A water-soluble polysaccharide from finger citron ameliorates diabetes mellitus via gut microbiota-GLP-1 pathway in high-fat diet and streptozotocin-induced diabetic mice

FCP-2-1, a water-soluble polysaccharide isolated and purified from Finger Citron, demonstrated hypoglycemic effect in vitro in our previous study. However, its antidiabetic effect and underlying mechanism in vivo remain to be elucidated. In this study, the antidiabetic effect of FCP-2-1 and its effects on the gut microbiota, short-chain fatty acids (SCFAs), and glucagon-like peptide-1 (GLP-1) in high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic mice were investigated. The results showed that FCP-2-1 could significantly alleviate diabetic symptoms in diabetic mice, restore the balance of the gut microbiota, and increase the content of acetic acid and propionic acid. In particular, FCP-2-1 was found to be able to promote the secretion of GLP-1, a new therapeutic target for diabetes. Moreover, propionic acid and FCP-2-1 were able to promote GLP-1 secretion in NCI-H716 cells, suggesting that FCP-2-1 could stimulate the secretion of GLP-1 through itself and propionic acid produced by the gut microbiota. These findings indicated that the antidiabetic mechanism of FCP-2-1 might be related to the gut microbiota-GLP-1 pathway.