Immunomodulatory; Anti-inflammatory/antioxidant Effects of Polyphenols: A Comparative Review on the Parental Compounds and Their Metabolites

Polyphenols are a big family of phytochemicals that includes a wide range of natural substances with various biological activities. Amongst these activities, the immunomodulatory property has significant importance due to the central and vital roles of the immune system in the human body. The biological activities of polyphenols depend crucially on the chemical structure and the biotransformation undergone in the body. The glycosylation state of polyphenols and its diversity have a significant impact on the immunomodulatory activity, while there is a lack of a comprehensive review paper in this concept. Hence, we aimed to review the body of literature to light the way for effective modulation of the immune system function using dietary polyphenols. However, due to the significant diversity in the structure and biotransformation of polyphenols, it is hard to draw a general pattern in this regard. The sugar moiety, type, position, and extent of glycosylation determine the antioxidant, anti-inflammatory, and generally the immunomodulatory activities of polyphenols. In conclusion, this study provides a new comparative approach regarding the immunomodulatory activities of polyphenols versus their metabolites. Moreover, we conclude that polyphenols can modulate the immune system, while each polyphenol has its structural relevance and should be assessed case by case.

Automated summary

This study investigates the immunomodulatory activities of polyphenols and highlights the importance of their chemical structure and biotransformation. The type, position, and extent of glycosylation significantly impact the immunomodulatory activities of polyphenols. Each polyphenol has its own structural relevance and should be individually assessed for their effects on the immune system.