Biosynthesis of Liriodendrin by Liriodendron tulipifera

Abstract

^<14>C-Labeled lignin precursors (L-phenylalanine-U-^<14>C, ferulic acid-2-^<14>C, coniferyl alcohol-2-^<14>C, sinapic acid-2-^<14>C and sinapyl alcohol-2-^<14>C) were administered to young twigs of a yellow poplar (Liriodendron tulipifera). Sinapyl alcohol was most effectively incorporated into liriodendrin (dilution value, 6.5～13.5) and syringaresinol (dilution value, 1.1), and followed by L-phenylalanine. However, the incorporation of sinapic acid was rather low and coniferyl alcohol was scarcely incorporated. Liriodendrin isolated as its octaacetate and syringaresinol were all levorotatory. Biogenetic relationship between liriodendrin and syringyl lignin was discussed.