Abstract

Obesity is a complex multifactorial disease associated with chronic low grade inflammation, gut microbiota dysbiosis, and impaired gut-brain communication. Oligomeric procyanidins from grape seed extracts (GSE) are promising prebiotic candidates, capable of modulating host metabolism through interactions with the gut microbiota. C57Bl/6J male mice were rendered obese by feeding them a high fat, ;sucrose diet and were orally administered GSE at a dose of 1or 2 g/kg/day for 12 weeks. We assessed body weight, adiposity, glucose tolerance, insulin sensitivity, circulating hormones, brain homeostasis markers, colonic and liver gene expression, 16S rRNA gene sequencing of the gut microbiota profiles, and untargeted cecal metabolomics. GSE reduced body weight gain, visceral adiposity, adipocyte hypertrophy, and improved oral glucose tolerance and insulin sensitivity. It normalized circulating lipid and glucose levels and lowered fasting insulin and leptin while increasing endogenous GLP1. Hepatic gene expression analysis revealed a dose-dependent restoration of antioxidant defenses (SOD, CAT) and lipogenic transcription factors (SREBP, ChREBP). In the colon, GSE attenuated pro-inflammatory IL6 cytokine expression and strikingly upregulated GLP1 and GLP1 receptor expression. Microbiota analysis revealed a profound, dose-dependent remodeling of gut microbiota composition and diversity, with an expansion of health-associated taxa, such as Akkermansia muciniphila. Brain analyses revealed restoration of NAA and BDNF levels together with markers consistent with improved mitochondrial function. Cecal metabolomics revealed normalization of secondary bile acid metabolism, restoration of arginine bioavailability, and reduction in the accumulation of L-DOPA and spermidine. An oligomeric procyanidin rich grape seed extract acts as a multitarget prebiotic that alleviates diet induced obesity and is associated with coordinated restoration of gut microbiota composition, GLP-1 signaling, and gut brain and gut-liver communication pathways. Convergent dose dependent effects on Akkermansia muciniphila abundance, GLP 1, NAA, and BDNF identify key mechanisms underlying its metabolic benefits.