Characterization of the chemical constituents in Hongjingtian injection by liquid chromatography quadrupole time‐of‐flight mass spectrometry

Hongjingtian injection is made from Rhodiola wallichiana and used in the treatment of stable angina pectoris associated with coronary heart disease. In this study, the chemical constituents in Hongjingtian injection were comprehensively studied using liquid chromatography quadrupole time‐of‐flight mass spectrometry. A total of 49 compounds were identified or assumed, including 10 organic acids, nine phenylethanoids, 10 phenylpropanoids, two flavonoid glycosides, seven monoterpene glycosides, seven octylglycosides and four other types of compounds. The structures of seven compounds were confirmed by comparing their retention times, MS and UV spectra with the corresponding authentic standards. Amongst the 49 compounds, 35 were firstly found in R. wallichiana, while they have been reported in other species of the genus Rhodiola, including Rhodiola crenulata, Rhodiola sacra, Rhodiola rosea and Rhodiola kirilowii. The possible fragmentation pathways in the mass spectrometry of the major types of compounds are proposed and summarized. Our study demonstrates a rapid method for characterizing the chemical constituents present in the Hongjingtian injection, which could also be applied to the identification of chemical constituents in other TCM formulae containing R. wallichiana.     

Synthesis,structures, and electrochemistry of diiron toluene-3,4-dithiolate complexes containing phosphine ligands

Transition Metal Chemistry - In this paper, four diiron toluene-3,4-dithiolate complexes with phosphine ligands were synthesized and characterized. Treatment of complex...     

A new endocytic model based on the co-rotational grid method

Endocytosis plays important roles in many cellular physiological processes, such as metabolism and immune. Many theoretical models have been proposed to study the endocytic process, but little has considered the tensile deformation of the membrane and the actin forces. In this paper, a new endocytic model is proposed based on the co-rotational grid method. Our model gives a direct estimation of the in-plane strain of the plasma membrane and provides a basis for the calculation of further scission process of the vesicle. The results fit well with experimental data in the literature. Moreover, it is suggested that the active forces of actin at the endocytic site is the main mechanism driving the invagination of the plasma membrane.     

Solvent‐free ring‐opening polymerization of lactones with hydrogen‐bonding bisurea catalyst

Development of effective organocatalysts for the living ring‐opening polymerization (ROP) of lactones is highly desired for the preparation of biocompatible and biodegradable polyesters with controlled microstructures and physical properties. Herein, a new class of hydrogen‐bond donating bisurea catalysts is reported for the ROP of lactones under solvent‐free conditions. ROP of lactones mediated by the bisurea/7‐methyl‐1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (MTBD) catalyst exhibits a living/controlled manner, affording the polymers and copolymers with the well‐defined structure, predictable molecular weight, narrow molecular weight distribution, and high selectivity for monomer at low catalyst loadings at ambient temperature. The possible mechanism of bisurea/MTBD‐catalyzed ROP of lactones is proposed, in which the bisurea activates the carbonyl group of lactones while MTBD facilitates the nucleophilic attack of the initiating/propagating alcohol by hydrogen bonding. Moreover, the poly(ε‐caprolactone‐co‐δ‐valerolactone) [P(CL‐co‐VL)] random copolymers with various compositions were synthesized using the bisurea/MTBD catalyst. The measurements of thermal properties and crystalline structure demonstrate that the CL and VL units are cocrystallized in the crystalline phase of P(CL‐co‐VL) copolymers. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 90–100     

Functional Organic Semiconductors Based on Bay‐Annulated Indigo (BAI)

The advancement of organic electronics has been continually pushed by the need for stable and high performance acceptor materials. By utilizing inexpensive and stable indigo dye as a starting material, Bay‐Annulated Indigo (BAI) provides a new motif for the development of semiconducting materials. Modular and straightforward synthesis makes BAI an outstanding platform for molecular design, while excellent stability, strong absorption, and high ambipolar mobility render BAI‐based materials excellent candidates for organic electronics. BAI‐based polymers and small molecules have taken advantage of these properties to show promising results in a variety of applications.     

A novel PCR-based technology for rapid and non-sequencing authentication of Bombyx batryticatus using species-specific primers

A novel PCR technology was developed to detect short DNA fragments using species-specific primers for rapid and non-sequencing authentication of Bombyx batryticatus based on differences in the mitochondrial genome. Three specifically designed primer reactions were established to target species for the reliable identification of their commercial products. They were confirmed to have a high inter-species specificity and intra-species stability. The limit of detection was estimated as 1 ng of genomes for Beauveria bassiana and 100 pg for Bombyx mori and Metarhizium anisopliae. Furthermore, validation results demonstrated that raw materials and their processed products can be conveniently authenticated with good sensitivity and precision using this newly proposed approach. In particular, when counterfeits were assayed, these primer sets performed well, whereas COI barcoding technology did not. These could also assist in the discrimination and identification of adulterates of other animal-derived medicines in their pulverized and processed forms and even in complexes.     

One-step synthesis of magnetic composite UiO-66/Fe3O4/GO for the removal of radioactive cesium ions

Journal of Radioanalytical and Nuclear Chemistry - In this study, the UiO-66/Fe3O4/GO composite was prepared by one step method for removal of cesium ions (Cs+) in water and exhibited excellent...     

Simultaneous quantitation of 23 bioactive compounds in Tanreqing capsule by high‐performance liquid chromatography electrospray ionization tandem mass spectrometry

Tanreqing capsule (TRQC) is a formulation frequently used in traditional Chinese medicine to treat pyrexia, cough, expectoration and pharyngalgia. Since the pharmacological action of traditional Chinese medicines is closely related to their complex and diverse constituents, understanding the exact composition of TRQC is important to elucidate its clinical effectiveness and mechanism of action as well as to establish quality control methods and resolve safety issues. Herein, we employed high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry for the simultaneous quantitation of 23 bioactive compounds in five batches of TRQC; the analytes could be categorized into five types: organic acids (seven compounds), flavonoids (10 compounds), iridoids (two compounds), phenylethanoid glycosides (two compounds) and bile acids (two compounds). The calibration curves for all analytes showed good linearity (r > 0.9953), and the inter‐ and intra‐day precisions did not exceed 4.94 and 4.97%, respectively. The recoveries varied from 90.47% to 109.80%; the corresponding relative standard deviations (RSDs) did not exceed 4.94%; and the repeatability (RSD < 4.72%) and stability (RSD < 4.88%) were also within acceptable limits. Thus, this study can be viewed as a fundamental reference for setting comprehensive TRQC quality standards.