Ginsenoside Rb1 inhibits free fatty acids-induced oxidative stress and inflammation in 3T3-L1 adipocytes

Free fatty acids (FFAs) increase in visceral fat and are inferred to be one of the underlying inducers of adipose tissue inflammation. In our previous study, it was demonstrated that ginsenoside Rb1 stimulates endothelial nitric oxide synthase (eNOS) and Sirtuin 1 to protect against endothelial cell senescence. In the present study, 3T3-L1 adipocytes were exposed to 0.5 mM FFAs with or without Rb1 (10-40 mu M). Monocyte chemotactic protein-1 (MCP-1) and interleukin-6 (IL-6) secretion was measured using ELISA. Tumor necrosis factor-alpha (TNF-alpha) expression and nuclear factor-kappa B (NF-kappa B) p65 phosphorylation were detected using western blot analysis. Oxidative stress was determined via measuring intracellular reactive oxygen species (ROS) and nitric oxide (NO) production. The results demonstrated that MCP-1 and IL-6 secretion, as well as TNF-alpha expression, were significantly increased following FFA treatment, which was attenuated by Rb1 in a dose-dependent manner. Furthermore, Rb1 attenuated FFA-induced NF-kappa B phosphorylation, suggesting that the inhibitory effect of Rb1 on inflammatory cytokines was partially mediated through blockade of NF-kappa B phosphorylation. Further experiments demonstrated that Rb1 ameliorated FFA-induced ROS generation and NO reduction through upregulation of superoxide dismutase 2 and eNOS expression. Taken together, these results demonstrate proinflammatory and pro-oxidant effects of FFA on 3T3-L1 adipocytes, which are effectively ameliorated by Rb1. Suppression of inflammatory responses and oxidative stress may be a novel mechanism for attenuating the effect of Rb1 on adipocyte dysfunction.