BACKGROUND

Since AMP-activated protein kinase (AMPK) activation in skeletal muscle of obese rodents stimulates fatty acid oxidation, it is reasonable to hypothesize that pharmacological activation of AMPK might be of therapeutic benefit in obesity.

OBJECTIVE

To investigate the effects of the traditional Korean anti-obesity drug GGEx18, a mixture of three herbs, Laminaria japonica Aresch (Laminariaceae), Rheum palmatum L. (Polygonaceae), and Ephedra sinica Stapf (Ephedraceae), on obesity and the involvement of AMPK in this process.

METHODS

After high fat diet-induced obese mice were treated with GGEx18, we studied the effects of GGEx18 on body weight, fat mass, skeletal muscle lipid accumulation, and the expressions of AMPK, peroxisome proliferator-activated receptor ά (PPARα), and PPARα target genes. The effects of GGEx18 and/or the AMPK inhibitor compound C on lipid accumulation and expression of the above genes were measured in C2C12 skeletal muscle cells.

RESULTS

Administration of GGEx18 to obese mice for 9 weeks significantly (p < 0.05) decreased body and adipose tissue weights compared with obese control mice (p < 0.05). Lipid accumulation in skeletal muscle was inhibited by GGEx18. GGEx18 significantly (p < 0.05) increased skeletal muscle mRNA levels of AMPKα1 and AMPKα2 as well as PPARα and its target genes. Consistent with the in vivo data, GGEx18 inhibited lipid accumulation, and similar activation of genes was observed in GGEx18-treated C2C12 cells. However, compound C inhibited these effects in C2C12 cells.

CONCLUSIONS

These results suggest that GGEx18 improves obesity through skeletal muscle AMPK and AMPK-stimulated expression of PPARα and its target enzymes for fatty acid oxidation.