CHEMICAL ENGINEERING SCIENCE
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2023
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IF 4.7
Yaoguo Wang,Jie Sun,Weiwei Tang,Junbo Gong
Deracemization is a promising chiral resolution technique that combines racemization reaction with stereoselective crystallization for complete chiral symmetry breaking and has attracted much attention. However, the integration process of reaction-crystallization is rather complex and often requires long operation time with high initial solid enantiomer excess which greatly limits its wide application. Herein, we proposed a novel strategy that combines the use of both ultrasound and temperature cycles to accelerate the process of deracemization and thereby chiral separation. A chiral compound, N-acetyl- dl -leucine, was selected as a model drug for experimental validation. We found that either ultrasound or temperature cycle process was capable of accelerating the deracemization efficiency, nonetheless, the combination of the two methods leads to the antagonistic action, decreasing process efficiency and product chiral purity. Through the time-elapsed characterizations on enantiomeric purity of N-acetyl- l -leucine over the course of deracemization, we revealed that the ultrasound negatively impacted the process efficiency of chiral separation via promotion of primary heterogeneous nucleation during the cooling stage. Finally, we strategically designed a synergistic process intensification of crystallization-induced deracemization between temperature cycling and the periodic ultrasound that switches on only during the heating stage to achieve highly efficient separation of pure N-acetyl- l -leucine with theoretical 100% yield at extremely low initial solid ee %.
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高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2020
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IF 2.369
Shengzheng Guo,Yang He,Gang Wang,Weibing Dong,Xuxing Wan,Yanxiao Zhao,Shichao Du
The solubility of N-acetyl-l-leucine in 12 mono organic solvents (methanol, ethanol, n-propanol, 2-propanol, 1-butanol, isobutanol, 2-butanol, methyl acetate, ethyl acetate, propyl acetate, acetone, and acetonitrile) was determined by the gravimetric method over the temperatures ranging from 283.15 to 323.15 K at 0.1 MPa. The solubility of N-acetyl-l-leucine in each experimental solvent increases with increasing temperature. Moreover, the solubility is an order of magnitude higher in alcohol solvents than in other solvents, which is mainly attributed to the hydrogen bond formation. In addition, the experimental solubility data are correlated by three models, including the modified Apelblat equation, λh equation, and the nonrandom two-liquid (NRTL) model. All of the average relative deviation % values are less than 3.72%, which indicates that the three models have satisfactory correlations. Furthermore, the mixing thermodynamic properties of N-acetyl-l-leucine in 12 mono solvents including ΔmixG0, ΔmixH0, and ΔmixS0 are calculated based on the NRTL model, indicating that the mixing process was spontaneous.
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International Journal of Nanomedicine
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2020
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IF 5.115
Lu Hou,Zheyu Song,Zhonghang Xu,Yuanyu Wu,Wei Shi
Background siRNA-mediated polo-like kinase 1 (PLK1) silencing has been proposed as a promising therapeutic method for multiple cancers. However, the clinic application of this method is still hindered by the low specific delivery of siPLK1 to desired tumor lesions. Herein, folate (FA)-modified and leucine-bearing polyethylenimine was successfully synthesized and showed excellent targeted silencing to folate receptor overexpressed cells. Materials and Methods The condensation of siPLK1 by FA-N-Ac-L-Leu-PEI (NPF) was detected by the gel retardation assay. The targeted and silencing efficiency was evaluated by flow cytometry and confocal laser scanning microscope. The PLK1 expressions at gene or protein levels were detected by quantitative real-time PCR and Western blotting assay. Further impacts of the PLK1 silencing on cell viability, cell cycle, migration, and invasion were studied by MTT, colony formation, wound healing and transwell assays. Results The NPF and siPLK1 could efficiently assemble to stable nanoparticles at a weight ratio of 3.0 and showed excellent condensation and protection effect. Owing to the FA-mediated targeted delivery, the uptake and silencing efficiency of NPF/siPLK1 to SGC-7901 cells was higher than that without FA modification. Moreover, NPF-mediated PLK1 silencing showed significant antitumor activity in vitro. The anti-proliferation effect of PLK1 silencing was induced via the mitochondrial-dependent apoptosis pathway with the cell cycle arrest of 45% at G2 phase and the apoptotic ratio of 28.3%. Conclusion FA-N-Ac-L-Leu-PEI (NPF) could generate targeted delivery siPLK1 to FA receptor overexpressed cells and dramatically downregulate the expression of PLK1 expression.
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PubMed
高影响因子
Antioxidants
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2019
·Vol. 8
·期 8
·321
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IF 4.52
Dandan Wang,Liangxiao Zhang,Yueqing Xu,Xin Qi,Xuefang Wang,Xiupin Wang,Qi Zhang,Peiwu Li
Sesame is a nutritional agricultural product with medicinal properties. Accurate determination of micronutrients is important for the improvement of sesame quality and nutrition assessments. Our previous study showed that 10 antioxidants—d-homoproline, vitamin B2, coniferyl aldehyde, hesperidin, phloretin, N-acetyl-l-leucine,l-hyoscyamine, ferulic acid, 5-methoxypsoralen, and 8-methoxypsoralen—in sesame were potential characteristic nutrients in sesame. Herein, simultaneous detection of 10 different types of antioxidants was developed by using ultrasound-assisted extraction coupled with liquid chromatography-tandem mass spectrometry (UAE-LC-MS/MS) with the help of response surface methodology. The significant variables and levels were screened and optimized by combining the single factor experiment, Plackett–Burman test, and Box–Behnken design. The optimal conditions for extraction of target antioxidants in sesame were methanol solution of 75.0%, liquid-to-material ratio of 20:1 (mL/g), extraction temperature of 50 °C, extraction power of 410.0 W, extraction time of 65 min. The total yield of targets was 21.74 μg/g under the optimized conditions. The mobile phase used was 0.1% formic acid in acetonitrile and 0.1% formic acid in water, and the column was a Thermo Syncronis C18 reverse phase column (100 mm × 2.1 mm, 3 μm). All targets required only one injection and could be quickly separated and assayed within 7 min. The limits of detection and limits of quantification for these 10 nutritional compounds ranged from 0.01 to 0.11 µg/kg and from 0.04 to 0.34 µg/kg, respectively. The validation results indicated that the method had reasonable linearity (R2≥ 0.9990), good recoveries (71.1%–118.3%), satisfactory intra-day precision (≤9.6%) and inter-day precision (≤12.9%), and negligible matrix effects (≤13.8%). This simultaneous quantification method was accurate, fast, and robust for the assessment of sesame nutrition.Keywords:antioxidants;ultrasound-assisted extraction;liquid chromatography-tandem mass spectrometry (LC-MS/MS);sesame;simultaneous detection;response surface methodology
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高影响因子
COLLOIDS AND SURFACES B-BIOINTERFACES
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2015
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IF 4.152
Zhiyuan Li,Liu Zhang,Quanshun Li
Herein, N -acetyl- l -leucine-modified polyethylenimine was successfully constructed through the EDC/NHS-mediated coupling reaction and employed as vectors to accomplish p53 gene delivery using HeLa (p53wt) and PC-3 cells (p53null) as models. Compared with PEI25K, the derivatives exhibited lower cytotoxicity, protein adsorption and hemolytic activity, together with satisfactory pDNA condensation capability and gene transfection efficiency. After p53 transfection, MTT analysis confirmed that the cell proliferation was inhibited. Flow cytometric analysis showed that the derivative-mediated p53 delivery could induce stronger early apoptosis than PEI25K and Lipofectamine 2000 . Further, PC-3 cells showed higher sensitivity to the exogenous p53 transfection than HeLa cells. The mechanism for inducing apoptosis was determined to be up-regulation of p53 expression at both mRNA and protein levels using RT-PCR and western blotting analysis. Expression level and activity analysis of caspase-3, -8 and -9, and mitochondrial membrane potential measurement revealed that p53 transfection mediated by these derivatives facilitated early apoptosis of tumor cells via a mitochondria-dependent apoptosis pathway. Thus, the derivatives showed potential as biocompatible carriers for realizing effective tumor gene therapy.
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PubMed
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WEAR
·
2024
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IF 5.3
Mingyuan Dou,Qing Feng,Jing Yang,Shuai Zou,Kangchun Li,Zhenpeng Li,Maoli Yang,Fuchuan Huang
With the increasing average lifespan of human beings, the wear and tear caused by daily activities on joints will also escalate. Consequently, there is a growing focus on the development of green, environmentally friendly, and biocompatible non-toxic lubricating materials. The presence of dual chemical active centers in natural amino acids results in anions and cations that lead to precipitation and poor lubrication effects in traditional choline amino acid ionic liquids . In this study, nine types of choline acetyl-amino acid ionic liquids ([Ch][Ac-AA]ILs) were synthesized using acetylated amino acids (Ac-AA) as anions and choline (Ch) as cations. The physicochemical properties and tribological behavior of [Ch][Ac-AA]ILs at different frequencies were evaluated. The results demonstrated that [Ch][Ac-AA]ILs exhibited excellent tribological properties and maintained effective lubrication even under high-frequency friction conditions compared to sodium hyaluronate (HA-T). This performance was attributed to the carbon chain length and functional group composition of [Ch][Ac-AA]ILs' anions. Energy dispersive spectroscopy and X-ray photoelectron spectroscopy analysis revealed that the superior lubrication performance of [Ch][Ac-AA]ILs was associated with the formation of chemical reaction films and physical adsorption films on the surface of friction pairs . This research enriches our understanding of [Ch][AA]ILs-based lubrication systems while providing valuable insights for selecting joint lubricants suitable for different activity frequencies.
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高影响因子
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