An unlikely therapy derived from green tea and gold can successfully treat prostate cancer, a study has shown.
Scientists used a compound found in green tea to deliver tiny particles of radioactive gold dust to cancer sites.
The early research, conducted in mice, showed that the treatment shrank tumours by 80%.
Green tea compounds 'could treat prostate cancer'
Further studies are now planned on dogs with prostate cancer before moving on to human trials.
Lead scientist Professor Kattesh Katti, from the University of Missouri in the US, said: "In our study, we found that a special compound in tea was attracted to tumour cells in the prostate.
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"When we combined the tea compound with radioactive gold nanoparticles, the tea compound helped 'deliver' the nanoparticles to the site of the tumours and the nanoparticles destroyed the tumour cells very efficiently."
The research is reported today in the journal Proceedings of the National Academy of Sciences.
Scientists believe it could pave the way to new and more effective treatments for patients with aggressive, spreading prostate cancer.
Each year around 41,000 men are diagnosed with prostate cancer in the UK and just under 11,000 die from the disease.
The injected gold nanoparticles are just the right size to destroy tumours by zapping them with radiation while not harming surrounding healthy tissue.
With a half-life of 2.7 days, their radioactivity is depleted within around three weeks.
The green tea compound used to deliver the gold particles is called epigallocatechin-gallate (EGCg), a powerful antioxidant.
EGCg has been shown in laboratory tests to have anti-cancer properties. It naturally targets and latches on to a protein found on the surface of prostate cancer cells.
The new therapy agent was created by joining together radioactive gold nanoparticles and molecules of EGCg.
Co-author Dr Cathy Cutler, also from the University of Missouri, said: "Current therapy for this disease is not effective in those patients who have aggressive prostate cancer tumours.
"Most of the time, prostate cancers are slow-growing; the disease remains localised and it is easily managed. Aggressive forms of the disease spread to other parts of the body, and it is the second-leading cause of cancer deaths in US men. However, we believe the gold nanoparticles could shrink the tumours, both those that are slow-growing and aggressive, or eliminate them completely."