Ginsenoside Rb2 (Rb2), the most abundant saponin contained in Panax ginseng, has been used to treat variety of metabolic diseases. However, its effects in obesity and potential mechanism are not well understood. In the present study, we investigate the metabolic performances with Rb2 supplement in diet induced obese (DIO) mice, focusing on assessing the effects and mechanisms of Rb2 on brown and beige fat functions. Our results demonstrated that Rb2 effectively reduced body weight, improved insulin sensitivity, as well as induced energy expenditure in DIO mice. Histological and gene analysis revealed that Rb2 induced activation of brown fat and browning of white fat as shown by reduced lipid droplets, increased UCP1 staining and increased thermogenic and mitochondrial genes, which could be recapitulated in 3T3-L1, C3H10T1/2 and primary adipocytes. In addition, Rb2 induces AMPK phosphorylation both in vitro and in vivo and these effects were shown to be dependent on AMPK since its inhibitor blocked Rb2 induced expressions of Pgc1α and Ucp1. Overall the present study revealed that Rb2 activates brown fat and induces browning of white fat, which increases energy expenditure and thermogenesis and consequently ameliorates obesity and metabolic disorders, suggesting Rb2 to be a promising beneficial compound treating obesity.

X. Gu: None.

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