Polysaccharide from Plantago asiatica L. attenuates hyperglycemia, hyperlipidemia and affects colon microbiota in type 2 diabetic rats

Type 2 diabetes is a complex metabolic and endocrine disorder worldwide, which causes severe health and economic problems. The effects of polysaccharide from Plantago asiatica L. (PLP) on high-fat diet and streptozotocin-induced type 2 diabetic rats were examined. Administration of PLP caused significant decreases in the concentrations of blood glucose, insulin, total cholesterol, triglyceride, non-esterified fatty acid and maleic dialdehyde, and significant increases in the levels of high density lipoprotein-cholesterol and the activities of antioxidant enzymes compared with diabetic rats after 4 weeks’ treatment. The concentrations of short-chain fatty acids (SCFA) were significantly higher in the feces of diabetic rats after treatment with PLP. Moreover, colon bacterial diversity and abundance of bacteria, including Bacteroides vulgatus, Lactobacillus fermentum, Prevotella loescheii and Bacteroides vulgates were significantly increased by PLP treatment. These results indicated that the anti-diabetic effect of PLP in type 2 diabetic rats may be associated with regulation of gut microbiota and increased levels of SCFA.