Studies on Ailanthus altissima cell suspension cultures : Precursor feeding of L-[methylene-(14)C]tryptophan and L-tryptophan.

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.