Traditional herbal tea could help combat breast cancer, say scientists.
Extracts from the plant known as virgin's mantle, which is used as a medicinal tea in some countries, can kill cancerous cells in the test tube, the Daily Mail reported.
The plant-based tea is already drunk by women in rural Pakistan who have breast cancer, but until now its use as a treatment has been regarded as folklore.
Research by scientists at Aston University, Birmingham, and Russells Hall Hospital, Dudley, suggests it contains potent anti-cancer agents that act singly or in combination against the proliferation of cancer cells.
Laboratory tests showed they arrested the growth of cells within five hours of application and caused them to die within 24 hours.
The plant, which has the botanical name Fagonia cretica, is found in arid, desert regions of Pakistan, India, Africa and parts of Europe.
Professor Helen Griffiths and Professor Amtul R Carmichael, who headed the study, found herbal tea made from the extract of the plant destroys cancer cells but, unlike conventional chemotherapy, treatment does not damage normal breast cells, thus reducing side effects.
Reports from breast cancer sufferers in Pakistan suggest that the plant extract does not trigger any serious side effects such as loss of hair, drop in blood count or diarrhoea.
The research found the plant extract had a novel mechanism which could remedy defects in cell DNA that would normally resist tumour growth.
An impaired DNA response not only allows the cancer to flourish, it also inhibits the way chemotherapy works which reduces its effectiveness.
Professor Carmichael said a small hospital 100 miles north of Lahore in Pakistan started using the herbal tea 40 years ago to treat breast cancer patients.
"It appears to keep them in remission, although we can't use the word cure at this stage," she said.
"However, they live for a long time without losing their hair or putting on a large amount of weight, or experiencing other toxic side effects associated with chemotherapy, so we are confident this extract has something to contribute."
She said stringent safety tests would be needed in developing a drug based on the extract.
At present the herbal tea is being used to treat Asians but there might be different effects in Caucasian patients, she added.
The study is published in the science journal PloS One.