title: Piperidine alkaloids from Piper retrofractum Vahl. protect against high-fat diet-induced obesity by regulating lipid metabolism and activating AMP-activated protein kinase.
abstract: The fruits of Piper retrofractum Vahl. have been used for their anti-flatulent, expectorant, antitussive, antifungal, and appetizing properties in traditional medicine, and they are reported to possess gastroprotective and cholesterol-lowering properties. However, their anti-obesity activity remains unexplored. The present study was conducted to isolate the anti-obesity constituents from P. retrofractum Vahl. and evaluate their effects in high-fat diet (HFD)-induced obese mice. Piperidine alkaloids from P. retrofractum Vahl. (PRPAs), including piperine, pipernonaline, and dehydropipernonaline, were isolated as the anti-obesity constituents through a peroxisome proliferator-activated receptor δ (PPARδ) transactivation assay. The molecular mechanism was investigated in 3T3-L1 adipocytes and L6 myocytes. PRPA treatment activated AMP-activated protein kinase (AMPK) signaling and PPARδ protein and also regulated the expression of lipid metabolism-related proteins. In the animal model, oral PRPA administration (50, 100, or 300mg/kg/day for 8weeks) significantly reduced HFD-induced body weight gain without altering the amount of food intake. Fat pad mass was reduced in the PRPA treatment groups, as evidenced by reduced adipocyte size. In addition, elevated serum levels of total cholesterol, low-density lipoprotein cholesterol, total lipid, leptin, and lipase were suppressed by PRPA treatment. PRPA also protected against the development of nonalcoholic fatty liver by decreasing hepatic triglyceride accumulation. Consistent with the in vitro results, PRPA activated AMPK signaling and altered the expression of lipid metabolism-related proteins in liver and skeletal muscle. Taken together, these findings demonstrate that PRPAs attenuate HFD-induced obesity by activating AMPK and PPARδ, and regulate lipid metabolism, suggesting their potential anti-obesity effects.
authors: Department of Biomaterials Science and Engineering, Yonsei University, Seoul 120-749, Republic of Korea.
authors: Kyung Jin
authors: KJ
authors: Kim
authors: Myoung-Su
authors: MS
authors: Lee
authors: Keunae
authors: K
authors: Jo
authors: Jae-Kwan
authors: JK
authors: Hwang
mesh_terms: D016475:3T3 Cells; D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D050154:Adiposity / Q000187:drug effects; D000470:Alkaloids / Q000008:administration & dosage* / Q000302:isolation & purification; D000818:Animals; D019440:Anti-Obesity Agents / Q000008:administration & dosage*; D019556:COS Cells; D002522:Chlorocebus aethiops; D004032:Diet / Q000009:adverse effects*; D004041:Dietary Fats / Q000008:administration & dosage / Q000819:agonists*; D050356:Lipid Metabolism / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000209:etiology / Q000517:prevention & control*; D047494:PPAR delta / Q000378:metabolism; D031701:Piper / Q000737:chemistry*; D010880:Piperidines / Q000008:administration & dosage* / Q000302:isolation & purification; D051381:Rats; D015430:Weight Gain / Q000187:drug effects
chemical_list: D000470:Alkaloids; D019440:Anti-Obesity Agents; D004041:Dietary Fats; D047494:PPAR delta; D010880:Piperidines; D055372:AMP-Activated Protein Kinases