Abstract
A Glu-Phe (EF) was isolated from onion (Allium cepa L. cv. Sunpower). The chemical structure of EF was determined by nuclear magnetic resonance and electrospray ionization-mass (ESI-MS) spectroscopy. We showed that EF reduced lipid accumulation in mouse hepatocytes by inhibiting the expression of sterol regulatory element-binding protein-1c (SREBP-1c) and its lipogenic target genes. We also found that AMP-activated protein kinase (AMPK) was required for the inhibitory effect of EF on lipid accumulation in mouse hepatocytes. Furthermore, EF was qualified in nine onion cultivars by selective multiple reaction-monitoring detection of liquid chromatography-ESI-MS. These results suggest that EF could contribute to the beneficial effect of onion supplement in maintaining hepatic lipid homeostasis.
Keywords:
SREBP-1c; dipeptide; hepatocytes; lipogenesis; onion.
MeSH terms
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AMP-Activated Protein Kinases / genetics
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AMP-Activated Protein Kinases / metabolism
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Acetyl-CoA Carboxylase / genetics
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Acetyl-CoA Carboxylase / metabolism
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Animals
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Cell Line
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Cell Survival / drug effects
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Dipeptides / isolation & purification
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Dipeptides / pharmacology*
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Fatty Acid Synthase, Type I / genetics
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Fatty Acid Synthase, Type I / metabolism
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Gene Expression Regulation
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Hepatocytes / cytology
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Hepatocytes / drug effects*
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Hepatocytes / metabolism
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Hypolipidemic Agents / isolation & purification
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Hypolipidemic Agents / pharmacology*
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Lipogenesis / drug effects*
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Lipogenesis / genetics
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Mice
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Onions / chemistry*
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Plant Extracts / chemistry
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Signal Transduction
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Stearoyl-CoA Desaturase / genetics
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Stearoyl-CoA Desaturase / metabolism
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Sterol Regulatory Element Binding Protein 1 / antagonists & inhibitors
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Sterol Regulatory Element Binding Protein 1 / genetics*
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Sterol Regulatory Element Binding Protein 1 / metabolism
Substances
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Dipeptides
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Hypolipidemic Agents
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Plant Extracts
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Srebf1 protein, mouse
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Sterol Regulatory Element Binding Protein 1
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gamma-glutamylphenylalanine
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Scd1 protein, mouse
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Stearoyl-CoA Desaturase
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Fatty Acid Synthase, Type I
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AMP-Activated Protein Kinases
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Acetyl-CoA Carboxylase