The structures of two new monodesmosidic spirostanosides and a new bisdesmo
sidic furostanol glycoside isolated from the roots of Asparagus africanus L
am. (Liliaceae) have been elucidated as (25R)-3 beta-hydroxy-5 beta-spirost
an-12-one 3-O-{beta-D-glucopyranosyl-(1 --> 2)-[alpha-L-arabinopyranosyl-(1
--> 6)]-beta-D-glucopyranoside} (1), (25R)-5 beta-spirostan-3 beta-ol 3-O-
{beta-D-glucopyranosyl-(1 --> 2)-[alpha-L-arabinopyranosyl-(1 --> 6)]-beta-
D-glucopyranoside} (2) and 26-O-beta-D-glucopyranosyl]-22 alpha-methoxy-(25
R)-furostan-3 beta,26-diol 3-O-{beta-D-glucopyranosyl-(1 --> 2)-[beta-D-glu
copyranoside} (3), respectively, by the combined use of one and two dimensi
onal NMR experiments. The complete C-13 and H-1 assignments of the peracety
l spirostanosides and the furostanol oligoside were derived. The interconve
rsions between the methoxyl and hydroxyl group at C-22 of the furostanol gl
ycoside was investigated and the genuine furostanol oligoside of A. african
us appears to be the hydroxyl type based on the comparative study of the me
thanol, pyridine and dioxane extracts. (C) 1999 Elsevier Science Ltd. All r
ights reserved.