Enhancement of glucose utilization by loesenerine through AMPK activation in myotubes

Abstract

Type 2 diabetes is characterized by hyperglycemia derived from insulin resistance in periphery tissue. Effects of skeletal muscle on glucose disposal are closely related to insulin resistance. The potential effects on mitochondrial function of loesenerine, a macrocyclic spermidine alkaloid from the aerial part of Euonymus fortunei (TURCZ.) HAND.-MAZZ were observed after a high-throughout screening based on mitochondrial membrane potential (MMP) assay. Further pharmacological studies revealed that loesenerine activates AMP-activated protein kinase (AMPK) pathway through increasing ADP/ATP ratio by inhibiting mitochondrial respiration. In addition, loesenerine induced 1.07-, 1.14-, and 1.22-fold increment of glucose uptake in C2C12 cells at the concentrations of 20, 40 and 80µmol/L, respectively. Meanwhile, incubated with loesenerine for 12h increased glucose consumption in a dose-dependent manner in C2C12 cells. This is the first report that macrocyclic spermidine alkaloid possesses potential hypoglycemic activity in vitro.