The interaction between polyphenols and food proteins: prospects for diet therapy of metabolic syndrome and type 2 diabetes mellitus

The use of minor biologically active components of food (flavonoids) as functional food ingredients for foods for special dietary uses is a promising trend in prevention and treatment of carbohydrate and lipid metabolism disorders resulting from the metabolic syndrome and type 2 diabetes mellitus. Unlike the in vitro studies that are conducted mainly on cell cultures, the results of clinical studies may be influenced by low bioavailability of polyphenols. This fact makes it impossible to reach the beneficial effects of polyphenols in some cases. Thus, the problem of polyphenol bioavailability enhancement is the main direction in producing highly effective specialized anti-diabetic food products. In this review, the interaction between proteins and polyphenolic compounds is discussed from the viewpoint of the potential to protect polyphenols against degradation in the digestive tract, to increase their stability and pharmacological activity compared to those of the conventional compositions. The problems of interactions between polyphenols and food proteins, digestive enzymes and cell transporters in the gastrointestinal tract have not been sufficiently covered in Russian academic publications. The studies focused on the mechanisms of interactions between polyphenols and proteins, considering the corresponding structural changes are of interest for predicting possible changes in their bioavailability. Polyphenol binding to proteins is influenced by the primary structure of a protein macromolecule, the spatial distribution of amino acid residues responsible for polyphenol binding, and some other parameters characterizing the conditions of interactions.