title: Toona sinensis leaf extract inhibits lipid accumulation through up-regulation of genes involved in lipolysis and fatty acid oxidation in adipocytes.
abstract: Toona sinensis leaf (TSL) has been shown to lower plasma triacylglycerol levels and diminish the size of visceral fat cells in vivo. The molecular mechanism of TSL ethanol extract (TSL-E) on lipid metabolism in 3T3-L1 adipocytes was investigated in this study. Oil Red O staining as well as immunoblotting, real-time PCR, and dual-Luciferase reporter system were performed to investigate the effect of TSL-E on lipid accumulation and the regulation of lipid metabolism, respectively. In addition, active compounds in the TSL-E were analyzed by HPLC. TSL-E significantly decreased lipid accumulation, stimulated free fatty acid (FFA) release, and up-regulated peroxisome proliferator-activated receptor-α (PPARα) and genes involved in peroxisomal (acyl-CoA oxidase) and mitochondrial (uncouple protein 3) fatty acid oxidation. TSL-E also up-regulated cytoplasmic triacylglycerol hydrolysis gene (adipose triglyceride lipase) and genes related to fatty acid oxidation (AMP-activated protein kinase, acetyl-CoA carboxylase, carnitine palmitoyltransferase I, PPARγ, and adiponectin). The major constituents directly inducing PPARα transactivity in TSL-E are gallic acid, rutin, palmitic acid, linoleic acid, and α-linolenic acid. These results indicate that the inhibitory effect of TSL-E on lipid accumulation was through PPARα activation and further up-regulation of PPARα-mediated genes plus up-regulation of cytoplasmic genes involved in lipid catabolism.
authors.affiliation: Department of Life Sciences, National Cheng Kung University , Tainan, Taiwan.
authors.forename: Hung-Wen
authors.initials: HW
authors.lastname: Liu
authors.forename: Yue-Tseng
authors.initials: YT
authors.lastname: Tsai
authors.forename: Sue-Joan
authors.initials: SJ
authors.lastname: Chang
mesh_terms: D016475:3T3 Cells; D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D042962:Acyl-CoA Oxidase / Q000378:metabolism; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D005227:Fatty Acids / Q000378:metabolism*; D050356:Lipid Metabolism / Q000187:drug effects; D008066:Lipolysis / Q000187:drug effects*; D029582:Meliaceae / Q000737:chemistry*; D051379:Mice; D010084:Oxidation-Reduction; D047493:PPAR alpha / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D005227:Fatty Acids; D047493:PPAR alpha; D010936:Plant Extracts; D042962:Acyl-CoA Oxidase; D000103:Acetyl-CoA Carboxylase