RECENT ADVANCES IN ULTRA-HIGH PERFORMANCE LIQUID CHROMATOGRAPHY FOR THE ANALYSIS OF TRADITIONAL CHINESE MEDICINE

Preparation and application of UPLC silica microsphere stationary phase:A review

In this review, microspheres for ultra-performance liquid chromatography (UPLC) were reviewed in accordance with the literature in recent years. As people's demands for chromatography are becoming more and more sophisticated, the preparation and application of UPLC stationary phases have become the focus of researchers in this field. This new analytical separation science not only maintains the practicality and principle of high-performance liquid chromatography (HPLC), but also improves the step function of chromatographic performance. The review presents the morphology of four types of sub-2 μm silica microspheres that have been used in UPLC, including non-porous silica microspheres (NPSMs), mesoporous silica microspheres (MPSMs), hollow silica microspheres (HSMs) and core-shell silica microspheres (CSSMs). The preparation, pore control and modification methods of different microspheres are introduced in the review, and then the applications of UPLC in drug analysis and separation, environmental monitoring, and separation of macromolecular proteins was presented. Finally, a brief overview of the existing challenges in the preparation of sub-2 μm microspheres, which required further research and development, was given.

Surface-enhanced Raman spectroscopy as a powerful method for the analysis of Chinese herbal medicines

Chinese herbal medicines (CHMs) derived from nature have received increasing attention and become more popular. Due to their diverse production processes, complex ingredients, and different storage conditions, it is highly desirable to develop simple, rapid, efficient and trace detection methods to ensure the drug quality. Surface-enhanced Raman spectroscopy has the advantages of being time-saving, non-destructive, usable in aqueous environments, and highly compatible with various biomolecular samples, providing a promising analytical method for CHM. In this review, we outline the major advances in the application of SERS to the identification of raw materials, detection of bioactive constituents, characterization of adulterants, and detection of contaminants. This clearly shows that SERS has strong potential in the quality control of CHM, which greatly promotes the modernization of CHM.

A new approach to examining the extraction process of Zhishi and Zhiqiao considering the synergistic effect of complex mixtures by PAMPA

Zhishi (ZS) and Zhiqiao (ZQ) are two important traditional Chinese medicines (TCMs) that exert various pharmacological functions due to their active ingredients. However, the oral absorption of these ingredients requires further study. At the early drug discovery stage, the high-throughput parallel artificial membrane permeability assay (PAMPA) is one of the most frequently used to predict transcellular passive absorption in in-vitro models. This study aims to establish a new approach to examine an optimal extraction process that can take into account not only the concentration of active ingredients but also the overall absorption properties of the mixtures extracted from TCMs. A high-performance liquid chromatography triple-quadrupole mass spectrometry (HPLC-QqQ-MS/MS) method was validated for the determination of the effective permeability value (P_e) applied to the above experimental medium. The PAMPA experiment showed that certain active ingredients such as diosmin, rhoifolin, eriocitrin, narirutin, naringin, hesperidin and neohesperidin were not detected in the permeability assay of mono-constituents but were well detected and achieved a better absorption in the permeability assay of the mixture, indicating that certain unknown ingredients may act as cosolvents to improve the solubility or permeability of other ingredients. Furthermore, solid phase extraction (SPE) as an enrichment and purification process enhances absorption. In the present study, a novel in vitro approach was developed to decipher the potential role of TCMs in global absorption, and the extraction process for complex TCMs was described and systematically optimized.

Correlation between Quality and Geographical Origins of Poria cocos Revealed by Qualitative Fingerprint Profiling and Quantitative Determination of Triterpenoid Acids

Poria cocos (Schw.) Wolf (PC) is a well-known saprophytic fungus, and its sclerotium without the epidermis (PCS) is widely used in traditional Chinese medicine and as a functional food in many countries. PCS is normally collected from multiple geographical regions, but whether and how the quality of PCS correlates with where it grows have not been determined. This correlation could be significant both for quality control and optimum utilization of PCS as a natural resource. In this study, a qualitative fingerprint profiling method performed by ultra-performance liquid chromatography (UHPLC) with diode array detection (DAD) combining quadrupole time-of-flight-mass spectrometry (QTOF-MS/MS) and a quantitative UHPLC coupled with triple quadrupole mass spectrometry (QqQ-MS/MS) approach were established to investigate whether and how the quality of PCS correlates with its collection location. A standard fingerprint of PCS was generated by median simulation of 25 tested samples collected from four main producing areas of China, and similarity analysis was applied to evaluate the similarities between the fingerprints of samples and the standard fingerprint. Twenty three common peaks occurring in the fingerprint were unequivocally or tentatively identified by UHPLC-QTOF-MS/MS. Meanwhile, principal component analysis (PCA), supervised orthogonal partial least squares-discriminate analysis (OPLS-DA) and hierarchical cluster analysis (HCA) were employed to classify 25 batches of PCS samples into four groups, which were highly consistent with the four geographical regions. Ten compounds were screened out as potential markers to distinguish the quality of PCS. Nine triterpene acids, including five compounds that played important roles in the clusters between different samples collected from the four collection locations, were simultaneously quantified by using the multiple reaction monitoring (MRM) mode of UHPLC-QqQ-MS/MS. The current strategy not only clearly expounded the correlation between quality and geographical origins of PCS, but also provided a fast, accurate and comprehensive qualitative and quantitative method for assessing the quality of PCS.

Study on the Alkaloids in Tibetan Medicine Aconitum pendulum Busch by HPLC-MSn Combined with Column Chromatography

A rapid, convenient and effective identification method of alkaloids was established and an attempt on isolating and analyzing the alkaloids in Aconitum pendulum Busch was conducted successfully. In this article, four high-content components including deoxyaconitine, benzoylaconine, aconine and neoline were isolated by using column chromatography. HPLC-MS(n)was employed to deduce the regulations of fragmentation of diterpenoid alkaloids which displayed a characteristic behavior of loss of CO(28u), CH3COOH(60u), CH3OH(32u), H2O(18u) and C6H5COOH(122u). Then, according to fragmentation regulation of mass spectrometry, 42 alkaloids were found inA. pendulum Among them, 38 compounds were identified and 29 alkaloids were reported for the first time for this herb. Therefore, this means that HPLC-MS(n)combined with column chromatography could work as an effective and reliable tool for rapid identification of the chemical components of herbal medicine.