Ingredient in fruit may slow breast tumours

Research has shown that ellagitannins found in the fruit inhibits an enzyme known to play a key role in the disease.

The enzyme, aromatase, helps the body produce extra amounts of the female hormone oestrogen, which fuels most breast cancers.

Aromatase inhibitors such as Arimidex make up a key class of drugs used to treat breast cancer in post-menopausal women.

Ellagitannins in pomegranates have the same effect as the drugs, a team of US scientists found.

The chemicals are converted to ellagic acid in the body, which in turn breaks down into anti-cancer agents, the research suggests.

The scientists screened 10 "phytochemical" plant compounds derived from pomegranates to investigate their ability to combat breast cancer.

One, an ellagic acid break-down chemical or metabolite called urolithin B, significantly slowed the growth of cancer cells in the laboratory.

"We were surprised by our findings," said lead scientist Dr Shiuan Chan, from the City of Hope cancer centre in Duarte, California.

"Phytochemicals suppress oestrogen production and that prevents the proliferation of breast cancer cells and the growth of oestrogen-responsive tumours."

The findings are published in the journal Cancer Prevention Research.

Commenting on the study, Professor Gary Stoner, from Ohio State University, pointed out that high levels of plant chemicals were needed to have an effect. "It is not clear that these levels could be achieved in animals or in humans because the ellagitannins are not well absorbed into blood when provided in the diet."

Previous research has shown that drinking pomegranate juice can slow prostate cancer in men.