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

Abstract

In this study, the chloroform-soluble extract of Cuscuta auralis was separated successfully using off-line two-dimensional high-performance countercurrent chromatography, yielding a γ-pyrone, two alkaloids, a flavonoid, and four lignans. The first-dimensional countercurrent separation using a methylene chloride/methanol/water (11:6:5, v/v/v) system yielded three subfractions (fractions I-III). The second-dimensional countercurrent separations, conducted on fractions I-III using n-hexane/ethyl acetate/methanol/water/acetic acid (5:5:5:5:0, 3:7:3:7:0, and 1:9:1:9:0.01, v/v/v/v/v) systems, gave maltol (1), (-)-(13S)-cuscutamine (2), (+)-(13R)-cuscutamine (3), (+)-pinoresinol (4), (+)-epipinoresinol (5), kaempferol (6), piperitol (7), and (9R)-hydroxy-d-sesamin (8). To the best of our knowledge, maltol was identified for the first time in Cuscuta species. Furthermore, this report details the first full assignment of spectroscopic data of two cuscutamine epimers, (-)-(13S)-cuscutamine and (+)-(13R)-cuscutamine.

Keywords: countercurrent chromatography; cuscutamine epimers; maltol; traditional Chinese medicine.