Which organosulfur compound gives horseradish its distinctive flavor?

The organosulfur compound that gives horseradish its distinctive, pungent flavor is allyl isothiocyanate ($C{H}_2=CHC{H}_{2}N=C=S$).1

This compound belongs to a class of chemicals known as isothiocyanates, which are produced when the enzyme myrosinase breaks down glucosinolates upon the physical damage of the plant's cells. Related compounds are also responsible for the sharp, peppery flavors found in other members of the Brassicaceae family, such as mustard, radish, and wasabi.21