Washington, May 6 - An over-the-counter natural remedy derived from beehives slows down the growth of prostate cancer cells and tumours in mice, says a new study.

Caffeic acid phenethyl ester, or CAPE, is a compound isolated from honeybee hive propolis, the resin used by bees to patch up holes in hives. Propolis has been used for centuries as a natural remedy for conditions ranging from sore throats and allergies to burns and cancer.

But the compound has not gained acceptance in the clinic due to scientific questions about its effect on cells, the journal Cancer Prevention Research reports.

Researchers combined traditional cancer research methods with cutting-edge techniques to find that CAPE arrests early-stage prostate cancer by shutting down the tumour cells' system for detecting sources of nutrition, according to a University of Chicago statement.

"If you feed CAPE to mice daily, their tumours will stop growing. After several weeks, if you stop the treatment, the tumours will begin to grow again at their original pace," said Richard B. Jones, assistant professor at the University of Chicago department of cancer research and senior study author. "So it doesn't kill the cancer, but it basically will indefinitely stop prostate cancer proliferation."

Natural remedies isolated from plant and animal products are often marketed as cure-alls for a variety of maladies, usually based on vague antioxidant and anti-inflammatory claims.

"It's only recently that people have examined the mechanism by which some of these herbal remedies work," Jones said.

CAPE was also effective at slowing the growth of human prostate tumours grafted into mice. Six weeks of treatment with the compound decreased tumour volume growth rate by half, but when CAPE treatment was stopped, tumour growth resumed its prior rate.

The results suggested that CAPE stopped cell division rather than killing cancerous cells.