Interaction of proteins with grapefruit furanocoumarins

Authors: Myung, Kyung; Manthey, John

Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: 11/1/2009
Publication Date: 3/19/2010
Citation: Myung, K., Manthey, J.A. 2009. Interaction of proteins with grapefruit furanocoumarins. Proceedings of Florida State Horticultural Society. 122:319-321.

Interpretive Summary: From our previous study, we observed that furanocoumarins in grapefruit juice bind to foods. In this study, we used different macromolecules in corn and salmon to identify components interacting with grapefruit furanocoumarins. We found that proteins interacted with furanocoumarins in grapefruit juice but carbohydrates and lipids did not. These results would be useful in understanding the interaction and for potential industrial application for the production of furanocoumarin-reduced grapefruit juice.

Technical Abstract: Grapefruit or Grapefruit juice (GFJ) interferes with the cytochrome P450 3A4 activity responsible for metabolizing certain medications. This interference is referred to as the “grapefruit-drug interaction”. Previously, we observed that a number of foods sequester furanocoumarins (FCs) in GFJ. In this study, interactions between macromolecules and GFJ FCs were investigated to determine which food components are responsible for the previously found sequestration. When we removed lipids from corn and salmon by extractions with organic solvents, the resulting defatted corn and salmon powders still sequestered FCs in GFJ. Further binding experiments with cellulose, pectin, and purified fungal cell wall showed that these carbohydrates did not interact with GFJ FCs. In contrast, isolated proteins from salmon differentially interacted with GFJ FCs, in which tighter interaction with BM occurred, compared to DHB. Overall, our results suggest that the previously observed sequestration of GFJ FCs by foods is likely due to protein-FC interactions.