Synthesis and spin trapping behavior of three novel DMPO derivatives, namely 5-hydroxymethyl-5-methyl-pyrroline N-oxide (HMMPO), 5-(2-furanyl)-oxymethyl-5-methyl-pyrroline N-oxide (FMMPO), and 5-(2-pyranyl)-oxymethyl-5-methyl-pyrroline N-oxide (PMMPO) towards different oxygen- and carbon-centered radicals are described. The stabilizing effect of a series of cyclodextrins on the superoxide adducts was
Kinetics of Spin Trapping Superoxide, Hydroxyl, and Aliphatic Radicals by Cyclic Nitrones
作者:Sara Goldstein、Gerald M. Rosen、Angelo Russo、Amram Samuni
DOI:10.1021/jp048441i
日期:2004.8.1
Spintrapping coupled with electron paramagnetic resonance (EPR) spectroscopy has surfaced as one of the most specific and reliable methods for identifying free radicals in biological systems. Despite extensive studies focused on the kinetics of radicaltrapping by cyclicnitrones, the mechanism has not been fully elucidated. Moreover, major controversies still persist even regarding the efficiency
Spin trapping with 5,5-dimethylpyrroline-N-oxide in aqueous solution.
作者:YUTAKA KIRINO、TAKAAKI OHKUMA、TAKAO KWAN
DOI:10.1248/cpb.29.29
日期:——
Spin trapping with 5, 5-dimethylpyrroline-N-oxide (DMPO) of various radicals was carried out in aqueous solutions and the ESR parameters for the spin adduct radicals were determined. Comparison of hyperfine coupling constants obtained in aqueous solutions and in benzene revealed that considerable solvent effect exists. For the radical obtained by the addition of a hydroxyl radical to DMPO, the hyperfine coupling constant was found to depend on the basicity of the solution. This phenomenon was analyzed in terms of the acid dissociation equilibrium of the hydroxyl proton of the adduct radical, and the pK value was determined to be 12.96.
Enhanced peroxidase-like activity of porphyrin functionalized ZnFe<sub>2</sub>O<sub>4</sub> hollow nanospheres for rapid detection of H<sub>2</sub>O<sub>2</sub> and glucose
作者:Bing Bian、Qingyun Liu、Shitao Yu
DOI:10.1039/c8nj00720a
日期:——
microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). In comparison with bare ZnFe2O4 HSs, Por–ZnFe2O4 HSs exhibit enhanced intrinsic peroxidase-like activity. They demonstrate a fast colorimetric response to H2O2 with a detection limit as low as 0.86 μM. The catalytic mechanism of the system was proved to be a hydroxyl radical mechanismusingelectronspinresonance (ESR). By combining the Por–ZnFe2O4
使用简单的一锅溶剂热法,制备了由5,10,15,20-四(4-羧基苯基)-卟啉(Por–ZnFe 2 O 4 HSs)功能化的二元金属氧化物,磁性和空心ZnFe 2 O 4纳米球。随后被用作天然过氧化物酶的替代品。使用粉末X射线衍射(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM)和X射线光电子能谱(XPS)对Por-ZnFe 2 O 4 HS进行了表征。与裸ZnFe 2 O 4 HS相比,Por–ZnFe 2 O 4HS表现出增强的内在过氧化物酶样活性。他们展示了对H 2 O 2的快速比色响应,检测限低至0.86μM。使用电子自旋共振(ESR)证明了该体系的催化机理是羟基自由基机理。通过结合Por-ZnFe 2 O 4 HSs催化的反应和葡萄糖与葡萄糖氧化酶的酶促氧化,建立了用于葡萄糖检测的比色平台。Por-ZnFe 2 O 4 HSs /葡萄糖氧化酶(GOx)/ TMB系统对葡萄糖的响应良好,检出限为5
6-Methyl 3-chromonyl 2,4-thiazolidinedione/2,4-imidazolidinedione/2-thioxo-imidazolidine-4-one compounds: novel scavengers of reactive oxygen species
作者:Paweł Berczyński、Ewa Duchnik、Irena Kruk、Teresa Piechowska、Hassan Y. Aboul-Enein、Oya Bozdağ-Dündar、Meltem Ceylan-Unlusoy
DOI:10.1002/bio.2554
日期:2014.6
chemiluminescence, electron paramagnetic resonance, spin trapping and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH•) methods. The total antioxidant capacity was also measured using a ferric‐ferrozine reagent. Compounds having a hydrogen atom at the N3‐position of the β‐ring were effective in quenching CL resulted from the KO2/18‐crown‐6‐ether system (a source of superoxide anion radical, ) in a dose‐dependent