Structures of new acylated oleanene-type triterpene oligoglycosides, theasaponins E1 and E2, from the seeds of tea plant, Camellia sinensis (L.) O. KUNTZE

Abstract

Two new acylated oleanene-type triterpene oligoglycosides, theasaponins E1 and E2, were isolated from the seeds of tea plant [Camellia sinensis (L.) O. KUNTZE]. The structures of theasaponins E1 and E2 were elucidated on the basis of chemical and physicochemical evidence to be expressed as 21- O-angeloyl-22-O-acetyltheasapogenol E 3-O-[β-D-galactopyranosyl(1→2)][β- D-xylopyranosyl(1→2)-α-L-arabinopyranosyl (1→3)]-β-D- glucopyranosiduronic acid and 21-O-angeloyl-28-O-acetyltheasapogenol E 3-O- [β-D-galactopyranosyl(1→2)][β-D-xylopyranosyl(1→2)-α-L-arabinopyranosyl (1→3)-β-D-glucopyranosiduronic acid, respectively. Theasaponin E1 was found to show antisweet activity.