Researchers in the United States say that a compound found in green tea kills off cancer cells in one form of leukaemia.
A team led by Neil Kay at the Mayo Clinic used laboratory cell cultures to show that the compound, known as epigallocatechin-3-gallate (EGCG), helped to kill leukaemia cells.
Writing in the journal Blood, the researchers reported that patients with B-cell chronic lymphocytic leukaemia (CLL), common among people in their mid-to-late sixties, showed a reduction in cancer cells after being given the compound.
The EGCG from green tea interrupted survival signals, prompting leukaemia cells to die in eight of 10 patient samples tested.
The team said they would continue to look for therapeutic agents that were non toxic to the patient but kill cancer cells.
Kay said the EGCG finding was “an excellent start”.
He said researchers now had a lot to work with in finding earlier, less toxic therapies for CLL patients, who are normally only given chemotherapy if the disease progresses.
CLL progresses at a different pace, and towards a different outcome, depending on the individual.
For some patients, it is a question of managing the disease over many years, and for others it may be fatal within just a few months, in spite of treatment.
Physicians have tended to adopt a “wait-and-see” attitude with CLL in its early stages, in the hope of sparing elderly patients the exposure to toxic chemotherapy.
The problem is now focused around how to identify which patients have the more aggressive form of the disease at a relatively early stage.
Non-toxic therapies like EGCG could be offered as an early-stage therapy before patients consider whether or not to have chemotherapy, researchers said.
Epidemiological studies since the 1970s have shown lower incidence of solid tumour cancers in parts of the world where green tea is consumed.
In mice, green tea has been shown to protect against solid tumour formation, while EGCG has also been shown to kill solid tumour cells in the laboratory.
The researchers speculate that EGCG kills leukaemia cells by inhibiting their ability to communicate with each other, and to receive blood flow.