Indole-3-carbinol 

Indole-3-carbinol is formed from a substance called glucobrassicin found in vegetables such as broccoli, Brussels sprouts, cabbage, collards, cauliflower, kale, mustard greens, turnips, and rutabagas. Indole-3-carbinol is formed when these vegetables are cut, chewed or cooked. It can also be produced in the laboratory.