skip to main content

SciTech ConnectSciTech Connect

Title: Citrus nobiletin suppresses inducible nitric oxide synthase gene expression in interleukin-1β-treated hepatocytes

Highlights: •Nobiletin is a polymethoxylated flavone that is abundant in citrus peels. •Nobiletin is a major constituent of the Citrus unshiu peel extract. •Nobiletin suppresses induction of NO and reduces iNOS expression in hepatocytes. •Nobiletin reduces the iNOS promoter activity and the DNA-binding activity of NF-κB. -- Abstract: Background: Nobiletin is a polymethoxylated flavone that is abundant in the peels of citrus fruits, such as Citrus unshiu (Satsuma mandarin) and Citrus sinensis. The dried peels of C. unshiu (chinpi) have been included in several formulae of Japanese Kampo medicines. Nobiletin may suppress the induction of inducible nitric oxide synthase (iNOS), which synthesizes the inflammatory mediator nitric oxide (NO) in hepatocytes. Methods: A C. unshiu peel (CUP) extract was prepared. Primary cultured rat hepatocytes were treated with the CUP extract or nobiletin in the presence of interleukin 1β (IL-1β), which induces iNOS expression. NO production and iNOS gene expression were analyzed. Results: High-performance liquid chromatography analyses revealed that the nobiletin content in the CUP extract was 0.14%. Nobiletin dose-dependently reduced the NO levels and decreased iNOS expression at the protein, mRNA and antisense transcript levels. Flavone, which does not contain any methoxy groups, also suppressed iNOS induction. Nobiletin reduced the transcriptionalmore » activity of iNOS promoter-luciferase constructs and the DNA-binding activity of nuclear factor κB (NF-κB) in the nuclei. Conclusions: The suppression of iNOS induction by nobiletin suggests that nobiletin may be responsible for the anti-inflammatory effects of citrus peels and have a therapeutic potential for liver diseases.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ; ; ;  [1] ;  [4] ;  [5] ;  [6] ;  [3] ;  [5] ;  [1]
  1. Department of Biomedical Sciences, College of Life Sciences, Kusatsu, Shiga (Japan)
  2. (R-GIRO), Kusatsu, Shiga (Japan)
  3. Ritsumeikan Global Innovation Research Organization (R-GIRO), Kusatsu, Shiga (Japan)
  4. Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga (Japan)
  5. (Japan)
  6. Department of Pharmacy, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga (Japan)
Publication Date:
OSTI Identifier:
22242093
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 439; Journal Issue: 1; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; CITRUS; DNA; GENES; HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY; INDUCTION; INFLAMMATION; LIVER; LIVER CELLS; LUCIFERASE; MESSENGER-RNA; NITRIC OXIDE; RATS