Multi-scale structural profiling and microbiota-linked metabolic benefits of Golden Flower Tibetan Tea polysaccharide components in high-fat diet-induced obese mice

Golden Flower Tibetan Tea polysaccharide components (GFTTPs) are polysaccharide-rich matrices generated during standardised “flowering” fermentation and may co-exist with tea pigments, phenolics and proteins. This study aimed to characterise GFTTPs and evaluate their metabolic effects in high-fat diet (HFD)-induced obese mice. GFTTPs were prepared by hot-water extraction, ethanol precipitation and dialysis, followed by compositional analysis and structural fingerprinting using FTIR, XRD, SEM, TGA/DTG and Py-GC/MS. GFTTPs exhibited an acidic, GalUA-rich composition with a medium-to-low molecular-weight distribution, predominantly amorphous organisation and an apparent porous morphology after freeze-drying. In vitro, GFTTPs showed concentration-dependent DPPH and ABTS radical-scavenging activities and FRAP reducing power, while α-glucosidase inhibition was modest compared with acarbose. In HFD-induced obese mice, 6-week administration of GFTTPs (600 mg kg −1 day −1 ) improved glucose tolerance and insulin responsiveness, reduced OGTT and IPITT AUCs, and improved fasting insulin-derived indices. GFTTPs also alleviated dyslipidaemia and transaminase elevation, accompanied by improved liver and pancreatic histopathology. Inflammatory and redox responses were partly restored, as shown by reduced TNF-α, increased IL-4, and recovered serum CAT and SOD activities, whereas IL-6 and MDA were less responsive. Microbiota and SCFA analyses indicated partial reversal of HFD-associated dysbiosis and SCFA remodelling, particularly increases in valerate and butyrate. Integrated correlation patterns suggested association-based links among gut microbiota, SCFAs and host metabolic phenotypes. Overall, GFTTPs provide a composition- and structure-characterised polysaccharide-rich tea-derived matrix with potential functional-food applications for metabolic health management.