Bioactive peptides human studies

Observations of lower rates of certain chronic diseases in several Asian countries compared to the United States served as the impetus for studies that were conducted to identify the factors that were accountable (Tham et al., 1998). Consumption of soy is one factor that correlated with these lower rates. From this information, much research focused on soy protein and accompanying bioactive compounds with regard to elucidating mechanisms associated with risk markers for chronic disease, particularly CVD. The combination of macro- (protein, fiber, fat) and micro-components (isoflavones, saponins, tocopherols) as part of many traditional soy foods may underlie the epidemiological observations associated with soy intake. A body of cell culture and animal data shows potential health effects of a multitude of bioactive components in soy (i.e., saponins, phenolic acids, peptides). However, studies determining the independent effects of saponins, phenolic acids, and protease inhibitors in humans are yet to be conducted. 

Table 3.3 Human studies on hypotensive effects of milk-based products containing bioactive peptides IPP and VPP... 

The generation of bioactive peptides during microbial fermentation of milk and soybean is now well documented. Such peptides have been shown to exert several bioactivities that have been demonstrated in animal and human studies. Potential health benefits associated with bioactive peptides have been subject of growing commercial interest, especially in the context of functional foods. Milk proteins are the best-known source of bioactive peptides, but peptides with similar properties have also been identified in soybean. Anti-hypertensive peptides derived from milk proteins have already found commercial applications both in Japan and in Europe. This trend is likely to continue, although controversial results in cUnical trials and global differences in health claim regulations call for further scientific and clinical research. 

To our knowledge, the only report of the application of DFM and TFM to peptides has been on the effect of these replacements on the chemotactic activity of the tripeptide formyl-Met-Leu-Phe [19]. The methionine residue in this peptide has been shown to be critical to the bioactivity of the peptide, as replacement by other methionine analogues such as ethionine, norleucine,. S -me thy I cysteine,. S -e thy I cysteine or 2-aminoheptanoic acid results in -4-fold to 264-fold decrease in chemotactic activity in human and rabbit neutrophil migration assays [22-24], Interestingly the DFM- and TFM-containing peptides were found to enhance by -10-fold the directed migration responses of human blood neutrophils. Studies of the effects of DFM and TFM on the bioactivity of other peptides would certainly be worthy of further investigation. 

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