HPLC Separation of Glucosinolates from Leaves and Seeds of Arabidopsis thaliana and Their Identification Using Thermospray Liquid Chramatography/Mass Spectrometry

Leaf and seed extracts of Arabidopsis thaliana var. Columbia contain a large number of glucosinolates, representing close to 25% of those known to occur in nature. The glucosinolates, in the form of their desulphated analogs, are separated by reversed-phase, high-performance liquid chromatography (HPLC). Seventeen are identified using thermospray liquid chromatography/mass spectrometry (TSP LC/MS). Additional glucosinolates, present in trace amounts, are identified as isothiocyanates by electron impact and chemical ionization gas chromatography/MS (GC/MS). In total, 23 glucosinolates are detected and these include four series of homologs and analogs. Fifteen possess aliphatic side chains, of which six contain ω-methylthioalkyl and six contain ω-methylsulphinylalkyl side chains; eight possess aromatic side chains, of which four constitute an homologous series of benzoic acid esters and three possess 3-indolylmethyl-based structures. Sixteen of the glucosinolates are detected in Arabidopsis thaliana for the first time and three of these, 4-hydroxybutyl glucosinolate, 5-benzoyloxypentyl glucosinolate, and 6-benzoyloxyhexyl glucosinolate, represent novel plant constituents.