Polysaccharide from Rosa roxburghii Tratt fruit attenuates hyperglycemia, hyperlipidemia and regulates colon microbiota in diabetic db/db mice.

This study was aimed to investigate the hypoglycemic and hypolipidemic effects of a polysaccharide (RTFP) isolated from Rosa roxburghii Tratt fruit on type 2 diabetic db/db mice. The results indicated that oral administration of RTFP could significantly decrease the body weight, fat and liver hypertrophy, the levels of fasting blood glucose, serum insulin and serum lipids of the db/db mice. Histopathological observation showed that RTFP could effectively protect the pancreas, liver and epididymal fat against damage and dysfunction. Real-time quantitative PCR analysis confirmed that the gene expression levels of peroxisome proliferator-activated receptors-γ (PPAR-γ), sterol regulatory element-binding protein-1 (SREBP-1c), acetyl-CoA carboxylase-1 (ACC-1), fatty acid synthase (FAS) and glucose-6-phosphatase (G6Pase) were significantly down-regulated in the liver of db/db mice after treatment with RTFP. Moreover, RTFP treatment reversed gut dysbiosis by lowering the Firmicutes-to-Bacteroidetes ratio and enhancing the relative abundances of beneficial bacteria including Bacteroidaceae, Bacteroidaceae S24-7 group and Lactobacillaceae. These findings suggested that RTFP can be used as a promising functional supplement for the prevention and treatment of type 2 diabetes mellitus.