A University of Wisconsin School of Medicine and Public Health research team has found a chemical compound common in many fruits, lupeol, which proved promising in preventing prostate cancer, the second-leading cause of cancer death among men.

Lupeol, an antioxidant found in some fruits, including strawberries, mangoes and figs, may have the ability to kill existing cancer cells and prevent new tumors from initiating or progressing.

"The cancer process takes about 20 years," dermatology professor Hasan Mukhtar said. "If we can slow it down, the process might take 30 or 40 years. This is a goal I'm working on."

According to Mukhtar, lengthening the cancer process allows more time for prevention and treatment.

"Prostate cancer is the most commonly diagnosed malignancy in men and accounts for almost 230,000 cancer cases each year," UW urologist David Jarrard said. "Mukhtar presents interesting information that may be found as beneficial for other cancers."

Mukhtar and his research team observed the effects of lupeol in "nude" mice, those that accept foreign disease. The team injected the mice with human prostate-cancer cells and investigated the results of those given lupeol alone and lupeol in conjunction with a laboratory-produced antibody.

Mice injected with lupeol alone showed a substantial slowing of the cancer process, and those that received both showed even greater results.

Mukhtar's goal was to define the active agents and understand the mechanics of the chemical.

"We found that lupeol significantly slows down carcinogenesis," Mukhtar said.

Mukhtar added that he strongly believes these agents inhibit cancer growth in other tissues, including the prostate.

Lupeol may be effective in preventing prostate cancer by localizing the cancer. Biochemical pathways become defective in the process of cancer and, if lupeol can repair these pathways, the cancer cannot spread.

"So long as the cancer is localized, it cannot spread," Mukhtar said. "The problem with cancer is that it escapes and deposits in other tissues, multiplying. If the cancer is localized, it can then be surgically removed."

Mukhtar said his ultimate goal is to develop a cocktail fruit platter that may slow down the cancer process.

"If people do not consume fruit, we can put the agent into a capsule," Mukhtar said. "Just like one-a-day pills, it could be a one-a-day cancer preventative pill."

Mukhtar's previous study investigated the effects of pomegranate juice on the prevention of prostate cancer. He found that the juice, which contains more antioxidants than red wine or green tea, also inhibits prostate carcinogenesis.

In contrast to green tea, which may prevent breast, lung and prostate cancer, among others, pomegranate juice has only been shown to slow the progression of prostate cancer.

This study prompted Mukhtar to question whether there are other agents that can achieve the same effects.

The study of lupeol was reported in the Dec. 1 edition of Cancer Research.