Influence of alkaloid precursors on the alkaloid content of Nicotiana alata root cultures

Abstract

Root cultures of Nicotiana alata Link and Otto, growing in a Murashige and Skoog medium, contained the following alkaloid composition: nicotine (5 %), nornicotine (58%), anabasine (10%), and anatabine (27%), all with the (S)-configuration with high enantiomeric excess. When the root growth was carried out in the presence of increasing concentrations of [2-3H]nicotinic acid (0.002–5 mM), there were profound changes in the amounts and composition of the alkaloids after three days incubation. High concentrations of nicotinic acid inhibited both alkaloid formation and the demethylation of nicotine to nornicotine. Anatabine production was stimulated with increasing nicotinic acid concentration. A second series of experiments with a fixed concentration of [2-3H]nicotinic acid and increasing amounts of 1-methyl-Δ1-pyrrolinium chloride indicated that this latter compound stimulated nicotine production and also inhibited its demethylation. In a third set of experiments it was found that increasing concentrations of [2-14C]-Δ1-piperideine promoted the production of [2′-14C]anabasine and also stimulated nornicotine production.