Compounds That Colour Fruits Are Cancer-Fighters -- MEDICA - World Forum for Medicine
Picture: Bilberrys 
Bilberry extracts seem to
slow colon cancer; © SXC

In their studies on human colon cancer cells grown in laboratory dishes, the researchers tested the anti-cancer effects of anthocyanin-rich extracts from a variety of fruits and vegetables, like radishes, purple corn, chokeberries, bilberries and purple carrots. The plants were chosen due to their extremely deep colours, and therefore high anthocyanin content. Some of these plants are also used as a source of food colouring.

The researchers found that the amount of anthocyanin extract needed to reduce cancer cell growth by 50 percent varied among the plants. Extract derived from purple corn was the most potent, in that it took the least amount of this extract (14 micrograms per millilitre of cell growth solution) to cut cell numbers in half. Chokeberry and bilberry extracts were nearly as potent as purple corn. Radish extract proved the least potent, as it took nine times as much (131 µg/ml) of this compound to cut cell growth by 50 percent.

In additional laboratory studies, the researchers found that pigments from purple corn and chokeberries not only completely stopped the growth of cancer cells, but also killed roughly 20 percent of the cancer cells while having little effect on healthy cells.

In animal studies, rats induced with colon cancer cells were fed a daily diet of anthocyanin extracts either from bilberries and chokeberries, which are most often used as flavourings or to make jams and juices. The dietary addition of the anthocyanin extracts reduced signs of colon tumours by 70 and 60 percent, respectively, when compared to control rats.

Monica Giusti, the lead author of the study and an assistant professor of food science at Ohio State University says the results suggest that anthocyanins may protect against certain gastrointestinal cancers. “Very little anthocyanin is absorbed by the bloodstream,” Giusti said. “But a large proportion travels through the gastrointestinal tract, where those tissues absorb the compound.”; Source: The Ohio State University