Glucosinolate pattern in Isatis tinctoria and I-indigotica seeds

The glucosinolate patterns in seeds of five Isatis tinctoria and two Isatis indigotica accessions were assessed with a recently developed and validated LC-MS assay for direct analysis of glucosinolates without prior desulfatation. Glucosinolate peaks were identified with in-source fragmentation and detection of the sulfate anion (m/z=97), and by MS/MS experiments. The glucosinolate patterns of the seeds showed characteristic differences compared to leaves. Glucoisatisin and epiglucoisatisin were diagnostic of seed samples. Qualitative and quantitative differences in glucosinolate patterns between both Isatis species were found for seed samples, enabling a differentiation of the two medicinal plants at the level of seed material.