Inhibition of NO production in LPS-stimulated mouse macrophage-like cells by trihaloacetylazulene derivatives.
The effect of 20 trihaloacetylazulene derivatives with one halogen atom, on nitric oxide (NO) production by mouse macrophage-like cells Raw 264.7 was investigated. 2-Methoxyazulenes and 2-ethoxyazulenes exhibited comparable cytotoxicity. Trichloroacetylazulenes generally exhibited higher cytotoxicity, as compared with the corresponding trifluoroacetylazulenes. Substitution of chloride, bromide or iodine at the C-3 position further enhanced their cytotoxicity. All of these compounds failed to stimulate the Raw 264.7 cells to produce detectable amounts of NO, but did inhibit NO production by LPS-activated Raw 264.7 cells to different extents. 1-Trichloroacetyl-2-methoxyazulene and 1-trichloroacetyl-2-ethoxyazulene, with less cytotoxic activity, inhibited NO production to the greatest extent, producing the highest selectivity index (SI) of >24.7 and >28.7, respectively. This was accompanied by the efficient inhibition of inducible NO synthase (iNOS) mRNA expression, but not by iNOS protein abundance. Electron spin resonance (ESR) spectroscopy showed that neither of these compounds produced radicals, nor scavenged NO, superoxide anion or diphenyl-2-picrylhydrazyl radicals. The present study suggests that the inhibitory effects of trifluoroacetylazulenes and trichloroacetylazulenes on NO production by activated macrophages might be derived from the perturbation of NO anabolism (inhibition of iNOS mRNA expression and possibly the inactivation of iNOS protein) rather than NO catabolism (NO scavenging).
Takahashi
Juri
J
Faculty of Science, Josai University, Sakado, Saitama, Japan.
Sekine
Takashi
T
Nishishiro
Masayuki
M
Arai
Atsuhiro
A
Wakabayashi
Hidetsugu
H
Kurihara
Teruo
T
Hashimoto
Ken
K
Satoh
Kazue
K
Motohashi
Noboru
N
Sakagami
Hiroshi
H
D000107:Acetylation; D000818:Animals; D052176:Azulenes / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000494:pharmacology; D006846:Hydrocarbons, Halogenated / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013329:Structure-Activity Relationship
D052176:Azulenes; D016166:Free Radical Scavengers; D006846:Hydrocarbons, Halogenated; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse