Ginsenoside Rg2 inhibits adipogenesis in 3T3-L1 preadipocytes and suppresses obesity in high-fat-diet-induced obese mice through the AMPK pathway
Ginsenoside Rg2 is one of the specific ginsenosides in red ginseng, which was reported to have protective effects against neurotoxicity, memory impairment, and also inhibit hepatic glucose production. However, the effect of Rg2 on the prevention of obesity has not been investigated. In this study, we evaluated the anti-obesity and anti-adipogenic effects of Rg2 in high-fat diet-induced obese mice (HFD mice) and 3T3-L1 preadipocytes. Oral administration of Rg2 (10 mg/kg) to HFD mice significantly decreased body weight gain, total triglycerides, and free fatty acid levels. In 3T3-L1 preadipocytes, Rg2 (80 M) inhibited adipocyte differentiation and reduced the accumulation of intracellular lipid. Quantitative PCR and Western blot analysis revealed that Rg2 decreased the expression levels of adipogenic transcription factors (PPARγ, C/EBPα, and SREBP1-c), then regulated target genes such as acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS). The Rg2 significantly promoted AMP-activated protein kinase (AMPK) both in vivo and in vitro, which is known to suppress adipogenesis. It was also found that pretreating with compound C, a typical inhibitor of AMPK attenuated the inhibitory effect of Rg2 on AMPK phosphorylation. These findings suggested that Rg2-induced activation of AMPK leads to a decrease in expression of adipogenic transcription factors, and suppression of adipogenesis in vivo and in vitro. Hence, Rg2 have the potential for the development of healthy foods and the prevention of obesity.