Isothiocyanates occur widely in nature and are of interest in food science and medical research.  Vegetable foods with characteristic flavors due to isothiocyanates include bok choy, broccoli, cabbage, cauliflower, kale, wasabi, horseradish, mustard, radish, Brussels sprouts, watercress, papaya seeds, nasturtiums, and capers. These species generate isothiocyanates in different proportions, and so have different, but recognizably related, flavors. They are all members of the order Brassicales, which is characterized by the production of glucosinolates, and of the enzyme myrosinase, which acts on glucosinolates to release isothiocyanates.
* Sinigrin is the precursor to allyl isothiocyanate
* Glucotropaeolin is the precursor to benzyl isothiocyanate
* Gluconasturtiin is the precursor to phenethyl isothiocyanate
* Glucoraphanin is the precursor to sulforaphane