Ramalin inhibits differentiation of 3T3-L1 preadipocytes and suppresses adiposity and body weight in a high-fat diet-fed C57BL/6J mice.

Obesity is a serious global health problem. Natural substances that could be effective remedies for treatment of obesity, and which are relatively safe, are desired. The aim of this study was to examine the anti-obesity effect and the mechanism of ramalin in 3T3-L1 preadipocytes and high fat diet (HFD)-induced obese mice. In this study, 3T3-L1 cells were treated with various concentrations of ramalin (1, 5, and 10 μg/ml). Ramalin reduced the accumulation of intracellular lipid droplets in 3T3-L1 cells. In addition, ramalin inhibited 3T3-L1 adipocyte differentiation by blocking adipogenic gene expression including CCAAT enhancer binding proteins (C/EBPs), peroxisome proliferator-activated receptors γ (PPARγ), adipocyte fatty acid-binding protein (aP2), and leptin. The suppression of adipogenesis by ramalin was mediated through the inhibition of MAPK pathways. Ramalin also reduced the secretion of TNF-α and IL-6 in 3T3-L1 adipocytes. Oral administration of ramalin (50 and 100 mg/kg) to HFD-fed mice reduced body weight gain and abdominal fat accumulation without changes in food intake. Ramalin also attenuated organ weight and basal serum level by inhibiting Iiver X receptors (LXRs), sterol regulatory element-binding protein-1c (SREBP-1c), and lipoprotein lipase (LPL) mRNA expression in HFD-fed mice. Taken together, these results indicate that ramalin inhibits adipogenesis in 3T3-L1 preadipocytes and prevents HFD-induced obesity. The present study also provides insight into the mechanisms underlying the anti-obesity activity of ramalin and suggests that ramalin has the potential to prevent obesity.