University of Wisconsin researchers reported this summer that lupeol, a triterpene present in the oils and resin of many plants, caused cells from human pancreas tumours to die when tested in the laboratory.
The same team, led by Professor Hasan Mukhtar, has now found that the compound also kills prostate cancer cells from humans injected into mice.
Writing in the 1 December issue of Cancer Research (vol 65, issue 23, pp11203-13), the researchers reported that mice fed with lupeol showed significantly slower growth of cancer tumours and increased death of prostate cancer cells.
After examining the receptor targets for this cell death, they found that lupeol specifically caused a significant increase in the expression of Fas receptor.
Furthermore, when given with an anti-Fas monoclonal antibody, the substances had an even greater impact against the cancer, suggesting a synergistic effect.
"The results of the present study suggest that lupeol may have a potential to be an effective agent against prostate cancer," concluded the researchers.
The compound is one of many found in fruits and vegetables that appears to fight prostate cancer. The cancer is the second leading cause of death from cancer in European and American men, following lung cancer.