A chemical found in green tea has been used to successfully treat two types of skin cancer, scientists say.
The extract, known as epigallocatechin gallate (EGCg), has no impact when consumed in tea but when applied to cancerous cells in laboratory tests it shrank or removed two-thirds of tumours it was used on within one month.
Scientists at the universities of Strathclyde and Glasgow, who carried out the research, found it had no side-effects on other cells or tissue.
They created a cell with EGCg and transferrin, a protein that naturally targets and latches on to the surface of cancer cells, and applied it to tumours.
Tests were done on two types of skin cancer: epidermoid carcinoma which forms like scales on the surface of the skin and melanoma which often develops in people who have moles on their skin.
In both studies, 40% of tumours vanished, while 30% of tumours in carcinoma cases and 20% in melanoma cases shrank. A further 10% of melanoma tumours were stabilised, so did not grow or shrink.
Around 10,000 people in the UK are diagnosed with melanoma each year, with the majority women, according to the Macmillan Cancer Support charity.
Anti-cancer properties of EGCg were established in earlier laboratory tests elsewhere. Scientists at other universities around the world have experimented with it to treat prostate cancer and leukaemia.
Lead researcher Dr Christine Dufes, from the University of Strathclyde, said: "These are very encouraging results which we hope could pave the way for new and effective cancer treatments.
"When we used our method, the green tea extract reduced the size of many of the tumours every day, in some cases removing them altogether. By contrast, the extract had no effect at all when it was delivered by other means, as every one of these tumours continued to grow.
"This research could open doors to new treatments for what is still one of the biggest killer diseases in many countries."
The research is published in the medical journal Nanomedicine.