title: Heme oxygenase-1 mediates the inhibitory actions of brazilin in RAW264.7 macrophages stimulated with lipopolysaccharide.
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 microM, and activated heme oxygenase-1 (HO-1) protein synthesis in a concentration-dependent manner at 10-300 microM 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 E(2) (PGE(2)), interleukin (IL)-1beta and tumor necrosis factor-alpha (TNF-alpha), 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.
authors.affiliation: Emergency Department, Taipei Medical University Hospital, Taipei, Taiwan, ROC.
authors.forename: Chien-Ming
authors.initials: CM
authors.lastname: Hu
authors.forename: Yung-Hung
authors.initials: YH
authors.lastname: Liu
authors.forename: Khoot-Peng
authors.initials: KP
authors.lastname: Cheah
authors.forename: Joe-Sharg
authors.initials: JS
authors.lastname: Li
authors.forename: Carlos-Shu Kei
authors.initials: CS
authors.lastname: Lam
authors.forename: Wen-Yu
authors.initials: WY
authors.lastname: Yu
authors.forename: Cheuk-Sing
authors.initials: CS
authors.lastname: Choy
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D001578:Benzopyrans / Q000494:pharmacology*; D001663:Bilirubin / Q000096:biosynthesis; D029911:Caesalpinia; D002460:Cell Line; D015232:Dinoprostone / Q000096:biosynthesis; D051547:Heme Oxygenase-1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D053583:Interleukin-1beta / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D011524:Protoporphyrins / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001578:Benzopyrans; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D011524:Protoporphyrins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C017803:zinc protoporphyrin; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D051547:Heme Oxygenase-1; C044362:brazilin; D015232:Dinoprostone; D001663:Bilirubin