Cholestane- and pregnane-type glycosides from the roots of Tribulus cistoides

From the methanolic extract of the roots of Tribulus cistoides the cardioactive saponin-3, which is known to occur in the leaves, was isolated along with tribulosin, a pregnane-type glycoside and eight new cholestane glycosides. D-(+)-Pinitol and sucrose were major constituents. The structures were established by spectroscopic studies of the isolated compounds, their acetylated derivatives and their hydrolysation products. Chemical conversions revealed the configurations at C-22 and C-25, respectively.