UNCHARACTERISTIC ALKALOID SYNTHESIS BY SUSPENSION-CULTURES OF CINCHONA-PUBESCENS FED WITH TRYPTOPHAN-L

The growth and alkaloid prodution of a liquid suspension culture of Cinchona pubescens has been studied, particularly with attention to the effect on the alkaloid spectrum of feeding cultures with L-tryptophan. This treatment did not enhance the production of any of the known alkaloids of Cinchona. Above 2 mM, however, the presence of the amino acid was toxic, causing extreme acidification of the medium and cell death. Under these conditions a number of indole and quinoline derivatives accumulated. The principal component of the alkaloid fraction proved to be norharman; indole-3-aldehyde was also isolated. Both these products probably occur by uncharacteristic metabolism of L-tryptophan. Furthermore, evidence for the degradation of endogenous alkaloids was obtained, as 4-hydroxymethylquinoline was also isolated. None of the known quinoline alakolids of Cinchona, which were present in untreated cells, could be detected after L-tryptophan treatment, even when large amounts of culture were analysed. It is concluded that, in this instance. Cinchona alkaloid production cannot be improved by feeding with a precursor.