Trilobatin regulates glucose metabolism by ameliorating oxidative stress and insulin resistance in vivo and in vitro

Abstract

Objectives Trilobatin, a glycosylated dihydrochalcone, has been reported to have anti-diabetic properties. However, the underlying mechanism remains unexplained. Methods In this investigation, the regulation of trilobatin on glucose metabolism of insulin resistance (IR)-HepG2 cells and streptozocin (STZ)-induced mice and its mechanism were evaluated. Key findings Different doses of trilobatin (5, 10 and 20 μM) increased glucose consumption, glycogen content, hexokinase (HK), and pyruvate kinase (PK) activity in IR-HepG2 cells. Among them, the HK and PK activity in IR-HepG2 cells treated with 20 μM trilobatin were 1.84 and 2.05 times than those of the IR-group. The overeating, body and tissue weight, insulin levels, liver damage, and lipid accumulation of STZ-induced mice were improved after feeding with different doses of trilobatin (10, 50, and 100 mg/kg/d) for 4 weeks. Compared with STZ-induced mice, fasting blood glucose decreased by 61.11% and fasting insulin (FINS) increased by 48.6% after feeding trilobatin (100 mg/kg/d). Meanwhile, data from quantitative real-time polymerase chain reaction (qRT-PCR) revealed trilobatin ameliorated glycogen synthesis via the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) signaling pathway in IR-HepG2 cells and in STZ-induced mice. Furthermore, in vitro and in vivo experiments showed that trilobatin ameliorated oxidative stress by regulating the mRNA expression of nuclear erythroid-2 related factor 2 (Nrf2)/kelch-like ECH associated protein-1 (Keap-1) pathway as well as heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase-1 (NQO-1). Conclusions Our research reveals a novel pharmacological activity of trilobatin: regulating glucose metabolism through PI3K/Akt/GSK-3β and Nrf2/Keap-1 signaling pathways, improving insulin resistance and reducing oxidative stress. Trilobatin can be used as a reliable drug resource for the treatment of glucose metabolism disorders.