Structural Features of a Dancong Tea Polysaccharide and Its Amelioration of Glucolipid Metabolic Disorders Associated with Gut Microbiota Modulation

A novel acidic polysaccharide, Dancong tea polysaccharide (DTP), was obtained from Dancong tea, and its structural characteristics and regulatory effects on glucolipid metabolism were investigated. With a molecular weight of 52 kDa, DTP is a pectic polysaccharide consisting mainly of a linear α-1,4-linked homogalacturonan backbone (72.7% galacturonic acid) with a methyl-esterification degree of 34.12%. In C57BL/6J mice fed a high-fat diet (HFD), administration of DTP effectively alleviated obesity, insulin resistance, dyslipidemia, and hepatic steatosis, which was accompanied by attenuated oxidative stress and inflammation. 16S rRNA gene sequencing demonstrated that DTP ameliorated gut dysbiosis through targeted regulation of specific taxa rather than a broad reversal at the phylum level. The medium dose of DTP reduced the abundance of obesity-associated genera (Allobaculum, Dubosiella), while high-dose DTP enriched beneficial Bifidobacterium species. Correlation analysis indicated that these microbial shifts were closely associated with the restoration of glucose and lipid homeostasis. Overall, our findings support the potential of DTP as a functional prebiotic ingredient for the management of metabolic diseases.