The compounds that colour most red, purple and blue fruits and vegetables -- anthocyanins (花青素) -- can slow down the growth of colon cancer cells (結腸癌細胞). Researchers at Ohio State University tested the anti-cancer effects of anthocyanin-rich extracts (from a variety of fruits and vegetables including grapes, radishes, purple corn, chokeberries, bilberries, purple carrots and elderberries) on rats and on human colon cancer cells.
Anthocyanin pigments obtained from black carrots and radishes slowed the growth of cancer cells by between 50 to 80%. Pigments from purple corn and chokeberries not only stopped the growth of cancer cells, but also killed roughly 20% of the cancer cells while having little effect on healthy cells.
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.