Fig. 3From: Isatis indigotica: from (ethno) botany, biochemistry to synthetic biologyBiosynthetic pathway of indole alkaloids in I. indigotica. Indoxyl can be biosynthesized from indole or from the degradation of indican; the oxidation or glycosylation reaction make it stable. Indigo, indirubin, and isatin are produced outside of the cells. The figure is adapted from Maier et al. (1990) and Xia and Zenk (1992)Back to article page