Preparative isolation of swainsonine from locoweed: extraction and purification procedures.
The trihydroxy indolizidine alkaloid swainsonine, a plant toxin with potent alpha-mannosidase-inhibitory activity and chemotherapeutic potential, was isolated in gram quantities from locoweed (Astragalus lentiginosus). The key isolation and purification step was a continuous liquid/liquid extraction procedure using dichloromethane to extract a basified aqueous methanol solution obtained after isolation of the polar base fraction by ion-exchange. The concentration of swainsonine was increased from ca. 7% in the polar base material to 68% using the liquid/liquid extraction procedure. Pure swainsonine was then obtained by recrystallisation from ammonia-saturated chloroform or by sublimation. Small samples of swainsonine were also purified by formation of the chloroform-soluble methylboronate derivative, from which the alkaloid could be regenerated easily by hydrolysis.
Gardner
Dale R
DR
Poisonous Plant Research Laboratory, Agricultural Research Service, USDA,1150 E. 1400 N., Logan, UT 84341, USA. gardnerd@cc.usu.edu
Lee
Stephen T
ST
Molyneux
Russell J
RJ
Edgar
John A
JA
D000470:Alkaloids / Q000032:analysis; D027883:Astragalus Plant / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D007212:Indolizines / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification; D013057:Spectrum Analysis; D017026:Swainsonine / Q000032:analysis* / Q000302:isolation & purification
D000470:Alkaloids; D007212:Indolizines; D010936:Plant Extracts; C434292:2-epilentiginosine; D017026:Swainsonine