Furthermore, in all the four accessions the double small peak after the 4-OMeGBS peak, has been presumably identified as the epimeric mixture of the novel GLs glucoisatisin and epiglucoisatisin, recently observed in I. tinctoria seeds ( Fréchard et al., 2001) and considered a marker of both seeds of I. indigotica and I. tinctoria ( Mohn and Hamburger, 2008). Interestingly, Agerbirk and Olsen (2012) described the novel glucosinolates, glucoisatisin and epiglucoisatin, as natural GLs with an unusual complicated and unexpected structure. They originate from epi-PRO and PRO GLs, of which the hydroxyl group is esterified to two different indole acetic acid (IAA) derivatives.