Biologically active labdane-type diterpene glycosides from the root-stalks of Gleichenia japonica.

A glycoside showing a strong growth inhibition of lettuce was isolated from the root-stalks of Gleichenia japonica and its structure was established to be the 3-O-alpha-rhamnopyranosyl-(1----2)-beta-glucopyranoside of 13-O-alpha-rhamnopyranosyl-(+)-3 beta-hydroxymanool. In addition, two related glycosides were also isolated and they were characterized as the 3-O-beta-fucopyranosyl-(1----3)-alpha-rhamnopyranosyl-(1----2)-beta- glucopyranoside of 13-O-alpha-rhamnopyranosyl-(+)-3 beta-hydroxymanool and the 13-O-rhamnopyranoside of the same diterpene alcohol. The diterpene alcohol accelerated the growth of lettuce.