JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2013
·Vol. 18
·期 1
·269-278
·
IF 2.279
Lu Daban,Lin Shaoxiong,Wang Letao,Li Tong,Wang Chunming,Zhang Yan
Poly(diallyldimethylammonium chloride) (PDDA)-functionalized graphene sheets-multiwalled carbon nanotubes (G-CNTs) hybrid materials (PDDA-G-CNTs) were successfully synthesized. The materials were characterized by transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectra. Then, an electrochemical sensor based on PDDA-G-CNTs/β-cyclodextrin (PDDA-G-CNTs/β-CD) was fabricated for the sensitive determination of luteolin. In 0.2 M HAc–NaAc buffer solution (pH 5.0), the redox peak currents of luteolin increased significantly on PDDA-G-CNTs/β-CD modified glassy carbon electrode (GCE), suggesting that the composite film not only showed excellent electronic properties of PDDA-G-CNTs but also exhibited high molecular recognition capability of β-CD. The chronocoulometry investigation demonstrated that the composite could effectively increase the electrochemical active surface. Under the optimal conditions, the oxidation peak current of luteolin increased linearly with increasing the concentration in the range from 0.05 to 60 μM with the detection limit of 0.02 μM ( S / N = 3). The developed electrochemical sensor exhibited high selectivity, good stability and reproducibility, and also successfully determined luteolin in drug samples.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2015
·Vol. 308
·期 1
·287-295
·
IF 1.034
Jing P. F.,Liu H. J.,Zhang Q.,Hu S. Y.,Hu C.,Peng L.,Lei L. L.
The adsorption of thorium(IV) [Th(IV)] was studied using a novel 6-o-monotosyl-deoxy-β-cyclodextrin inclusion complex of dibenzoyl (inclusion complex), which was acquired by the reaction of dibenzoyl and 6-OTs-β-CD with the mole ratio of 1:2. The adsorption of Th(IV) onto inclusion complex were investigated as a function of pH value, contact time, temperature, interfering ions and Th(IV) concentration using batch adsorption technique. The maximum adsorption of Th(IV) and the equilibrium adsorption capacity were found to be 89 ± 1 % and 17.83 mg g −1 respectively at pH 3.0, equilibrium time 20 min and initial Th(IV) concentration 20 mg L −1 . Adsorption kinetics, adsorption isotherm and thermodynamics were carried out.
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ENZYME AND MICROBIAL TECHNOLOGY
·
2015
·
IF 2.322
Haoyu Zang,Shanshan Xie,Huijun Wu,Weiduo Wang,Xiankun Shao,Liming Wu,Faheem Uddin Rajer,Xuewen Gao
A novel thermostable mannanase from a newly isolated Bacillus pumilus GBSW19 has been identified, expressed, purified and characterized. The enzyme shows a structure comprising a 28 amino acid signal peptide, a glycoside hydrolase family 5 (GH5) catalytic domain and no carbohydrate-binding module. The recombinant mannanase has molecular weight of 45 kDa with an optimal pH around 6.5 and is stable in the range from pH 5–11. Meanwhile, the optimal temperature is around 65 °C, and it retains 50% relative activity at 60 °C for 12 h. In addition, the purified enzyme can be activated by several ions and organic solvents and is resistant to detergents. Bpman5 can efficiently convert locus bean gum to mainly M2, M3 and M5, and hydrolyze manno-oligosaccharides with a minimum DP of 3. Further exploration of the optimum condition using HPLC to prepare oligosaccharides from locust bean gum was obtained as 10 mg/ml locust bean gum incubated with 10 U/mg enzyme at 50 °C for 24 h. By using this enzyme, locust bean gum can be utilized to generate high value-added oligosaccharides with a DP of 2–6.
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CARBOHYDRATE POLYMERS
·
2015
·
IF 4.074
Cong Chen,Yan Meng,Sheng Li,Wenhua Wu,Chuanjun Liu,Xiaojuan Xu,Lina Zhang
A polysaccharide coded as PR-CA was extracted from Polyporus rhinoceros and determined to be a β-(1→3)- d -glucan with multiple branches. The weight-average molecular weights ( M w ) of PR-CA in dimethylsulfoxide (DMSO) and in water were determined with static light scattering (SLS) to be 3.57 × 10 5 and 1.79 × 10 7 , indicating existence of the single chains in DMSO and co-existence of single chains and aggregates in water. Moreover, the stiffness of single chains of PR-CA in water was directly visualized by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The hollow structure of PR-CA nanofibers with width of 30–40 nm and length of ∼350 nm formed in the water/DMSO (9:1, v:v) was demonstrated by a fluorescent probe tetraphenylethylene (TPE) via aggregation-induced emission (AIE). The formation of PR-CA nanofibers was ascribed to the parallel aggregation of the extended PR-CA chains due to the hydrogen bonding and hydrophobic interaction. This work offered valuable results for promising applications of natural branched β-glucans in the biological fields of drug inclusion, delivery and disease diagnosis.
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CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
·
2014
·
IF 0.7
Ren-Dan ZHOU,Lai-Sheng LI,Biao-Ping CHENG,Gui-Zhen NIE,Hong-Fu ZHANG
A 6-azido-β-cyclodextrin was synthesized and derivatized with p -nitrophenyl isocyanate as chiral ligand. Then the ligand was chemically bonded to mesoporous SBA-15 via a ‘Click Chemistry’ reaction of the azido group with alkynyl group. A new p -nitrophenylcarbamoylated β-cyclodextrin bonded SBA-15 chiral stationary phase (NPCSP) for HPLC was thus obtained. The new stationary phase was first used for enantioseparation of propranolol in human plasma under the polar organic solvent mode. The effects of methanol content, concentration of glacial acetic acid/triethylamine in mobile phase and the temperature on the enantioseparation were studied in detail. The optimized chromatographic conditions were as follows: mobile phase was acetonitrile/methanol/glacial acetic acid/triethylamine (90/10/1.25/2.25, V/V ) at 288 K, with a flow rate of 0.5 mL min −1 , an injection volume of 20 μL and detection wavelength at 290 nm. The resolution was 2.04 with a short run time (< 15 min) under the optimal conditions. The content of propranolol in plasma was quantitatively measured by HPLC-MS under selected ion monitoring mode ([M + H] + m/z 260.10) with hydrochlorothiazide as an internal standard. The good linear relationship was observed in the range of 2.5−50 μg L −1 . The detection limits were 1 μg L −1 according to S/N = 3 for both enantiomers. The experimental results showed that the chiral stationary phase exhibited excellent chiral separation ability to propranolol. The analytical method for propranolol enantiomers was sensitive, accurate, simple and fast, which was can be for the determination of propranolol in plasma and related pharmacokinetic studies.
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JOURNAL OF HETEROCYCLIC CHEMISTRY
·
2017
·Vol. 55
·期 1
·351-359
·
IF 0.893
Xiong-Wei Liu,Jun Yang,Guan-Lian Wang,Yi Gong,Ting-Ting Feng,Xiong-Li Liu,Yu Cao,Ying Zhou,Wei-Cheng Yuan
Described herein is a facile and efficient methodology toward the synthesis of novel convolutamydine A-incorporated β -ionone scaffold 3 from an Aldol addition event of β -ionone to isatins via enamine Et 2 NH catalysis. Products featuring a quaternary carbon center were smoothly obtained in good yields (up to 96% yield). This protocol also represents the first construction of ionone skeleton-fused oxindole molecules, thus leading to new knowledge in the fields of both molecular complexity and diversity-oriented synthesis and the lead compound discovery. Furthermore, their biological activities against human leukemia cells K562 have been preliminarily demonstrated by in vitro assays. The results demonstrated that most of these compounds obtained by this protocol showed comparable with or even much better than the positive control of Cisplatin.
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Materials Science & Engineering C-Materials for Biological Applications
·
2017
·
IF 4.164
Aihua Zou,Xiaotong Zhao,Ulrich A. Handge,Vasil M. Garamus,Regine Willumeit-Römer,Peihao Yin
Bufalin (BF), a traditional Chinese medicine, exhibited inhibitory activities against a broad spectrum of tumor cells. The present study elaborates that bufalin was successfully encapsulated into the cavity of β-cyclodextrin (β-CD), which was determined by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy ( 1 H NMR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The best reaction mole ratio of BF/β-CD was 1:5. The solubilities of bufalin in water and phosphate buffer solution (pH = 7.4) were increased up to 24 and 34 times after encapsulated into the cavity of β-CD respectively. The inclusion efficiency (IE) and drug loading (DL) of bufalin in the inclusion complex were (94.22 ± 0.85)% and (14.11 ± 0.20)%, respectively. Then β-CD conjugated with folic acid (FA) were further prepared and employed to improve the anti-tumor efficacy of inclusion complex. The in vitro dissolution and solubility study showed better values of inclusion complex and FA targeted inclusion complex than that of pure BF. Cytotoxicity experiments by using HCT116 cell line revealed that the antitumor efficiency of bufalin were enhanced more than two folds in the presence of β-CD and folate conjugated β-CD (FA-PEI-β-CD), which demonstrated the potential application of β-CD (FA-PEI-β-CD) as delivery vehicles of bufalin for antitumor therapy.
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EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
·
2017
·
IF 4.519
Jincan Chen,Fa Peng,Yao Zhang,Baojun Li,Ji She,Xinming Jie,Zhilin Zou,Man Chen,Lanmei Chen
Two new cyclometalated Ru(II) complexes of the general formula [Ru(N-N) 2 (1-Ph-βC)](PF 6 ), where N–N = 4,4′-dimethyl-2,2′-bipyridine (dmb, Ru1 ), 2,2′-bipyridine (bpy, Ru2 ), and 1-Ph-βC (1-phenyl-9 H -pyrido[3,4- b ]indole) is a β-carboline alkaloids derivatives , have been synthesized and characterized. The in vitro cytotoxicities, cellular uptake and localization, cell cycle arrest and apoptosis-inducing mechanisms of these complexes have been extensively explored by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, inductively coupled plasma mass spectrometry (ICP-MS), flow cytometry , comet assay , inverted fluorescence microscope as well as western blotting experimental techniques. Notably, Ru1 and Ru2 exhibit potent antiproliferative activities against selected human cancer cell lines with IC 50 values lower than those of cisplatin and other non-cyclometalated Ru(II) β-carboline complexes. The cellular uptake and localization exhibit that these complexes can accumulate in the cell nuclei. Further antitumor mechanism studies show that Ru1 and Ru2 can cause cell cycle arrest in the G0/G1 phase by regulating cell cycle relative proteins and induce apoptosis through mitochondrial dysfunction, reactive oxygen species (ROS) accumulation and ROS-mediated DNA damage.
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REACTIVE & FUNCTIONAL POLYMERS
·
2016
·
IF 2.725
Zhiqiang Jiang,Xiaoyan Dong,Hu Liu,Yongjian Wang,Lei Zhang,Yan Sun
Aggregation of amyloid β-protein (Aβ) is a major pathological hallmark of Alzheimer's disease. Curcumin has been recognized as an inhibitor of Aβ aggregation, but its low water solubility and bioavailability limits its clinical applications. In this work, we conjugated curcumin to hyaluronic acid and drastically improved its solubility and stability. We found that the conjugates self-assembled into nanosized hydrogels that inhibited Aβ fibrillogenesis and mitigated the amyloid cytotoxicity more efficiently than free curcumin. More importantly, we found that there was an optimal curcumin substitution degree, at which the hydrogel exhibited the strongest inhibitory effect. Based on these findings, a mechanistic model was proposed. It suggested that besides the inhibitory effect of the conjugated curcumin, HA provided three synergistic functions. The first is that curcumin encapsulation into nanogels protected cells from the toxicity of free curcumin. The second was an isolation effect of the hydrogel network, which hindered the interactions between Aβ molecules. The third was the counteraction of the hydrophobic binding between Aβ and the conjugated curcumin against the electrostatic repulsion between the like-charged Aβ and HA. The two opposite forces could stretch the conformation of Aβ monomers , slowing down the aggregation and/or leading to off-pathway aggregations. This work offered new insights into the development of more potent nanoparticles for inhibiting Aβ fibrillogenesis and cytotoxicity.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2016
·Vol. 34
·期 6
·730-738
·
IF 1.811
Wen Ji-jie,Lu Hong-guang,Liu De-e,Gao Hui
A series of β -cyclodextrin-conjugated 4-arm poly(ethylene glycol)-poly(lactide- co -glycolide) (4-arm PEG-PLGA) copolymers were synthesized by a ring-opening polymerization of D,L-lactide and glycolide using 4-arm PEG as initiator, and then conjugated with mono(6-ethylenediamine-6-deoxy)- β -cyclodextrin (CDen) or ethylenediamino-bridged bis- β -CD (BCDen). The chemical structures of copolymers were confirmed by 1 H-NMR and FTIR spectroscopy. The β -CD-conjugated PEG-PLGA formed stable reverse micelles due to the formation of β -CD and bovine serum albumin (BSA) inclusion complexation, which could accommodate BSA in the organic solvent with improved encapsulation efficiency. Moreover, we demonstrated a one-step approach to construct macroporous protein-containing films using these reverse micelles. The films with ordered pore arrays were directly prepared from reverse micelles. Interestingly, the protein was totally located in the whole matrix except for the pores.
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JOURNAL OF PHARMACY AND PHARMACOLOGY
·
2017
·Vol. 69
·期 6
·663-674
·
IF 2.405
Li Jing,Jiang Qihua,Deng Ping,Chen Qian,Yu Mingan,Shang Jingchuan,Li Wei
ObjectivesBaicalin (BCL) has potential therapeutic benefits, but its clinical outcomes are restricted mainly because of low water solubility. This study sought to improve the water solubility of BCL by the formation of inclusion complex with β-cyclodextrin (β-CD).MethodsThe inclusion complex was studied by solubility test, differential scanning calorimeter (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), 1H Nuclear magnetic resonance (1HNMR) and scanning electron microscopy (SEM). Molecular docking was conducted to verify the experimental findings. The dissolution rate was determined by dialysis membrane method. In vivo absorption studies in rats were conducted and high-performance liquid chromatography (HPLC) was used to analyse the plasma level of BCL after oral administration.Key findingsThe DSC, FTIR, XRD, 1HNMR and SEM findings suggested the formation of inclusion complex between BCL and β-CD in 1 : 1 stoichiometry. Molecular docking demonstrated the insertion of benzene ring of BCL into β-CD cavity by hydrophobic interactions and possible H-bond formation. Moreover, β-CD markedly improved the solubility of BCL and displayed AL-type phase diagrams. The improvement in dissolution rate of the inclusion complex was reflected in the earlier Tmax, higher Cmax and larger AUC0–t than that of BCL after oral administration.Conclusionsβ-cyclodextrin complex can be used as an effective formulation strategy for development of BCL-loaded delivery system with better therapeutic outcomes.
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BIOTECHNOLOGY LETTERS
·
2017
·Vol. 39
·期 8
·1175-1181
·
IF 1.73
Zhou Youzhi,Liu Ke,Zhang Jinsong,Chu Jianlin,He Bingfang
Objective To improve the stability of β-galactosidase from Bacillus megaterium YZ08 (BMG) in aqueous hydrophilic solvents and promote its application in the galactosylation of natural products. Results The addition of 5 mM Mg 2+ significantly enhanced the stability of BMG in aqueous hydrophilic solvents, and the half-lives of BMG in these solutions reached 56 min to 208 h, while they were only 7 min to 5.9 h without addition of Mg 2+ . Studies on the kinetic parameters in buffer solution and 30% dimethyl sulfoxide (DMSO) indicated that the affinity of BMG to 2-nitrophenyl-β- d -galactopyranoside and its catalytic efficiency ( κ
cat / K
m ) increased with the addition of Mg 2+ . Furthermore, the addition of Mg 2+ facilitated galactosylation reactions in 30% DMSO and increased product conversions by 24–41% due to the reversal of the thermodynamic equilibrium of hydrolysis. Conclusion A convenient approach was established to improve the stability of BMG in aqueous hydrophilic solvents.
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