ANTISWEET NATURAL-PRODUCTS - XIII - STRUCTURES OF ALTERNOSIDES I-X FROM GYMNEMA-ALTERNIFOLIUM

From the dried roots of Gymnema alternifolium, ten new oleanane-type t riterpenoid glycosides, named alternosides I-X (1-10), mere isolated, as well as two artifactual compounds, 11 and 12. Their structures mere determined on the basis of spectroscopic data and chemical evidence, Compounds 1-5, and 6, 8 and 10 are 3,28-bis-O-glycosides of chichipege nin having an acyl group at position 16 or 18, and no acyl group, resp ectively. Compound 7 is 3-O-glycoside of chichipegenin. Compound 9 con sists of the 3,28-bis-O-glycosides of longispinogenin. Compounds 1-5 a nd II, having an acyl group, showed antisweet activity.