Edgeworthia gardneri (Wall.) Meisn. water extract improves diabetes and modulates gut microbiota

Ethnopharmacological relevance: In Chinese folk medicine, the flower of Edgeworthia gardneri (Wall.) Meisn. is used to treat various metabolic diseases, such as hyperglycemia, hypertension, and hyperlipidemia. Aim of the study: This study aimed to explore the antidiabetes potential of the flower of E. gardneri and investigate whether it can benefit the entire gut bacteria community. Materials and methods: Chemical constituents of the extract were analyzed by UHPLC-Q Exactive Mass Spectrometer (UHPLC-QE-MS). The antidiabetes effect of the water extract (WAE) of the flower of E. gardneri was evaluated in diabetic mice induced by high-fat diet (HFD) and streptozotocin (STZ) (six groups, n = 8) daily at doses of 1, 2, and 3 g/kg for 4 weeks. The gut microbiota was analyzed using high-throughput 16S rRNA gene sequencing. Short-chain fatty acids (SCFAs) in the fecal were also investigated. Results: UHPLC-QE-MS analysis identified 29 compounds, including five alkaloids, six coumarins, four flavonoids, 11 organic acids, and three additional compounds, in the WAE. Results showed that the high dose of WAE considerably decreased the blood glucose level by 30.0%. Furthermore, E. gardneri significantly ameliorated insulin resistance and lipid metabolism dysfunction and repaired islet, hepatic, and white fat and colon histology in diabetic mice. Diabetic mice treated with WAE showed apparent changes in the structure and composition of the gut microbiota. WAE reversed the changes in Clostridiales, Lachnospiraceae, S24-7, Rikenellaceae, and Dorea in diabetic mice. The correlation analysis indicated that key OTUs were related to diabetes indices. The amounts of SCFAs, including acetic, propionic, and valeric acids, were significantly high in WAE-treated diabetic groups. Conclusions: E. gardneri treatment improved the glucose metabolism and reshaped the unbalanced gut micro biota of diabetic mice. Our study provides evidence for application of E. gardneri to treatment of diabetes mellitus.