Extracts from a mushroom used for centuries in Eastern Asian medicine may be able to boost the power of a leading chemotherapy drug for prostate cancer, researchers said on Tuesday.

They found that when the mushroom called Phellinus linteus was added to the drug doxorubicin in the laboratory it improved its ability to kill cancerous cells.

“This species of mushroom has been reported to have some degree of activity in cancer patients. Our aim was to study what effect, if any, extracts of Phellinus linteus have, but we also need to know precisely how it produces these effects,” said Dr Chang-Yan Chen, of the Boston University School of Medicine in Massachusetts, the lead researcher of the study.

The researchers added the mushroom extract to doses of the drug that would have otherwise been too small to have any effect. They found that the combination was just as effective in killing cancerous cells as larger doses of the drug alone, but without harming healthy cells.

The findings, reported in the British Journal of Cancer, suggest lower doses of chemotherapy combined with the extract could be as effective in treating prostate cancer and less toxic than higher doses.

Prostate cancer kills about 200,000 men worldwide each year. It is the third most common cancer in men in the world, with 543,000 new cases each year, according to the International Agency for Research on Cancer (IARC) in Lyon, France.

Professor Sung-Hoon Kim of Kyung Hee University in South Korea provided the researchers with the extract of the mushroom, which is known as “sang-hwang” in Korean, “mesimakobu” in Japanese and “song gen” in Chinese.

Dr Richard Lewis, of the charity Cancer Research UK, said many important drugs have been derived from natural sources. But he added that further studies are needed to understand the full effects of the mushrooms.

“There was evidence that extracts of Phellinus linteus slowed tumour progression. Now they have shown promise in combination with one type of chemotherapy drug, but it is still too early to say whether it will be successful in the long-run,” Lewis said in a statement.