Triterpene glycosides from Tupidanthus calyptratus. I. Structure of glycosides B-1, B-2, F-1, and F-2 from leaves of hooded Tupidanthus

Chromatographically inseparable mixtures of oleanolic and urisolic 3-O-alph a-L-rhamnopyranosyl-(1-->2)-O-alpha-L-arabinopyranosides glycosides B-1 and B-2) and their 28-O-alpha-L-rhamnopyranosyl-(1-->4)-O-beta-D-glucopyranosy l-(1-->6)-O-beta-D-glucopyranosyl eaters (glycosides F-1 and F-2) arc isola ted from the leaves of Tupidanthus calyptratus Hook. f. (Araliaceae). The s tructures of the isolated glycosides are established from chemical methods and H-1 and C-13 NMR spectra. Glycoside F-2 is a new triterpene glycoside.