Curcumin, Gut Microbiota, and Neuroprotection.

Crispi Crispi,Di Meo Di Meo,Galderisi Galderisi,Peluso Peluso,Margarucci Margarucci

doi:10.3390/nu11102426

Abstract

Curcumin, a nontoxic, naturally occurring polyphenol, has been recently proposed for the management of neurodegenerative and neurological diseases. However, a discrepancy exists between the well-documented pharmacological activities that curcumin seems to possess in vivo and its poor aqueous solubility, bioavailability, and pharmacokinetic profiles that should limit any therapeutic effect. Thus, it is possible that curcumin could exert direct regulative effects primarily in the gastrointestinal tract, where high concentrations of curcumin are present after oral administration. Indeed, a new working hypothesis that could explain the neuroprotective role of curcumin despite its limited availability is that curcumin acts indirectly on the central nervous system by influencing the “microbiota–gut–brain axis”, a complex bidirectional system in which the microbiome and its composition represent a factor which preserves and determines brain “health”. Interestingly, curcumin and its metabolites might provide benefit by restoring dysbiosis of gut microbiome. Conversely, curcumin is subject to bacterial enzymatic modifications, forming pharmacologically more active metabolites than curcumin. These mutual interactions allow to keep proper individual physiologic functions and play a key role in neuroprotection.

Highlights

Over the last decades, the interest in herbal medicines has greatly increased since they can exert preventive effects against chronic and degenerative diseases including cancer
There are findings showing that polyphenols can exert their biological effects following chemical modifications performed by gut microbiota
This study reported that curcumin administration induced significant weight loss in ovariectomized rats, increasing the number of species of seven different bacterial genus: Serratia, Anaerotruncus, Shewanella, Pseudomonas, Papillibacter, Exiguobacterium, and Helicobacter

Summary

Introduction

The interest in herbal medicines has greatly increased since they can exert preventive effects against chronic and degenerative diseases including cancer These molecules play an important role in neuroprotection by modulating different cellular functions. There are findings showing that polyphenols can exert their biological effects following chemical modifications performed by gut microbiota. Specific biological properties often depend on bioactive metabolites produced by gut microbiota digestion [28]. In this regard, it is worthy to note that curcumin, after administration, accumulates in the gut where, after microbial digestion, it can be transformed into biologically active metabolites [29,30,31]. We discuss the curcumin–gut microbiota interplay that allows transforming dietary curcumin into bioactive derivatives and how these molecules can exert neuroprotective functions

Curcumin Metabolism

Biotransformation of Curcumin by Gut Microbiota

Curcumin Effects on Gut Microbiota

Curcumin and Gut Microbiota

Findings

Conclusions