白杨素锰配合物消除超氧基阴离子自由基的理论

采用量子化学中的DFT法,在uB3LYP水平上,添加溶剂化效应用高斯09程序包优化了O_2˙-,白杨素(Chrysin),及2Chrysin-Mn^(2+),2Chrysin-Mn^(3+)与超氧基自由基阴离子相互作用后的2Chrysin-Mn^(2+)-O_2˙-,2Chrysin-Mn3+-O_2˙-的几何构型,并在同样的计算水平上计算和分析了频率和NBO电荷,得到相应的优化后的几何优化参数,电荷变化,能量,电子密度等。得出白杨素锰配合物与超氧基自由基阴离子有较强的相互作用;配合物几何构型趋于保持原有的平面结构,但自由基构型的发生了变化,配合物对自由基阴离子有很好的消除作用;而从能量上看2Chrysin-Mn^(3+)分子比2Chrysin-Mn^(2+)分子有更好的消除作用。

桑色素铁配合物消除超氧基阴离子自由基的理论研究

采用量子化学的密度泛函(DFT)法,用Gaussian 09程序包优化了桑色素(Morin)与Fe^(2+)三种可能的配合物及其与超氧基阴离子自由基(O·―2)相互作用后的几何构型,并在同样的研究条件下计算和分析了三个体系的自然电子布居(NPA)即电荷分布。得到相应的优化几何结构参数、NPA电荷、相互作用能量等。结果表明,所有优化体系均无虚频,结构稳定。Morin-Fe^(2+)配合物与O·―2的相互作用能表明,三种络合方式均对该自由基有良好的消除作用。相互作用能数值在基组重叠误差(BSSE)校正后分别为:7.075 kJ/mol(5,6元环配合物)、-32.832 kJ/mol(5元环配合物)、-59.612 kJ/mol(6元环配合物)。其中Fe^(2+)以六元环的方式与双分子Morin结合的方式与自由基的相互作用能最大,作用结果使得O·―2的NPA电荷增加最多,因此推测强相互作用的主导因素为电荷,这与前线轨道电子云分布一致。最高占据轨道(HOMO)中电子云集中分布在以Fe^(2+)为中心的六元环,分子骨架上共轭体系的电子云向金属中心迁移。最低空轨道(LUMO)中电子云集中分布在以Fe^(2+)为中心的六元环周围,呈现基本对称的分布形式,而金属中心与自由基上分布较少,这与自由基电荷增加相一致。

红细胞膜的ESR研究——冷冻固化新鲜膜的各向异性及氧化特性

冷冻干燥膜和冷冻固化新鲜膜都得到各向异性的ESR谱,表明红细胞膜之间存在电磁相互作用。经超氧阴离子O_2^-氧化后的红细胞膜在ESR谱图中出现了g=2.0062的吸收峰,故本文还对O_2^-与细胞膜的相互作用了实验研究。

牙周炎患者龈组织中的自氧化作用与临床指数的相关性研究

目的：探讨内源性超氧基（Ｏ２）损伤在慢性成人牙周炎（ＡＰ）发生发展过程中的作用。方法：采用化学发光法、氧化法和比色法对４２例ＡＰ患者龈组织中的超氧基（Ｏ２）、超氧化物歧化酶（ＳＯＤ）活性和过氧化脂质产物（ＭＤＡ）含量进行测定。并将反映自氧化作用的ＳＯＤ．ＭＤＡ与临床指数进行直线相关及多元线形回归分析。结果：实验组与对照组 Ｏ２、ＳＯＤ、 ＭＤＡ活性水平有显著性差异（Ｐ＜ ０． ００１）； ＳＯＤ与周袋深度（ＰＤ）、附着丧失（ＡＬ）呈负相关（Ｐ＜０．００１）；ＭＤＡ与ＰＤ、ＡＬ呈正相关（Ｐ＜０．００１）。结论：氧自由基参与牙周病的病理过程。

SOD-like Activities of Fifteen Constituents from Rhubarb

It is important to search for the ingredients with SOD—like activity present in Chinese traditional drugs.Four classes of constituents including fifteen compounds isolated from Chinese rhubarb were studied for their SOD-like activity by determining the percentage of scavenging effect of the superoxide radical anion (O2),(S％),The results showed that the SOD-like activities of four tanninoid compounds were stronger among which(—)-epi- catechin has the strongest SOD-like activity at lower concentrations:the activity of five stil- bene compounds is weaker:while chrysophanol-8-glucoside and desoxyrhaponticin have no SOD-like activity and,on the contrary.may promote the production of O_2^-

Studies on the Anti-lipid Peroxidative Actions of the Methanolic Extract of the Root of Aegle marmelos and Its Constituents In Vivo and In Vitro

The inhibitory effect of the methanolic extract of the root of Aegle marmelos (MERA) and its constituents on the lipid peroxidation in vivo and in vitro were studied. The results suggested that MERA increased the activities of superoxide dismutase (SOD) and GSH-peroxidase in the liver cytosol of mice, but showed no significant effect on the activity of catalase, and one of its major constituents, 4-methoxy-1-methyl-2-quinolone (MMQ) increased the activity of SOD in liver tissue of mice intoxicated with FeCl2-ascorbic acid (AA)-ADP in vivo. Various constituents isolated from the root of title plant inhibited the lipid peroxidation in rat liver homogenate, which was in vitro induced by FeCl2-ascorbic acid, CCl4-NADPH, or ADP- NADPH. Of the test compounds, MMQ and its derivatives integriquinolone were similar to (-tocopherol in inhibiting MDA production in rat liver microsomes induced by Fe2+-ascorbate, CCl4-NADPH, or ADP-NADPH.

Extraction of Pumpkin Polysaccharide by Complex Enzyme Method and Its Antioxidant Research

[Objective] This paper aims to study a new method of extracting pumpkin polysaccharide from pumpkin. Single factor experiments were conducted to examine the effects of extracting time,temperature,the solid-liquid ratio and pH value on the extraction yield of polysaccharide from pumpkin. [Method] The best enzyme ratio and extraction conditions for complex enzymes extraction were determined through orthogonal tests. Scavenging ·OH and O-2 activities of pumpkin polysaccharides were also investigated by salicylic acid and improved self-oxidation of o-pheno methods respectively. [Results] The results showed that the biggest extraction yield of polysaccharide from pumpkin can be got when adding 1% cellulose enzyme,1.5% pectinase,1.0% papain and Na2HPO4-citric acid buffer solution (pH was 4.6),and oscillating for 30 min under water at 40 ℃ with the solid-liquid ratio of 1:30. In addition,pumpkin polysaccharides had a strong activity of eliminating ·OH,but very weak activity to scavenge O-2. [Conclusion] This study provided basic data for research and application of Pumpkin polysaccharide.

Decorating Ag/AgCl on UiO-66-NH2: Synergy between Ag plasmons and heterostructure for the realization of efficient visible light photocatalysis

UiO-66-NH2, as typical visible light responsive Zr-based metal-organic frameworks (MOFs), has attracted great interest in recent years. However, rapid combination of the photoinduced carriers limits its further application. Here, we designed a facile precipitation-photoreduction method to post-synthetically decorate Ag/AgCl on the surface of UiO-66-NH2 and form a heterostructure. Metallic Ag can not only transmit electrons between UiO-66-NH2 and AgCl but also absorb visible light, because of the surface plasmon resonance (SPR) effect. The rhodamine B photodegradation rate of UiO-66-NH2/Ag/AgCl (16.2 wt.% Ag) is about 10 and 4 times those of UiO-66-NH2 and Ag/AgCl, respectively. The SPR effect of Ag NPs and the formation of a heterostructure synergistically increase the absorbability of visible light, accelerate the separation of photoinduced charges, and promote the formation of superoxide radicals. We expect that our work could provide a new viewpoint for constructing efficient MOF-based photocatalytic systems.

Effect of Cu(11)-Salicylate in Micellar Systems onScavenging Superoxide Ion Released by CulturedMacrophages

基于胶束与球状蛋白的相似性，用胶束模拟超氧化物歧化酶（ＳＯＤ）的微环境，以促进ＳＯＤ模拟物─水杨酸铜络合物对Ｏ歧化的催化作用，达到清除Ｏ＿２的目的。本文首次用培养的巨噬细胞受刺激产生的“呼吸暴发”为Ｏ的发生源，研究了在ＣＴＡＢ、ＳＤＳ、ＴｒｉｔｏｎＸ－１００及Ｔｗｅｅｎ２０胶束体系中水杨酸铜络合物对Ｏ的清除作用。研究结果表明，以水杨酸铜－ＳＤＳ胶束体系对Ｏ的清除率最高，达９０．４％。其他胶束体系对Ｏ的歧化亦均有促进作用。

N-acetylcysteine attenuates alcohol-induced oxidative stess in rats

AIM:To investigate free-radical scavenger effect of n- acetylcysteine in rats intragastrically fed with ethanol. METHODS:Twenty-four rats divided into three groups were fed with ethanol (6 g/kg/day,Group 1),ethanol and n- acetylcysteine (1 g/kg,Group 2),or isocaloric dextrose (control group,Group 3) for 4 weeks.Then animals were sacrificed under ether anesthesia,and intracardiac blood and liver tissues were obtained.Measurements were made in both serum and homogenized liver tissues. Malondialdehyde (MDA) level was measured by TBARS method.Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels were studied by commercial kits. Kruskal-Wallis test was used for statistical analysis. RESULTS:ALT and AST in Group 1 (154 U/L and 302 U/L, respectively) were higher than those in Group 2 (94 U/L and 155 U/L) and Group 3 (99 U/L and 168 U/L) (P=0.001 for both).Serum and tissue levels of MDA in Group 1 (1.84 nmol/mL and 96 nmol/100 mg-protein) were higher than that in Group 2 (0.91 nmol/mL and 64 nmol/100 mg protein) and Group 3 (0.94 nmol/ml and 49 nmol/100 mg-protein) (P<0.001 for both).On the other hand,serum GSH-Px level in Group 1 (8.21 U/g Hb) was lower than that in Group 2 (16 U/g Hb) and Group 3 (16 U/g-Hb) (P<0.001).Serum and liver tissue levels of SOD in Group 1 (11 U/mL and 26 U/100 rag-protein) were lower than that in Group 2 (18 U/ mL and 60 U/100 mg protein) and Group 3 (20 U/mL and 60 U/100 rag-protein) (P<0.001 for both). CONCLUSION:Ethanol-induced liver damage was associated with oxidative stress,and co-administration of n-acetylolsteine attenuates this damage effectively in rat model.

Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals

The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD),peroxidase (POD),catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O2ˉ).The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H.pluvialis during exposure to reactive oxygen species (ROS) such as Oˉ2.Astaxanthin reacted with ROS much faster than did the protective enzymes,and had the strongest antioxidative capacity to protect against lipid peroxidation.The defensive mechanisms varied significantly between the three cell types and were related to the level of astaxanthin that had accumulated in those cells.Astaxanthin-enriched red cells had the strongest antioxidative capacity,followed by brown cells,and astaxanthin-deficient green cells.Although there was no significant increase in expression of protective enzymes,the malondialdehyde (MDA) content in red cells was sustained at a low level because of the antioxidative effect of astaxanthin,which quenched Oˉ2 before the protective enzymes could act.In green cells,astaxanthin is very low or absent;therefore,scavenging of ROS is inevitably reliant on antioxidative enzymes.Accordingly,in green cells,these enzymes play the leading role in scavenging ROS,and the expression of these enzymes is rapidly increased to reduce excessive ROS.However,because ROS were constantly increased in this study,the enhance enzyme activity in the green cells was not able to repair the ROS damage,leading to elevated MDA content.Of the four defensive enzymes measured in astaxanthin-deficient green cells,SOD eliminates Oˉ2,POD eliminates H2O2,which is a by-product of SOD activity,and APX and CAT are then initiated to scavenge excessive ROS.

Synthesis and Properties of Micron-size Magnetic Polymer Spheres with Epoxy Groups

Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA) spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe3O4 nanoparticles made by co-precipitation were first mixed with monomers of St, DVB, GMA, and benzoyl peroxide (BPO) to form oil in water suspension with the presence of poly(viny) pyrrolidone) (PVP-K30) as a stabilizer. Then the temperature of mixture was increased at a controlled rate to obtain small and relatively uniform droplets. Finally, the copolymerization reaction was initiated by the decomposition of BPO. The morphology and properties of magnetic PSt-DVB-GMA microspheres were examined by SEM, TEM, VSM, XRD and FT-IR. The magnetic microspheres obtained have very small size (about 4-7μm) in diameter with narrow size distribution and super-paramagnetic characteristics. Powder X-ray diffraction measurements show the inverse cubic spinel structure for the magnetite dispersed in polymer microspheres. FT-IR spectroscopy indicates extensive oxirane groups existed on the surface of magnetic PSt-DVB-GMA microspheres.

Studies on Biologically Active Principles of Huangqi,Root of Astragalus membranaceous,Isolation and Detection of Constituents Scavenging Superoxide Anion

本文使用黄嘌呤-黄嘌呤氧化酶—鲁米诺化学发光体系和化学发光检测法研究了黄芪中各成分的清除超氧阴离子自由基的能力,以药物抑制发光强度50%的浓度(IC_(50))为指标。经研究证明,黄芪总皂甙部分(N)具有较强的活性,IC_(50)为185μg/ml,再经进一步导向分离并鉴定证明,黄芪甙Ⅲ,Ⅳ和Ⅵ的 IC)_(50)分别为80、50和11μg/ml,从而证明黄芪的抗心力衰竭的有效成分可能为黄芪总皂甙部分。

Antioxidative Activity of Polysaccharide Fractions Isolated from Tricholoma Matsutake Sing. with Ultrafiltration

Polysaccharides of Tricholoma matsutake Sing. were extracted with boilingwater, followed by precipitating with ethanol. Two membranes of different molecular weight cut-off, namely, 30 kD and 10 kD were chosen with ultrafiltration. The antioxidant activity of the purification polysaccharides was evaluated by various antioxidant assay, including DPPH （l,l-diphenyl-2-picrylhydrazyl） radical scavenging, superoxide anion radical scavenging and hydrogen peroxide scavenging. The scavenging effect on hydroxyl radical and DPPH radical, which may be comparable to Vitamin C, while the scavenging effect on superoxide anion radicals was not obvious.

Preparation of Superparamagnetic Dextran-coated Iron Oxide Nanoparticles used as a Novel Gene Carrier into Human Bladder Cancer Cells'

Objective: Application of magnetic nanoparticles as gene carrier in gene therapy has developed quickly. This study was designed to investigate the preparation of superparamagnetic dextran-coated iron oxide nanoparticles (SDION) and the feasibility of SDION used as a novel gene carrier for plasmid DNA in vitro. Methods: SDION were prepared by chemical coprecipitation and separated by gel filtration on Sephacryl S-300HR, characterized by TEM, laser scattering system and Vibrating Sample Magnetometer Signal Processor. The green fluorescent protein (pGFP-C2) plasmid DNA was used as target gene. SDION-pGFP-C2 conjugate compounds were produced by means of oxidoreduction reaction. The connection ratio of SDION and pGFP-C2 DNA was analyzed and evaluated by agarose electrophoresis and the concentration of pGFP-C2 in supernatant was measured. Using liposome as control, the transfection efficiency of SDION and liposome was respectively evaluated under fluorescence microscope in vitro. Results: The diameter of SDION ranges from 3 nm to 8 nm, the effective diameter was 59.2 nm and the saturation magnetization was 0.23 emu/g. After SDION were reasonably oxidized, SDION could connect with pGFP-C2 to a high degree. The transfection efficiency of SDION as gene carrier was higher than that of liposome. Conclusion: The successes in connecting SDION with pGFP-C2 plasmid by means of oxidoreduction reaction and in transferring pGFP-C2 gene into human bladder cancer BIU-87 cells in vitro provided the experimental evidence for the feasibility of SDION used as a novel gene carrier.

Temperature-Dependent Formation of Redox Sites in Molybdenum Trioxide Studied by Electron Paramagnetic Resonance Spectroscopy

The formation and qualification of redox sites in transition metal oxides are always the active fields related to electronics, catalysis, sensors, and energy-storage units. In the present study, the temperature dependence of thermal reduction of MoO3 was surveyed at the range of 350℃ to 750℃. Upon reduction, the formed redox species characterized by EPR spectroscopy are the MoVion and superoxide anion radical (O2-) when the reduction was induced at the optimal temperature of 300-350℃. When heating-up from 350℃, the EPR signals started to decline in amplitude. The signals in the range of 400-450℃ decreased to half of that at 350℃, and then to zero at ~600℃. Further treatment at even higher temperature or prolonged heating time at 500℃ caused more reduction and more free electrons were released to the MoO3 bulk, which results in a delocalized means similar to the antiferromagnetic coupling. These data herein are helpful to prepare and study the metal-oxide catalysts.

Supramolecular Fixation of Three Amines using Cobalt Tetraphenyl- porphyrin for SO2 Removal

In this work, supramolecular fixation of three amines, including aniline, ethylenediamine, and diethylamine, using cobalt tetraphenylporphyrin （CoTPP） for SO2 removal was studied using UV-Vis and fluorescence measurements. The UV-Vis spectra showed that increasing amines concentrations resulted in bathochromic shift for CoTPP Soret absorption band （B band）. Once SO2 was introduced, it competed with CoTPP for aniline, ethylenediamine, and diethylamine, which eventually led to the release of CoTPP and the change of solution colour/absorption band. After that, the CoTPP was regenerated and got back to the first state. The fluorescence spectra offered that CoTPP interacted with aniline, ethylenediamine, and diethylamine to form 1：1 molecular adducts. The interactions of CoTPP with aniline, ethylenediamine, and diethylamine were entropy-driven. The interaction of CoTPP with aniline and diethylamine was endothermic, and that with ethylenediamine was exothermic. Ethylenediamine presented a stronger binding constant value for CoTPP, so it was considered as a potential agent for SO2 removal.

Nitroglycerine effects on portal vein mechanics and oxidative stress in portal hypertension

AIM:Тo examine the effects of nitroglycerine on portal vein haemodynamics and oxidative stress in patients with portal hypertension.METHODS:Thirty healthy controls and 39 patients with clinically verified portal hypertension and increasedvascular resistance participated in the study.Liver di-ameters,portal diameters and portal flow velocities were recorded using color flow imaging/pulsed Doppler detection.Cross-section area,portal flow and index of vascular resistance were calculated.In collected blood samples,superoxide anion radical (O 2-),hydrogen per-oxide (H 2 O 2),index of lipid peroxidation (measured as TBARS) and nitric oxide (NO) as a marker of endothelial response (measured as nitrite-NO 2-) were determined.Time-dependent analysis was performed at basal state and in 10th and 15th min after nitroglycerine (sublingual 0.5 mg) administration.RESULTS:Oxidative stress parameters changed sig-nificantly during the study.H 2 O 2 decreased at the end of study,probably via O 2-mediated disassembling in Haber Weiss and Fenton reaction;O 2-increased signifi-cantly probably due to increased diameter and tension and decreased shear rate level.Consequently O 2-and H 2 O 2 degradation products,like hydroxyl radical,initi-ated lipid peroxidation.Increased blood flow was to some extent lower in patients than in controls due to double paradoxes,flow velocity decreased,shear rate decreased significantly indicating non Newtonian char-acteristics of portal blood flow.CONCLUSION:This pilot study could be a starting point for further investigation and possible implemen-tation of some antioxidants in the treatment of portal hypertension.

Oxidation behaviors of wrought nickel-based superalloys in various high temperature environments

Oxidation characteristics of Alloy 617 and Haynes 230 at 900 oC in simulated helium environment,hot steam environment containing H2 as well as in air and pure helium conditions were investigated.Compared to air condition,the oxidation rate of Alloy 617 was not significantly affected in helium and hot steam environments,while Haynes 230 showed lower oxidation rate in helium environment.On the other hand,the oxide morphology and structure of Alloy 617 were strongly affected by the environments,but those of Haynes 230 were less dependent on the environments.For Haynes 230,a Cr2O3 inner layer and a protective MnCr2O4 outer layer were formed in all environments,which contributed to the better oxidation resistance.As the mechanical properties,such as creep and tensile properties,were significantly affected by the oxidation behaviors,surface treatment methods to enhance oxidation resistance of these alloys should be developed.

Chemical constituents and antioxidant activities of waste liquid extract from Apostichopus japonicus Selenka processing

Apostichopus japonicus Selenka is an ideal tonic food that is used traditionally in many Asian countries, and it contains many bioactive substances, such as antioxidant, antimicrobial, and anticancer materials. To convert waste liquid generated during production into a useful resource, extract from waste liquid was isolated by column chromatography and studied by the pyrogallol autoxidation and 1,10-phenanthroline-Fe^2＋ oxidation methods. Results show that the extract scavenged about 91% of the superoxide anion radical at a concentration of 1.4 mg/mL and 24% of the hydroxyl radical at 3.3 mg/mL. Four compounds were isolated and identified from the extract： 2,4-dihydroxy-5-methyl-1,3-azine; 2,4-dihydroxy- 1,3-diazine; 3-O-β-D-quinovopranosyl-（1→2）-4-O-sodium sulfate-β-D-xylopranosyl]-holosta-9（11）-ene313,12β,17α-triol; and 24-ethyl-5α-cholesta-7-ene-3β-O-β-D-xylopyranoside. All of these compounds are known in A. japonicus, and were found in the waste liquid for the first time.