The constituents of Eucommia ulmoides Oliv. V. Isolation of dihydroxydehydrodiconiferyl alcohol isomers and phenolic compounds.

Two new lignans, erythro-dihydroxydehydrodiconiferyl alcohol (1) and its threo isomer (2), were isolated from the bark of Eucommia ulmoides OLIV. (Eucommiaceae), together with six known lignans and three known phenolic compounds. Their structures were elucidated on the basis of spectroscopic analyses and chemical evidence.