Hawthorn polyphenols, D-chiro-inositol, and epigallocatechin gallate exert a synergistic hypoglycemic effect.

Hawthorn berry has been proved hypoglycemic effect due to the presence of some α-glucosidase inhibitors. Herein, screening and identifying of α-glucosidase inhibitors from hawthorn berry were conducted, and the results showed polyphenols mainly containing quercetin (74.58%) and hyperioside (9.58%) were responsible for its bioactivity. In order to enhance the hypoglycemic effect, the combined glucose-lowering complex (DEH) consisting of hawthorn polyphenols, D-chiro-inositol (DCI), and epigallocatechin gallate (EGCG) was prepared, where three ingredients exerted the synergistic hypoglycemic effect to enhance glucose consumption and glycogen levels and inhibit hepatic gluconeogenesis in IR-HepG2 cells. In STZ/HFD-induced mice, DEH effectively improved insulin resistance, reduced fasting blood glucose (FBG) and hepatic gluconeogenesis, and increased hepatic glycogen synthesis and storage via down-regulation of PI3K/Akt/FOXO1-mediated PEPCK and G6Pase and up-regulation of PI3K/Akt/GSK3-mediated GS activation in the liver. In summary, these findings indicate that DEH is a potential novel strategy for the treatment of type 2 diabetes. PRACTICAL APPLICATIONS: Glucose-lowering complex (DEH) with superior hypoglycemic effect, can effectively improve the insulin resistance, reduce the fasting blood glucose, hepatic gluconeogenesis and increase the hepatic glycogen synthesis and storage in mice, which represents a potential novel strategy for the treatment of type 2 diabetes.