Isatis canescens is a rich source of glucobrassicin and other health-promoting compounds

BACKGROUND: Glucobrassicin (GBS), a glucosinolate contained in many brassica vegetables, is the precursor of chemopreventive compounds such as indole-3-carbinol. Large amounts of GBS would be needed to perform studies aimed at elucidating its role in the diet. This study was mainly undertaken to evaluate the flower buds of Isatis canescens as a source for GBS purification. In order to investigate the health-promoting potential of this species, glucosinolate, phenol and flavonoid content as well as the whole antioxidant capacity were also determined. Flower bud samples were collected in four localities around Mount Etna in Sicily, Italy, where I. canescens is widespread, as they are locally traditionally eaten. RESULTS: I. canescens flower buds displayed high GBS concentrations, up to 60 μmol g-1 dry weight. The purification method consisted of two chromatographic steps, which made it possible to obtain GBS with a purity of 92-95%, with a yield of 21 g kg-1. The total glucosinolates, phenols, flavonoids and antioxidant activity were considerable, with the southern locality showing the highest concentrations for all the phytochemicals. CONCLUSION: I. canescens flower buds represent a naturally rich source of GBS, at a level suitable for its purification. Furthermore, flower bud consumption could provide an intake of health-promoting compounds, with possible antioxidant and chemopreventive properties.