Spirostane glycosides

Table 9. Effect of spirostane glycosides 45 and 46 and furostane glycosides 47-50 on virus infected cells.

Agapanthussaponin D (= (25/ )-5a-Spirostane-2a,3(3,5a,9a-tetrol 3-0-Rha-[Gal]-Glc) (triterpene glycoside) Agapanthus inapertus (Liliaceae) [bulb, root] cAMP PDE (20)... 

Structure determinations of the homogeneous saponins are usually carried out by a combination of chemical and spectroscopic methods. Extensive investigations of the aglycones demonstrated that most of them are spirostane derivatives or modified spirostanes. Furostanol glycosides have also been isolated and characterized, which according to Marker and Lopez (41) are precursors of sugar conjugates of spirostanes. 

Thus, the furostanol glycoside 26-0-/3-glucosidasc from the rhizomes of Costus speciosus cleaves the furostanol glycosides protodioscin and protogracillin to the corresponding spirostanes (74). 

Five glycosides of the two new (25/ )-3 -amino-5a,22aO-spirostanes, isojurubidine and its 6a-hydroxy derivative isojuripidine, have been isolated from Solatium paniculatum (99,100), the structures of which may be of the same type as that of jurubine, the (255)-3)3-amino-5a-furostane 22a,26-diol-0(26)-j -D-g ucopyranoside from the same species and from Solanum torvum (112,168,169 cf. 3), but their structures have not yet been elucidated. 

The spirostane structure is the basic skeleton of this class of plant constituents which occurs partly together with the cardiac glycosides. Additional isomers are possible here, depending on the a- or jS-position of the methyl group at 25 and the tetrahydropyran ring at... 

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