Adapted from Dr. Fuhrman's book Eat to Live:
Allium compounds Flavonoids Phenolic acids Alllyl sulfides Glucosinolates Phytoesterols Anthocyanins Indoles Polyacetylenes Caffeic acid Isoflavones Polyphenols Catechins Isothiocyanates Protease inhibitors Coumarins Lignans Saponins Dithiolthiones Liminoids Sulphorophane Ellagic Acid Pectins Sterols Ferulic acid Perillyl alcohol Terpenes
The list above is only a small sample of beneficial compounds, and more are being discovered daily. Cancer-prevention studies attempting to dissect the precise ingredients or combination of ingredients in fruits and vegetables are ongoing; but these studies, like the many others before them, are likely to be a huge waste of resources. There are simply too many protective factors that work synergistically to expect significant benefit from taking a few isolated substances. These beneficial compounds have overlapping and complementary mechanisms of action. They inhibit cellular aging, induce detoxification enzymes, bind carcinogens in the digestive tract, and fuel cellular repair mechanisms.1
1. Steinmetz, K.A., and J.D. Potter. 1991. Vegetables, fruit and cancer. II Mechanisms. Cancer Causes Control 2 (6): 427-42.