Cinnamaldehyde is a natural molecular component of cinnamon, and is a “potent” inhibitor of colorectal cancer in mice, two UA researchers say.

Ron Medvescek / Arizona Daily Star

Two pharmacy researchers at the University of Arizona have made progress in showing that a compound in cinnamon could help prevent colon cancer.

Research conducted by Georg Wondrak and Donna Zhang of the UA College of Pharmacy concluded that a natural molecular component of cinnamon called cinnamaldehyde is a “potent” inhibitor of colorectal cancer in mice. Cinnamaldehyde gives cinnamon its distinctive flavor and smell.

The study has been published online by the journal Cancer Prevention Research and will appear in an upcoming print edition, UA officials said last week.

The finding is significant, the researchers say, because the progressive nature of colon cancer and its poor prognosis have created an urgent need for more preventive work.

Of cancers that affect both men and women, colon cancer is the second-leading cause of cancer-related deaths in the U.S., according to the U.S. Centers for Disease Control and Prevention. (Lung cancer is No. 1.)

In 2011 — the most recent available data — 51,783 people in the United States died of colorectal cancer, including 26,804 men and 24,979 women. That same year, 135,260 people in the U.S. were diagnosed with colon cancer.

Cinnamon is the third-most consumed spice in the world (pepper and vanilla are No. 1 and No. 2, respectively), but there is very little research on its potential health benefits, said Wondrak, an associate professor in the UA College of Pharmacy’s department of pharmacology and toxicology.

“There are hundreds of compounds that are in some way part of the human diet, and very few of these compounds have been very stringently tested as to how they work,” Wondrak said.

Cinnamon comes from the bark of evergreen trees. There are two major types in the world — cassia cinnamon, the kind most often sold in supermarkets, and true (or “Ceylon”) cinnamon. Cinnamaldehyde can be derived from both cassia and Ceylon cinnamon.

Ceylon cinnamon is generally more expensive than cassia, and compared with cassia, contains lower amounts of a naturally occurring substance called coumarin. Scientists say coumarin may have a toxic effect at high doses, so consuming large amounts of cassia cinnamon could be dangerous to one’s health.

Wondrak and Zhang say evidence suggests the cinnamaldehyde activates the Nrf2 molecular pathway, which is involved in strengthening cells against stressors like carcinogen exposure. Zhang is an expert in the Nrf2 molecular pathway.

The next step is testing the mice with cinnamon, not just the cinnamaldehyde.

“The key to this paper was that a) we used a cinnamon compound and b) we had a very stringent mouse model,” Wondrak said.

“We could see that only the mice that had this (Nrf2) pathway switched on were protected. If you take out the pathway genetically, the mice, even though supplemented with cinnamaldehyde, still get cancer.”

By activating the Nrf2 molecular pathway, cinnamaldehyde may also protect cells from other kinds of chemical carcinogens, UV-induced cancers and more, UA officials say.

“We are not preaching at this point, ‘You have to eat a lot of cinnamon,’” Wondrak said. “We are just saying that cinnamaldehyde has interesting properties that are consistent with protecting cells through activation of the Nrf2 pathway.”

Because cinnamon is a common food additive that is already considered safe, a study in humans may not be too far off, the researchers say.

“If you read the literature, there is a lot of indication that cinnamon is providing some health benefits. There is a lot of literature in providing benefit with regard to blood sugar. Some people take it as a supplement in capsules,” Wondrak said. “We are neutral on this.”

Neither Wondrak nor Zhang takes cinnamon supplements, though they do sprinkle it in coffee.

“There’s a lot of good stuff in our diet, why not leverage it?” Wondrak said. “But it’s too early to make recommendations.”

Contact health reporter Stephanie Innes at sinnes@tucson.com or 573-4134.