Scientific Reports
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2016
·Vol. 6
·期 1
·1-9
·
IF 5.228
Xue Shan-Shan,Zhao Meng,Ke Zhuo-Feng,Cheng Bei-Chen,Su Hua,Cao Qian,Cao Zhen-Kun,Wang Jun,Ji Liang-Nian,Mao Zong-Wan
It is challenging to create artificial catalysts that approach enzymes with regard to catalytic efficiency and selectivity. The enantioselective catalysis ranks the privileged characteristic of enzymatic transformations. Here, we report two pyridine-linked bis(β-cyclodextrin) (bisCD) copper(II) complexes that enantioselectively hydrolyse chiral esters. Hydrolytic kinetic resolution of three pairs of amino acid ester enantiomers (S 1 –S 3 ) at neutral pH indicated that the “back-to-back” bisCD complex CuL 1 favoured higher catalytic efficiency and more pronounced enantioselectivity than the “face-to-face” complex CuL 2 . The best enantioselectivity was observed for N -Boc-phenylalanine 4-nitrophenyl ester (S 2 ) enantiomers promoted by CuL 1 , which exhibited an enantiomer selectivity of 15.7. We observed preferential hydrolysis of L -S 2 by CuL 1 , even in racemic S 2 , through chiral high-performance liquid chromatography (HPLC). We demonstrated that the enantioselective hydrolysis was related to the cooperative roles of the intramolecular flanking chiral CD cavities with the coordinated copper ion, according to the results of electrospray ionization mass spectrometry (ESI-MS), inhibition experiments, rotating-frame nuclear Overhauser effect spectroscopy (ROESY), and theoretical calculations. Although the catalytic parameters lag behind the level of enzymatic transformation, this study confirms the cooperative effect of the first and second coordination spheres of artificial catalysts in enantioselectivity and provides hints that may guide future explorations of enzyme mimics.
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ADVANCED SYNTHESIS & CATALYSIS
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2016
·Vol. 358
·期 24
·4019-4029
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IF 6.453
Yulin Han,Xinjun Tang,Jiajia Cheng,Shengming Ma
We report here an indium(III) triflate (In(OTf) 3 )-catalyzed Prins-type cyclization of disubstituted β-allenols in the presence of aldehydes in dichloromethane (CH 2 Cl 2 ) affording different 3,6-dihydro-2 H -pyran at room temperature or 45 °C. The high efficiency of the reaction and easily available nature of the starting materials/catalyst make it useful in synthesizing different dihydropyran derivatives. A rationale for the formation of all the products was proposed.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2016
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IF 3.902
Qi Ma,Jinping Song,Sufang Zhang,Meifang Wang,Yong Guo,Chuan Dong
β-Cyclodextrin-grafted citrate was used for the first time as a stabilizer and reducer to prepare silver nanoparticles (AgNPs). The as-synthesized AgNPs were further characterized by UV–vis absorption spectroscopy, powder X-ray diffraction spectroscopy, and transmission electron microscopy. The results show that the presence of riboflavin caused severe aggregation of the nanoparticles, thereby inducing a colour change from yellow to red. 1 H NMR further verified the formation of non-inclusion complexes between riboflavin and β-cyclodextrin-grafted citrate. Hydrogen bond was considered the main driving force of the interaction between the riboflavin and external rim of β-cyclodextrin. Based on these observations, the as-synthesized AgNPs were utilized to develop a novel colorimetric sensor for riboflavin detection. This colorimetric probe showed excellent selectivity and high sensitivity for riboflavin with a detection limit of 167 nM.
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FOOD HYDROCOLLOIDS
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2016
·
IF 3.858
Ping Shao,Yueqiong Zhu,Weiping Jin
The objectives of this study were to investigate the effect of Ulva fasciata polysaccharide (UFP) on the physical and chemical characteristics of β-carotene oil-in-water (O/W) emulsions. The β-carotene (O/W) emulsions were prepared by combining 95 wt% UFP (1–5%, wt/wt) solutions with 5 wt% soybean oil containing β-carotene (0.05 wt% in the final emulsion). The stability of β-carotene emulsions was evaluated by droplet size and distribution, viscosity, zeta-potential, visual phase separation, light microscopy imaging and β-carotene degradation of the emulsions during storage. In addition, the influences of ionic strength and pH on physical stabilities of emulsions were characterized. Emulsions stabilized with high concentration (>2% wt/wt) of UFP had an average droplet size (D [3, 2]) less than 1.0 μm, and the average droplet size significantly decreased until the polysaccharide concentration reached 3%. Light microscopy images and emulsion zeta-potentials demonstrated 3% (wt/wt) UFP to be the optimum emulsifying agent concentration. UFP revealed better emulsifying properties and improved physical stabilities of β-carotene emulsions when compared to other commercial polysaccharides, including gum Arabic and beet pectin.
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CERAMICS INTERNATIONAL
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2017
·
IF 2.986
Shenglei Feng,Fupo He,Jiandong Ye
In this study, for the first time honeycomb β-tricalcium phosphate (β-TCP) scaffolds were fabricated through an extrusion technique. The physicochemical properties and cell behaviors of the honeycomb β-TCP scaffolds were investigated. The results showed that scaffolds were characterized by ordered channel-like macropores and unidirectional interconnection. The pore structure and mechanical strength could be tailored by changing the parameters of extrusion molds. The pore size of scaffolds was in the range of 400–800 µm approximately, while their compressive strength parallel to the pore direction and porosity ranged from 14 to 20 MPa and 60–70%, respectively. The in vitro cell behavior demonstrated that cells could well attach on the surfaces and grow into the inner channel-like pores of the scaffolds; the scaffolds with higher porosity showed better cell proliferation but poorer cell differentiation. The honeycomb scaffolds fabricated by extrusion technique are potential candidate for bone tissue engineering.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2017
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IF 2.714
Peng Li,Sen Li,Yu Wang,Yu Zhang,Guo-Zhi Han
Increasing application of noble-metal nanoparticles (MNPs) urges the development of a nontoxic and environmentally friendly synthesis methodology. In this paper,using β-Cyclodextrin (β-CD) as reducer and stablizer, a green synthetic approach of monodispersed silver nanoparticles (AgNPs) with diameter between 10–25 nmin aqueous alkaline medium is reported. By varying the molar ration of β-CD/AgNO 3 , the size of as-prepared silver particles can be readily controlled. Furthermore, the formation mechanism of the AgNPs was discussed. On the basis, the catalytic activity of the as-prepared AgNPs was studied toward reduction of p -nitrophenol by NaBH 4 . The experimental results shown that surface modified by β-CD can improve the catalytic activity of the silver nanoparticles.
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FOOD CHEMISTRY
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2017
·
IF 4.529
Ting Hu,Qilin Huang,Kahing Wong,Hong Yang,Jingsi Gan,Yanru Li
An alkali-soluble polysaccharide was extracted from Lignosus rhinocerotis sclerotia (LRP). Its structural characteristics were determined by GC–MS, FT-IR, GC, 1D and 2D NMR combined with Smith degradation and methylation analysis. The LRP had a (1 → 3)-β- d -Glcp backbone with every three residues bearing a (1 → 6)-linked and hyperbranched side chain that contained three (1 → 6)-β- d -Glcp residues as secondary main chain and two terminal β- d -Glcp residues linked at O3. The degree of branching was 0.76 from GC–MS analysis, implying a highly branched structure for LRP. The M w , < S 2 > z 1/2 , R h and [ η ] values of LRP in 0.25 M LiCl/DMSO were measured by SEC-MALLS-Vis-RI combination technology to be 2.88 × 10 5 g/mol, 30.36 nm, 22.34 nm and 131.50 ml/g, respectively. Furthermore, the exponent α of [ η ] –M w , β of < S 2 > z 1/2 –M w , the fractal dimension d f and molecular parameter ρ were determined to be 0.20, 0.33, 2.50 and 1.36, demonstrating that the LRP was a hyperbranched polysaccharide and adopted a compact coil conformation in LiCl/DMSO.
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FLAVOUR AND FRAGRANCE JOURNAL
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2016
·Vol. 32
·期 2
·102-111
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IF 1.693
Zujin Yang,Liyun Huang,Xingdong Yao,Hongbing Ji
Estragole (ES) has multiple biological activities and is widely used in food preservation. However, the applications of ES are limited because of its low water solubility and high volatility nature. In this paper, the β-cyclodextrin (β-CD) inclusion complex of ES was prepared by a co-precipitation method with the aim of enhancing its thermal stability and realize its controlled release. Solubility experiments were performed to evaluate the effect of β-CD on ES aqueous solubility. Release experiments of ES from its inclusion complexes were carried out at different temperatures with a relative humidity (RH) and Avrami's equation was used to analyse the release data. The antimicrobial activity of the free and included ES was also examined. The results indicated that the host–guest interactions played a crucial role in enhancing the properties of ES. The inclusion complex was investigated using physico-chemical techniques such as Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA and DSC), 1H and 2D nuclear magnetic resonance (NMR). The inclusion processes between β-CD and ES were simulated using the semi-empirical PM3 and ONIOM [B3LYP/6-31g(d):PM3] methods. Copyright © 2016 John Wiley & Sons, Ltd.
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JOURNAL OF POLYMER SCIENCE
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2024
·
IF 3.9
Na Liang,Caixia Yan,Zhenrong Liu,Wenlong Hu,Kun Jiang,Gang Li,Shaoping Sun
To improve the therapeutic efficiency of paclitaxel (PTX) and reduce its toxicity to normal tissues, a novel hydroxypropyl-β-cyclodextrin (HP-β-CD) derivative has been designed and developed. The polymer (bio-HP-β-CD(NAC)-PLA) is synthesized by modifying HP-β-CD with polylactic acid, cysteine, and biotin. Using bio-HP-β-CD(NAC)-PLA as the carrier, a PTX-loaded nanoparticulate system is developed by a modified emulsion solvent evaporation method. The optimized drug-loaded nanoparticles are obtained with a mean diameter of 162.4 nm and drug loading of 16.1%. In vitro drug release study exhibits that PTX is released in a redox-dependent manner. Cellular uptake study suggests that the bio-HP-β-CD(NAC)-PLA nanoparticles can be specifically taken up by MCF-7 cells via the biotin receptor-mediated endocytosis. In vitro and in vivo anticancer efficacy evaluations demonstrate the superior antitumor activity and negligible toxicity of the PTX-loaded nanoparticles. It can be concluded that the proposed polymer bio-HP-β-CD(NAC)-PLA offers a promising drug delivery system for targeted delivery and controlled release of PTX. Graphical
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BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
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2024
·
IF 2.5
Hangyu Shen,Wenhui Liu,Yun Dou,Yongxin Lu,Chunling Zhang,Xiaoying Wang,Fangong Kong,Shoujuan Wang
In general, Cu(II) is the critical factor in catalyzing reactive oxygen species (ROS) production and accelerating amyloid-β (Aβ) oligomer formation in Alzheimer's disease (AD). Natural chelating agents with good biocompatibility and appropriate binding affinity with Cu(II) have emerged as potential candidates for AD therapy. Herein, we tested the capability of guluronic acid disaccharide (Di–GA), a natural chelating agent with the moderate association affinity to Cu(II), in inhibiting ROS production and Aβ oligomer formation. The results showed that Di−GA was capable of chelating with Cu(II) and reducing ROS production, even in solutions containing Fe(II), Zn(II), and Aβ. In addition, Di−GA can also capture Cu(II) from Cu−Aβ complexes and decrease Aβ oligomer formation. The cellular results confirmed that Di−GA prevented SH−SY5Y cells from ROS and Aβ oligomer damage by reducing the injury of ROS and Aβ oligomers on cell membrane and decreasing their intracellular damage on mitochondria. Notably, the slightly higher efficiency of Di–GA in chelating with Cu(I) than Cu(II) can be benefit for its in vivo applications, as Cu(I) is not only the most active but also the special intermediate specie during ROS production process. All of these results proved that Di–GA could be a promising marine drug candidate in reducing copper-related ROS damage and Aβ oligomer toxicity associated with AD.
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ENZYME AND MICROBIAL TECHNOLOGY
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2024
·
IF 3.4
Jiehu Liu,Runtian Huo,Huixian Fu,Shiheng Chen,Xueyi Qiao,Bo Xu,Zhaoyuan Zhang,Jing Wu,Lingqia Su
β-nicotinamide mononucleotide (β-NMN) is a key precursor of nicotinamide adenine dinucleotide, and becomes attractive in the nutrition and health care fields, but its enzymatic synthesis is expensive. In this study, a six-enzyme cascade catalytic system was constructed to produce β-NMN. Using D-ribose and nicotinamide as substrates, the β-NMN yield reached 97.5 % catalyzed by purified enzymes. Then, after knocking out the genes encoding proteins that consume β-NMN in E. coli BL21(DE3), the similar β-NMN yield, 97.2 %, using the crude enzymes could be also obtained. After that, β-NMN synthesis was performed under increased substrate concentration, and 'modular' crude enzymes cascade catalytic reaction system was proposed to reduce the inhibition of polyphosphate on ribose-phosphate diphosphokinase activity, and the β-NMN yield reached 78.4 % at 10 mM D-ribose, which is 1.82 times of that in 'one-pot' reaction and represents the highest β-NMN preparation level with phosphoribosylpyrophosphate as the core reported till now.
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
·
2024
·
IF 5.3
Yibo Pan,Xiaoqiang Ma,Jianxia Sun,Weibin Bai
Anthocyanins, one of the important water-soluble pigments, are sensitive to environmental factors, which limits the application of anthocyanins in food field. In order to overcome this limitation, double Pickering emulsions stabilized by β-cyclodextrin were developed. The optimum preparation conditions of the emulsions were determined firstly and the performance and structure of emulsions were investigated. Results showed that the optimum preparation conditions of emulsions were the ratio of (W 1 /O): W 2 = 6:4 and 4 % β-cyclodextrin concentration. Optical microscope and confocal laser scanning microscope results confirmed that β-cyclodextrin adsorbed onto the surface of droplets forming stable double Pickering emulsions structure. In vitro gastrointestinal digestion experiments proved that double Pickering emulsions played a controlled-release effect in the small intestine. Rheological analysis proved that the emulsions exhibited elastic properties and demonstrated shear thinning behavior. The emulsions showed excellent stability under centrifugation and thermal conditions. These findings will promote anthocyanins’ application in daily diet.
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