Floratheasaponins A−C, Acylated Oleanane-Type Triterpene Oligoglycosides with Anti-hyperlipidemic Activities from Flowers of the Tea Plant (Camellia sinensis)

The methanolic extract and its n-butanol-soluble fraction from the flowers of the tea plant (Camellia sinensis) were found to suppress serum triglyceride elevation in olive oil-treated mice. From the n-butanol-soluble fraction, three new acylated oleanane-type triterpene oligoglycosides, floratheasaponins A-C (1-3), were isolated together with several flavonol glycosides and catechins. The structures of 1-3 were elucidated on the basis of chemical and physicochemical evidence as 21-O-angeloyl-22-O-acetyltheasapogenol B 3-O-[beta-D-galactopyranosyl(1-->2)][beta-D-xylopyranosyl(1-->2)-alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, 21,22-di-O-angeloyl-R1-barrigenol 3-O-[beta-D-galactopyranosyl(1-->2)][beta-D-xylopyranosyl(1-->2)-alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, and 21-O-angeloyl-22-O-2-methylbutyryl-R1-barrigenol 3-O-[beta-D-galactopyranosyl(1-->2)][beta-D-xylopyranosyl(1-->2)-alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, respectively. Floratheasaponins (1-3) showed inhibitory effects on serum triglyceride elevation, with their activities being more potent than those of theasaponins E1 (4) and E2 (5) obtained previously from the seeds of C. sinensis.