title: Onion peel extract increases hepatic low-density lipoprotein receptor and ATP-binding cassette transporter A1 messenger RNA expressions in Sprague-Dawley rats fed a high-fat diet.
abstract: In the present study, we hypothesized that onion peel extract (OPE) alters hepatic gene expression to improve blood cholesterol profiles. To investigate the effect of OPE to test our hypothesis, Sprague-Dawley rats were fed ad libitum for 8 weeks with the control, high-fat diet (HFD) or the high-fat diet with 0.2% OPE supplementations (HFD + OPE). Messenger RNA (mRNA) levels of genes in cholesterol metabolism and fatty acid metabolism were examined by semiquantitative reverse transcriptase polymerase chain reaction. The OPE in HFD reverted high fat-induced reduction in mRNA levels of sterol regulatory element-binding protein-2, low-density lipoprotein receptor, and hydroxyl-3-methylglutaryl coenzyme reductase genes in the liver comparable with the levels of the control group. Onion peel extract slightly increased stearoyl-coA desaturase 1 (SCD-1) expression compared with high-fat feeding. However, sterol regulatory element-binding protein-1c and fatty acid synthase were not affected by high-fat or OPE feeding. Onion peel extract also enhanced expression of ATP-binding cassette transporter A1, peroxisome proliferator-activated receptor γ2 and scavenger receptor class B type I genes when compared with high-fat feeding. However, OPE did not influence high fat-triggered changes in apolipoprotein A1 mRNA levels and liver X receptor α were not affected by either high-fat or OPE feeding. Our results suggest that OPE changes the expression of genes associated with cholesterol metabolism in favor of lowering blood low-density lipoprotein cholesterol and enhancing high-density lipoprotein cholesterol through increasing mRNA abundance of low-density lipoprotein receptor and ATP-binding cassette transporter A1 genes.
authors.affiliation: Department of Food and Nutrition, Institute of Health Sciences, Korea University, Seoul, Republic of Korea.
authors.forename: Seung-Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Moon
authors.forename: Hyun Ju
authors.initials: HJ
authors.lastname: Do
authors.forename: Ji Hyung
authors.initials: JH
authors.lastname: Chung
authors.forename: Kyung-Hea
authors.initials: KH
authors.lastname: Lee
authors.forename: Yong-Jun
authors.initials: YJ
authors.lastname: Cha
authors.forename: Min-Jeong
authors.initials: MJ
authors.lastname: Shin
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D059305:Diet, High-Fat / Q000009:adverse effects*; D004041:Dietary Fats / Q000009:adverse effects; D015870:Gene Expression / Q000187:drug effects; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics / Q000378:metabolism; D006937:Hypercholesterolemia / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D050356:Lipid Metabolism / Q000235:genetics; D008099:Liver / Q000378:metabolism*; D019697:Onions; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D018517:Plant Roots; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011973:Receptors, LDL / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051782:Sterol Regulatory Element Binding Protein 2 / Q000235:genetics / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D004041:Dietary Fats; D010936:Plant Extracts; D012333:RNA, Messenger; D011973:Receptors, LDL; D051782:Sterol Regulatory Element Binding Protein 2; D006903:Hydroxymethylglutaryl CoA Reductases