An exotic mushroom could help in the fight against cancer, it emerged yesterday.
Tests show extracts from Phellinus linteus, a yellow tropical fungus, can combat breast, prostate, skin and lung cancers.
It is thought the mushroom, a mainstay of Oriental medicine since ancient times, stops blood vessels from growing and feeding tumours.
Study of the fungus, which grows on the bark of dead mulberry trees, could lead to the development of new anti-cancer drugs.
Alternatively, the extract itself may be used to treat patients. Dietary supplements could even help ward off the cancer in healthy individuals, the U.S. researchers believe.
Scientists from the Methodist Research Institute in Indianapolis showed that a powdered extract of the mushroom can halt the growth of breast cancer cells.
Experiments suggest it does this by blocking an enzyme involved in the development of the blood vessels needed to nourish the growth and spread of cancer cells.
Lead researcher Dr Daniel Sliva said: "We saw a number of positive results from our investigation of aggressive human breast cancer cells, including a lower rate of uncontrolled growth of new cancer cells, suppression of their aggressive behaviour and the formation of fewer blood vessels that feed cancer cells' essential nutrients."
Previous studies have shown the mushroom is also effective against prostate, lung and skin cancers.
Together with breast cancer, they kill more than 55,000 Britons a year.
Dr Sliva, whose results are published in the British Journal of Cancer, said the extract may have a place alongside conventional cancer drugs and help develop new medicines or supplements.
However he urged people not to buy the extract until further tests show it to be safe and effective, saying there were also concerns that some powders are of poor quality or even dangerous.
Those wishing to boost their health should instead make the sort of mushrooms readily available in supermarkets part of their everyday diet, said Dr Sliva.
Dr Lesley Walker, of Cancer Research UK, said: "Although natural products have been used to develop many important drugs, there is no guarantee that they are all safe or will be effective in the clinic. "Further research is needed to know if mushroom extracts can be used to treat cancer patients."