Early Steps of Dauricine Biosynthesis in Cultured Roots of Menispermum dauricum

Abstract

Culturedultured roots of Menispermum dauricum, a rich source of the bisbenzylisoquinoline alkaloid dauricine (1), were fed with l-[U-14C] tyrosine, L-[3-13C] tyrosine, and [2-13C] tvramine independently, and the incorporation of possible early precursors into 1 was studied. The results demonstrated that 1 was composed of four molecules of tyrosine, and that tyramine was specifically incorporated into the isoquinoline portions of 1. The unusual chlorine-containing alkaloid acutumine (3), into which 14C-labeled tyrosine was also incorporated, was identified as one of the main constituents in the alkaloid fraction from the roots. © 1996, Taylor & Francis Group, LLC. All rights reserved.