Uncoupled protein 3 and p38 signal pathways are involved in anti-obesity activity of Solanum tuberosum L. cv. Bora Valley

Aim of studyThis study was undertaken to elucidate the anti-obesity mechanism of a new purple potato variety that has been used for the prevention of metabolic diseases as a folk remedy in Korea.Materials and methodsProliferation assay, differentiation assay, Western blotting, were performed in 3T3-L1 adipocytes, while blood chemistry for hyperlipidemic parameters, measurement of body weight and abdominal fats, reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, magnetic resonance image (MRI) scanning were carried out in high fat diet fed Sprague-Dawley rats with ethanol extract of Solanum tuberosum L. cv. Bora Valley (ESTBV).ResultsESTBV significantly inhibited the proliferation and differentiation of 3T3-L1 cells as well as reduced the cellular leptin level. ESTBV also significantly attenuated the levels of insulin and leptin at 500 mg/kg in high fat diet fed rats. In addition, ESTBV significantly reduced total fat and whole body lipid in a therapeutic experiment, which was confirmed by MRI scanning and also significantly inhibited the retroperitoneal and epididymal fats in a preventive experiment compared with control. Similarly, the levels of total cholesterol, triglyceride and low density lipoprotein (LDL) were significantly reduced at a lower dose 200 mg/kg of ESTBV in a preventive experiment than at 500 mg/kg in a therapeutic experiment. Furthermore, body weight gain was significantly suppressed by over 4 weeks treatment of ESTBV compared with control. Interestingly, the expression of p38 mitogen-activated protein kinase (MAPK) was significantly downregulated in 3T3-L1 cells by ESTBV and the expression of uncoupled protein 3 (UCP-3) was activated in fats and liver tissues of ESTBV treated group compared with high fat diet control.ConclusionESTBV has anti-obesity potential via inhibition of lipid metabolism through p38 MAPK and UCP-3 pathways.