Preparative isolation of ganoderic acid S, ganoderic acid T and ganoderol B from Ganoderma lucidum mycelia by high-speed counter-current chromatography.

Ganoderic acid S, ganoderic acid T and ganoderal B are the main bioactive triterpenes of Ganoderma lucidum. In this study, mycelia of G. lucidum were obtained by two-stage fermentation and then extracted by ethanol and petroleum ether sequentially to obtain crude triterpenes. The crude sample was further purified by recycling high-speed counter-current chromatography with n-hexane-ethyl acetate-methanol-water (7:12:11:5, v/v/v/v) as the optimized two-phase solvent system. A 16.4 mg aliquot of ganoderol B with a purity of 90.4% was separated from 300 mg of the crude sample in a single run. After employing the recycling elution mode of HSCCC with n-hexane-ethyl acetate-methanol-water (6:10:8:4.5, v/v/v/v) for five cycles, 25.7 mg ganoderic acid T and 3.7 mg ganoderic acid S with purities of 97.8 and 83.0%, respectively, were obtained. The purities of three compounds were determined by high-performance liquid chromatography and their chemical structures were identified by NMR and MS data.