From Castanospermum

Castanospermine (6), isolated from Castanospermum australe by Ho-henschutz and coworkers and characterized as a strong inhibitor for )S-d-... 

Fig. 4.13 Compounds 357 and 358 from Castanospermum and Alexa. Compounds 359-364, diterpenes from Scoparia dulcis...

R. J. Molyneux, M. Benson, R. Y. Wong, J. E. Tropea, and A. D. Elbein, Australine, a novel pyrrolizidine alkaloid glucosidase inhibitor from Castanospermum australe, J. Nat. Prod., 51 (1988) 1198-1206. 

Molyneux et al. [5] hypothesize that the JV-(hydroxyethyl)-2-(hydroxymethyl)-3-hydroxypyrrohdine (6) isolated from Castanospermum ctustrale might be a precursor of the octahydroindolizines (castanospermines) in that plant by insertion of an additional carbon atom between the 2-(hydroxymethyl) group and the terminal carbon atom of the N-(hydroxyethyl) group and of the pyrrolizidines (australines and alexines) by insertion of the extra carbon... 

Alternatively, the diastereomeric mixture of aldol adducts undergoes lithium aluminum hydride reduction, primary alcohol silylation, and chromatographic separation to afford 291. Subsequent Mitsunobu inversion at C-3 to furnish the j -alcohol 292 followed by a depro-tective sequence and ring closure provides (+ )-castanospermine (293). This poly-hydroxylated indolizidine alkaloid isolated from Castanospermum australe and Alexa leipetala is a potent inhibitor of various a- and j8-glucosidases [98] (Scheme 68). 

Jones L, HoUinshead J, Fleet GWJ, Thompson AL, Watkin DJ, Gal ZA, et al. Iso-lation of the pyrroUzidine alkaloid 1-epialexine from Castanospermum austiaL Phy-tochem Lett 2010 3(3) 133-5. 

A more complex alkaloid, swainsonine (40) (from Swain-sona species, Fabaceae), also inhibits a-mannosidase activity. A similar complex alkaloid, castanospermine (41) (from Castanospermum australe, Fabaceae) inhibits 3-glucosi-dases [but not a-glucosidases as in (38)] (Fellows, 1987 Fellows et al., 1992). 

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