Calystegines isolation procedures

Subsequent calystegine isolations followed enrichment schemes that were developed for the isolation of other polyhydroxy alkaloids, such as swainsonine (5) and 1-deoxynojirimycin (6) from S. canescens (Fabaceae) (7) and from Streptomyces strains (31), respectively. Due to the hydrophilicity and the basic nature of those alkaloids, they were purified from aqueous extracts by a sequence of ion exchange resin columns that were designed to bind the alkaloids as cations, or to adsorb contaminating anions, while the alkaloids were eluted with water (Figure 3, method 2). An overview of the procedures was expertly summarised by Fellows and Fleet (32). Calystegines of the A-group are the most difficult to... 

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