The compound, CDDO-Im, is derived from oleanolic acid that is found in many plants around the world.
Researchers led by Johns Hopkins University said CDDO-Im may prove effective in treating liver, colon, prostate and gastric cancers that have a strong inflammatory component.
"The results show that the potency of this compound is more than 100 times as great as that of other chemopreventive agents in protecting against cancer," said David Schwartz, director of the National Institute of Environmental Health Sciences.
"This compound has a much greater effect at a far lower dose than any other compound currently used for preventing aflatoxin-induced cancer in humans," said John Hopkins' Thomas Kensler.
Aflatoxin is a known cancer-causing mold.
Kensler said CDDO-Im activates a protein that protects cells and stimulates enzymes that remove aflatoxins.
The federally funded study was published in the journal Cancer Research.