[Study on lignans from Diphylleia sinensis].

A new lignan along with eight known lignans and a flavonoid were isolated from the rhizomes of Diphylleia sinensis Li.. Their structures were elucidated on the basis of chemical and spectral analysis. The new lignan, compound IX, was named as picropodophyllin-1-ethyl ether (IX). The eight known lignans were identified as podophyllotoxin (I), isopicropodophyllone (II), dehydropodophyllotoxin (III), diphyllin (IV), picropodophyllin (V), podophyllotoxone (VI), 4'-demethylpodophyllotoxin (VII) and picropodophyllin glucoside (VIII). Compounds II, VI, VII and VIII were found for the first time from the rhizome of this plant. The flavonoid was identified as kaempferol.