Phenolic constituents of Taxus cuspidata I:: lignans from the roots

The phenolic constituents of the roots of Taxus cuspidata (Japanese yew) were investigated. Four lignans, [(+)-taxiresinol (1), (+)-lariciresinol (2), (-)-secoisolariciresinol (3), and (+)-pinoresinol (4)] were isolated and identified. The assignment of proton and carbon atoms for the lignans were finally solved by one- and two-dimensional-nuclear magnetic resonance spectra. The enantiomeric excess of these lignans were determined by chiral high-performance liquid chromatographic analyses. (+)-Lariciresinol and (-)-secoisolariciresinol were optically pure, (+)-taxiresinol was also suggested to be optically pure, although (+)-pinoresinol was not (77% enantiomeric excess).