electron pathway to get H2O. Electrolysis of water has an important place in storage and electrochemical energy conversion process where problem is to choose a sufficiently stable and active electrode for anodic oxygen evolution reaction. Most commonly used catalysts on the cathode are carbon based materials such as carbon black, carbon nanotubes, graphite, carbon sponge, and carbon fiber. In perspective of expanding demand of production and usage of hydrogen peroxide we review the past literature to summarize different production processes of H2O2. In this review, we mainly focus on electrochemical production of hydrogen peroxide along with other alternatives, such as anthraquinone method for industrial H2O2 production and direct synthesis process. We also review the catalytic activity, selectivity and stability for enhanced yield of H2O2. From revision of last two decade’s literature including experimental and theoretical data;we argue that successful implementation of electrochemical H2O2 production can be realized on the basis of stable, active and selective catalyst. 展开更多
关键词 hydrogen peroxidE direct SYNTHESIS ELECTROCHEMICAL SYNTHESIS oxygen reduction reaction CATALYTIC SELECTIVITY and activity
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