By Jayne Elliott, BBC News
Chemicals used by plants as a defence against fungal infection could benefit cancer sufferers, researchers say.
Salvestrols were found in red fruits and green vegetables
Experts from research company Nature's Defence told a conference in Lincolnshire a product based on fruit skin extracts "may have benefits".
They claim salvestrols, a compound found in food, can induce cell death, particularly targeting an enzyme found only in cancer cells.
Cancer Research UK said they did not endorse products awaiting trial.
Full clinical trials on Fruit Force are expected to take place next year.
The compounds were discovered when experts from Nature's Defence and the Cancer Drug Discovery Group, headed by professor Gerry Potter, investigated the link between diet and cancer prevention.
They looked at how the body protects itself from cancer, and disposes of cancer cells as they are forming.
Professor Potter said salvestrols are "a wolf in sheep's clothing" referring to the potency of substances that were previously thought to be only mildly active.
Max Drake, medical herbalist at Nature's Defence, in Leicester, told the conference: "It is likely that we have discovered a mechanism that can tackle cancer cells whether they are formed or forming.
"Whether this could lead to a cure or not, we do not know."
Researchers found salvestrols destroyed the CYP1B1 enzyme which is present in both pre-cancerous and cancerous cells.
The compound targets cancer cells but leaves healthly ones untouched
Experts said anecdotal evidence was "promising" but full clinical trials have to be carried out to confirm the treatment's benefits.
Ed Yong, of Cancer Research UK, said: "Cancer Research UK does not endorse any supplement or drugs which have not been rigorously tested in clinical trials.
"Until this supplement has passed these trials, we cannot say if it has any preventive effects against cancer or any harmful side effects."
A spokesman at Grimsby's Diana Princess of Wales Hospital said: "There are many forms of cancer and tumours and they all need treating in different ways."