METABOLISM OF (S)-RETICULINE IN AN ALKALOID NONPRODUCING CELL-CULTURE STRAIN OF THALICTRUM-TUBEROSUM

A stable variant cell culture line of Thalictrum tuberosum which is totally blocked in alkaloid biosynthesis was used in this study. Triply C-13-labelled (S)-reticuline was synthesized, administered to these cell cultures and was shown to enter the biosynthetic chain after that block. As a consequence very high incorporation of label into the protoberberine alkaloids occurred, which was followed by C-13 NMR spectroscopy. The time course of metabolism of this precursor indicated rapid formation of scoulerine as a primary reaction, followed by the formation of further tetrahydro- and dehydroprotoberberines. The formation of dehydroscoulerine, which was formed in significant amounts, seems to be reversible and may serve as an alkaloidal storage product from which scoulerine can be