Sulforaphane is found in many of the cruciferous veggies, like broccoli, cauliflower, cabbage, collards, and watercress, to name a few. Broccoli sprouts contain about 20 to 50 times the amount of sulforaphane as mature broccoli does. Researcher Marc A. Riedl and his team wondered if administering high concentrations of sulforaphane to participants would have an effect on the levels of antioxidant enzymes in the airways — specifically a group called Phase II enzymes, which scout out and rid the body of destructive particles known as reactive oxygen species. Sulforaphane has already been shown to increase the activity of Phase II enzymes under other circumstances.
Broccoli sprouts contain about 20 to 50 times the amount of sulforaphane as mature broccoli does.