Urolithin B protects mice from diet-induced obesity, insulin resistance, and intestinal inflammation by regulating gut microbiota composition.

The increasing prevalence of obesity and type 2 diabetes (T2D) signifies the failure of conventional treatments for these diseases. The gut microbiota has been proposed as a key player in the pathophysiology of diet-induced T2D. Urolithin B (Uro B), a gut microbiota-derived polyphenol metabolite, exerts several beneficial health effects. In this study, we investigated the metabolic effects of Uro B on high-fat/high-sucrose (HFHS)-fed mice and determined whether its antidiabetic effects are related to the modulation of the gut microbiota. C57BL/6J mice were fed either a chow or HFHS diet. HFHS-fed mice were administered daily with either a vehicle (water) or different doses of Uro B (100 or 200 mg kg) for eight weeks. The composition of the gut microbiota was assessed by 16S rRNA sequencing. The results showed that Uro B treatment reduced HFHS-induced weight gain and visceral obesity and decreased liver weight and triglyceride accumulation associated with blunted hepatic oxidative stress and inflammation. Furthermore, Uro B administration improved insulin sensitivity as revealed by improved insulin tolerance, a lower homeostasis model assessment of insulin resistance, and decreased glucose-induced hyperinsulinemia during the oral glucose tolerance test. Uro B treatment was found to lower the intestinal triglyceride content and alleviate intestinal inflammation and oxidative stress. Remarkably, Uro B treatment markedly increased the proportion of the mucin-degrading bacterium in metagenomic samples. In conclusion, Uro B exerts beneficial metabolic effects by alleviating HFHS diet-induced features of metabolic syndrome, which is associated with a proportional increase in the population of spp.