A study has shown that a synthetic version of a plant extract prevents mold toxin-induced liver cancer in rats.
The extract, a derivative of oleanolic acid, is a building block of many plants, including herbs, and has known anti-inflammatory effects.

Recently created by chemists at Dartmouth College, the man-made version of oleanolic acid used in the study is dubbed CDDO-Im.

Investigators at Johns Hopkins teamed up with the Dartmouth chemists to determine whether the compound could help flush out of the body chemicals that trigger the development of liver cancer.

The researchers used rat models that simulate precancerous liver tumors caused by a carcinogen called aflatoxin.

Aflatoxin is produced by microscopic molds found on dietary staples, such as corn and peanuts. It also is known to cause liver cancer in people infected with hepatitis B.

" We know that aflatoxin can't be eliminated from our environment, but we can try to diminish its effects," says Thomas Kensler, at the Johns Hopkins Bloomberg School of Public Health.

In the Hopkins-Dartmouth study, the amount of precancerous tissue in the rats totaled approximately 1 percent of liver volume – enough to cause full-blown cancer. Very low doses of CDDO-Im reduced that fraction by 85 percent. Larger doses of the compound virtually obliterated all signs of precancerous tissue.

The team's research on gene expression patterns and knock-out mice also revealed that CDDO-Im works by activating a protein called Nrf2, the master switch that controls other genes crucial to cell-survival. " Essentially, CDDO-Im may make cells more resistant to aflatoxin," says Kensler.

Compared with other compounds used in clinical studies to prevent liver cancer, the researchers say that a much smaller dose of CDDO-Im may be needed to have an impact on preventing the disease. Studies in humans are not yet planned.

Source: Johns Hopkins Medical Institutions, 2005


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