Table of Content

25 November 2009, Volume 25 Issue 6

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Content of Chemical Research in Chinese Universities Vol.25 No.6(2009)

2009, 25(6):  0. 

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Volume Contents of Chemical Research in Chinese Universities to Vol.25(2009)

2009, 25(6):  0. 

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Articles

Preparation and Visible-light Photocatalytic Activity of Mesoporous H₃PW₁₂O₄₀/TiO₂ Composite

KANG Wan-li, LI Jin-huan, HUANG Jian-bin*, YU Xiao-dan and GUO Yi-hang*

2009, 25(6):  781-785. 

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Wormhole-like mesostructured H₃PW₁₂O₄₀/TiO₂ composite catalyst was prepared by the combination of sol-gel chemistry and solvothermal treatment technique in the presence of a triblock copolymer surfactant. Results of Raman spectra, XRD, BJH pore distribution and TEM image indicate that the composite possess a three-dimensionally interconnected pore mesostructure with a high porosity and large pore size. Keggin units were homogeneously dispersed throughout the composite. This composite can catalyze the photodegradation of crystal violet (CV) under visible-light. The photocatalytic activity is much higher than that of pure TiO₂ or H₃PW₁₂O₄₀/TiO₂ composite prepared in the absence of the surfactant.

Influence of Transparent Anode on Luminescent Performance of Near-infrared Organic Light-emitting Diodes

GUAN He-song, CHENG Chuan-hui, LI Wan-cheng, GENG Dong-feng, FAN Zhao-qi, ......

2009, 25(6):  786-790. 

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The optical transmission(200―2000 nm), sheet resistance and work functions of indium-tin oxide(ITO)(100 Ω/□), ITO(12 Ω/□), zinc-oxide(ZnO), aluminum-doped ZnO(AZO) and polyaniline(PANI) films were investigated. Near-infrared organic light-emitting diodes(NIR-OLEDs) emitting around 1.54 μm based on Er(DBM)₃Phen with ITO(100 Ω/□), ITO(12 Ω/□) and PANI as anodes, respectively, were fabricated. The device structure was anode/4''-tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine(m-MTDATA)/N,N′-di-1-naphthyl-N,N′-diphenylbenzidine(NPB)/Er(DBM)₃Phen/tris-(8-hydroxyquinoline) aluminum(Alq₃)/Al. The results suggest that the performance of NIR-OLEDs with ITO(100 Ω/□), which has a lower Sn content, as anodes appear to be better than that of NIR-OLEDs with ITO(12 Ω/□) and PANI as anodes, respectively. The high NIR transmittance of ITO(100 Ω/□) is a major reason for the relatively high NIR EL efficiency. The more balanced holes and electrons in the device based on ITO(100 Ω/□) are another reasons.

Preparation and Characterization of Phosphorus Pentafluoride Gas for Lithium Ion Battery Electrolyte Salt

LIU Jian-wen*, LI Xin-hai, WANG Zhi-xing, GUO Hua-jun and HU Qi-yang

2009, 25(6):  791-795. 

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A novel preparation method of phosphorus pentafluoride(PF₅) is introduced in details in the article. Phosphorus pentafluoride is mainly used to synthesize lithium ion battery electrolyte salt. In the experiment mesneproduct—hexafluorophosphoric acid(HPF₆) was firstly prepared from phosphorus pentoxide(P₂O₅) and anhydrous hydrogen fluoride(HF), according to the chemical stoichiometrics, the optimum amount of excess HF used was about 60% and the optimum reaction time was 4 h; then HPF₆ was dehydrated by oleum with an excess amount of 35%―40% which was heated for 40―50 min at 150 °C; thus HPF₆ was decomposed to a mixture of gases containing PF₅; impurity gases were removed through condensation in the presence of cooling water at 0 °C, then PF₅ of high purity was eventually prepared. The production was characterized by infrared(IR) spectrometry and gas chromatography-mass spectroscopy-selected ion monitoring(GC-MS-SIM). Eventual results indicate that PF₅ prepared by the novel method has a high target purity and a low amount of impurity and water.

Two Novel Lanthanide Coordination Polymers with Differently Bridging Pyridine-2,4,6-tricarboxylate Ligand

CHEN Zi-yun and PENG Meng-xia*

2009, 25(6):  796-800. 

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Two new lanthanide-pyridinetricarboxylic complexes formulated as [Lu(pyta)(H₂O)₃](1) and [La(pyta)(H₂O)₂]·1.5H₂O(2) were synthesized through hydrothermal reactions of LuCl₃ or La(NO₃)₃·6H₂O with pyridine-2,4,6-tricarboxylic acid(H₃pyta), respectively, and characterized by X-ray crystallography. Complex 1 crystallized in the monoclinic system with space group P2₁/n, a=1.01930(12) nm, b=0.73423(9) nm, c=1.45449(17) nm, β=94.734(2)°, V=1.0848(2) nm³, Z=4. Complex 2 crystallized in the monoclinic system with space group P2₁/c, a=0.68474(8) nm, b=1.20982(15) nm, c=1.36063(17) nm, β=99.823(2)°, V=1.1106(2) nm³, Z=4. The overall structure of complex 1 consists of 2D binuclear Lu₂(pyta)₄-based grid coordination layers which are further extended into a 3D supramolecular architecture via hydrogen bonding interactions. With different coordination modes of the pyta ligand, complex 2 is a 3D porous network comprised of La-carboxylate framework.

Simultaneous Determination of Bufadienolides and Qualitative Evaluation for Venenum Bufonis by High Performance Liquid Chromatography

HUANG Hao, LIANG Ming-jin, LUO Heng and ZHANG Wei-dong*

2009, 25(6):  801-806. 

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A high performance liquid chromatographic method was used for the simultaneous identification and qualitative evaluation of 12 bufadienolides(resibufogenin, cinobufagin, cinobufaginol, arenobufagin, bufalin, bufotalin, gamabufotalin, cinobufotalin, Ψ-bufaranogin, desacetylcinobufagin, telocinobufagin and resibufogenol) in Venenum Bufonis. The chromatographic separation was performed on a Dikma C₁₈ analytical column via gradient elution with an aqueous solution of acetonitrile and 0.3% acetic acid at a flow rate of 0.8 mL/min. The method was validated to be acceptable in consideration of linearity(r²>0.9992) and recovery(ranged from 98.9% to 102.0%). The limits of detection of the bufadienolides were from 0.48 ng for bufalin to 6.00 ng for cinobufotalin. The intra-day and inter-day precisions of the method were evaluated and were less than 3.0%. The method was successfully used to analyze 19 batches of Venenum Bufonis, and the similarity values between batches were calculated by Similarity Evaluation System for Chromatographic Fingerprint of TCM(Version 2004A, Chinese Pharmacopoeia Committee, Beijing). The results show that the contents of bufadienolides in the medicine and the similarity values based on these bufadienolides varied significantly from batch to batch. This proposed method could be utilized to qualify and control Venenum Bufonis to ensure its safety and efficacy in application.

Voltammetric Behavior of Degradation Product and Determination of Cefdinir

DONG She-ying*, YU Zhu-qing, HAN Xiao-feng, HUANG Ting-lin and ZHENG Jian-bin

2009, 25(6):  807-811. 

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The electrochemical behavior of the degradation product of cefdinir(CDR) was studied in a 0.05 mol/L NaOH solution by means of linear sweep voltammetry(LSV) and cyclic voltammetry(CV). The results indicate that the C=N bond in the oxime group was reduced. Moreover, a saturated adsorption amount of 1.32×10^–10 mol/cm² at Hg electrode was obtained. The adsorption coefficient β was 1.56×10⁵ L/mol. Gibbs standard energy of adsorption ?G⁰ at 25 °C was –29.63 kJ/mol and the number of electrons transferred n was 2. A method for the determination of CDR was proposed by differential pulse voltammetry(DPV). The reduction peak currents of the CDR’s degradation product were found to be linear in a concentration range of 4.0×10^–7―4.0×10^–6 mol/L and that of 4.0×10^–8―4.0×10^–7 mol/L, respectively. The detection limit was found to be 3.0×10^–8 mol/L under the optimized conditions. The applicability of this approach was illustrated by the determination of CDR in capsules. In addition, the mechanism about the degradation of CDR in 0.2 mol/L NaOH was discussed by UV spectrophotometry.

GC-MS Analysis of Amino Acids in Extract of Cornus Caprae Hircus

XU Jin-zhong, SHEN Jie, CHENG Yi-yu and QU Hai-bin*

2009, 25(6):  812-816. 

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Amino acids are an important type of bioactive components in Chinese traditional medicines, especially  animal drugs. However, few modern analytical methods targeted at amino acids have been developed for the quality control of animal drugs. A gas chromatography-mass spectrometric method was built for the quantification analysis of amino acids in the extracts of Cornus Caprae Hircus which has been widely used in Chinese medicine compound prescriptions. The full method validation, including the linearity, limit of detection and quantification, repeatability, precision, stability, and recovery test, was examined. The results indicate that the developed method is suitable for the quantification of amino acids in the extracts of Cornus Caprae Hircus. The developed method was applied to the quantification analysis of twelve amino acids in different batches of extracts of Cornus Caprae Hircus.

Isolation and Purification of Plantamajoside and Acteoside from Plant Extract of Plantago asiatica L. by High Performance Centrifugal Partition Chromatography

LI Li, LIU Chun-ming*, CHEN Zhao-jie, WANG Jing, SHI Dong-fang and LIU Zhi-qiang

2009, 25(6):  817-821. 

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Two phenylethanoid glycosides(PhGs), plantamajoside and acteoside, were isolated and purified from the aerial parts of Plantago asiatica for the first time by high performance centrifugal partition chromatography(HPCPC) with ethyl acetate, n-butanol, ethanol and water(0.5:0.5:0.1:1, volume ratio) as solvent system. A total of 45.6 mg of  plantamajoside and 293.8 mg of acteoside were purified from 1341 mg of the n-butanol extract of P. asiatica, with a purity of >93.3% as determined by HPLC. The HPCPC fractions were analyzed by HPLC-DAD and the structures were identified by their retention time, UV, electrospray ionization multi stage tandem mass spectrometry(ESI-MSⁿ) in the negative ion mode, and confirmed by NMR experiments. The characteristic fragment ions of ESI-MS of the two PhGs isolated from Plantago asiatica were discussed, which are specific and useful for the identification of the structures of PhGs.

Modification of Chiral Stationary Phases with L-Proline as a Selector for Ligand-exchange Chromatography via Introducing Hydrophobic Groups

SHI Hong-yu, ZHANG Hai-zhu, LONG Yuan-de and HUANG Tian-bao*

2009, 25(6):  822-826. 

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Three chiral stationary phases(CSP1, CSP2 and CSP3）for ligand-exchange chromatography were prepared by firstly using dimethylchlorosilane as an endcapping reagent for decreasing residual silanol groups on the surface of silica gel, and then modifying the surface of silica gel with allyl glycidyl ether and alkenes through the hydrosilation reaction, and lastly introducing L-proline as a chiral selector. The enantiomer resolutions of 14 amino   acids and 2 hydroxyl acids were completed on the CSPs by using an aqueous solution of Cu(Ac)₂ as mobile phase at a flow rate of 1.0 mL/min and column temperature of 40 °C with detection at UV 254 nm. In terms of enantioselectivity α, column efficiency and resolution R_s, the chromatographic behaviors of the analytes on the CSPs were discussed via comparing them to those on the CSP4 prepared via the reference method. The results show that enantioselectivity α, column efficiency and resolution R_s of the analytes on the CSPs could be improved by using the above modifying method.

Electrocatalytic Determination of Dopamine in the Presence of Ascorbic Acid by Poly-L-proline and Ferricyanide Compound Film Modified Electrode

CAO Yan-xiu, LIU Xing-mei, HUANG Hui, ZHANG Xue-yu and ZHANG Zhi-quan*

2009, 25(6):  827-831. 

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A novel biosensor was fabricated by the electrochemical polymerization of poly-L-proline(P-LP) and ferricyanide(FC) to form a compound film on a glassy carbon electrode(GCE). The compound film modified electrode(P-LP/FC/GCE) shows electrocatalytic activity toward dopamine(DA) in a phosphate buffer solution(PBS, pH = 4.0) with a diminution of the overpotential and an increase in peak current. P-LP/FC/GCE was used to study the electrocatalytic oxidation of DA and ascorbic acid(AA) by means of cyclic voltammetry(CV), differential pulse voltammetry(DPV) and amperometric i-t curve techniques. The overlapping anodic peaks of DA and AA were resolved into two well-defined voltammetric peaks in CV and DPV with the potential differences of about 200 and 225 mV, respectively. The peak current of DA is linearly change with the concentration of DA in a range of 1×10^–7 to 1.14×10^–4 mol/L with the correlation coefficient of 0.9997. The detection limit is 4.4×10^–8 mol/L(S/N=3). P-LP/FC/GCE exhibited an excellent selectivity, sensibility and stability for the determination of DA, and can be applied to the determination of dopamine injections with satisfied results.

Extraction of Tetracycline via Ionic Liquid Two-phase System

MA Chun-hong, WANG Liang, YAN Yong-sheng*, CHE Guang-bo, YIN Yan-su, ......

2009, 25(6):  832-835. 

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A new method to extract and separate tetracycline(TC) in a new aqueous two-phase system(ATPS) consisting of hydrophilic [Bmim]BF₄ and NaH₂PO₄ was investigated. The effects of the amount of salt, ionic liquid as well as tetracycline on extraction efficiency were studied systematically. The results show that ionic liquid-ATPS exhibited the highest extraction efficiency higher than 90%. When the concentration of NaH₂PO₄ was 33.3%―38.5% (mass fraction), the amounts of ionic liquid and TC were 1.0―2.0 mL and 1.8 mL, respectively, and ionic liquid could be re-used.

Synthesis of (S)-N-(2-Ethyl-6-methylphenyl)alanine by Enzyme-catalyzed Resolution and Chemical Racemization

ZHENG Liang-yu, ZHANG Suo-qin*, Lü Xiao-li and CAO Shu-gui

2009, 25(6):  836-840. 

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A practical synthesis of (S)-N-(2-ethyl-6-methylphenyl)alanine, a key intermediate for (S)-metolachlor, was completed by means of lipase-catalyzed hydrolytic kinetic resolution and chemical racemization of the remaining ester. The effects of operating temperature and enzyme concentration on the activity and enantioselectivity of enzyme were initially studied, and it was found that the enantioselectivity of CAL-B towards the resolution was not high enough to obtain enantiomerically pure compound(E=12.1). When diethyl ether(15%, volume fraction) was added in the reaction medium, the lipase gave an excellent enantioselectivity(E=117.8), which is about 9.7-fold that in pure buffered aqueous solution. For overcoming the limitation of a maximum theoretical yield of 50%, the acid product was separated from the remaining ester by a simple extraction procedure and the remaining ester was racemized with aldehyde and acetic acid under microwave irradiation or conventional heating condition. The results show the microwave irradiation was more effective than the conventional heating method and gave the desired (R,S)-N-(2- ethyl-6-methylphenyl)alanine methyl ester a high yield(92%) with R/S=50/50 in 1 h.

Synthesis and Biological Activities of Quinoline Derivatives as HIV-1 Integrase Inhibitors

LUO Zai-gang, ZENG Cheng-chu, WANG Fang, HE Hong-qiu, WANG Cun-xin, ......

2009, 25(6):  841-845. 

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Based on the structure of the integrase core domain and pharmacophore perception, the authors picked out the hit quinolone derivative 1 as the lead compound via virtual screen in ACD, MDDR, NCI and Chinese Herb three-dimensional database with the aid of DOCK4.0 program and synthesized a series of analogues of compound 1. Their primary anti-HIV properties against integrase reveal that 6-position methyl group on the benzene ring of  quinolone plays a more important role than chlorine, 7-position methyl group or no substituted group. But the    title compounds exhibit little difference when the substituted group was phenyl or thienyl on the pyridine ring of quinoline.

Synthesis and Biological Activities of α-Amino Acylamines Derivatives Containing Furan and Pyridine Ring

XU Yang and XUE Si-jia*

2009, 25(6):  846-850. 

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In order to find better herbicidal activity and fungicidal activity of α-amino acid derivatives, we introduced furan rings and pyridyl groups to seven different α-amino acids to form a series of 14 novel α-amino acylamines derivatives via dicyclohexylcarbodiimide/4-dimethylaminopyridine(DCC/DMAP) coupling method. The structures of all the compounds prepared were confirmed by IR, LC/MS, ¹H NMR, and elemental analysis. The herbicidal and fungicidal results show that some compounds containing glycine and valine substrate have good activities.

Synthesis, Crystal Structure and Biological Activities of Novel Di-n-butyl Tin Di-carboxylate

WANG Yan-hua, DU Da-feng, ZHU Chao-guang, DU Xi-guang and ZHU Dong-sheng*

2009, 25(6):  851-855. 

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A novel macrocyclic complex 2{[(n-Bu₂Sn)₄O₂·L₂]₂·DMF} was synthesized by the reaction of 4-(1,2-dithioethylene)methylene-3,5-disoxo-1,6-heptadiene-1,7-dis-(o-formyl)-dis-p-phenoxyacetic acid(LH₂, compound 1) with di-n-butyltin oxide. Compound 1 and complex 2 were characterized by elemental analysis, FTIR spectroscopy, and ¹H NMR spectroscopy. The crystal structure of complex 2 was determined by single crystal X-ray diffraction analysis. There are two crystallographic independent molecules in complex 2, and each molecule structure is centro-symmetric and features a central rhombus cyclic Bu₄Sn₂O₂ unit with two exocyclic Sn atoms linked at the O atoms of the four-membered ring. In molecule A, the four Sn atoms are five-coordinated. However, in molecule B, the four Sn atoms have two different coordination geometries, the endocyclic Sn atoms are five-coordinated and the exo- cyclic Sn atoms are four-coordinated. The dicarboxylate ligands in molecules A and B bridge exocylic or endocyclic tin atoms, forming two macroheterocycles with 26 atoms. Pilot studies have indicated that complex 2 has good antibacterial and antitumour activities.

Design and Synthesis of New Anti-AIDS Drugs——Introducing an Immunomodulator into Delavirdine Derivative

LU Hai-bin, MI Hao-yu, CUI Lin-lin, YU Xiang-Hui, LIANG Tie* and WANG En-si

2009, 25(6):  856-860. 

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In consideration of the anti-HIV activities of delavirdine, resveratrol and Pidotimod, a novel kind of   anti-AIDs drug(compounds 5 and 7) was synthesized. Compound 5 was synthesized by linking the delavirdine derivative to pidotimod, compound 7 was synthesized via linking the delavirdine derivative to resveratrol with terephthalic acid as the conjugated compound by two different routes. The structures were confirmed by means of ¹H NMR,   ¹³C NMR, IR, MS and elemental analysis. The results for HIV-1 reverse transcriptase assay, quantitative titration of HIV-1 by using MAGI assay and pharmacokinetics assay show that a novel kind of anti-AIDs drug has been synthesized.

CuCl-catalyzed Oxidative N-Demethylation of Arylamines with tButyl Hydroperoxide

LIAO Qian and XI Chan-juan*

2009, 25(6):  861-865. 

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CuCl-catalyzed oxidative N-demethylation of arylamines proceeded in the presence of tert-butyl hydroperoxide. The one-electron transfer route of oxidative N-demethylation competed favorably with the H-atom abstraction route.

Efficient Synthesis of 2-Substituted Quinolino[7', 8':5, 6]pyrano-[2, 3-d]pyrimidin-4(3H)-ones via Tandem Aza-Wittig Reaction

FANG Zheng-dong*, WANG Guo-hong and WANG Dun-jia

2009, 25(6):  866-869. 

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An efficient method is described for the synthesis of 2-substituted quinolino[7',8':5,6]pyrano[2,3-d] pyrimidin-4(3H)-ones(6) via a tandem aza-Wittig annulation process. The iminophosphorane(3) reacted with aromatic isocyanates, followed by heterocyclization on the addition of secondary amines, phenols or alcohols to give the corresponding guanidine intermediates(5), which were cyclized in the presence of a catalytic amount of a base to tetracyclic compounds 6 in good yields. The corresponding carbodiimide(4) and guanidine-type intermediate compounds 5 need not be isolated.

Synthesis and Photo-acid Generation of a Novel Bis(trichloromethyl)-1,3,5-triazine

JIANG Yu-ren*, LI Jin-liang and XU Hui

2009, 25(6):  870-875. 

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A new environmentally friendly photo-acid generator(PAG), 1-{4'-[4,6-bis(trichloromethyl)-1,3,5-triazin- 2-yl][1,1'-biphenyl]-4-yl}-O-acetyloxime ethanone(TZ4) consisting of both an oxime ester group and a triazine group was designed and synthesized. From the measurements of absorption, fluorescence and the photo-acid generation, it was found that the novel PAG has an excellent radical-generating efficiency. And the other three bis-(trichloromethyl) triazine derivatives 2-[2-(4-methoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine(TZ1), 2-[2-(3,4-dimeth- oxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine(TZ2) and 2-(1,3-benzodioxol-5-yl)-4,6-bis(trichlorometh-  yl)-1,3,5-triazine(TZ3) were synthesized and studied in this work. In the acid measurement, the acid-forming performance of S-triazinyl derivatives was evaluated by the method ascertained in our laboratory. The results indicate that the novel triazine has the better acid-forming performance that subsequently catalyzes the deblocking of a protecting group in copolymers.

Knoevenagel Condensation Catalyzed by DBU Brönsted Ionic Liquid without Solvent

YING An-guo, LIU Luo, WU Guo-feng, CHEN Xin-zhi*, YE Wei-dong*, ......

2009, 25(6):  876-881. 

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A protocol for the Knoevenagel condensation of aromatic aldehydes with methylene compounds catalyzed by task specifed ionic liquid 1,8-diazabicyclo[5.4.0]-undec-7-en-8-ium lactate under solvent-free conditions has been developed. The reactions proceed at ambient temperature and the work-up procedures are very simple. Good to excellent yields could be obtained. The ionic liuid could be simply prepared and recycled efficiently.

Construction of Saccharomyces cerevisiae Strain Stably Expressing a Fusion Protein Containing Ten Tandem Recombinant Human Glucagon-like Peptide-1 Analogues

WU Zhi-qiang, JIA Nai-bing, LI Na, MA Bai-cheng and LI Ming-gang*

2009, 25(6):  882-886. 

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The recombinant Saccharomyces cerevisiae strain stably expressing recombinant human glucagon-like peptide-1(rhGLP-1) analogue, as a potential oral drug delivery system for diabetes type II treatment, was successfully constructed by the homologous recombination between chromosomal DNA and yeast and integrating vector pNK-GLP containing yeast ribosomal DNA fragments. The amount of rhGLP-1 analogue fusion protein in transformant SG2 reached ca. 0.84 mg per gram of packed cells when SG2 was grown for 24 h in the YPD medium with a inoculum and medium ratio of 1:1. Oral administration of 5 g lyophilized SG2/kg to hyperglycemic rats decreased serum glucose from (24.8±1.40) to (21.2±1.36) mmol/L.

Direct Activation of CFTR Chloride Channel by Natural Compound Theophylline

LIU Xin, GE Hong, ZHAO Xue-liang, HOU Ting-ting, SUN Juan-juan, YANG Jing-bo,...

2009, 25(6):  887-890. 

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Theophylline has been widely used in the treatment of airway disease but molecular mechanism has not been clearly elucidated. Previous studies have manifested that theophylline increases intracellular cAMP concentration. Because cystic fibrosis transmembrane conductance regulator(CFTR) is a cAMP-dependent Cl^– channel that plays key roles in fluid secretion in vivo, we postulated that theophylline activates CFTR channel gating. We found  (1) theophylline stimulated CFTR-mediated anion transport in a concentration-dependent manner, and CFTR specific blocker completely reversed the effect; (2) theophylline had no effect on ΔF508 or G551D mutant CFTR chloride channel activity; (3) theophylline had additive effect with forskolin(FSK) and 3-isobutyl-xanthin(IBMX), thus a direct binding activation mechanism was suggested. In conclusion, the results may provide a clue to elucidating the molecular mechanism of theophylline activities and theophylline may present a novel lead drug in treating CFTR-related disease.

Preparation of Adenovirus 5 E1A Polyclonal Antibody

SHEN Qiang, MENG Fan-kai, YU Yin, ZHANG Yu and RUO Qi*

2009, 25(6):  891-894. 

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The adenovirus E1A proteins are primarily concerned with modulating cellular metabolism to make the cell more susceptible to virus replication. In this study, adenovirus E1A gene was amplified via PCR on the HEK-293 cells genome and cloned into prokaryotic expression vector pRsetB. The recombinant plasmid pRsetB-E1A was expressed in E. coli BL21 and the relative molecular mass(M_r) of expressed fusion protein was approximately 36000. The recombinant protein was purified on a Ni-NIA agarose column and detected by SDS-PAGE and Western blot. The purified recombinant protein was then injected into rabbits and anti-E1A polyclonal antibody with high titer was obtained.

Inhibition of Matrix Metalloproteinases Activities by Luteolin

JI Hai-tao, SHI Xiu-juan, HONG Yuan, WANG Ye, WANG Hui-ling, WANG Zhi-yong, ...

2009, 25(6):  895-898. 

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Matrix metalloproteinases(MMPs) are a family of zinc dependent enzymes that can degrade the components of the extracellular matrix(ECM) and basement membranes. Because MMPs play roles in many important physiological and pathological processes, many MMP inhibitors(MMPIs) have been developed with the aim of interfe- ring in and treating diseases. The authors conclude via a fluorescence based assay in vitro that luteolin inhibits the enzymatic activities of MMP-2, MMP-7, MMP-9, MMP-14, and MMP-16. This compound most specifically inhibits MMP-7 of all the  MMPs tested. Finally, we used molecular modeling to dock luteolin with MMPs and revealed the binding mode of the luteolin-MMP interaction. Our results suggest that luteolin may exert its therapeutic effects via MMP inhibition.

Effects of Solvents on Extraction of Effective Components from Cell Wall Tissues of Chinese Traditional Medicines

LIU Cheng-bai, TIAN Luo, YU Zhen-xiang, ZHANG Feng-chun and CHEN Xia*

2009, 25(6):  899-903. 

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The effects of different solvents on the extraction of effective components from the cell wall tissues of Chinese traditional medicines were studied by the histochemical methods, such as the bare-handed section, swelling ratio, paraffin section, IR spectrum and cell wall component analysis. The results show that the ethanol-alkali solvent could increase the swelling ratio as well as the swelling speed. The effective components of cell wall tissues extracted by ethanol-alkali solvent become loose shown by the paraffin section. According to the IR spectrum analysis and the results of cell wall tissue component analysis, it was found that the ethanol-alkali solvent could decrease the contents of pectin and hemicellulose in the cell wall to make the wall broken, and therefore the effective components can be extracted easily by the solvent and the extraction rate is increased.

Role of Residue 90 in Catalysis of Cytochrome P450 2C9

WANG Ying, ZHOU Yi-han, GUO Ying-jie, XU Xue-lian, SI Da-yong, ZHOU Hui*, ......

2009, 25(6):  904-908. 

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The cytochrome P450 mutant CYP2C9.13(L90P) shows a greatly impaired catalytic activity compared with the wild-type. We constructed the mutants by substitution at residue 90 of CYP2C9, expressed in COS-7 cells, assayed their thermal stability and catalysis activity and analyzed the mutants via molecular dynamic(MD) simulation and flexible docking. Mutant L90E exhibits a significantly lower catalytic activity than the wild-type for the hydro- xylation of diclofenac, lornoxicam and luciferin and its molecular dynamics simulation results indicate that the size of the entrance of substrate access was reduced significantly. An increase or minor decrease of catalytic activity was observed for mutants L90Q, L90W, L90R, L90I and L90G, and the sizes of the entrances of substrate access and the active site cavities had a little change in those mutants. The thermal stability and the potential energy of the MD simulation of these mutants showed a similar tendency as the catalysis assays did. Flexible docking results show the fluctuation of interaction energy is due to the change of electrostatic potential distribution. All the above facts show that the changes in the catalysis activity of the mutants caused by the substitution at residue 90 are due to the changes in the size of entrance, the shape and size of active site cavity, electrostatic potential distribution and thermal stability. The residue 90 of CYP2C9 has an important effect on the enzyme catalytic activity.

Ginkgolide C Stimulates CFTR-mediate Anion Conductance in Distal Colon: Implication for Therapy of Gastrointestinal Diseases

LIAO Qi, MA Xiao-yan*, WU Fu-ju, YANG Li-xiao and WANG Shuai

2009, 25(6):  909-913. 

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The effects and the mechanisms of natural compounds ginkgolides on CFTR-mediate anion transport were investigated. The CFTR-mediate iodide influx rates were studied via a cell-based fluorescence assay done for FRT cells stably transfected by CFTR; transepithelial short-circuit current recordings of FRT cells and rat distal colon mucosa were respectively obtained. Cellular cAMP concentrations were measured via a radioimmunoassay analysis kit. Ginkgolide C dose-dependently increases CFTR-mediate anion transport, whereas ginkgolide A and B show no effect. The activation is sensitive to CFTR specific activator CFTR_inh-172. Ginkgolide C stimulated amiloride and indomethacin pre-treated Cl^- currents in rat distal colon mucosa. Studies on FRT cells also manifest that ginkgolide C had additive effect with FSK/IBMX mixture and didn’t elevate intracellular cAMP concentration, which implies it works through a direct binding mechanism. In conclusion, Ginkgolide C directly stimulates CFTR-mediate anion transport. Ginkgolide C may be a promising drug for the prevention and treatment of CFTR-related diseases such as idiopathic chronic pancreatitis(ICP), habitual constipation, and keratoconjunctivitis sicca(KCS).

Catalytic Performance of MnO_x-WO₃/TiO₂ Catalyst for Selective Catalytic Reduction of NO_x with NH₃ and Its Tolerance Towards SO₂

2009, 25(6):  914-919. 

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The performance of Mn-W/TiO₂ for selective catalytic reduction(SCR) of NO_x with NH₃ and its resistance to different concentrations of SO₂ at various temperatures were investigated. The results show that WO₃ increased the active sites and enhanced the strength of acid, so it was an effective promoter of MnO_x/TiO₂. The NO_x conversion on Mn-W/TiO₂ ranges from 80.3% to 99.6% between 100 °C to 350 °C at GHSV=18900 h^–1, while N₂ product selectivity changes from 100% to 98.7%. In the presence of 0.01% SO₂ and 6% H₂O, NO_x conversion maintained 98.5% at 120 °C. The influence of more than 0.01% SO₂ on the activity of MnO_x-WO₃/TiO₂ will disappear if the temperature rises above 250 °C. By means of heating and sweeping with He, the activity of the catalysts can be recovered. At 300 °C, NO_x conversion yielded 99% with 0.07% SO₂ and reached the level of commercial V-W/TiO₂ catalysts. The Mn-W/TiO₂ catalyst showed excellent performance for SCR of NO_x with NH₃ in a wider range of temperature with strong tolerance to SO₂.

Influence of Carbon-doped Content on Formation Conditions of Coesite

2009, 25(6):  920-923. 

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The mixtures of α-quartz and graphite powder with different mass ratios were, respectively, high-energetically mechanically milled and then treated under high pressure and high temperature. The influences of carbon content on the synthesis conditions of coesite were investigated. The experimental products were characterized by XRD, TEM, and Raman spectrometry. The results show that the existence of carbon can obviously inhibit the formation of coesite, and the higher the carbon content of the initial material, the higher the pressure for forming coesite.

Partial Oxidation of Toluene on VO_x-TiO_x/SBA-15

FANG Ke-gong, WANG Bin and SUN Yu-han*

2009, 25(6):  924-928. 

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A series of VO_x-TiO_x/SBA-15 catalysts was prepared by the grafting method. The catalysts were characterized by different techniques such as N₂-sorption, TPR, UV-Vis and NH₃-TPD in order to verify the vanadium and titanium species, and their catalytic properties were investigated for the partial oxidation of toluene. The results show that vanadium mainly existed in the forms of isolated tetrahedral and octahedral species at the low loadings. The introduction of a certain amount of titanium improved the dispersion of vanadium on the support and then the catalytic performance for toluene oxidation at the same vanadium content. Both toluene conversion and benzaldehyde selectivity, showed the maximum values and then decreased with increasing the amount of titanium in the catalyst.

Theoretical Investigation on Intermolecular Interactions Between HCCF and HCCR(R=F, Cl, Br)

WANG Zhao-xu, ZHENG Bai-shu*, ZHANG Jing-chang and CAO Wei-liang*

2009, 25(6):  929-935. 

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Geometries, interaction energies and electronic properties for four types of dimers(hydrogen bonded, halogen bonded, π-halogen bonded, and π-hydrogen bonded) between HCCF and HCCR(R=F, Cl, Br) were studied via MP2/6-311++G(d,p) ab initio calculation. It is shown that the strength of the π-hydrogen bonded dimers turns out to be greater than those of the other three types of dimers, with the interaction energies –4.611 kJ/mol for HCCF-HCCF, –4.700 kJ/mol for HCCF-HCCCl, and –4.850 kJ/mol for HCCF-HCCBr respectively at the CCSD(T)/6-311++ G(d,p)//MP2/6-311++G(d,p) level. In an effort to understand the nature of the intermolecular interactions prevalent in these dimers, the interaction energies were decomposed into physically distinct energy components with the aid of the symmetry adapted perturbation theory(SAPT). The dispersion force is found to be the main origin of the intermolecular interactions in hydrogen bonded and halogen bonded dimers. In the π-halogen bonded system, the dispersion is the major bonding force in HCCF-HCCF and HCCF-HCCCl, while the induction energy is the most important component in HCCF-HCCBr. However, both the dispersion and electrostatic energy play a key role in π-hydrogen bonded dimers.

Fe₃O₄ Nanoparticles Decorated Multi-walled Carbon Nanotubes and Their Sorption Properties

DONG Cun-ku, LI Xin*, ZHANG Yan, QI Jing-yao and YUAN Yun-fang

2009, 25(6):  936-940. 

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This paper reports a simple and efficient chemical method to decorate multi-walled carbon nanotubes(MWCNTs) with iron oxide nanoparticles. The TEM, FTIR, Raman and UV analysis demonstrate that iron oxide nanoparticles were well deposited on the outer walls of MWCNTs. The size of the nanoparticles ranges from 30 to 50 nm. The sorption property of MWCNTs/Fe3O4 composites for the removal of 2,4-dichlorophenol(2,4-DCP) and Cu²⁺ ions from aqueous solution was explored. The results present that MWCNTs decorated with Fe₃O₄ possessed higher sorption capability for removing 2,4-DCP and Cu²⁺ ions, which favour the highly potential applications for pollutants removal from water.

SbCl₃ Catalyzed Solventless Synthesis of Bis(indolyl)alkanes under Grinding

ZHANG Ji-ming*, XU Rui-ping, TIAN Yan and ZHOU Jian-hua

2009, 25(6):  941-944. 

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A clean and efficient method for the synthesis of bis(indolyl)alkanes with antimony trichloride(SbCl₃) as the catalyst under solvent-free grinding conditions is described. This method provides several advantages, such as simple work-up procedure, neutral conditions and high yields.

Biopolymer Entering into and Escaping from a Nanometer Pore

DING Ke-jian, ZHENG Yan-peng, GUAN Wei-jun* and MA Yue-hui*

2009, 25(6):  945-949. 

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We theoretically investigated negative entropy S of biopolymer which passes through a nanometer pore(such as α-hemolysin), especially entering process and escaping process, on the basis of which we also studied biopolymer entering-pore time τ_ent, biopolymer entering mean velocity v_ent, biopolymer escaping-pore time τ_esc, and biopolymer escaping mean velocity v_esc, respectively. Our results illustrate that the entering and escaping processes of biopolymer depend on its negative entropy, and entering process is more difficult than escaping process for biopolymer translocation. This tremendous difference between the two processes will offer a useful engineering hint for single macromolecule identification.

Molecular Properties of 9,10-Phenanthrenequinone and Benzil

Muddasir Hanif, LU Ping, GU Cheng, WANG Zhi-ming, YANG Shu-min, YANG Bing, ...

2009, 25(6):  950-956. 

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9,10-Phenanthrenequinone(PQ) and benzil are important α-diketones. This manuscript explains the first comparison of PQ and benzil molecular properties. We have used ¹H NMR, ¹³C NMR, ¹H-¹H COSY, HMBC, HMQC, UV-Vis absorption and emission, CV and TGA experiments to study PQ and benzil that provided the following novel results. (1) The ¹H NMR(CDCl₃) of PQ show δ 8.19(H₁), 8.02(H₄), 7.72(H₃), 7.47(H₂) instead of an earlier reported δ  8.25(H₄), 8.08(H₁), 7.80(H₂), 7.55(H₃); (2) in the ¹³C NMR(CDCl₃), the C₉/C₁₀(C=O) signal of PQ appears upfield(δ 180.3) compared to C₉/C₁₀(C=O) signal of benzil(δ 194.5), which shows higher electrophilic character(more attractive for nucleophiles) of C₉/C₁₀(C=O) of benzil; (3) the first λ_max for the UV-Vis absorption and emission of PQ are blue-shifted compared to benzil despite increased conjugation attributed to the different symmetries(C_2v for PQ and C_2h for Benzil) of the two molecules; (4) the emission spectrum of benzil is broader compared to that of PQ due to slower relaxation of the excited state; (5) The CV study shows that PQ and benzil are good electron acceptors and PQ shows a better reduction process than benzil due to an extra ring that provides stability for the reduced species(mono or diradical anions); (6) TGA shows the higher thermal stability of PQ than benzil attributed to the presence of phenanthrene unit in PQ.

Aggregation Behavior and Structure of Associated Polyacrylamide Hydrophobically Modified with 2-Phenoxylethylacrylate

DAI Yu-hua*, WU Fei-peng, LI Miao-zhen and WANG Er-jian

2009, 25(6):  957-962. 

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The aggregation behavior and structure of hydrophobically modified block copolymers of acrylamide and 2-phenoxylethylacrylate were investigated by viscometry, ¹H NMR relaxation, ²D NOESY, fluorescence and dynamic light scattering. It was found that the aggregation behavior was strongly dependent on the concentration of polymer solution and the hydrophobe contents. With varying concentration from 2.0, 6.0, 8.0 to 12.0 g/L, there were different aggregate morphologies distributed in aqueous solutions, such as monopolymer chain, micelle-like aggregate, multi-micelle aggregate and cross-linked network. According to the model of aggregation, it can give a reasonable explanation on the large magnitude enhancement of viscosity with the increasing of polymer concentration. Additional data of 2D NOESY and fluorescence show that the copolymer with higher hydrophobe content(molar fraction≥1%) is likely to form intra-molecular association.

Letter

Template-free Synthesis of a Novel 3D Cage-like Nanostructured α-Fe₂O₃

YU Ran-bo*, LI Zhen-min, WANG Dan, XING Chao-jian, LAI Xiao-yong , ...

2009, 25(6):  963-965. 

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Novel three-dimensional (3D) cage-like α-Fe₂O₃ nanostructures were successfully prepared by a template-free hydrothermal synthetic route. The characterization results indicated that the nanostructures were assembled by α-Fe₂O₃ nanoparticles. The assembled cage-like α-Fe₂O₃ nanostructures show weak ferromagnetic behavior at room temperature, and the corresponding values were higher than those of α-Fe₂O₃ nanoparticles reported in the literature.

Research Note

Capacity of Tea Scavenging Singlet Oxygen Studied by Means of 1,3-Diphenylisobenzofuran as Fluorescence Probe

Lü Qing-luan, YUE Ning-ning, ZHANG Miao, GONG Bin and WANG Huai-you*

2009, 25(6):  966-970. 

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In this study, we present a spectrofluorimetric method of estimating scavenging effect of tea leaf on singlet oxygen(¹O₂) using 1,3-diphenylisobenzofuran (DPBF) as fluorescence probe. ¹O₂ generated by irradiation of methylene blue (MB) could oxidize DPBF resulting in its fluorescence quenching at 447 nm, however, the relative fluorescence intensity of DPBF in the system would recover in the presence of antioxidant which could scavenge ¹O₂. So, We could evaluate the scavenging capacity of tea leaf to ¹O₂ according to the recovery extent of the relative fluorescence intensity of DPBF, which was a simple, precise and selective method. Effects of pH, reagent concentration, foreign substances, reaction time on the reaction system had been discussed and the availability of proposed method was confirmed by adding NaN₃ into the system, which was a potent quencher of ¹O₂.