Abstract
Following the investigation of assamsaponins A, B, C, D, and E, four new saponins termed assamsaponins F, G, H, and I were isolated from the seeds of the tea plant (Cammellia sinensis L. var. assamica PIERRE), while assamsaponin J was isolated from its leaves. The structures of assamsaponins F-J were elucidated on the basis of chemical and physicochemical evidence and found to be 16, 22-O-diacetyl-21-O-angeloyltheasapogenol E 3-O-[β-D-galactopyranosyl(1→2)][β-D-glucopyranosyl(1→2)-α-L-arabinopyranosyl(1→3)]-β-D-glucopyranosiduronic acid, 21-O-angeloyl-22-O-acetyltheasapogenol E 3-O-[β-D-galactopyranosyl(1→2)][β-D-glucopyranosyl(1→2)-α-L-arabinopyranosyl(1→3)]-β-D-glucopyranosiduronic acid, 21-O-angeloyl-28-O-acetyltheasapogenol E 3-O-[β-D-galactopyranosyl(1→2)][β-D-glucopyranosyl(1→2)-α-L-arabinopyranosyl(1→3)]-β-D-glucopyranosiduronic acid, 21-O-tigloyl-28-O-acetyltheasapogenol E 3-O-[β-D-galactopyranosyl(1→2)][β-D-glucopyranosyl(1→2)-α-L-arabinopyranosyl(1→3)]-β-D-glucopyranosiduronic acid, and 16, 21-O-biacetyl-22-O-cinnamoyltheasapogenol B 3-O-[β-D-galactopyranosyl(1→2)][β-D-rhamnopyranosyl(1→2)-α-L-arabinopyranosyl(1→3)-β-D-glucopyranosiduronic acid, respectively.The saponin mixture from the seeds of the tea plant was found to exhibit an inhibitory effect no gastric emptying and an accelerating effect on gastrointestinal transit in mice. Theasaponin E1, the principle saponin of the tea plant, showed potent activity, while theasaponin E2 showed none, so that the position of the acyl groups in the sapogenin moiety is important from a pharmacological point of view.
