Tumor cell growth inhibition is correlated with levels of capsaicin present in hot peppers.

There are conflicting reports with regard to the value of hot peppers and their primary active component compound, capsaicin, as an anticancer agent. We tested extracts from a number of peppers and found them to induce significant growth arrest and apoptosis in human breast and leukemia cancer cell lines in vitro with no significant effect on normal breast epithelial cells. Further, cell growth inhibition and cell death induction were positively correlated with the capsaicin content (based on the Scoville scale) of the peppers, and the hydroxyl radical scavenger thiourea significantly inhibited the activity of pepper extracts, suggesting the involvement of free radicals in mediating the biological activity of the pepper extracts. These results suggest a potential use of pepper extracts as anticancer agents.