Medicinal Foodstuffs. VII. On the Saponin Constituents with Glucose and Alcohol Absorption-Inhibitory Activity from a Food Garnish "Tonburi", the Fruit of Japanese Kochia scoparia (L.) SCHRAD.: Structures of Scoparianosides A, B, and C.

The methanolic extract of a food garnish "Tonburi", the fruit of Japanese kochia scoparia (L.) Schrad. (Chenopodiaceae), was found to inhibit the increase in serum glucose-loaded rats. Through bioassay-guided separation, momordin Ic and its 2'-O-beta-D-glucopyranoside were isolated as the active principles from this medicinal foodstuff together with three new saponins named scoparianosides A, B, and C. The structures of scoparianosides A, B, and C were elucidated on the basis of chemical and physicochemical evidence as 3 beta, 22 alpha-dihydroxyolean-12en-28-oic acid (22 alpha-hydroxyoleanolic acid), 3-O-beta-D-xylopyranosyl (1 --> 3)-beta-D-glucopyranosiduronic acid, 3 beta-hydroxyolean -18-en-28-oic acid (morolic acid), 3-O-beta-D-xylopyranosyl(1 --> 3)-beta-D -glucopyranosiduronic acid, and 3 beta-hydroxyolean-13(18)-en-28-oic acid, 3-O-beta-D-xylopyranoxyl(1 --> 3) -beta-D-glucopyranosiduronic acid. Momordin Ic and its 2'-O-beta-D-glucopyranoside, both of which are the principal saponin constituents of this medicinal foodstuffs, were found to potently inhibit glucose and ethanol absorption in rats.