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101.
Montserrat Cortina-Puig Xavier Muoz-Berbel Regis Rouillon Carole Calas-Blanchard Jean-Louis Marty 《Bioelectrochemistry (Amsterdam, Netherlands)》2009,76(1-2):76
This paper describes the development of an amperometric cytochrome c (cyt c)-based biosensor and its later application to the quantification of the scavenging capacity of antioxidants. The enzymatic biosensor was constructed by covalently co-immobilizing both cyt c and XOD on a mercaptoundecanol/mercaptoundecanoic acid (MU/MUA) mixed self-assembled monolayer (SAM)-modified screen-printed gold electrode. The applicability of this method was shown by analyzing the antioxidant capacity of pure substances, such as ascorbic acid and Trolox, and natural sources of antioxidants, particularly 5 orange juices. 相似文献
102.
Hakim Karoui 《Tetrahedron letters》2004,45(5):1043-1045
In phosphate buffer solution the half-life of the PBN-superoxide spin adduct is very short. However, as a result of the formation of inclusion complexes, its ESR signal was easily detected for up to 25 min when the trapping of superoxide anion with PBN was carried out in the presence of different cyclodextrins. Furthermore, the formation of these inclusion complexes results in a significant protection of the PBN-superoxide adduct against l-ascorbate monoanion reduction. 相似文献
103.
The capacity of estrogen and stilbene derivatives to modulate the activity of superoxide dismutases in relation with their estrogenic properties has been studied. The properties of trans-resveratrol (3,5,4′-trihydroxystilbene) and its analogues, 4-hydroxystilbene, 4,4′-dihydroxystilbene, 3,5-dihydroxystilbene, 3,5,4′-trimethoxystilbene and 4,4′-dihydroxy-3,5,3′,5′-tetramethylstilbene were compared to 17β-estradiol and its analogues (2-methoxyestradiol, estrone, 2-hydroxyestradiol and 2-methoxyestrone). Measurement of estrogen receptor-β (ER-β) binding capacity was carried out by a receptor competitor assay associated with fluorescence polarisation detection. The superoxide dismutase (SOD) modulation activity was followed with a spectrophotometric assay using the sequence xanthine/xanthine oxidase-2,3-bis[2-methoxy-4-nitro-sulfo-phenyl]-2H-tetrazolium-5-carboxanilide (X/XO-XTT). The structure-activity relationship was different for the two series tested. In the estrogenic series, a compound which does not inhibit SOD, is recognized by the ER-β. In contrast for the stilbenic series both properties are parallel each other. 相似文献
104.
分析了可见光/H2O2体系中产生协同敏化效应的原因. 通过分析苯酚红、 甲基橙、 天青Ⅰ及三者混合物的紫外-可见光谱发现, 三者混合后拓宽了在可见光区的响应范围, 提高了对可见光的利用率. 采用邻菲罗啉法、 二苯基卡巴肼法和磷钼酸铵分光光度法分别测试了上述有色物在可见光/H2O2体系中产生光生电子e、 单线态氧和超氧阴离子自由基的量, 结果表明, 三者混合物在可见光下超氧阴离子自由基的产量明显比单独有色物的高, 光生电子和单线态氧的产量相差不大, 说明超氧阴离子自由基产量的提高是产生协同敏化的主要原因. 测试结果还证实光生电子不能催化过氧化氢产生羟自由基. 相似文献
105.
SU Yan-bin JIANG Yi-zhong LU Ming CHENG Ying-kun SU Yan-wen ZHANG Fen-rong LI Zheng-qiang . Key Laboratory for Molecular Enzymology Engineering the Ministry of Education Jilin University Changchun P. R. China . School of Chemical Pharmaceutical Engineering Jilin Institute of Chemical Technology Jilin . Jilin Provincial Institute for Drug Food Control Changchun . Cardiovascular Surgery 《高等学校化学研究》2009,25(5):686-689
Effect of Siqi decoction on myocardial ischemia is to prevent cardiac myocyte membrane from damage associated with oxygen free radicals related to NO. To research the regulatoin of the content of malondialdehyde by Siqi decoction, an index of lipid peroxidation, via increasing activity of superoxide dismutase in blood serum of rats with Myocardial Ischemia, the model of myocardium ischemia was made in Wistar rats with posterior pituitary injection through vein in tail. Siqi decoction, Diaoxinxuekang(DK) and... 相似文献
106.
水溶性C60-β丙氨酸衍生物清除超氧阴离子自由基O-·2及对小鼠胸腺细胞生长影响的研究 总被引:4,自引:0,他引:4
合成具有特殊生物活性的富勒烯衍生物及其生物活性的研究是近年来十分活跃的研究领域.许多实验显示C 60衍生物在抗爱滋病毒、神经保护、抗菌、 DNA切割和光动力学治疗等方面具有良好的应用前景[1]. 其中C 60衍生物对自由基的清除显得十分重要[2]. 相似文献
107.
. Five neutral mixed‐ligand mononuclear square‐pyramidal copper(II) complexes of the type [Cu(cpf)(Ln)Cl] (cpf = ciprofloxacin and Ln = phenanthroline derivatives) ( 1 – 5 ) were synthesized and characterized. The complexes were screened for their antibacterial activity and bactericidal activity against two Gram(+ve) and three Gram(–ve) microorganisms and the results showed that all complexes studied are more potent than the quinolone standard drug ciprofloxacin. Absorption titration, viscosity, and thermal denaturation measurement studies revealed that each of these square‐pyramidal complexes moderately interacts with calf thymus DNA. The binding constants for mixed ligand complexes are in order of 1.5 × 104–3.0 × 104 M–1. Based on the data obtained in the DNA binding studies an intercalative mode of binding is suggested for these complexes. The nucleolytic cleavage activity of adducts and gyrase inhibition assay were studied on double stranded pUC19 DNA by gel electrophoresis experiments. From the SOD mimic study; the concentration of complexes ranging from 0.45 μM to 1.45 μM are enough to inhibit the reduction rate of NBT by 50 % (IC50) in NADH/PMS system. 相似文献
108.
Aysu Yarman Thomas Nagel Nenad Gajovic‐Eichelmann Anna Fischer Ulla Wollenberger Frieder W. Scheller 《Electroanalysis》2011,23(3):611-618
We report on the redox behaviour of the microperoxidase‐11 (MP‐11) which has been electrostatically immobilized in a matrix of chitosan‐embedded gold nanoparticles on the surface of a glassy carbon electrode. MP‐11 contains a covalently bound heme c as the redox active group that exchanges electrons with the electrode via the gold nanoparticles. Electroactive surface concentration of MP‐11 at high scan rate is between 350±50 pmol cm?2, which reflects a multilayer process. The formal potential (E°′) of MP‐11 in the gold nanoparticles‐chitosan film was estimated to be ?(267.7±2.9) mV at pH 7.0. The heterogeneous electron transfer rate constant (ks) starts at 1.21 s?1 and levels off at 6.45 s?1 in the scan rate range from 0.1 to 2.0 V s?1. Oxidation and reduction of MP‐11 by hydrogen peroxide and superoxide, respectively have been coupled to the direct electron transfer of MP‐11. 相似文献
109.
110.