Flavonoid-protein interactions

Naturally occurring flavonoids are ubiquitous in all parts of plants where they display a huge structural diversity based on different C rings (Figure 9.1), aglycone substitutions by OH and OMe groups, and glycosidation and acylation patterns. In addition to their important biological roles in plants and plant-insect interactions, flavonoids have been thoroughly investigated during the last two decades because of their possible health effects in man via a diet rich in plant products.1,2 Indeed, flavonoids, especially flavanols, flavonols, and anthocyanins, are relatively abundant in human diet, partially bioavailable, and possibly involved in still incompletely understood mechanisms related to the prevention of cancers, cardiovascular diseases, and neurodegenerescence. However, whatever these mechanisms may be, most of them must be related to at least one of the two fundamental properties of flavonoids: their reducing ability (antioxidant properties by electron or H-atom donation) and their ability to interact with proteins.