A compound derived from fruits and vegetables could be used to enhance a drug for bladder and bowel cancer, Canadian researchers said on Tuesday.

The chemotherapy drug, mitomycin C (MMC), damages DNA in tumour cells to prevent it from growing. It is activated by enzymes produced naturally in the body but it can cause severe side effects such as anaemia in high doses.

When Canadian scientists tested the effect of the compound called dimethylfumarate (DMF) in cancerous mice it enhanced the effect of the drug. They believe a pill based on DMF could have the same effect in humans.

“Our results show that DMF given with MMC significantly reduced the size of tumours compared to MMC alone or no treatment at all,” said Dr Asher Begleiter, of Manitoba Institute of Cell Biology in Canada, who headed the research team.

“It gives us a bigger bang for our buck when using mitomycin C, which should allow us to treat patients with lower doses.”

In the study, the mice were fed normally or given a diet high in DMF, which increases the amount of NQO1, the activating enzyme.

Tumours usually produce higher amounts of NQO1 than healthy cells, which makes it a good target for drugs to increase the effectiveness of MMC with lower doses and fewer side effects.

“The activating enzyme NQO1 is induced by several compounds. We chose DMF because of its natural origin and the fact that we could easily administer it in the diet, but there might be even better candidates for future clinical use,” Begleiter, who reported the findings in the British Journal of Cancer, added in a statement.

Dr Leslie Walker of the charity Cancer Research UK which publishes the journal said mitomycin C has been used to treat certain forms of cancer for many years.

“This study shows that it may be possible to achieve the same anticancer effect with lower doses, which means fewer and less severe side effects in patients,” he added.

Br J Cancer 2004.