An effective method based on medium‐pressure liquid chromatography and recycling high‐speed counter‐current chromatography for enrichment and separation of three minor components with similar polarity from Dracocephalum tanguticum

Abstract

The separation of minor compounds, especially those with similar polarities from a complex sample, remains challenging. In the proposed study, an effective method based on medium‐pressure liquid chromatography and recycling high‐speed counter‐current chromatography was developed for the enrichment and separation of three minor components from Dracocephalum tanguticum. The crude extract was directly introduced to medium‐pressure liquid chromatography for the enrichment of the three minor components. Based on high‐performance liquid chromatography analysis, the total content of these three compounds increased from 0.48% in the crude extract to 85.3% in the medium‐pressure liquid chromatography fraction. In addition, high‐speed counter‐current chromatography was employed to separate the enriched compounds using the solvent system hexane/ethyl acetate/methanol/water (1.18:8.82:1.18:8.82, v/v/v/v). As a result, compound 3 and a mixture of compounds 1 and 2 were obtained. In order to improve the resolution of compounds 1 and 2 while saving separation time, a recycling and heart‐cut mode was used. Finally, compounds 1 and 2 were obtained after five cycles. These compounds were identified as 3‐phenylethyl β‐d‐glucopyranoside (1), tazettoside E (2), and cirsiliol‐4′‐glucoside (3). Compounds 1 and 2 were primarily separated from D. tanguticum. Moreover, the developed method provided a reference for the separation of minor components from the complex sample.

Separation of five flavonoids with similar polarity from Caragana korshinskii Kom. by preparative high speed counter‐current chromatography with recycling and heart cut mode

“…Compared with traditional column chromatography, HSCCC has the advantages of large sample loading, high recovery, high efficiency, and easy scale‐up potential [5,6]. In addition, the various modes available to date, such as normal phase [7,8], reverse phase [9,10], gradient mode [11,12], recycling mode [13,14], pH Zone refining [15,16], extrusion [17], and dual‐mode [18], have made it widely used in the isolation and purification of active components from natural products. However, it is sometimes not easy to find a suitable solvent system, especially for compounds with a similar polarity, to perform an ideal separation.…”

“…However, it is sometimes not easy to find a suitable solvent system, especially for compounds with a similar polarity, to perform an ideal separation. Fortunately, the recycling that especially coupled with heart cut mode of HSCCC could serve as a good choice for the separation of compounds with small differences in K values [13,14]. Furthermore, the application mainly focused on the semi‐preparative scale.…”

Separation of five flavone glycosides including two groups with similar polarities fromDracocephalum tanguticumby a combination of three high‐speed counter‐current chromatography modes

“…The solvent system for HSCCC separation was selected based on the K-and α-values. The K-values of target compounds were determined by HPLC following the previous study [19]. Ethyl acetate/methanol/water (5% acetic acid) (8:2:10, v/v) was used in HSCCC process after screening.…”

“…Recycling HSCCC has been successfully applied to separate compounds with similar polarities [13][14][15][16][17]. Sometimes, the heart-cut mode is often introduced in recycling HSCCC to improve peak resolution [18,19]. Besides, the flow rate is one of the important parameters that significantly influence the separation effect, especially for the complex sample [20][21][22].…”

Targeted Separation of COX-2 Inhibitor from Pterocephalus hookeri Using Preparative High-Performance Liquid Chromatography Directed by the Affinity Solid-Phase Extraction HPLC System

“…Then, preparation can substantially purify the target compound with a purity of >95% [ 32 ]. The medium-pressure chromatographic tower is based on the absorption chromatography with the advantage of higher sample loading, the convenience of packing procedure, lower cost, and online detection and has widely used for crude extracts purification and natural compounds enrichment [ 15 , 28 , 33 ]. Therefore, it is necessary to isolate the potential COX-2 inhibitors by pretreatment of medium-pressure chromatographic tower and suitable preparative HPLC strategy for chemical structural characterization and inhibitory activity verification.…”