Isolation of Three Lycorine Type Alkaloids from (Herb.) Ravenna Using pH-Zone-Refinement Centrifugal Partition Chromatography and Their Acetylcholinesterase Inhibitory Activities.

Preparative separation of three lycorine type alkaloids from (Amaryllidaceae) was successfully carried out using pH-zone-refinement centrifugal partition chromatography (CPC) using the solvent system methyl-tert-butyl ether/acetonitrile/water (4:1:5, //) in descending mode. Using this system, Alkaloid 1 (165.7 mg, 88.