Co-reporter:Saipeng Huang, Rongcheng Han, Qianfen Zhuang, Libo Du, Hongying Jia, Yangping Liu, Yang Liu
Biosensors and Bioelectronics 2015 Volume 71() pp:313-321
Publication Date(Web):15 September 2015
DOI:10.1016/j.bios.2015.04.056
•NPA–TPP can accumulate in mitochondria of live cells with high specificity.•NPA–TPP exhibits superior photostability which makes it well suitable for real-time tracking movement changes of mitochondria within a long term.•High water solubility and low cytotoxicity manifest superiority for the imaging and analysis in vitro.•Mitochondrial dynamics morphology, movement and number of changes induced by stimulus can be real-time tracking depending on NPA–TPP.Monitoring mitochondria morphological changes temporally and spatially exhibits significant importance for diagnosing, preventing and treating various diseases related to mitochondrial dysfunction. However, the application of commercially available mitochondria trackers is limited due to their poor photostability. To overcome these disadvantages, we designed and synthesized a mitochondria-localized fluorescent probe by conjugating 1,8-naphthalimide with triphenylphosphonium (i.e. NPA–TPP). The structure and characteristic of NPA–TPP was characterized by UV–vis, fluorescence spectroscopy, 1HNMR, 13CNMR, FTIR, MS, etc. The photostability and cell imaging were performed on the laser scanning confocal microscopy. Moreover, the cytotoxicity of NPA–TPP on cells was evaluated using (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. The results showed that NPA–TPP not only has high sensitivity and specificity to mitochondria, but also exhibits super-high photostability, negligible cytotoxicity and good water solubility. In short, NPA–TPP indicates great potential for targeting mitochondria and enables a real-time and long-term tracking mitochondrial dynamics changes.
Co-reporter:Libo Du, Saipeng Huang, Qianfen Zhuang, Hongying Jia, Antal Rockenbauer, Yangping Liu, Ke Jian Liu and Yang Liu
Nanoscale 2014 vol. 6(Issue 3) pp:1646-1652
Publication Date(Web):20 Nov 2013
DOI:10.1039/C3NR04559E
The detection of free radicals and related species has attracted significant attention in recent years because of their critical roles in physiological and pathological processes. Among the methods for the detection of free radicals, electron spin resonance (ESR) coupled with the use of the spin trapping technique has been an effective approach for characterization and quantification of these species due to its high specificity. However, its application in biological systems, especially in in vivo systems, has been greatly limited partially due to the low reaction rate between the currently available spin traps with biological radicals. To overcome this drawback, we herein report the first example of nitrone functionalized gold nanoparticles (Au@EMPO) as highly efficient spin traps in which the thiolated EMPO (2-(ethoxycarbonyl)-2-methyl-3,4-dihydro-2H-pyrrole 1-oxide) derivative was self-assembled on gold nanoparticles. Kinetic studies showed that Au@EMPO has a 137-fold higher reaction rate constant with ˙OH than PBN (N-tert-butyl-α-phenylnitrone). Owing to the high rate of trapping ˙OH by Au@EMPO as well as the high stability of the resulting spin adduct (t1/2 ∼ 56 min), Au@EMPO affords 124-fold higher sensitivity for ˙OH than EMPO. Thus, this new nanospin trap shows great potential in trapping the important radicals such as ˙OH in various biological systems and provides a novel strategy to design spin traps with much improved properties.
Co-reporter:Qianfen Zhuang, Hongying Jia, Libo Du, Yanchao Li, Zhao Chen, Saipeng Huang, Yang Liu
Biosensors and Bioelectronics 2014 Volume 55() pp:76-82
Publication Date(Web):15 May 2014
DOI:10.1016/j.bios.2013.12.003
•A mitochondria-targeted fluorescent probe (AuNCs@CS-TPP) was synthesized.•The prepared AuNCs@CS-TPP possess excellent photostability, low cytotoxicity, high sensitivity.•The AuNCs@CS-TPP are capable of targeting specifically mitochondria in living cells.Due to mitochondria involved in both apoptotic and necrotic cell death, labeling and imaging mitochondria has attracted considerable interest. However, conventional organic dyes used for mitochondrial imaging are limited because of their poor photostability. Considering that gold nanoclusters (AuNCs) possess some advantages over considerable interest, such as excellent photostability and strong fluorescence emission, we herein prepared a mitochondria-targeted fluorescent probe, AuNCs@CS-TPP, based on a covalent link between triphenylphosphonium (TPP) cations and chitosan-coated AuNCs (AuNCs@CS). The as-prepared AuNCs@CS-TPP exhibited a bluish fluorescence emission at 440 nm with a quantum yield of 8.5%. Meanwhile, the fluorescence intensity of AuNCs@CS-TPP labeled HeLa cells did not show apparent decrease after 8 min irradiation. Cytotoxicity assay showed that AuNCs@CS-TPP did not display any appreciable cytotoxicity on cells even at a concentration of 60 μg mL−1. In addition, the result of fluorescence co-localization imaging in vitro indicated that AuNCs@CS-TPP could selectively accumulate into mitochondria of HeLa cells and HepG2 cells. These findings demonstrated that AuNCs@CS-TPP possessed superior photostability, low cytotoxicity, high sensitivity and target-specificity to mitochondria, allowing labeling and imaging of the mitochondria in living cells.
Co-reporter:Libo Du, Yanli Gao, Hui Yang, Yanchao Li, Qianfen Zhuang, Hongying Jia, Guangjun Nie and Yang Liu
RSC Advances 2013 vol. 3(Issue 34) pp:14791-14797
Publication Date(Web):18 Jun 2013
DOI:10.1039/C3RA42100G
A non-viral gene vector based on hydroxyethyl ultra-low molecular weight chitosan nanoparticles (HE-ULMWCh NPs) has been synthesized. The HE-ULMWCh is used to form nanoparticles with an enhanced green fluorescence protein (pEGFP) encoding plasmid that possesses diameters of 30–50 nm and a molecular weight of less than 2 kDa. The cytotoxicity assay shows that this new gene vector is significantly less cytotoxic than polyethylenimine whilst still retaining the characteristics of a cationic polyelectrolyte. Cellular uptake of HE-ULMWCh NP–pDNA nanocomplexes shows that HE-ULMWCh NPs can readily enter into cells via endocytosis and then be delivered to lysosomes. pDNA can be easily released from HE-ULMWCh NPs in the acidic vesicles of lysosomes, therefore resulting in a significant increase in the transfection efficiency in three different cell lines compared to naked pDNA. The in vitro results using the new gene vector are further confirmed by in vivo transfection in which HE-ULMWCh NPs provided 3.2 fold greater transfection efficiency than naked pDNA. The HE-ULMWCh NPs can therefore be concluded to be a promising delivery system for in vitro and in vivo gene transfection.
Co-reporter:Dr. Libo Du;Siqingaowa Suo;Guangqing Wang;Dr. Hongying Jia;Dr. Ke Jian Liu;Dr. Baolu Zhao;Dr. Yang Liu
Chemistry - A European Journal 2013 Volume 19( Issue 4) pp:1281-1287
Publication Date(Web):
DOI:10.1002/chem.201203506
Abstract
The enhanced antioxidant activity of surface-functionalized gold nanoparticles (AuNPs) synthesized by self-assembly has attracted great attention, but little is known about the mechanism behind the enhanced activity. To address this challenge, the antioxidant activity of Au@PEG3SA (i.e., surface-functionalization of spherical AuNPs with the antioxidant salvianic acid A) was used as an example to illustrate the mechanism of the enhanced activity. Evaluation of the antioxidant activity was performed in a radical-scavenging reaction between Au@PEG3SA and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. As expected, the rate constant for the reaction of Au@PEG3SA with DPPH was about nine times greater than that for the salvianic acid A monomer. A comparative analysis of the spectral characteristics of Au@PEG3SA and the salvianic acid A monomer further imply that the enhancement of the antioxidative reaction kinetics may be ascribed to the variation in the transition state for the DPPH-radical scavenging reaction through π–π stacking interactions between and among adjacent groups on the surface of Au@PEG3SA. On the other hand, the kinetic enhancement of Au@PEG3SA on reactive-oxygen-species (ROS) scavenging can be observed in living cells and in vivo, which possibly provides new insight for the bioapplication of self-assembly of surface-functionalized AuNPs.
Co-reporter:Lu Han, Li-Bo Du, Anil Kumar, Hong-Ying Jia, Xing-Jie Liang, Qiu Tian, Guang-Jun Nie, Yang Liu
Biomaterials 2012 33(33) pp: 8517-8528
Publication Date(Web):
DOI:10.1016/j.biomaterials.2012.07.034
Co-reporter:Liangbing Chen;Hongying Jia;Qiu Tian;Libo Du;Yanli Gao
Photosynthesis Research 2012 Volume 112( Issue 2) pp:141-148
Publication Date(Web):2012 June
DOI:10.1007/s11120-012-9750-9
The physiological significance of photosystem II (PSII) core protein phosphorylation has been suggested to facilitate the migration of oxidative damaged D1 and D2 proteins, but meanwhile the phosphorylation seems to be associated with the suppression of reactive oxygen species (ROS) production, and it also relates to the degradation of PSII reaction center proteins. To more clearly elucidate the possible protecting effect of the phosphorylation on oxidative damage of D1 protein, the degradation of oxidized D1 protein and the production of superoxide anion in the non-phosphorylated and phosphorylated PSII membranes were comparatively detected using the Western blotting and electron spin resonance spin-trapping technique, respectively. Obviously, all of three ROS components, including superoxide anion, hydrogen peroxide and hydroxyl radical are responsible for the degradation of oxidized D1 protein, and the protection of the D1 protein degradation by phosphorylation is accompanied by the inhibition of superoxide anion production. Furthermore, the inhibiting effect of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), a competitor to QB, on superoxide anion production and its protecting effect on D1 protein degradation are even more obvious than those of phosphorylation. Both DCMU effects are independent of whether PSII membranes are phosphorylated or not, which reasonably implies that the herbicide DCMU and D1 protein phosphorylation probably share the same target site in D1 protein of PSII. So, altogether it can be concluded that the phosphorylation of D1 protein reduces the oxidative damage of D1 protein by decreasing the production of superoxide anion in PSII membranes under high light.
Co-reporter:Libo Du, Xiaoxiang Miao, Hongying Jia, Yanli Gao, Ke Liu, Xueji Zhang, Yang Liu
Talanta 2012 Volume 101() pp:11-16
Publication Date(Web):15 November 2012
DOI:10.1016/j.talanta.2012.08.044
In this paper, an electrochemical method using a nitric oxide sensor was employed for quantitative evaluation of NO released from AuNPs-treated macrophage cells. Our results indicate that the AuNPs initiate NO release from macrophage cells and the amount of NO released is positively correlated with concentration of AuNPs. Meanwhile, total nitrite/nitrate concentrations in the AuNPs-treated macrophage cells have been determined via the Griess reaction and we demonstrate that the variation of the nitrite/nitrate concentrations is in accordance with that measured by the electrochemical method. In contrast to the citrate-coated gold nanoparticles (CT-AuNPs), when AuNPs were protected by thiolated poly ethylene glycol (PEG), the NO-releasing in macrophage upon the addition of AuNPs was relieved, implying that the PEG-coated AuNPs having less cytotoxicity and oxidative stress potential is probably due to inhibition of NO production. In conclusion, this work has demonstrated an effective sensing platform for the evaluation of the cytotoxicity of AuNPs by detecting the extracellular NO released from macrophage cells.Highlights► Electrochemical method can be used for the detection of NO release from cells induced by AuNPs. ► The amount of NO release from macrophage cells was dependent on the concentration of AuNPs. ► The amount of NO release was evaluated by using an electrochemical method and Griess assay. ► The mechanism of NO release from macrophage cells induced by AuNPs was explained. ► We proposed one possible solution to solve the problem of the AuNPs-induced oxidative stress.
Co-reporter:Yangping Liu, Yuguang Song, Libo Du, Frederick A. Villamena, Yiqiong Ji, Qiu Tian, Ke-Jian Liu and Yang Liu
New Journal of Chemistry 2011 vol. 35(Issue 7) pp:1485-1490
Publication Date(Web):04 May 2011
DOI:10.1039/C1NJ20033J
The detection and identification of transient radicals in biological systems is of importance for the understanding of their roles in a variety of biological processes. Electron paramagnetic resonance spectroscopy coupled with the use of the spin trapping technique has been an indispensable tool for this application owing to its high specificity. In this study, we developed a general method using dual function free radical probes (GS-PBN and its phosphorylated analogue GS-PPN) for the simultaneous determination of transient radicals and the microenvironment where the corresponding spin adducts are situated. This conception was initially proved by high spectral sensitivity of the p-ClPh˙ spin adduct of GS-PBN towards its rotational motion in the glycerol–water system. Results showed that a relatively bulky glutathionyl group in the spin adduct plays an important role in its high sensitivity to the molecular motion. This was further verified by high sensitivity of the p-ClPh˙ spin adduct of the newly synthesized probe GS-PPN to its molecular motion. Unlike GS-PBN, GS-PPN can be used to detect O2˙− generated in the enzymatic system and PSII membranes of chloroplasts. Based on the relationship between the τC values of the superoxide spin adduct and the medium viscosity, the local environment of the adduct in the PSII membranes was determined to be similar to that of the aqueous solution containing ∼15% glycerol (η ≈ 1.33 p).
Co-reporter:Liangbing Chen;Hongying Jia;Libo Du;Qiu Tian;Yanli Gao
Chinese Journal of Chemistry 2011 Volume 29( Issue 12) pp:2631-2636
Publication Date(Web):
DOI:10.1002/cjoc.201180434
Abstract
So far it is unclear whether the release of oxygen-evolving complex (OEC) subunits including PsbO, PsbP, and PsbQ proteins is affected by the phosphorylation of photosystem II (PSII) membranes under light stress. In this work, different phosphorylated PSII membranes were obtained from spinach. Phosphorylation partially suppressed the release of PsbO, PsbP, and PsbQ proteins from PSII membranes under light stress. Reactive oxygen species including superoxide anion, hydrogen peroxide and hydroxyl radical, were involved in the release of a small part of PsbO protein, but not in the release of PsbP and PsbQ proteins in the non-phosphorylated and phosphorylated PSII membranes. All of the results suggested that the release of PsbO, PsbP, and PsbQ proteins was partially regulated by phosphorylation in PSII membranes, and the role of reactive oxygen species in the release of OEC subunits in non-phosphorylated PSII membranes was the same as in phosphorylated PSII membranes.
Co-reporter:Hongying Jia, Xu Han, Zhiwei Li, Qiu Tian, Xiaoxiang Miao, Libo Du, Yang Liu
Talanta 2011 Volume 85(Issue 4) pp:1871-1875
Publication Date(Web):30 September 2011
DOI:10.1016/j.talanta.2011.07.028
Accumulating evidence suggests that S-nitrosothiols (RSNOs) play key roles in human health and disease. To clarify their physiological functions and roles in diseases, it is necessary to promote some new techniques for quantifying RSNOs in blood and other biological fluids. Here, a new method using gold nanoparticle catalysts has been introduced for quantitative evaluation of RSNOs in blood serum. The assay involves degrading RSNOs using gold nanoparticles and detecting nitric oxide (NO) released with NO-selective electrodes. The approach displays very high sensitivity for RSNOs with a low detection limit in the picomolar concentration range (5.08 × 10−11 mol L−1, S/N = 3) and is free from interference of some endogenous substances such as NO2− and NO3− co-existing in blood serum. A linear function of concentration in the range of (5.0–1000.0) × 10−9 mol L−1 has been observed with a correlation coefficient of 0.9976. The level of RSNOs in blood serum was successfully determined using the described method above. In addition, a dose-dependent effect of gold nanoparticles on the sensitivity for RSNOs detection is revealed, and thereby the approach is potentially useful to evaluate RSNOs levels in various biological fluids via varying gold nanoparticles concentration.
Co-reporter:Y. -G. Song;B. Liu;Y. -P. Liu;L. -B. Du;F. A. Villamena;Y. Liu
Photosynthetica 2011 Volume 49( Issue 3) pp:
Publication Date(Web):2011 September
DOI:10.1007/s11099-011-0044-9
In the past decades, it has become clear that superoxide radical (O2·−) can be generated from photosystem II (PSII) during photosynthesis. Depending on the extent of its accumulation, O2·− plays an important role in plant physiology and pathology. The photoinhibition/repair cycle is a typical process in PSII which is mainly responsible for the survival of plants under the photoinihibition condition. It is therefore of significant importance to determine O2·− production in this cycle, and then explore how O2·− is controlled by PSII within a normal physiological level. With this in mind, we herein investigate the variation of the O2·− levels in PSII under Mn-depleted and photoactivated conditions mimicking the photoinhibition/repair cycle in vitro. The effect of intrinsic SOD-like component on the O2·− levels was also studied. Results show that PSII has the ability to regulate the O2·− levels in these two processes by simultaneously modulating the O2·− generation activity and intrinsic SOD-like activity. This finding could shed new lights on the photoprotective property of PSII against O2·− and other reactive oxygen species.
Co-reporter:Xinge Qiao, Cheng Huang, Yabing Ying, Xinlin Yang, Yang Liu, Qiu Tian
Journal of Photochemistry and Photobiology B: Biology 2010 Volume 98(Issue 3) pp:193-198
Publication Date(Web):8 March 2010
DOI:10.1016/j.jphotobiol.2010.01.001
Co-reporter:Yi-Qiong JI;Zhao-Yi WANG;Lan-Fen WANG;Ke-Jian LIU
Chinese Journal of Chemistry 2008 Volume 26( Issue 10) pp:1780-1786
Publication Date(Web):
DOI:10.1002/cjoc.200890321
Abstract
Two linear spin traps, α-piperonyl-N-tert-butylnitrone (PiBN) and its phosphoryl analogue N-(α- piperonylidene)-1-diethoxyphosphoryl-1-methylethylamine N-oxide (PiPN), have been first synthesized and structurally characterized. To improve the limitation in evaluating the kinetics of O2−·-spin trapping in the aqueous solution, a nitroblue tetrazolium (NBT)-mediated spectral assay has been first fulfilled and examined in this work. On the other hand, to simplify the theoretical prediction on the kinetics, a density functional theory (DFT) LUMO calculation at the B3LYP/6-311+G(d,p)//B3LYP/6-31G(d) level has been comparatively performed. All the results, when combined with calculating their optimized spin adducts, reveal that an introduction of the phosphoryl group not only can significantly stabilize its superoxide spin adducts, but increases the rate constant for the O2−·-spin trapping as well.
Co-reporter:Li Tan, Xiu-Feng Zhang, Bao-Zhen Yan, Hai-Ming Shi, Li-Bo Du, Ya-Zhou Zhang, Lan-Fen Wang, Ya-Lin Tang, Yang Liu
Bioorganic & Medicinal Chemistry Letters 2007 Volume 17(Issue 22) pp:6311-6315
Publication Date(Web):15 November 2007
DOI:10.1016/j.bmcl.2007.09.003
Bioactivity guided fractionation of the ethanolic extract of the whole plants of Lespedeza virgata (Thunb.) DC. resulted in the isolation of a novel flavonoid (1) along with five known compounds 2–6. The molecular and structural formula as well as the stereochemistry of compound 1 were determined using data obtained from 1H and 13C NMR spectra, DEPT135 and by 2D HSQC, HMBC, 1H–1H correlated spectroscopy (1H–1H COSY), and nuclear overhauser effect spectroscopy (NOESY) experiments. The superoxide anion scavenging activities of all isolated compounds were evaluated by the hypoxanthine nitro blue tetrazolium and ESR methods and the new compound 1 showed the strongest antioxidative activity 95.79% (IC50 = 0.14 mg/ml).From Lespedeza virgata (Thunb.) DC. five known and one new (1) flavonoids were isolated. This new compound when tested in superoxide anion scavenging assay exerted the highest antioxidant activity (IC50 = 0.14 mg/ml).
Co-reporter:Xiu-feng Zhang, Yan Cui, Jia-jun Huang, Ya-zhou Zhang, Zhou Nie, Lan-fen Wang, Bao-zhen Yan, Ya-lin Tang, Yang Liu
Bioorganic & Medicinal Chemistry Letters 2007 Volume 17(Issue 9) pp:2408-2413
Publication Date(Web):1 May 2007
DOI:10.1016/j.bmcl.2007.02.039
The effects of three diosgenyl saponins isolated from Paris polyphylla on the immuno-stimulating activity in relation to phagocytosis, respiratory burst, and nitric oxide production in mouse macrophage cells RAW 264.7 have been investigated. Our results showed that all three diosgenyl saponins significantly enhanced phagocytic activity that increased with the concentration of saponins to reach a maximum, and then tended to decrease with higher concentrations. Saponins with sugar moiety directly induced respiratory burst response in RAW 264.7 cells that increased with the concentrations and reached a maximum, then decreased with higher concentrations after 2-h incubations, however, diosgenin had no PMA-triggered respiratory burst response. Treatment of RAW 264.7 cells with saponins with sugar moiety for 24-h caused a significant increase in the production of nitric oxide, while diosgenin had no effect at all. Consequently, relationship between molecular structures of three diosgenyl saponins and their immunomodulatory activities was discussed, and a possible mechanism of immuno-stimulating function of diosgenyl saponins was accordingly explored.The effects of three diosgenyl saponins on the immuno-stimulating activity in relation to phagocytosis, respiratory burst, and nitric oxide production in RAW 264.7 cells have been investigated. Only saponins with sugar moiety have more immunomodulatory activities than diosgenin.
Co-reporter:Xiu-feng Zhang, Hong-mei Wang, Yuan-li Song, Li-hua Nie, Lan-fen Wang, Bin Liu, Ping-ping Shen, Yang Liu
Bioorganic & Medicinal Chemistry Letters 2006 Volume 16(Issue 4) pp:949-953
Publication Date(Web):15 February 2006
DOI:10.1016/j.bmcl.2005.10.096
Two new dihydrocoumarin derivatives, compounds 1 and 2, were isolated from Aloe vera. Their structures were determined by X-ray crystallographic diffraction analysis and extensive 1D, 2D NMR spectroscopic data. Both of them evidently showed antioxidant activity against superoxide and hydroxyl radicals. Only 1 obviously exhibited immunomodulatory activity in relation to increasing the phagocytic activity and stimulating the production of superoxide anions in the oxygen respiratory burst of rat peritoneal macrophages.Only the isolated compound 1 is probably beneficial in regulating the ROS levels by scavenging ROS and promoting immunomodulatory activity.
Co-reporter:Nie Zhou;Tian Qiu;Liu Yang-ping;Liu Yang
Magnetic Resonance in Chemistry 2006 Volume 44(Issue 1) pp:38-44
Publication Date(Web):21 NOV 2005
DOI:10.1002/mrc.1730
Formation of free radical intermediates in a NaOH/H2O2/Fe(III) system has been studied by ESR spectroscopy in the presence of the spin trap 5,5-dimethy-1-pyrroline N-oxide (DMPO). DMPO/O− and DMPO/•OH signals were simultaneously detected in this system, but only the DMPO/•OH signal could be observed in the absence of Fe(III). Effects of pH values and Fe(III) concentrations on the ESR signal intensities were investigated in detail. Formation of DMPO/O− adduct was inhibited by the addition of superoxide dismutase (SOD), catalase or nitro blue tetrazolium (NBT), and by chelating the Fe(III) with some chelators, including ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and desferrioxamine (DFO). Deoxygenation from the NaOH/H2O2/Fe(III) mixture had a slight effect on the formation of DMPO/O−. DMPO/O− signal was also detected from the NaOH/H2O2/Fe(II) mixture, but it can be totally suppressed under anaerobic conditions. Considering the hydrolysis of Fe(III) into polymerization iron species with oxide phases in the alkaline medium, Fe2O3 was directly suspended into a mixture of NaOH/H2O2 for comparison. Fortunately, the presence of Fe2O3 suspension was found to be of benefit to the production of DMPO/O−. Influence of aging time of hydrolytic iron species on the superoxide anion radical generation was also studied. These results suggest that the generation of O− from the NaOH/H2O2/Fe(III) system was probably caused by the heterogeneous surface catalysis initiated by hydrolytic iron species. Copyright © 2005 John Wiley & Sons, Ltd.
Co-reporter:Yang Ping Liu, Yi Qiong Ji, Yu Guang Song, Ke Jian Liu, Bin Liu, Qiu Tian and Yang Liu
Chemical Communications 2005 (Issue 39) pp:4943-4945
Publication Date(Web):07 Sep 2005
DOI:10.1039/B509903J
A novel spin trap containing an iodoacetamide group has been synthesized and then used to target polypeptides, i.e. glutathione and bovine serum albumin, by which the resulting covalently bonded bioconjugates exhibit great potential for the application of spin trapping of transient radicals in biological systems.
Co-reporter:Y. Meng;B. Z. Yan;H. M. Wang;G. F. Hu;F. Y. Liu;Y. G. Song;Y. Liu
Magnetic Resonance in Chemistry 2004 Volume 42(Issue 6) pp:
Publication Date(Web):16 MAR 2004
DOI:10.1002/mrc.1377
1H and 13C NMR spectra of 8-C-β-D-[2-O-(E)-p-coumaroyl] glucopyranosyl-2-(2-hydroxy)propyl-7-methoxy-5-methylchromone were completely assigned by 2D NMR observations. Especially the 1H assignments of the glucosyl and hydroxyl protons were achieved by utilizing HMQC, HMBC, 1H–1H COSY and DEPT techniques together with a heavy water exchange 1H NMR experiment. Copyright © 2004 John Wiley & Sons, Ltd.
Co-reporter:Shi Wei;Li Wei;Xu Ying-Kai;Wang Hong-Mei;Shi Mei;Liu Yang;Shen Ping-Ping
Chinese Journal of Chemistry 2003 Volume 21(Issue 6) pp:
Publication Date(Web):26 AUG 2010
DOI:10.1002/cjoc.20030210616
Mn(bzimpy)2(1) [bzimpy = 2, 6-bis (benzimidazol-2-yl) pyridine], a mononuclear manganese (IT) complex, was synthesized by the reaction of Mn (OOCMe)2 with bzimpy in absolute ethanol. The complex was structurally characterized by elemental analysis, cyclic voltammetry, and X-ray crystallography. In the complex, the manganese-nitrogen distances were different, and the geometry and the metal ion environment showed the distortion. The cyclic voltammetric measurements have been performed to assess its redox characteristics. The presence of oxidation wave at + 0.62 V and + 0.81 V vs. SCE or + 0.8 V and + 1.0 V vs. NHE suggested that this complex could catalyze the oxidation of water, therefore, simulate the water-oxidizing complex (WOC) of photosystem II (PS II). The measurements of photoreduction of 2, 6-dichlorophenolindophenol (DCPIP), and oxygen evolution in the manganese-depleted and the complex 1-reconstituted PS II preparations just support our conjecture.
Co-reporter:H. M. Wang;W. Shi;J. Q. Pa;M. J. Lü;W. Chen;P. Wang;Y. Liu;Y. K. Xu
Magnetic Resonance in Chemistry 2003 Volume 41(Issue 4) pp:301-303
Publication Date(Web):5 MAR 2003
DOI:10.1002/mrc.1148
4-Methyl-6,8-dihydroxy-7H-benz[de]anthracen-7-one was isolated from the sap of Aloe by column chromatography. Its 1H and 13C NMR spectra were completely assigned by utilizing two-dimensional 1H-detected heteronuclear one-bond (HMQC) and multiple-bond (HMBC) chemical shift correlation experiments together with 1H–1H COSY and DEPT techniques. These techniques were also valuable in assigning the protons and carbons of those benzanthrone compounds which were previously incompletely reported because of the overlap of proton signals. The molecular structure was elucidated by 2D NMR analysis. The spectral properties (MS, IR and UV) are also presented. Copyright © 2003 John Wiley & Sons, Ltd.
Co-reporter:H. M. Wang;W. Shi;Y. K. Xu;M. J. Lü;J. Q. Pan;Y. Liu
Magnetic Resonance in Chemistry 2003 Volume 41(Issue 9) pp:718-720
Publication Date(Web):4 AUG 2003
DOI:10.1002/mrc.1211
A novel dihydroisocoumarin, 3,4-dihydro-6,8-dihydroxy-3-(2′-acetyl-3′-hydroxy-5′-methoxy)methyl-1H-[2]benzopyran-1-one, was isolated from the chloroform extract of the sap of the traditional herb Aloe vera. Its structure was determined by high-resolution negative fast atom bombardment mass spectrometry (MS), 2D NMR spectroscopy and x-ray crystallography. The molecular structure was elucidated by 2D NMR analysis. The complete assignment of the 1H and 13C NMR spectra of this compound was performed by using 1H detected one-bond heteronuclear multiple quantum correlation (HMQC) and long-range (two and three bonds) heteronuclear multiple quantum bond correlation (HMBC) experiments. Detailed analyses of the one- and two-dimensional NMR techniques are presented in additional to the spectral properties (MS, IR and UV). Copyright © 2003 John Wiley & Sons, Ltd.
Co-reporter:Zhou Nie, Ke Jian Liu, Chuan-Jian Zhong, Lan-Fen Wang, ... Yang Liu
Free Radical Biology and Medicine (1 November 2007) Volume 43(Issue 9) pp:1243-1254
Publication Date(Web):1 November 2007
DOI:10.1016/j.freeradbiomed.2007.06.011
Because of its potent antioxidant function and important role in clinical treatment, α-tocopherol (vitamin E) is a good starting point in the development of new synthetic antioxidants with improved properties. In this paper the first example of antioxidant-functionalized gold nanoparticles, Au@Trolox, was synthesized by self-assembly of thiol ligands derived from Trolox, a vitamin E analogue, on gold nanoparticles. DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging experiments revealed that the rate constant for the reaction of Au@Trolox with DPPH was about eight times greater than that for Trolox. The product analysis showed that both the quinonoid and the diepoxide forms were possible oxidized products of the chromanol group of Au@Trolox treated with DPPH radical. No remarkable influence was found on the antioxidant activity of Au@Trolox when the coverage rate of the antioxidant group on the surface of the gold was varied. All our results proved that the assembly of chromanol groups on gold nanoparticles could efficiently enhance the activity of the vitamin E-derived antioxidant, which presents a potential new strategy for antioxidant design with novel perspectives in potential applications.
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](http://img.cochemist.com/ccimg/27000/26913-06-4.png)
](http://img.cochemist.com/ccimg/27000/26913-06-4_b.png)
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