Preparation of Ursane Triterpenoids from Centella asiatica Using High Speed Countercurrent Chromatography with Step‐Gradient Elution

Abstract

Pentacyclic triterpene aglycones and glycosides of the ursane type were successfully separated from 600 mg of a polar extract from Centella asiatica (Apiaceae) by high speed countercurrent chromatography (HSCCC), applying a mobile phase gradient with a step‐wise increase of elution strength. The lower phase of the biphasic liquid system composed of n‐hexane–n‐butanol–0.05 M NaOH (5:1:6, v/v/v) was used as the stationary phase, the upper phase was used as the initial mobile phase. The mobile phase was changed systematically into 1:1, 1:2 and 1:4 consisting of n‐hexane–n‐butanol saturated by 0.05 M NaOH. The separation mainly yielded five fractions with asiatic acid (18 mg), madecassic acid (13 mg), asiaticoside (140 mg), and madecassoside (75 mg). The chemical structures of the four compounds were confirmed by means of electrospray ionization ion trap multiple mass spectrometry (ESI–MS–MS) and NMR analysis.

Keywords:

• Centella asiatica
• Triterpenoids
• Ursane
• Step‐gradient high speed countercurrent chromatography
• Preparative isolation
• ESI–MS–MS
• NMR

Acknowledgment

Qizhen Du is grateful for financial support by the Alexander‐von‐Humboldt Foundation for the present study.