DIM, from green vegetables that prevent some cancers, may eventually yield cures, Texas researcher says

Jan 16, 2004 –Broccoli, cabbage, turnip and mustard greens, kale, brussel sprouts and collards - everyone agrees, these greens are nutritious. But when was the last time you ate them?

Cabbage, cauliflower, broccoli and these other greens are known as cruciferous vegetables – so named for the cross-like shape of their flowers – and have been widely documented in research around the world as having properties that prevent cancer.

Greens used to be a staple of poor peoples' health. Today, frozen storage makes distribution easy all year round, yet many North Americans rarely eat these greens and few eat daily servings.

Some childrens' and adults' tastebuds are so sensitive to bitter flavors in these vegetables, they gag on them. When the first President Bush made a public issueof his dislike of broccoli, he was not alone. The bitter flavors that make these greens unpalatable to super-tasters probably evolved in the plants evolve to protect against predators. Ironically, these flavors are tied to chemicals that protect against cancer.

For people who, regardless of diet, do develop cancer, chemicals extracted from the broccoli family of vegetables may ultimately help control the disease.

Research at the Texas Agricultural Experiment Station
has led to a patent for a new use for derivatives of DIM, or
diindolylmethane, a natural compound derived from certain vegetables, to
treat cancer.

"We took advantage of a natural chemical, that research has shown will prevent cancer, and developed several more analogs," said Dr. Steve Safe, an Experiment Station chemist who has been studying cancer for about 10 years.

Safe's patent has been picked up by Plantacor, a new biotech company headquartered in College Station, and is expected to enter clinical trials soon in collaboration with M.D. Anderson in Houston.

DIM already is commercially available as a natural supplement for cancer prevention and for treating estrogen-related health issues.

"DIM is a potent substance," Safe said. "But we made it even more potent against various tumors."

The first development in this research using chemically altered DIM from broccoli came when the growth of breast cancer cells was inhibited in laboratory studies. Subsequent research showed these compounds also inhibited growth of pancreatic, colon, bladder and ovarian cancer cells in culture, Safe said. Limited trials on lab mice and rats have produced the similar results, he noted.

Safe said the research began by considering compounds that protect a person from developing cancer. After a stream of articles from other researchers extolling the scientific evidence that cruciferous vegetables prevent cancer, Safe and his team wondered whether the similar compounds could be developed for treatment of cancer. They looked at the mechanism – how the compounds block cancer cell growth – and found that they target PPAR gamma, a protein that is highly active in fat cells. This same PPAR gamma is over-expressed in many tumors and tumor cells and is a potential target for new drugs, he said.

Safe's lab chemically modified "natural" DIM to give a series of compounds that target the PPAR gamma and stop the growth of cancer.

"One of the best parts is that this treatment appears to have minimal or no side effects, in the mice trials; it just stops tumor growth," he said. "The hope now is that the patented chemicals can be developed into useful drugs for clinical trials and then be used for cancer treatment.

"It looks promising in cancer cells and animals at this time. We need future studies in humans to see if it is beneficial with people as well," he added.

Other laboratories are looking at phytochemicals called isothiocyanates (ITCs), which are generated in broccoli and other vegetables when they are chewed. ITCs significantly reduces the risk for prostate cancer, studies suggest. Another approach is to breed plants like "super-broccoli," under development in Norwich, UK. "The super-broccoli looks and tastes the same as ordinary broccoli," says a member of the Norwich team that bred the plant. Compared with regular broccoli, super-broccoli contains 10 to 100 times as much sulphoraphane, a substance that helps to neutralize cancer-causing agents in the gut.

Cruciferous Gardening

These vegetables should be planted in a sunny location, in rich, well-drained soil, according to Dr. Doug Welsh, a Texas Master Gardener and coordinator at Texas Cooperative Extension. All are hardy annuals that will tolerate evening temperatures in the 40-70 degrees range, so gardeners should watch weather reports and cover plants during occasional freezing spells which last 24 hours or longer.

Welsh pointed out that one can easily plant these vegetables in existing flower beds around the home if a formal vegetable garden space is not possible.

Here are some other facts to consider when raising these crops at home:

Broccoli – a 10-foot row yields about 10-20 pounds. For each person, raise about 8-10 pounds, depending on how much the members of the family like it, Welsh said. This plant requires 65-110 days from planting to maturity. Multiple harvests can be made from each plant.

Cabbage – a 10-foot row produces 10-18 pounds. Plan to raise 15 pounds per person. Allow 65-100 days from transplanting to maturity.

Cauliflower – a 10-foot row makes 15-20 pounds, and one should allot 8-10 pounds per person. From planting to maturity, count on 65-90 days.

For more information, on the Web go to http://aggie-horticulture.tamu.edu/mastergd/index.html or contact the local county Extension office.

 

This page created Jan 16, 2004. Ed. J. Strax.