Characterization of products from the reaction of glucosinolate-derived isothiocyanates with cysteine and lysine derivatives formed in either model systems or broccoli sprouts.
Glucosinolates, present in Brassica vegetables, are thought to contribute to human health prevention due to their enzymatically induced breakdown products – primarily isothiocyanates (ITC). ITC are reactive substances that readily react with nucleophilic (food) compounds. The reactivity of allyl-ITC and 4-(methylsulfinyl)butyl-ITC (sulforaphane) towards thiol and amino groups of cysteine and lysine derivatives was studied in buffered model systems as well as in broccoli sprouts. The thiol group is the preferred reaction site and it was demonstrated that even endogenously released sulforaphane is able to react very fast with cysteine in broccoli sprouts. Amino groups reacted slower and only under basic conditions. However, great differences in the reactivity between the different amino compounds were revealed. The aliphatic allylamine reacted very fast with allyl-ITC, forming N,N’-diallylthiourea, a compound identified as a main thermal degradation product of allyl-ITC.
Hanschen, F.; Brueggemann, N.; Brodehl, A.; Mewis, I.; Schreiner, M.; Rohn, S.; Kroh, L. 2012. Characterization of products from the reaction of glucosinolate-derived isothiocyanates with cysteine and lysine derivatives formed in either model systems or broccoli sprouts. Journal of Agricultural and Food Chemistry 60 (31), 7735-7745.