Heme oxygenase-1 mediates the inhibitory actions of brazilin in RAW264.7 macrophages stimulated with lipopolysaccharide

Chien-Ming Hu, Yung Hung Liu, Khoot Peng Cheah, Joe Sharg Li, Carlos Shu Kei Lam, Wen Yu Yu, Cheuk-Sing Choy

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Brazilin, the main constituent of Caesalpinia sappan L., is a natural red pigment that has been reported to possess anti-inflammatory properties. This study aimed to identify a novel anti-inflammatory mechanism of brazilin. We found that brazilin did not cause cytotoxicity below 300 μM, and activated heme oxygenase-1 (HO-1) protein synthesis in a concentration-dependent manner at 10-300 μM in RAW264.7 macrophages without affecting mRNA transcription of HO-1. Additionally, brazilin increased bilirubin production and HO-1 activity in RAW264.7 macrophages. In lipopolysaccharide (LPS)-stimulated macrophages, brazilin suppressed the release of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin (IL)-1β and tumor necrosis factor-α (TNF-α), and reduced the expression of inducible nitric oxide synthase (iNOS). A specific inhibitor of HO-1, Zn(II) protoporphyrin IX, blocked the suppression of NO production, cytokines release and iNOS expression by brazilin. These results suggest that brazilin possesses anti-inflammatory actions in macrophages and works through a novel mechanism involving the action of HO-1.

Original languageEnglish
Pages (from-to)79-85
Number of pages7
JournalJournal of Ethnopharmacology
Volume121
Issue number1
DOIs
Publication statusPublished - Jan 12 2009

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Keywords

  • Anti-inflammation
  • Brazilin
  • Heme oxygenase-1
  • Inducible nitric oxide synthase
  • Lipopolysaccharide
  • Macrophages

ASJC Scopus subject areas

  • Pharmacology
  • Drug Discovery

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