Detection and visualization of food-derived polyphenols by matrix-assisted laser desorption/ionization mass spectrometry imaging

Food-derived polyphenols have health benefits owing to their ability to prevent some diseases. Knowledge of their bioavailabilities and metabolism is important for understanding the mechanisms underlying their benefits. Thus, mass spectrometry (MS)-based analytical techniques, such as liquid chromatography-MS (LC-MS), that are capable of highly sensitive and simultaneous detection of absorbed polyphenols and their metabolites are essential tools in this field. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging is currently used in biological sciences for visualizing the spatial information of various compounds, such as peptides, proteins, lipids, drugs, and food compounds, in various biological tissues. However, the application of MALDI-MS imaging to polyphenols is challenging owing to the lack of appropriate matrix reagents for visualizing (or detecting) polyphenols absorbed in target biological tissues. This review highlights the development of the MALDI-MS imaging technique for the detection and visualization of food-derived polyphenols. First, the development of new matrices and matrix additives for the detection and visualization of polyphenols is discussed, followed by their introduction to inhibitor-aided MALDI-MS imaging for the elucidation of intestinal absorption routes and the metabolic behaviors of polyphenols. The MALDI-MS imaging technique shows great potential as a novel analytical tool for elucidating the bioavailabilities of food-derived polyphenols.