Biotransformation of deuterated-4'-O-methylnorbelladine into alkaloids galanthamine and lycorine in tissue cultures of Leucojum aestivum was demonstrated using HPLC coupled to mass spectrometry. GC-MS screening was also carried to investigate other native and deuterated alkaloids. A total of six labeled alkaloids were identified indicating that 4'-O-methyl-d(3)-norbelladine is incorporated into three different groups of Amaryllidaceae alkaloids that are biosynthesized by three modes of intramolecular oxidative phenol coupling.