Significantly reduced the incidence, multiplicity and rate of development of chemically induced mammary tumors in rats. It has demonstrated an ability to detoxify a number of carcinogens and thus might have the ability to protect against a variety of cancers (by keeping cancer from forming). Abundant in three-day old broccoli sprouts. The levels in three-day old broccoli sprouts are from 10 to 100 times greater than in mature broccoli. Also found in cabbage, brussels sprouts, cauliflower, cauliflower sprouts, bok choy, kale, collards, arugula, kohlrabi, mustard, turnip, red radish and watercress. See also indoles.