The plant natural products known as polyphenols are found at micronutrient levels in fruits, vegetables, and plant-based beverages
such as wine, tea, coffee and cocoa. Consumption of a fruit- and vegetable-rich diet, the “Mediterranean diet”, has been epidemiologically
related to health benefits especially for chronic diseases including diabetes, cardiovascular disease, and Alzheimer’s disease.
The abundance of polyphenols in plant-rich diets, and the potent bioactivities of polyphenols, provide indirect evidence for a role for
polyphenols in maintaining good health. However, molecular mechanisms for therapeutic or preventative activity have not been demonstrated
in vivo. We summarize the chemical classes of natural polyphenols, their bioactivities and bioavailability and metabolism. Because
many polyphenols bind protein, we focus on the potential of protein binding to mediate the health-related effects of polyphenols.
We discuss interactions with plasma proteins as the first target organ past the digestive tract for these orally-ingested compounds.