Indigo and indirubin derivatives from indoles in Polygonum tinctorium tissue cultures

Substituted indoles (5-bromo-, 5-fluoro-, 5-chloro-, 5-hydroxy-, 4-methyl-, 5-methyl-, 6-methyl-, and 7-methylindole) were fed at 1 mM for 10 to 21 da ys into the tissue cultures of Polygonum tinctorium including cell suspensi on, root and shoot cultures. They were converted into the corresponding ind irubin and indigo derivatives with the exception of 5-hydroxyindole. The yi eld ranged between 0.7-1.1 mg/g dried weight for indigos and 0.007-0.024 mg /g dried weight for indirubins. Presence of the corresponding indican deriv atives in the shoot culture suggested that the pigment production proceeded through the indican formation.