title: Eugenolol and glyceryl-isoeugenol suppress LPS-induced iNOS expression by down-regulating NF-kappaB AND AP-1 through inhibition of MAPKS and AKT/IkappaBalpha signaling pathways in macrophages.
abstract: Eugenol and isoeugenol, two components of clover oil, have been reported to possess several biomedical properties, such as anti-inflammatory, antimicrobial and antioxidant effects. This study aims to examine the anti-inflammatory effects of eugenol, isoeugenol and four of their derivatives on expression of inducible nitric oxide synthase (iNOS) activated by lipopolysaccharide (LPS) in mouse macrophages (RAW 264.7), and to investigate molecular mechanisms underlying these effects. We found that two derivatives, eugenolol and glyceryl-isoeugenol, had potent inhibitory effects on LPS-induced upregulation of nitrite levels, iNOS protein and iNOS mRNA. In addition, they both suppressed the release of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) induced by LPS. Moreover, they both attenuated the DNA binding of NF-kB and AP-1, phosphorylation of inhibitory kB-alpha (IkB-alpha), and nuclear translocation of p65 protein induced by LPS. Finally, we demonstrated that glyceryl-isoeugenol suppressed the phosphorylation of ERK1/2, JNK and p38 MAPK, whereas eugenolol suppressed the phosphorylation of ERK1/2 and p38 MAPK. Taken together, these results suggest that that eugenolol and glyceryl-isoeugenol suppress LPS-induced iNOS expression by down-regulating NF-kB and AP-1 through inhibition of MAPKs and Akt/IkB-alpha signaling pathways. Thus, this study implies that eugenolol and glyceryl-isoeugenol may provide therapeutic benefits for inflammatory diseases.
authors.affiliation: Department and Graduate Institute of Pharmacology, College of Medicine, Kaohsiung Medical University, and Department of Paediatrics, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: J L
authors.initials: JL
authors.lastname: Yeh
authors.forename: J H
authors.initials: JH
authors.lastname: Hsu
authors.forename: Y S
authors.initials: YS
authors.lastname: Hong
authors.forename: J R
authors.initials: JR
authors.lastname: Wu
authors.forename: J C
authors.initials: JC
authors.lastname: Liang
authors.forename: B N
authors.initials: BN
authors.lastname: Wu
authors.forename: I J
authors.initials: IJ
authors.lastname: Chen
authors.forename: S F
authors.initials: SF
authors.lastname: Liou
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004731:Endotoxins / Q000494:pharmacology*; D005054:Eugenol / Q000031:analogs & derivatives / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005990:Glycerol / Q000494:pharmacology*; D020672:I-kappa B Proteins / Q000378:metabolism*; D018836:Inflammation Mediators / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D004731:Endotoxins; D020672:I-kappa B Proteins; D018836:Inflammation Mediators; D053583:Interleukin-1beta; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D012333:RNA, Messenger; C498144:Rela protein, mouse; D018808:Transcription Factor AP-1; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; C560287:glyceryl-isoeugenol; D000072000:NF-KappaB Inhibitor alpha; D009569:Nitric Oxide; D005054:Eugenol; C044101:endotoxin, Escherichia coli; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D005990:Glycerol