Beneficial effects of polysaccharide-rich extracts from Apocynum venetum leaves on hypoglycemic and gut microbiota in type 2 diabetic mice.

Diabetes is one of the most concerned metabolic diseases worldwide and threaten public health. In the present work, two polysaccharide-rich extracts from Apocynum venetum leaves were extracted using distilled water and alkaline solution (0.05 M NaOH), and fully characterized. Hypoglycemic and hypolipidemic effects of two polysaccharide-rich extracts on high-fat diet and streptozocin-induced type 2 diabetic mice were investigated. Treatment of alkaline extracted polysaccharide-rich products significantly decreased the levels of fasting blood glucose, serum insulin, glycated serum protein, as well as serum lipids profiles including total cholesterol, triacylglycerols, low-density lipoprotein cholesterol, and nonesterified fatty acid. Meanwhile, the reduced glycogen contents in liver were prominently improved, and the oxidative damage were markedly ameliorated by alkaline extracted polysaccharide products in diabetic mice. Furthermore, both polysaccharide-rich extracts could reverse the gut microbiota dysbiosis in diabetic mice by increasing the abundance of genera Odoribacter, Anaeroplasma, Parasutterella, and Muribaculum; while by decreasing the abundance of genera Enterococcus, Klebsiella, and Aerococcus. This study provides new sights for exploitation of Apocynum venetum extracts as a promising anti-diabetic nutraceutical for the treatment of type 2 diabetes and metabolic syndrome.