title: Induction of apolipoprotein A-I gene expression by black seed (Nigella sativa) extracts.
abstract: BACKGROUND
  Black seed [Nigella sativa L. (Ranunculaceae)] has been shown in animal models to lower serum cholesterol levels.
  
  
  OBJECTIVE
  In order to determine if extracts from black seed have any effects on high-density lipoprotein (HDL), we characterized the effects of black seed extract on apolipoprotein A-I (apo A-I) gene expression, the primary protein component of HDL.
  
  
  METHODS
  Hepatocytes (HepG2) and intestinal cells (Caco-2) were treated with black seed extracts, and Apo A-I, peroxisome proliferator-activated receptor α (PPARα), and retinoid-x-receptor α (RXRα) were measured by Western blot analysis. Apo A-I mRNA levels were measured by quantitative real-time polymerase chain reaction and apo A-I gene transcription was measured by transient transfection of apo A-I reporter plasmids.
  
  
  RESULTS
  Extracts from black seeds significantly increased hepatic and intestinal apo A-I secretion, as well as apo A-I mRNA and gene promoter activity. This effect required a PPARα binding site in the apo A-I gene promoter. Treatment of the extract with either heat or trypsin had no effect on its ability to induce apo A-I secretion. Treatment with black seed extract induced PPARα expression 9-fold and RXRα expression 2.5-fold. Furthermore, the addition of PPARα siRNA but not a control siRNA prevented some but not all the positive effects of black seed on apo A-I secretion.
  
  
  CONCLUSIONS
  Black seed extract is a potent inducer of apo A-I gene expression, presumably by enhancing PPARα/RXRα expression.
  
  
  CONCLUSIONS
  We conclude that black seed may have beneficial effects in treating dyslipidemia and coronary heart disease.
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Florida , Jacksonville, FL , USA and.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Haas
authors.forename: Luisa M
authors.initials: LM
authors.lastname: Onstead-Haas
authors.forename: Emad
authors.initials: E
authors.lastname: Naem
authors.forename: Norman C W
authors.initials: NC
authors.lastname: Wong
authors.forename: Arshag D
authors.initials: AD
authors.lastname: Mooradian
mesh_terms: D016632:Apolipoprotein A-I / Q000235:genetics*; D018938:Caco-2 Cells; D005786:Gene Expression Regulation / Q000187:drug effects; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008075:Lipoproteins, HDL / Q000187:drug effects* / Q000378:metabolism; D031881:Nigella sativa / Q000737:chemistry*; D047493:PPAR alpha / Q000235:genetics; D010936:Plant Extracts / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D047490:Retinoid X Receptor alpha / Q000235:genetics; D012639:Seeds
chemical_list: D016632:Apolipoprotein A-I; D008075:Lipoproteins, HDL; D047493:PPAR alpha; D010936:Plant Extracts; D012333:RNA, Messenger; D047490:Retinoid X Receptor alpha
keywords: Black seed; HDL; cardiovascular disease