Gut microbiota, probiotics and phytochemicals

The human gut is populated by an array of bacterial species with a marked effect on the nutritional and health status of the host. Phytochemicals are bioactive non-nutrient plant compounds, which have raised interest because of their potential effects as antioxidants, antiestrogenics, anti-inflammatory, immunomodulatory, and anticarcinogenics. Many phytochemicals are present in plant foods as glycosides or other conjugates and need to be hydrolyzed in order to be absorbed. Gut bacteria can hydrolyze glycosides, glucuronides, sulfates, amides and esters. They also carry out reduction, ring-cleavage, demethylation and dehydroxylation reactions. The hydrolysis of glycosides and glucuronides typically results in metabolites that are more biologically active than the parent compounds. Phytochemicals and their metabolic products may also inhibit pathogenic bacteria while stimulate the growth of beneficial bacteria, exerting prebiotic-like effects. Therefore, the intestinal microbiota is both a target for nutritional intervention and a factor influencing the biological activity of other food compounds acquired orally.Probiotic lactobacilli and bifidobacteria, bear several glycosyl-hydrolases and can contribute to release the aglycones from glycoconjugated phytochemicals.

The significance of this review is to focuses on the complex relationship between Phytochemicals phyto-metabolites and gut microbiota and the consequences of this on human metabolic homeostasis.