Gut microbiota as a driver of the interindividual variability of cardiometabolic effects from tea polyphenols.

Tea polyphenols have been extensively studied for their preventive properties against cardiometabolic diseases. Nevertheless, the evidence of these effects from human intervention studies is not always consistent, mainly because of a large interindividual variability. The bioavailability of tea polyphenols is low, and metabolism of tea polyphenols highly depends on individual gut microbiota. The accompanying reciprocal relationship between tea polyphenols and gut microbiota may result in alterations in the cardiometabolic effects, however, the underlying mechanism of which is little explored. This review summarizes tea polyphenols-microbiota interaction and its contribution to interindividual variability in cardiometabolic effects. Currently, only a few bacteria that can biodegrade tea polyphenols have been identified and generated metabolites and their bioactivities in metabolic pathways are not fully elucidated. A deeper understanding of the role of complex interaction necessitates fully individualized data, the ntegration of multiple-omics platforms and development of polyphenol-centered databases. Knowledge of this microbial contribution will enable the functional stratification of individuals in the gut microbiota profile (metabotypes) to clarify interindividual variability in the health effects of tea polyphenols. This could be used to predict individual responses to tea polyphenols consumption, hence bringing us closer to personalized nutrition with optimal dose and additional supplementation of specific microorganisms.

Hypoglycemic mechanism of polysaccharide from Cyclocarya paliurus leaves in type 2 diabetic rats by gut microbiota and host metabolism alteration.

Diabetes mellitus is a serious threat to human health. Cyclocarya paliurus (Batal.) Iljinskaja (C.paliurus) is one of the traditional herbal medicine and food in China for treating type 2 diabetes, and the C. paliurus polysaccharides (CP) were found to be one of its major functional constituents. This research aimed at investigating the hypoglycemic mechanism for CP. It was found that CP markedly attenuated the symptoms of diabetes, and inhibited the protein expression of Bax, improved the expression of Bcl-2 in pancreas of diabetic rats, normalized hormones secretion and controlled the inflammation which contributed to the regeneration of pancreatic ß-cell and insulin resistance. CP treatment increased the beneficial bacteria genus Ruminococcaceae UCG-005 which was reported to be a key genus for protecting against diabetes, and the fecal short-chain fatty acids levels were elevated. Uric metabolites analysis showed that CP treatment helped to protect with the diabetes by seven significantly improved pathways closely with the nutrition metabolism (amino acids and purine) and energy metabolism (TCA cycle), which could help to build up the intestinal epithelial cell defense for the inflammation associated with the diabetes. Our study highlights the specific mechanism of prebiotics to attenuate diabetes through multi-path of gut microbiota and host metabolism.

Isolation, structure, and bioactivities of polysaccharides from Cyclocarya paliurus (Batal.) Iljinskaja.

Cyclocarya paliurus (Batal.) Iljinskaja, a well-known edible and medicinal plant, has been widely used in China as a traditional medicine for treating hypertension and diabetes. C. paliurus possesses various bioactivities, such as antihyperglycemic, antihyperlipidemic, antihypertensive, anticancer, antifatigue, antioxidation, antimicrobial, colon health-promoting, and immunological activities. Polysaccharides, as natural macromolecules with various biological activities, are considered to be the main effective components in C. paliurus. Here, we summarize studies of polysaccharides from C. paliurus over the past 20 years, including extraction and purification processes, structure, and bioactivities.