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901.
Qiang-Ming Li Hui Jiang Xue-Qiang Zha Li-Hua Pan Jun Duan 《Natural product research》2020,34(4):563-566
AbstractThe stems of Dendrobium huoshanense have long been used to prevent various diseases, including inflammatory diseases. This study was aimed to explain the anti-inflammatory effect of D. huoshanense stems in LPS-induced RAW 264.7 macrophages and to discover potential anti-inflammatory compounds. Results exhibited that D. huoshanense stems ethanol extract could significantly inhibit LPS-induced production of NO, TNF-α and IL-1β. Based on bioassay guided strategy, four bibenzyls (1–4) were isolated from D. huoshanense stems for the first time. Anti-inflammatory assay showed 1–4 could remarkably inhibit the production of NO in LPS-induced macrophages. Moreover, quantitative RT-PCR analysis displayed that the mRNA levels of iNOs, TNF-α and IL-1β could also be significantly reduced by 1–4. These results suggested that D. huoshanense stems ethanol extract and bibenzyls 1–4 might be well developed as therapeutic agent to prevent inflammatory diseases. 相似文献
902.
AbstractThe study on inhibitory effects of resveratrol glucosides (REs) on advanced glycation endproducts (AGEs) formation is still unmet. Herein, for the first time, the antiglycation activities of five REs in the fetal bovine serum proteins (FBS)/fructose system were evaluated, and its structure-activity relationship and antiglycation mechanism were further explored. These REs showed remarkable inhibition toward AGEs formation. Among them, Piceatannol-3'-O-glucoside (PG) exhibited highest antiglycation activity as reflected in approximately 80% inhibition of fluorescent AGEs at the concentration of 1.0?mM. The structure-activity relationship analysis indicated that glucoside attached to the B ring of resveratrol displays a superior antiglycation activity. Moreover, the results of antiglycation mechanism showed that the antiglycation activity of REs was proportional to their antioxidant capacity and methylglyoxal (MGO) trapping capacity. Therefore, the REs are promising candidates worthy of further exploration for preventing AGEs accumulation in vivo, thereby treating AGEs-associated diseases. 相似文献
903.
Nan Wen Bojun Jiang Xiaojing Wang Zhifu Shang Dawei Jiang Lu Zhang Caiying Sun Zijian Wu Hui Yan Chuntai Liu Zhanhu Guo 《Chemical record (New York, N.Y.)》2020,20(8):773-792
The properties of polyvinyl alcohol (PVA) nanocomposite hydrogels influenced by nanoparticles are reviewed. Various kinds of nanoparticles with excellent mechanical and electrical properties have been introduced into PVA hydrogel to produce stretchable and conductive PVA nanocomposite hydrogel. Understanding the mechanism between the matrix of PVA hydrogel and nanoparticles is therefore critical for the development of PVA nanocomposite hydrogels. This review focuses on the nanoparticles include carbon nanotubes, graphene oxide and metal nanoparticles, and describes the effects of nanoparticles on the mechanical and conductive properties of PVA nanocomposite hydrogels. A new promising area of soft stretchable PVA nanocomposite hydrogel is highlighted for possible applications. Finally, a brief outlook for future research is presented. 相似文献
904.
Wei Li Zhuang‐Fei Jiang Ling Tan Shu‐Xian Wang Chong‐Zhi Wang Jia‐Wei Zhang Lian‐Di Zhou Qi‐Hui Zhang Chun‐Su Yuan 《Journal of separation science》2020,43(6):1173-1182
Curcumin widely exists in food, and rapid selective and accurate detection of curcumin have great significance in chemical industry. In this experiment, a new magnetic biocompatibility molecularly imprinted polymer was prepared with nontoxic and biocompatible Zein to adsorb curcumin selectively. The polymer has high biocompatibility, good adsorption capacity, and specific adsorption for curcumin. Combined with portable electrochemical workstations, the polymer can be used to detect curcumin rapidly and cost‐effectively. Using curcumin as a template and Zein as the crosslinking agent, the polymers were synthesized on the surface of Fe3O4 particles for solid phase extraction. The experimental results showed that the polymer reached large adsorption capacity (32.12 mg/g) with fast kinetics (20 min). The adsorption characteristic of the polymer followed the Langmuir isotherm and pseudo‐second‐order kinetic models. Hexacyanoferrate was used as electrochemical probe to generate signals, and the linear range was 5–200 µg/mL for measuring curcumin. The experimental analysis showed that the polymer was an ideal material for selective accumulation of curcumin from complex samples. This approach has been successfully applied to the determination of curcumin in food samples with electrochemical detection, indicating that this is a feasible and practical technique. 相似文献
905.
Deping Hu Yuandong Li Hui Zhao Yang Zhao Si Huang Juan Li Zhenjie Li Yuanxing Duan Yingzhuang Chen Jianjun Xia 《Journal of separation science》2020,43(8):1423-1430
An online high‐pH reversed‐phase liquid chromatography× low‐pH reversed‐phase liquid chromatography tandem electrospray ionization mass spectrometry combined with pulse elution gradient in the first dimension was constructed to separate and identify alkaloids from Macleaya cordata (willd.) R. Br. The modulation was performed by using a dual second dimensional columns interface combined with a make‐up dilution pump, which is responsible for dilution and neutralization of the first dimensional effluent, and the dual second dimensional columns integrated the trapping and the separation function to reduce the second dimension system dead volume. Taking advantage of the dissociable characteristics of alkaloids, mobile phases with different pH values were applied in the first dimension (pH 9.0) and the second dimension (pH 2.6) to improve the orthogonality of two‐dimension separation. Besides, the pulse elution gradient in first dimension and second dimensional gradient were carefully optimized and much better separation was achieved compared to the separation with the traditional two‐dimensional liquid chromatography approach. Finally, mass measurement was performed for alkaloids in M. cordata (willd.) R. Br. by coupling proposed two‐dimensional liquid chromatography system with triple quadrupole mass spectrometry, and 39 alkaloids were successfully identified by comparing the obtained result with the former reported results. 相似文献
906.
Wen‐Jing Zhao Xu‐Yan Chen Yu‐Qian Liu Ping Li Hui‐Jun Li 《Journal of separation science》2020,43(9-10):1755-1772
Alkaloids are a widespread group of basic compounds in herbal medicines and have attracted great interest due to various pharmaceutical activities and desirable druggability. Their distinctive structures make chromatographic separation fairly difficult. Peak tailing, poor resolution, and inferior column‐to‐column reproducibility are common obstacles to overcome. In order to provide a valuable reference, the methodologies and/or strategies on liquid chromatographic separation of alkaloids in herbal medicines proposed from 2012 to 2019 are thoroughly summarized. 相似文献
907.
Lu‐Ning Sun Ye Zhang Yu‐Qing Yang Ye Shen Yu‐Wen Ying Yu‐Wen Su Xue‐Hui Zhang Yun Liu Xu Huang Yong‐Qing Wang 《Journal of separation science》2020,43(16):3183-3196
Proton pump inhibitors, including omeprazole, rabeprazole, lansoprazole, and pantoprazole, achieved simultaneous enantioselective determination in the human plasma by chiral liquid chromatography–tandem mass spectrometry. The four corresponding stable isotope‐labeled proton pump inhibitors were adopted as the internal standards. Each enantiomer and the internal standards were extracted with acetonitrile containing 0.1% ammonia, then separated with a Chiralpak IC column (5 µm, 4.6 mm × 150 mm) within 10 min. The mobile phase was composed of acetonitrile–ammonium acetate (10 mM) containing 0.2% acetic acid (50:50, v/v). To quantify all enantiomers, an API 4000 tandem mass spectrometer was used, and multiple reaction monitoring transitions were performed on m/z 360.1→242.1, 384.1→200.1, 370.1→252.1, and 346.1→198.1, respectively. No significant matrix effect was observed for all analytes. The calibration curve for all enantiomers were linear from 1.25 to 2500 ng/mL. The precisions for intra‐ and inter‐run were < 14.2%, and the accuracy fell in the interval of –5.3 to 8.1%. Stability of samples was confirmed under the storage and processing conditions. The developed method was also suitable for separation and determination of ilaprazole enantiomers. The validated method combining the equilibrium dialysis method was applied to the protein binding ratio studies of four pairs proton pump inhibitor enantiomers in human plasma. 相似文献
908.
Transition metal catalysis is one of the most important tools to construct carbon-carbon and carbon-heteroatom bonds in modern organic synthesis. Visible-light photoredox catalysis has recently drawn considerable attention of the scientific community owing to its unique activation modes and significance for the green synthesis. The merger of photoredox catalysis with transition metal catalysts, termed metallaphotoredox catalysis, has become a popular strategy for expanding the synthetic utility of visiblelight photocatalysis. This strategy has led to the discovery of novel asymmetric transformations, which are unfeasible or not easily accessible by a single catalytic system. This contemporary area of organic chemistry holds promise for the development of economical and environmentally friendly methods for the asymmetric synthesis of chiral compounds. In this review, the advances in the enantioselective metallaphotoredox catalysis(EMPC) are summarized. 相似文献
909.
910.
Aiguo Song Xin Shen Tian Feng Shouchang Gai Haiqing Wei Xinxin Li Hui Chen 《化学:亚洲杂志》2020,15(9):1464-1468
GSTP1 has been considered to be a marker for malignancy in many tissues. However, the existing GST fluorescent probes are unfavorable for in vivo imaging because of the limited emission wavelength or insufficient fluorescence enhancement (six‐fold). The limited fluorescence enhancement of GST fluorescent probes is mainly ascribed to the high background signals resulting from the spontaneous reaction between GSH and the probes. In this work, a highly specific GST probe with NIR emission has been successfully developed through optimization of the essential unit of the probe to repress the spontaneous reaction. The novel GST probe exhibits over 100‐fold fluorescence enhancement upon incubation with GSTP1/GSH and high selectivity over other potential interference. In addition, the probe has been proved to be capable of tracking endogenous GST in A549 cells. Finally, the in vivo imaging results demonstrate that the probe can be used for effective imaging of endogenous GST activity in subcutaneous tumor mouse with high contrast. 相似文献