Propolis, the resin used by bees to patch up holes in hives, 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 by mainstream medicine because of questions about its effect on cells.
Caffeic acid phenethyl ester, or CAPE, a compound isolated from honeybee hive propolis, has been shown in lab tests to halt early-stage prostate cancer by shutting down the tumor cells’ system for detecting sources of nutrition.
“If you feed CAPE to mice daily, their tumors will stop growing. After several weeks, if you stop the treatment, the tumors will begin to grow again at their original pace,” says researcher Richard B. Jones, Ph.D., assistant professor at the University of Chicago Medicine. “So it doesn’t kill the cancer, but it basically will indefinitely stop prostate cancer proliferation.”
In this study, CAPE was also effective at slowing the growth of human prostate tumors grafted into mice. Six weeks of treatment with the compound decreased tumor volume growth rate by half, but when CAPE treatment was stopped, tumor growth resumed its prior rate. The results suggested that CAPE stopped cell division rather than killing cancerous cells.
“It appears that CAPE basically stops the ability of prostate cancer cells to sense that there’s nutrition available,” Jones says. “They stop all of the molecular signatures that would suggest that nutrition exists, and the cells no longer have that proliferative response to nutrition.”