1989 Volume 37 Issue 5 Pages 1293-1296
In the course of studies on the metabolism of saikosaponins, which are the main constituents of Bupleurum falcatum L., nine new compounds derived from saikosaponin c were isolated. On cleavage of the glycosidic bond of saikosaponin c at 80°C in alcoholic alkali metal solution, prosaikogenins E-1, E-2, and E-3 were isolated, and their structures were elucidated as 3-O-β-D-glucopyranosyl (1→6)-β-D-glucopyranoside of saikogenin E, 3-O-α-L-rhamnopyranosyl (1→4)-β-D-glucopyranoside of saikogenin E and 3-O-β-D-glucopyranoside of saikogenin E, respectively. Furthermore, on the treatment of prosaikogenins E-1, E-2, and E-3 with 1N sulfuric acid-dioxane solution for 4h at 60°C, prosaikogenins C-1, C-2, and C-3 were formed [elucidated as 3-O-β-D-glucopyranosyl (1→6)-β-D-glucopyranoside of saikogenin C, 3-O-α-L-rhamnopyranosyl (1→4)-β-D-glucopyranoside of saikogenin C, and 3-O-β-D-glucopyranoside of saikogenin C, respectively, possessing a heteroannular diene moiety at C-11, 13(18)], together with prosaikogenins B-1, B-2, and B-3 [elucidated as 3-O-β-D-glucopyranosyl (1→6)-β-D-glucopyranoside of saikogenin B, 3-O-α-L-rhamnopyranosyl (1→4)-β-D-glucopyranoside of saikogenin B, and 3-O-β-D-glucopyranoside of saikogenin B, respectively, possessing a homoannular diene moiety at C-9(11), 12].
