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. (C) 1997 Elsevier Science Ltd.