Promotion of Glucose Uptake in C2C12 Myotubes by Cereal Flavone Tricin and Its Underlying Molecular Mechanism

The effect of tricin, a methylated flavone widely distributed in cereals, on glucose uptake and the underlying molecular mechanism was investigated using C2C12 myotubes. Tricin significantly increased glucose uptake in C2C12 myotubes, regardless of the absence (1.4-fold at 20 μM) or presence (1.6-fold at 20 μM) of insulin. The GLUT4 expression on the plasma membrane was increased 1.6-fold after tricin treatment (20 μM) in the absence of insulin. Tricin treatment significantly activated the insulin-dependent cell signaling pathway, including the activation of insulin receptor substrate-1 (IRS1), phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and AKT substrate of 160 kDa (AS160). The oral administration of tricin (64 and 160 mg kg of body weight day) also significantly lowered blood glucose levels in glucose-loaded C57BL/6 mice (p < 0.05). These results suggest that tricin has great potential to be used as a functional agent for glycemic control.