Biologically active clerodane-type diterpene glycosides from the root-stalks of Dicranopteris pedata

The molecular structure of the biologically active diterpene alcohol isolated previously from the root-stalks of Dicranopteris pedata and Gleichenia japonica was confirmed to be (6S,13S)-cleroda-3,14-diene-6,13-diol by an X-ray crystallographic analysis, together with application of the octant rule to the Cotton effect observed in the CD spectrum of its 6-keto derivative. Further investigation of the root-stalks of D. pedata has resulted in the isolated two new glycosides, which were characterised as (6S,13S)-6-O-[beta-D-glucopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl] 13-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-fucopyranosyl] cleroda-3,14-diene and (6S,13S)-6-O-[beta-glucopyranosyl]-13-O-[beta-fucopyranosyl-(1-->2) -alpha-rhamnopyranosyl]-cleroda-3,14-diene. Of these two glycosides, the former glycoside accelerated the growth of the stems of lettuce and inhibited the growth of the roots.