Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/15/2008
Publication Date: 5/14/2008
Citation: Friedman, M., Levin, C.E., Lee, S., Lee, J., Ohnisi-Kameyama, M., Kozukue, N. 2008. Analysis by HPLC and LC/MS of Pungent Piperamides in Commercial Black,White, Green, and Red Whole and Ground Peppercorns.. Journal of Agricultural and Food Chemistry. 56(9):3028-3036. Interpretive Summary: The pepper plant produces pungent compounds called piperamides, secondary metabolites that are involved in the defense of the plant against invading phytopathogens including insects, bacteria, fungi, and viruses. These compounds also possess health-promoting properties including the ability to inactivate pathogenic microorganisms. As part of an effort to discover new and effective plant antimicrobials, we determined in a collaborative study with Korean and Japanese scientists the content and distribution of piperamides in 20 commercial ground peppers and peppercorns sold in the United States. Our data on the wide-ranging individual and total piperamide content of widely-consumed peppers will facilitate relating the composition of the ground peppers and peppercorns to their activities against foodborne pathogens and bacterial toxins and may also help consumers select pepper products with desirable piperamide content.
Technical Abstract: Pepper plants accumulate pungent bioactive alkaloids called piperamides. To facilitate studies in this area, HPLC and LC/MS methods were developed and used to measure the following piperamides in 10 commercial ground pepper products and in 10 black, white, green, and red commercial whole peppercorns piperanine; piperdardine, piperine, piperlonguminine, and piperettine. Structural identification of individual compounds in extracts was performed by associating the HPLC peak of each compound with the corresponding mass spectrum. The piperanine content of the peppers (in mg/g piperine equivalents), ranged from 0.3 for the ground white pepper to 1.4 in black peppercorns. The corresponding range for piperdardine was from 0.0 for seven samples to 1.8 in black peppercorns; for four isomeric piperines, from 0.7 for red to 128.6 in green peppercorns; for piperlonguminine, from 0 in red peppercorns to 1.0 in black peppercorns; and for piperyline, from 0.9 in ground black pepper to 5.9 for red peppercorn. Four well-separated stereoisomeric forms of piperettine with the same molecular weight were present in 19 peppers. The sums of the piperamides ranged from 6.6 for red to 152.5 for green peppercorns. In contrast to large differences in absolute concentrations among the peppers, the ratios of piperines to total piperamide were quite narrow, ranging from 0.76 for black to 0.90 for white peppercorns, with an average value of 0.84±0.04 (n=19). Thus, on average, the total piperamide content of the peppers consists of 84% piperines and 16% other piperamides. These results demonstrate the utility of the described extraction and analytical methods used to determine the wide-ranging individual and total piperamide content of widely-consumed peppers.