Participation of C6C1 unit in the biosynthesis of ephedrine in Ephedra

Feeding of benzoic acid-[7-14C], benzaldehyde-[7-14C] and cinnamic acid-[3-14C] to Ephedra distachya resulted in efficient incorporations of 14C into the α-carbon atom of the side chain of l-ephedrine. Thus ephedrine was shown to be biosynthesized by the condensation of a C6C1 portion which is derived from phenylalanine via cinnamate and an unidentified C2-N fragment.