Sinigrin

Sinigrin or allyl glucosinolate is a glucosinolate that belongs to the family of glucosides found in some plants of the family Brassicaceae such as Brussels sprouts, broccoli, and the seeds of black mustard (Brassica nigra). Whenever sinigrin-containing plant tissue is crushed or otherwise damaged, the enzymemyrosinase degrades sinigrin to a mustard oil (allyl isothiocyanate), which is responsible for the pungent taste of mustard and horseradish. Seeds of white mustard, Sinapis alba, give a less pungent mustard because this species contains a different glucosinolate, sinalbin.