Identification of Thuja occidentalis lignans and its biosynthetic relationship

Five lignans, (8R,8'R)-(-)-matairesinol, (8R,8'R)-(-)-thujaplicatin methyl ether, (8S,8'S)-(-)-wikstromol, 8-hydroxy-thujaplicatin methyl ether and ep i-pinoresinol were isolated from Thuja occidentalis branch xylem, besides t he previously identified (8R,8'R)-(-)-4-O-demethylyatein. Chiral HPLC analy ses of matairesinol, thujaplicatin methyl ether, wikstromol and 4-O-demethy lyatein indicated that these compounds were optically pure. A neolignan, di hydrodehydrodiconiferyl alcohol, was isolated from the acid-hydrolyzed extr acts of T. occidentalis leaves. The lignans pinoresinol and secoisolaricire sinol were also identified by GC-MS analysis of the extracts of xylem and l eaves, respectively. Feeding experiments of [9-H-2(2), (OCH3)-H-2]coniferyl alcohol into T. occi dentalis young shoots showed that two molecules of coniferyl alcohol were i ncorporated into pinoresinol and lariciresinol. (C) 1999 Elsevier Science L td. All rights reserved.