Chemopreventive peptides are peptides that help prevent the onset or development of a disease such as cancer or diabetes. These peptides can either originate from natural sources, for example from soy or milk, from the design of peptide mimetics, or from peptide screens using synthetic peptides. It is thought that some of these peptides may function as modulators of the cell-cycle that regulates the production and function of proteins needed to advance cells through the replication cycle. In addition, there is now increased evidence that specific dietary pattern, foods and drinks, and other dietary substances can and do protect against cancer. More and more epidemiological studies suggest that food, nutrition and physical activity are important in the prevention and modification of the cancer process. Different types of food proteins and peptides that include plant protease inhibitors, lactoferrin, lactoferricin, lectins and lunasin appear to act as chemopreventive agents. Proteins and peptides are now considered as one group of nutraceuticals that show potential in preventing different stages of cancer including initiation, promotion and progression. Furthermore, some protease inhibitors found in plants such as legumes and soy beans have been found to be effective suppressors of carcinogenesis. Carcinogenesis is the process of initiating and promoting cancer. The Bowman-Birk inhibitor and the Kunitz trypsin inhibitors are among them. Presently the biological function of these compounds in carcinogenesis is mainly attributed to suppress invasion and metastasis of cancer cells, however, the mechanisms of action are still not fully known and further research is needed to fully elucidate them.
