A chemical found in broccoli may provide the basis for a treatment for many cases of stomach ulcers and cancer.

Laboratory tests found that the chemical, sulforaphane can kill off the bacterium Helicobacter pylori.

This bug is widely thought to be responsible for the majority of cases of stomach ulcers and cancer.

Researchers from Johns Hopkins University in Baltimore and the French National Scientific Research Center now hope to test the chemical in clinical trials.

They hope to demonstrate that a diet rich in vegetables containing sulforaphane can help to relieve H. pylori infection.

Combinations of powerful antibiotics can kill off H. pylori in all but 15 to 20% of cases.

Unfortunately, the regions of the world where the infection is most common are the same places where using antibiotics is most economically and logistically difficult.

Major problem

Researcher Dr Jed Fahey said: "In some parts of Central and South America, Africa and Asia, as much as 80% to 90% of the population is infected with H. pylori, likely linked to poverty and conditions of poor sanitation.

"If future clinical studies show that a food can relieve or prevent diseases associated with this bacterium in people, it could have significant public health implications around the world."

The scientists discovered that purified sulforaphane even killed H. pylori that was resistant to commonly used antibiotics.

They also proved that sulforaphane can kill the bacterium inside or outside cells.

In people, cells lining the stomach can act as reservoirs of H. pylori, making it more difficult to get rid of the infection.

Dr Fahey said: "We've known for some time that sulforaphane had modest antibiotic activity.

"However, its potency against H. pylori, even those strains resistant to conventional antibiotics, was a pleasant surprise."

Dr Robert Owen, of the UK Public Health Laboratory Service, said: "This is interesting research, however various compounds in food such as garlic and honey and some spices have been found to be effective against H.pylori in a laboratory situation, as have many antibiotics.

"The real test is making such compounds or antibiotics effective against H.pylori in the acid environment of the human stomach, and also whether the strains of H.pylori resistant to antibiotics will be susceptible to these compounds found in food."

The research is published in the Proceedings of the National Academy of Sciences.