Broccoli has the highest amounts of glucoraphanin of any vegetable, but it is also found in Brussel sprouts, Kale, Cabbage, Bok Choy, and several others (R). (alivebynature.com)
Broccoli is also rich in the antioxidant sulforaphane, a chemical which is formed from the inactive compound called glucoraphanin when you chew it. (fitnessandpower.com)
Of particular interest here has been the isothiocyanate (ITC) sulforaphane, which is made from glucoraphanin (a glucosinolate) found in Brussels sprouts. (whfoods.org)