Broccoli and red chili peppers may help fight cancer by slowing the growth of cancerous tumor cells, U.S. researchers reported.

They may be especially helpful in hard-to-treat cancers such as pancreatic and ovarian cancer, the team at the University of Pittsburgh said.

"In our studies, we decided to look at two particular cancers -- ovarian and pancreatic -- with low survival rates, to ascertain the contribution of diet and nutrition to the development of these cancers," said Sanjay Srivastava, who led the study.

"We discovered that red chili pepper and broccoli appear to be effective inhibitors of the cancer process."

Speaking to a meeting of the American Association for Cancer Research in Anaheim, California, Srivastava said he and colleagues tested capsaicin, which makes peppers hot, against pancreatic cancer cells in a lab dish.

The compound caused the cancer cells to self-destruct in a process called apoptosis, while not affecting normal pancreatic cells.

"Our results demonstrate that capsaicin is a potent anticancer agent, induces apoptosis in cancer cells and produces no significant damage to normal pancreatic cells, indicating its potential use as a novel chemotherapeutic agent for pancreatic cancer," Srivastava said.

His team also examined phenethyl isothiocyanate (PEITC), a constituent of cruciferous vegetables such as broccoli, on ovarian cancer cells.

PEITC interfered with a protein called epidermal growth factor receptor, which is involved in the growth of ovarian and other cancerous tumors.

The studies may help explain why people who eat large amounts of fruits and vegetables have a lower risk of cancer, Srivastava said.