Chemical profiling of Qingfei Paidu Decoction by triplex off-line two-dimensional liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

Qingfei Paidu Decoction is a Chinese medicine formula that has been proved effective in the treatment of coronavirus disease 2019. However, the comprehensive separation and characterization of Qingfei Paidu Decoction are of a great challenge due to the diversity of chemical components in a wide range of polarity. In this study, a triplex off-line two-dimensional liquid chromatography coupled with quadrupole time-of-flight mass spectrometry is developed for the analysis of Qingfei Paidu Decoction. One reversed-phase liquid chromatography×hydrophilic interaction liquid chromatography system and two reversed-phase liquid chromatography×reversed phase liquid chromatography systems were constructed to separate polar components and weak-polar components in Qingfei Paidu Decoction, respectively. Benefiting from the good orthogonality of two-dimensional liquid chromatography and high sensitivity of quadrupole time-of-flight MS, chemical components with different polarities and content were discovered. A total of 749 peaks were detected in positive and negative ionization mode and presented as a four-dimensional data plot. Meanwhile, 498 compounds belonging to 14 categories were tentatively identified. These results provide good supplementary to elucidate the material basis of Qingfei Paidu Decoction. The triplex off-line two-dimensional liquid chromatography-quadrupole time-of-flight mass spectrometry strategy can be a powerful and efficient tool for the separation and characterization of chemical substances in traditional Chinese medicine formulas.     

Qualitative and quantitative analysis of Alpiniae Oxyphyllae Fructus by high-performance liquid chromatography coupled to Fourier transform-ion cyclotron resonance mass spectrometry

Alpiniae Oxyphyllae Fructus, as a homology of medicine and food, has been widely used in China for thousands of years. However, the existing qualitative and quantitative methods are difficult to evaluate the quality of Alpiniae Oxyphyllae Fructus samples from multiple sources. In this paper, an high-performance liquid chromatography fingerprint was established for assessing the quality of Alpiniae Oxyphyllae Fructus from different areas. Then, high-performance liquid chromatography was coupled to Fourier transform-ion cyclotron resonance mass spectrometry for characterization of the chemical compositions in Alpiniae Oxyphyllae Fructus. In fingerprint analysis, 54 common peaks were confirmed and six chromatographic peaks of them were identified. The similarity of 14 samples from different areas was between 0.990 and 1.000. Moreover, a total of 30 chemical components were characterized by high-performance liquid chromatography coupled to Fourier transform-ion cyclotron resonance mass spectrometry method, six compounds of which were decisively identified. Finally, the content of nootkatone was determined by high-performance liquid chromatography. In conclusion, the methods used in this study are efficient for qualitative and quantitative analysis of Alpiniae Oxyphyllae Fructus. Also, these methods can be used to control the quality of other traditional Chinese medicines.     

Rapid characterization of the constituents in Jigucao capsule using ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry

Jigucao capsule is a well-known Chinese patent medicine for the treatment of acute and chronic hepatitis and cholecystitis. The chemical components of Jigucao capsule were not clear resulting from the paucity of relevant studies, which hindered the research of the pharmacological mechanism, the comprehensive development, and utilization of Jigucao capsule in clinical studies. By establishing a high-throughput ultra-performance liquid chromatography quadrupole time of flight mass spectrometry in combination with intelligent UNIFI software data processing platform to automatically characterize and identify the chemical profile of Jigucao capsule, 144 compounds were determined rapidly, including 34 terpenoids, 25 flavonoids, 22 steroids, 21 phenylpropanoids, 10 glycosides, six alkaloids, 13 organic acids, and other 13 components. These compounds may be the active components of Jigucao capsule. In this study, a rapid and robust method for comprehensively analyzing the chemical composition of Jigucao capsule was described and established for the first time. The results will provide a reference for the quality control of Jigucao capsule and the establishment of a higher quality standard, as well as for the pharmacodynamic material basis research.     

Developing the liquid chromatography-mass spectrometry method for simultaneously quantifying five components in rat serums after oral administration of hawthorn aqueous extracts and its application to a pharmacokinetic study

Hawthorn, one of the widely-used traditional Chinese medicines, has been used to treat dyspepsia, hyperlipidemia, and cardiovascular disease in the clinic. Our previous study revealed that gallic acid, neochlorogenic acid, cryptochlorogenic acid, vitexin, and quercetin were active components of hawthorn. In this study, a simple, precise, and reliable liquid chromatography-mass spectrometry method was developed for the simultaneous quantification of five components in rat serums. The separation was achieved on the Hypersil GOLD C₁₈ column, and the mobile phases consisted of 0.1% acetic acid water and methanol at a flow rate of 0.3 mL/min. The mass spectrometry data acquisition was performed on Q-Extractive-Orbitrap mass spectrometry with an electrospray ionization source in negative ion mode. The proposed liquid chromatography-mass spectrometry method was validated in terms of linearity, intra- and inter-precision, accuracy, recoveries, matrix effects, and stability. Then this newly proposed liquid chromatography-mass spectrometry method was successfully applied to a pharmacokinetic study on rats after oral administration of hawthorn aqueous extracts. This study provided relevant information on the pharmacokinetics of active components of hawthorn and explained the underlying mechanism of their bioactivity.     

An efficient high-speed counter-current chromatography method for the preparative separation of potential antioxidants from Paeonia lactiflora Pall. combination of in vitro evaluation and molecular docking

Paeonia lactiflora Pall., one of the most famous classical herbal medicine, has been used to treat diseases for over 1200 years. In this research, the functional ingredients were purified by online-switch two-dimensional high-speed counter-current chromatography combined with inner-recycling and continuous injection mode. The antioxidant activity was evaluated by investigating the 2,2′-azobis (2-amidinopropane) dihydrochloride-induced oxidant damage in vitro and confirmed through molecular docking. n-Butanol/ethyl acetate/water (2:3:5, v/v) solvent system was used for the first-dimensional separation and optimized the sample loading. Two pure compounds and a polyphenol-enriched fraction were separated. The polyphenol-enriched fraction was separated with a solvent system n-hexane/ethyl acetate/methanol/water (2:8:4:6, v/v) with continuous injection mode. Five compounds were successfully separated, including gallic acid ( 1 ), methyl gallate ( 2 ), albiflorin ( 3 ), paeoniflorin ( 4 ), and ethyl gallate ( 5 ). Their structures were identified by mass spectrometry and NMR spectroscopy. The results from the antioxidant effect showed that albiflorin had stronger antioxidant activity. Molecular docking results indicated that the affinity energy of the identified compounds ranged from -3.79 to -8.22 kcal/mol and albiflorin showed the lowest affinity energy. Overall, all those findings suggested that the strong antioxidant capacity of albiflorin can be potentially used for the treatment of diseases caused by oxidation.     

基于生物电容的视觉假体无线能量传输系统建模及效率优化

为了解决视觉假体无线能量传输系统设计过程中参数选取的问题,本文进行了基于生物电容的视觉假体无线能量传输系统精确建模,并在该模型的基础上对次级线圈回路进行了优化,使能量传输效率较传统谐振耦合方法有明显提高。文中采用大、小两组线圈进行比较分析和验证,所得实验数据和建模仿真数据吻合度高,验证了所建模型的准确性及优化方案的可行性,为视觉假体临床应用线圈的选取和无线能量传输系统的设计提供了理论参考。     

半导体聚合物纳米荧光探针的制备及生物应用研究进展

半导体聚合物作为功能有机高分子材料被广泛应用于有机光电子器件领域的研究。近年来由半导体聚合物构成的荧光纳米粒子引起了广泛的研究兴趣。这类新型纳米探针具有光学吸收截面大、量子效率高、辐射跃迁速率快、光稳定性好等特性,在荧光成像和生物传感等领域获得了重要应用。本文简要概述了近年来半导体聚合物纳米粒子的研究进展,包括其光物理性质、表面功能化以及在细胞标记、体内成像、生物传感、单粒子示踪、药物输送和光动力学疗法等领域的应用。     

Towards validating new enzymatic routes for synthetic conversion: 7,10‐bis‐O‐(2,2,2‐trichloroethoxycarbonyl)‐10‐deacetyl baccatin III–ethyl acetate–water (1/1/1)

The title compound, C₃₄H₃₈Cl₆O₁₄·C₄H₈O₂·H₂O, prepared by the reaction of 10‐deacetyl baccatin III with 2,2,2‐trichloroethyl chloroformate in pyridine, crystallizes via strong intermolecular hydrogen bonds and noncovalent interactions between 7,10‐bis‐O‐(2,2,2‐trichloroethoxycarbonyl)‐10‐deacetyl baccatin III (7,10‐di‐Troc‐DAB), water and ethyl acetate. A detailed comparison of the molecular conformation with those of related structures is presented.     

Tetrahydroberberine,a pharmacologically active naturally occurring alkaloid

Tetrahydroberberine (systematic name: 9,10‐dimethoxy‐5,8,13,13a‐tetrahydro‐6H‐benzo[g][1,3]benzodioxolo[5,6‐a]quinolizine), C₂₀H₂₁NO₄, a widely distributed naturally occurring alkaloid, has been crystallized as a racemic mixture about an inversion center. A bent conformation of the molecule is observed, with an angle of 24.72 (5)° between the arene rings at the two ends of the reduced quinolizinium core. The intermolecular hydrogen bonds that play an apparent role in crystal packing are 1,3‐benzodioxole –CH₂...OCH₃ and –OCH₃...OCH₃ interactions between neighboring molecules.