title: Aciculatin inhibits lipopolysaccharide-mediated inducible nitric oxide synthase and cyclooxygenase-2 expression via suppressing NF-κB and JNK/p38 MAPK activation pathways.
abstract: OBJECTIVE
  Natural products have played a significant role in drug discovery and development. Inflammatory mediators such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) have been suggested to connect with various inflammatory diseases. In this study, we explored the anti-inflammatory potential of aciculatin (8-((2R,4S,5S,6R)-tetrahydro-4,5-dihydroxy-6-methyl-2H-pyran-2-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one), one of main components of Chrysopogon aciculatis, by examining its effects on the expression and activity of iNOS and COX-2 in lipopolysaccharide (LPS)-activated macrophages.
  
  
  METHODS
  We used nitrate and prostaglandin E2 (PGE2) assays to examine inhibitory effect of aciculatin on nitric oxide (NO) and PGE2 levels in LPS-activated mouse RAW264.7 macrophages and further investigated the mechanisms of aciculatin suppressed LPS-mediated iNOS/COX-2 expression by western blot, RT-PCR, reporter gene assay and confocal microscope analysis.
  
  
  RESULTS
  Aciculatin remarkably decreased the LPS (1 μg/mL)-induced mRNA and protein expression of iNOS and COX-2 as well as their downstream products, NO and PGE2 respectively, in a concentration-dependent manner (1-10 μM). Such inhibition was found, via immunoblot analyses, reporter gene assays, and confocal microscope observations that aciculatin not only acts through significant suppression of LPS-induced NF-κB activation, an effect highly correlated with its inhibitory effect on LPS-induced IκB kinase (IKK) activation, IκB degradation, NF-κB phosphorylation, nuclear translocation and binding of NF-κB to the κB motif of the iNOS and COX-2 promoters, but also suppressed phosphorylation of JNK/p38 mitogen-activated protein kinases (MAPKs).
  
  
  CONCLUSIONS
  Our results demonstrated that aciculatin exerts potent anti-inflammatory activity through its dual inhibitory effects on iNOS and COX-2 by regulating NF-κB and JNK/p38 MAPK pathways.
authors.affiliation: School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: I-Ni
authors.initials: IN
authors.lastname: Hsieh
authors.forename: Anita Shin-Yuan
authors.initials: AS
authors.lastname: Chang
authors.forename: Che-Ming
authors.initials: CM
authors.lastname: Teng
authors.forename: Chien-Chih
authors.initials: CC
authors.lastname: Chen
authors.forename: Chia-Ron
authors.initials: CR
authors.lastname: Yang
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D015232:Dinoprostone; D005419:Flavonoids / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors* / Q000096:biosynthesis
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D052246:Cyclooxygenase 2 Inhibitors; D005419:Flavonoids; D008070:Lipopolysaccharides; D016328:NF-kappa B; C074400:aciculatin; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2; D020928:Mitogen-Activated Protein Kinases; D015232:Dinoprostone