Artemisia princeps extract promoted glucose uptake in cultured L6 muscle cells via glucose transporter 4 translocation

Artemisia princeps is a familiar plant as a food substance and medicinal herb. In this study, we evaluated the effects of an ethanol extract of A. princeps (APE) on glucose uptake in differentiated L6 muscle cells. Treatment with APE elevated deoxyglucose uptake, and translocation of the insulin-responsive glucose transporter (GLUT4) to the plasma membrane in L6 myotubes occurred. The PI3K inhibitor LY294002 attenuated glucose uptake induced by APE. Phosphorylation of the Ser(473) residue of Akt was not observed, but phosphorylation of PI3K, Akt (Thr(308)), and atypical PKC was. In addition, APE stimulated phosphorylation of AMP-activated protein kinase (AMPK) at a level similar to 5'-amino-5-imidazolecarboxamide-riboside (AICAR). These results indicate that APE stimulates glucose uptake by inducing GLUT4 translocation, which is in part mediated by combination of the PI3K-dependent atypical PKC pathway and AMPK pathways.