ßber das Vorkommen von Indigovorstufen in Isatis-Species

Abstract

In temperate climates Isatis tinctoria L. (woad) was used for centuries to produce the blue dye indigo. Apparently this plant contains as indigo precursor isatan B = indoxyl-5-ketogluconate instead of plant indican as it was stated by EPSTEIN et al. (1967). We have confirmed the presence and structure of isatan B in Isatis. Moreover leaves of Isatis contain in trace amounts also indican and most surprisingly in roots indoxyl-β-D-glucoside as major indigo precursor is present. The obtainable yield of indigo from roots and leaves of a variety of Isatis species were estimated using an improved modified procedure.