Preparative Separation of Alkaloids from Stem of Dunn. by High-Speed Counter-Current Chromatography Using Stepwise Elution.

Dunn. is a Chinese herbal medicine with biological activity, but there are few studies on its components at present. Alkaloids in the stem of Dunn. were isolated and purified by high-speed counter-current chromatography (HSCCC) using stepwise elution. First of all, liquid-liquid extraction (methylene chloride-methanol-water, 5:1:4, /) was used for the preliminary enrichment. According to the partition coefficient () of a target compound in a series of different two-phase solvents, the final result was that carbon tetrachloride-methylene chloride-methanol-water (2:3:3:2, /) (1) and methylene chloride-methanol-water (5:3:2, /) (2) were suitable for the HSCCC using stepwise elution. As a result, the purity was all higher than 93% and matrine (), oxymatrine (), -formyl cytisine (), and -acetyl cytisine () can be eluted at one time by this mode. Cytisine-type alkaloids were isolated for the first time in this plant. Finally, the applicability of the mode was verified.