Silver Ion-Complexation High-Speed Countercurrent Chromatography Coupled with Prep-HPLC for Separation of Sesquiterpenoids from Germacrene A Fermentation Broth

Abstract

A silver ion high-speed counter-current chromatography ([Ag+]-HSCCC) was developed to separate and purify five sesquiterpenoids from germacrene A fermentation broth. The solvent system was consisted of n-hexane-methanol-silver nitrate (3 mol/L) solution (10:9.5:0.5, v/v). By employing this chromatographic protocol, five sesquiterpenoids named β-elemene (1; 54.1 mg), germacrene A (2; 28.5 mg), γ-selinene (3; 4.6 mg), β-selinene (4; 3.4 mg), and α-selinene (5; 1.3 mg) were obtained successfully from 500 mg extracted crude sample with purities of 97.1%, 95.2%, 98.2%, 96.3% and 98.5%, respectively, combined with preparative HPLC. The results reveal that the addition of metal ion in biphasic solvent system significantly improved the HSCCC separation factor of sesquiterpenoids. Meanwhile, our study also provided an alternate approach to separate the compounds with less polarity, also geometrical isomers and various natural product classes.

Purification of triterpenoid saponins and 25R/25S‐inokosterone from Achyranthes bidentata Bl. by high‐speed countercurrent chromatography coupled silver nitrate coordination

“…Among them, the former separation is a cyclic separation in the same pipeline, which greatly reduces the consumption of separation solvents. The latter one is characteristic of weak interactions between Ag + and the ligand, which is suitable for separation of compounds containing double bonds and hydroxyls [15][16][17][18][19]. It is known that triterpenoid saponins and sterones in A. bidentata usually contain functionalities of double bonds and hydroxyls, which fit the Ag + coordinate separation.…”