The norcoclaurine pathway is operative in berberine biosynthesis in Coptis japonica

The commercially used cell suspension culture of Coptis japonica Makino (Ranunculaceae) incorporates [β- 13 C]tyrosine into both halves of the berberine molecule (isoquinoline and benzyl portion) while L-[3'- 18 O]DOPA only labels the isoquinoline portion of this molecule. This labelling pattern indicates that different C 6 -C 2 units derived from tyrosine form this molecule