Impact of various factors on pharmacokinetics of bioactive polyphenols: an overview

Several epidemiological studies throughout the years have suggested that polyphenols from fruits and vegetables promote health and reduce the risk of certain chronic and neurodegenerative diseases. Yet, it has been proved to be extremely difficult to quantitatively establish the benefit afforded by polyphenols, principally due to the limited understanding of the extent of its absorption and metabolic fate. Pharmacokinetics includes the study of the mechanisms of absorption and distribution of an ingested polyphenol, its chemical changes in the body (e.g. by metabolic enzymes), and the effects and routes of excretion of the metabolites. In recent years, there have been major advances in our knowledge of polyphenol absorption and metabolism, and it is apparent that most classes of polyphenols are sufficiently absorbed to have the potential to exert biological effects. The pharmacokinetics of polyphenols includes the same steps as those for orally ingested drugs (LADME) and faces some of the same challenges, including transporters and enzymes. However, unraveling the bioavailability of polyphenols is even more challenging than with drugs, since many other factors, such as the variety in the chemical structure, the food matrix and the gut microbiota, can affect bioavailability of polyphenols during digestion. This review focuses on the most relevant factors that influence polyphenol pharmacokinetics, and also on the most recent technological strategies developed to overcome the poor bioavailability of phenolic compounds and thus increase their potential for greater health benefits.