The uptake of L-[methylene-(14)C]-tryptophan from culture medium into root organs of Cinchona ledgeriana and the subsequent incorporation of the radiolabel into quinine and quinidine is reported. In addition, feeding unlabelled L-tryptophan at levels of 500mg/l to the cultures results in a 5-fold increase in the yields of both quinoline alkaloids.

The results of preliminary time-course studies on the uptake of radio-labelled alkaloid precursors, L-Imethylene J4C]-tryptophan, [C-5 3H]-secologanin, [C-3 3H]-strictosidine, [Ar 3H]-strictosidine/vincoside and alkaloids, [C-8 3H]-quinine and -quinidine, byCinchona ledgeriana root organs at various stages of the growth cycle are presented. Incorporation of the radio-label from [C-5 3H]-secologanin and [side chain 2 14C]-tryptamine into quinine and quinidine is also reported. Improved alkaloid yields obtained on feeding L-tryptophan have been shown to be dependent on the stage of the growth cycle at which feeding takes place.

The uptake of L-[methylene (14)C]-tryptophan from culture medium and the subsequent incorporation of the radiolabel into canthin-6-one, 1-hydroxycanthin-6-one and 1-methoxycanthin-6-one has been demonstrated in cell suspension cultures of Ailanthus altissima. Efficient incorporation has been shown to depend significantly on the time of feeding. Furthermore, feeding of L-tryptophan, at levels of 500 mg/l resulted in improved alkaloid yields, particularly when fed during the lag phase of the growth cycle.