Licochalcone E (lico E) is a retrochalcone isolated from the root of Glycyrrhiza inflata. Retrochalcone compounds evidence a variety of pharmacological profiles, including anticancer, antiparasitic, antibacterial, antioxidative and superoxide-scavenging properties. In this study, we evaluated the biological effects of lico E on adipocyte differentiation in vitro and obesity-related diabetes in vivo. We employed 3T3-L1 preadipocyte and C3H10T1/2 stem cells for in vitro adipocyte differentiation study and diet-induced diabetic mice for in vivo study. The presence of lico E during adipogenesis induced adipocyte differentiation to a significant degree, particularly at the early induction stage. Licochalcone E evidenced weak, but significant, peroxisome proliferator-activated receptor gamma (PPARγ) ligand-binding activity. Two weeks of lico E treatment lowered blood glucose levels and serum triglyceride levels in the diabetic mice. Additionally, treatment with lico E resulted in marked reductions in adipocyte size and increases in the mRNA expression levels of PPARγ in white adipose tissue (WAT). Licochalcone E was also shown to significantly stimulate Akt signaling in epididymal WAT. In conclusion, lico E increases the levels of PPARγ expression, at least in part, via the stimulation of Akt signals and functions as a PPARγ partial agonist, and this increased PPARγ expression enhances adipocyte differentiation and increases the population of small adipocytes, resulting in improvements in hyperglycemia and hyperlipidemia under diabetic conditions.
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