3-(4-Hydroxyphenyl)propionic acid is involved in the biosynthesis of myricanol in Myrica rubra

There is little evidence concerning the biosynthetic pathways for cyclic diarylheptanoids. We previously demonstrated that the cyclic diarylheptanoids myricanol and myricanone were biologically synthesized from two molecules of 4-coumaric acid by the feeding of 4-[8,9-¹³C₂]coumaric acid to young shoots of Myrica rubra. In the present study, using a ¹³C-labeled compound, we revealed that two molecules of 3-(4-hydroxyphenyl)propionic acid could also be a biosynthetic precursor of myricanol in M. rubra. These results indicated that both 4-coumaric acid and its dihydro-derivative were incorporated into myricanol. Competitive feeding experiments with 4-[8,9-¹³C₂]coumaric acid and 3-(4-hydroxyphenyl)-[1-¹³C]propionic acid were performed in M. rubra to determine the preferential incorporation of these two precursors. ¹³C-NMR studies indicated that 3-(4-hydroxyphenyl)-[1-¹³C]propionic acid was preferentially incorporated into myricanol. The data provided evidence for a biosynthetic sequence originating from 4-coumaric acid and leading to myricanol, through 3-(4-hydroxyphenyl)propionic acid, in M. rubra.