Weiquan Zhao

An efficient strategy based on MAE, HPLC-DAD-ESI-MS/MS and 2D-prep-HPLC-DAD for the rapid extraction, separation, identification and purification of five active coumarin components from Radix Angelicae Dahuricae.

INTRODUCTION Further studies of active coumarin components in Radix Angelicae Dahuricae (AE) are absolutely essential to provide data on pharmacology, toxicology and quality for innovative drug candidates. Thus, the preparation of active component standards and the administration of coumarin monomers should be carried out. The isolation of the low-level active components from complex Traditional Chinese Medicine (TCM) samples necessitates the development of rapid, simple and economical modern extraction, separation, identification and purification methods. OBJECTIVE To develop an efficient strategy for the rapid extraction, separation, identification and purification of coumarins from AE. METHODOLOGY First, active coumarins in AE were extracted with microwave-assisted extraction (MAE) after the extraction conditions were optimised. Second, gradient extraction methods with MAE were used to partially purify AE. Third, a high-performance liquid chromatography-diode array detection-electrospray ionisation tandem mass spectrometry (HPLC-DAD-ESI-MS/MS) method was applied for the preliminary on-line identification and screening of the main coumarins in AE extract. Finally, a two-dimensional preparative high-performance liquid chromatography-diode array detection (2D-prep-HPLC-DAD) system was developed for further preparative separation of those target components. RESULTS Altogether 10 coumarins have been identified and five of them including xanthotoxol, osthenol, oxypeucedanin hydrate, byakangelicin and imperatorin were deemed as target components for the preparative isolation. All of the five isolated coumarins were at high purities of over 99% and the production rate was much higher than the traditional methods. CONCLUSION The present paper demonstrates that these consecutive approaches are very useful for to isolate chemical constituents from TCM.

Simultaneous chemical fingerprint and quantitative analysis of Rhizoma Smilacis Glabrae by accelerated solvent extraction and high-performance liquid chromatography with tandem mass spectrometry.

Rhizoma Smilacis Glabrae (RSG) is a well-known herbal medicine with the homology of medicine and food. In this study, simultaneous chemical fingerprint and quantitative analysis of the bioactive flavonoid components of RSG were developed using accelerated solvent extraction and high-performance liquid chromatography coupled with ion trap tandem mass spectrometry. The operational parameters of accelerated solvent extraction including extraction solvent, extraction temperature, static extraction time, solid-to-liquid ratio, and extraction cycles were optimized. Hierarchical cluster analysis, similarity analysis, and principal component analysis were performed to evaluate the similarity and variation of the samples collected from several provinces in China. Subsequently, high-performance liquid chromatography fingerprints were established for the discrimination of 16 batches of RSG samples, and the major six flavonoids, namely, toxifolin, neoastilbin, astilbin, neoisoastilbin, isoastilbin, and engeletin were then quantitatively determined. The calibration curves for all the six analytes showed good linearity (r(2) > 0.999), and the limits of detection and quantification were less than 0.10 and 0.27 μg·mL(-1) , respectively. Therefore, the proposed extraction and determination methods were proved to be robust and reliable for the quality control of RSG.

Isolation and purification of diastereoisomeric flavonolignans from silymarin by binary‐column recycling preparative high‐performance liquid chromatography

Silymarin extracted from Silybum marianum (L.) Gaertn consists of a large number of flavonolignans, of which diastereoisomeric flavonolignans including silybin A and silybin B, and isosilybin A and isosilybin B are the main bioactive components, whose preparation from the crude extracts is still a difficult task. In this work, binary-column recycling preparative high-performance liquid chromatography systems without sample loop trapping, where two columns were switched alternately via one or two six-port switching valves, were established and successfully applied to the isolation and purification of the four diastereoisomeric flavonolignans from silymarin. The proposed system showed significant advantages over conventional preparative high-performance liquid chromatography with a single column in increasing efficiency and reducing the cost. To obtain the same amounts of products, the proposed system spends only one tenth of the time that the conventional system spends, and needs only one eleventh of the solvent that the conventional system consumes. Using the proposed system, the four diastereoisomers were successfully isolated from silymarin with purities over 98%.