BIOSYNTHESIS OF INDIGO PRECURSORS IN HIGHER-PLANTS

Contradictory results in the literature concerning the role of L-tryptophan in the biosynthesis of the indigo precursors, indican and isatan B, in four higher plants belonging to four plant families have been resolved. [3-C-13]-Indole and L-[3-C-13]-tryptophan were synthesized by standard techniques. Feeding experiments with the labelled precursors unequivocally showed by C-13 NMR and mass spectroscopy, that indole and not L-tryptophan is the biosynthetic precursor for the indoxyl derivatives found in plants.