Wheat Bran Polyphenols Modulate Gut Microbiota and Liver Metabolomics in High-Fat Diet-Induced Obese Rats

Objectives: Numerous studies have indicated that whole grains may facilitate weight loss and lipid abatement, although the precise mechanisms remain unclear. The aim of this study is to investigate the potential beneficial effects of wheat bran polyphenols (WBP) in promoting weight loss and reducing lipids in rats through analysis of the gut microbiota and metabolomics. Methods: Eighty Sprague-Dawley rats, 6 weeks old, with an equal gender distribution, were adaptively raised for one week. Ten rats were randomly selected as the control group (C) and fed with basic feed, and the rest seventy rats were fed a high-fat diet to induce obesity. After 14 weeks, fifty obese rats were subdivided into five groups: model group (M), positive drug betaine (B, 0.10 g/kg) group, and WBP low (WBP -L, 1.50g/kg), medium (WBP -M, 3.00 g/kg), and high (WBP -H, 6.00 g/kg) dose groups, and the rats were administered 5.0 ml/kg daily by gavage for 9 weeks. 16S rDNA sequencing was used to analyze the cecal microbiota structure, and ultrahigh-performance liquid chromatograph Q extractive mass spectrometry (UHPLC-QE-MS) non-target metabolomics was used to screen differential metabolites in liver. Results: The results showed that WBP can reduce the food efficiency ratio of obese rats and inhibit weight gain. WBP can also significantly reduce the levels of serum lipids TG, TC, HDL-C, and LDL-C in obese rats. Hepatic metabolomic analysis shows that the important differential metabolites between WBP and M groups are Glycyrrhizaisoflavone B, Diethyl dicarbonate, and Leucyl-Asparagine, and the important differential metabolic pathways are Nicotinate and nicotinamide metabolism and Purine metabolism. WBP restores the imbalance of gut microbiota by increasing the abundance of Allobaculum, Phascolarctobacterium, and Blautia, and decreasing the abundance of Alistipes and Alloprevotella. Conclusions: WBP can reduce the degree of obesity in simple obesity rats, lower serum lipid levels, improve the intestinal microbiota and liver metabolic products, thereby aiding in weight loss and reducing lipids. WBP could promoting weight loss and reducing blood lipids in rats by altering the liver metabolites and gut microbiota composition. Funding Sources: This research was funded by the Natural Science Foundation of Xinjiang Uygur Autonomous Region (General Program) (2021D01A139).