Polysaccharide from <i>Rosa roxburghii</i> Tratt Fruit Attenuates Hyperglycemia and Hyperlipidemia and Regulates Colon Microbiota in Diabetic <i>db/db</i> Mice

Abstract

This study was aimed at investigating the hypoglycemic and hypolipidemic effects of a polysaccharide (RTFP) isolated from <i>Rosa roxburghii</i> Tratt fruit on type-2 diabetic <i>db/db</i> mice. The results indicated that the oral administration of RTFP could significantly decrease the body weight, fat, and liver hypertrophy and the levels of fasting blood glucose, serum insulin, and serum lipids of the <i>db/db</i> mice. Histopathological observation showed that RTFP could effectively protect the pancreas, liver, and epididymal fat against damage and dysfunction. Real-time quantitative polymerase chain reaction analysis confirmed that the gene expression levels of peroxisome proliferator-activated receptors-γ (<i>PPAR-γ</i>), sterol regulatory element-binding protein-1 (<i>SREBP-1c</i>), acetyl-CoA carboxylase-1 (<i>ACC-1</i>), fatty acid synthase (<i>FAS</i>), and glucose-6-phosphatase (<i>G6 Pase</i>) were significantly down-regulated in the liver of <i>db/db</i> mice after treatment with RTFP. Moreover, RTFP treatment reversed gut dysbiosis by lowering the <i>Firmicutes</i>-to-<i>Bacteroidetes</i> ratio and enhancing the relative abundances of beneficial bacteria including <i>Bacteroidaceae</i>, <i>Bacteroidaceae</i> S24-7 group, and <i>Lactobacillaceae</i>. These findings suggest that RTFP can be used as a promising functional supplement for the prevention and treatment of type-2 diabetes mellitus.