Three New Furostanol Saponins from the Bulbs of Ipheion uniflorum.

Abstract

Phytochemical screening of the bulbs of Ipheion uniflorum (Liliaceae) has led to the isolation of three new furostanol saponins (2-4) along with a known phytoecdysteroid, ecdysterone (1). The structures of the new compounds were determined by two-dimensional NMR techniques, 1H-1H correlation spectroscopy (COSY), homonuclear Hartmann-Hahn (HOHAHA), phase-sensitive nuclear Overhauser effect spectroscopy (NOESY), heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple-bond correlation (HMBC) spectra, and hydrolysis to be 3 beta-hydroxy-22 alpha-methoxy-26-O-beta-D- glucopyranosyloxy-5 alpha-furost-25(27)-en-2-one 3-O-[O-alpha-L-rhamnopyranosyl-(1-->2)-O-[O-alpha-L-arabinopyranosyl+ ++- (1-->2)-O-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucopyranosyl-(1-->4)]- beta-D-galactopyranoside) (2) and its 25(27)-dihydro derivatives (3: 25S; 4: 25R). The inhibitory activity exhibited by compounds 1-4 and the corresponding spirostanol saponins (2a and 3a) of 2 and 3 on cAMP phosphodiesterase was assayed as a primary screening test to identify new compounds with medicinal potential.