Pungency in radish is due to volatile compound

Pungency in radish is due to the volatile compound Isothiocyanates.
4-(Methylthio)-3-trans-butenyl isothiocyanate, a breakdown product of glucodehydroerucin, was reported to be the main volatile constituent of radish root responsible for its pungency.
Isothiocyanate is a volatile and aliphatic sulphur-containing compound. It is a main pungent compound of some relishes.