"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 Dr Sanjay Srivastava, lead investigator and assistant professor at the University of Pittsburgh School of Medicine's department of pharmacology.
The findings were presented this week at the annual meeting of the studies at the annual meeting of the American Association for Cancer Research in Anaheim, CA.
"We discovered that red chili pepper and broccoli appear to be effective inhibitors of the cancer process," said Srivastava.
In the first study, the researchers treated human pancreatic cells with capsaicin, the crystalline alkaloid found in chili peppers that gives them their fiery taste and which is already thought to have antioxidant and anti-inflammatory properties.
The capsaicin was found to disrupt the cells' mitochondrial function, resulting in the release of a protein called cytochrome c, which induced apoptosis (programmed cell death) in the cancerous cells. The normal pancreatic cells were not affected.
From these results, Srivastava concluded that capsaicin shows promise as a novel chemotherapeutic agent for pancreatic cancer.
For the second study, ovarian cancer cells were exposed to phenethyl isothiocyanate (PEITC), a compound found in broccoli and other cruciferous vegetables, for 24 hours. The concentration of PEITC used was consistent with the amount that may be achieved through dietary intake.
Since ovarian cancer is often not detected until it has already reached an advanced stage, it is notoriously difficult to treat with success.
But this study showed that PEITC may have useful therapeutic benefits, as it was found to result in "significant inhibition" of the protein expression of epidermal growth factor receptor (EGFR), which plays a role in the growth of ovarian cancer.
The PEITC was also found to inhibited the activation of akt, another protein that is responsible for protecting cancer cells against apoptosis.
In the past a good deal of research has also investigated sulphoraphane glucisinolate, an antioxidant thought to have anti-cancer and heart health benefits that is occurs abundantly in broccoli and other cruciferous vegetables such as Brussels sprouts and kale.
The latest study into the effects of SGS indicates that it may help reduce cholesterol levels in a matter of days.
Carried out at the Tokyo University of Agriculture and The Japan Institute for the Control of Aging and presented at Natural Products Expo West last month, it indicated that individuals who ate 3 1/2 ounces of broccoli sprouts every day for a week reduced their overall cholesterol level and increased levels of HDL or "good" cholesterol.
"This study is significant because it underscores the powerful preventive role that we think sulforaphane plays in assisting the body to help fend off a variety of diseases," said Dr Jed Fahey, Johns Hopkins School of Medicine. "There are human studies underway across the globe that are examining the diverse disease fighting potential of this compound."
The discovery of sulphoaphane at John Hopkins in 1992 led a company called Brassica Protection Products to market patented concentrated forms of broccoli sprouts - three-day-old broccoli plants said to provide 20 times the concentration of sulphoraphane glucosinolate as found in adult broccoli and currently sold in the US, Japan and New Zealand.