Elution–extrusion counter‐current chromatography for the separation of two pairs of isomeric monoterpenes from Paeoniae Alba Radix

Abstract

In this work, a simple and efficient protocol for the rapid separation of two pairs of isomeric monoterpenes from Paeoniae Alba Radix was developed by combining macroporous resin and elution-extrusion counter-current chromatography. The crude extract was firstly subjected to a D101 macroporous resin column eluted with water and a series of different concentrations of ethanol. Then, effluents of 30 and 95% ethanol were collected as sample 1 and sample 2 for further counter-current chromatography purification. Finally, a pair of isomers, 96 mg of compound 1 and 48 mg of compound 2 with purities of 91.1 and 96.2%, respectively, was isolated from 200 mg of sample 1. The other pair of isomers, 14 mg of compound 3 and 8 mg of compound 4 with purities of 93.6 and 88.9%, respectively, was isolated from 48 mg of sample 2. Their purities were analyzed by high-performance liquid chromatography, and their chemical structures were identified by mass spectrometry and (1) H NMR spectroscopy. Compared to a normal counter-current chromatography separation, the separation time and solvent consumption of elution-extrusion counter-current chromatography were reduced while the resolutions were still good. The established protocol is promising for the separation of natural products with great disparity of content in herbal medicines.

Application of off‐line two‐dimensional high‐performance countercurrent chromatography on the chloroform‐soluble extract of Cuscuta auralis seeds

“…Therefore, it is difficult to isolate target phytochemicals with largely differed partition coefficients from each other using a single biphasic solvent system. To overcome such obstacle, several CCC strategies have been introduced including flow rate gradient , mobile phase gradient , elution–extrusion , and off‐line 2D CCC methods . In 2D CCC, (1) compounds with similar K D values are grouped into different CCC fractions during the first‐dimensional CCC (“grouping process”) and (2) each compound group is separated by the second‐dimensional CCC using different biphasic solvent systems (“separation process”).…”

“…In 2D CCC, (1) compounds with similar K D values are grouped into different CCC fractions during the first‐dimensional CCC (“grouping process”) and (2) each compound group is separated by the second‐dimensional CCC using different biphasic solvent systems (“separation process”). The off‐line 2D CCC method enables us to improve peak resolution capacity of CCC .…”

Separation of six compounds from pigeon pea leaves by elution–extrusion counter‐current chromatography

“…The HSCCC exhibited superiorities including no irreversible adsorption, support‐free solid filler, less solvent consuming, rapid separation, and larger throughput of samples over the conventional separation techniques . As an efficient separation and purification technique, it was successfully applied in the isolation of various natural compounds, such as flavones , terpenoids , phthalides , and alkaloids . However, the multiple constituents in natural products usually possess distinct polarity, which results in longer isolation time or poorer resolution in a single solvent system for the classical HSCCC method.…”

Preparative separation of flavone dimers from Dysosma versipellis by counter‐current chromatography: Trifluoroacetic acid as a solvent system modifier

“…It allows considerable flexibility because of the array of solvent choices . Taking advantage of the liquid nature of the stationary phase, unique operations can be performed, such as elution‐extrusion, back‐extrusion, dual‐mode, and the reversal of the mobile phase and the stationary phase . In addition, it is easy to scale up to high‐capacity scale based on K values and frequently has maximum sample recovery .…”