Involvement of heme oxygenase-1 in the anti-inflammatory activity of Chrysanthemum boreale Makino extracts on the expression of inducible nitric oxide synthase in RAW264.7 macrophages.
OBJECTIVE
This study is to elucidate the involvement of anti-inflammatory heme oxygenase-1 (HO-1) in the inhibitory activity of a Chrysanthemum boreale Makino (CB) extract on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages.


METHODS
Cell viability and NO assay were performed. In addition, iNOS expression was detected by Western blotting and real-time PCR. HO-1 expression was also evaluated by Western blotting, and blocking HO-1 activity on NO production was performed.


RESULTS
The CB extract at the highest concentration (100 μg/ml) significantly inhibited NO production by approximately 90% and suppressed iNOS protein expression by approximately 84.8% compared to LPS-stimulated cells. Furthermore, the CB extract (100 μg/ml) inhibited iNOS mRNA expression in a concentration-dependant manner and suppressed iNOS mRNA expression by 94.8%. The CB extract induced the expression of HO-1 in a dose-dependent manner, and blocking HO-1 activity abolished the inhibitory effects of the CB extract. Moreover, the addition of carbon monoxide such as tricarbonyl dichlororuthenium (II) dimmer (RuCO), a byproduct derived from heme degradation, mimicked the inhibitory action of low concentrations of CB extract.


CONCLUSIONS
These results suggest that a CB extract has potent anti-inflammatory activity in RAW264.7 macrophages involving the induction of HO-1.
Kim
Younghwa
Y
Department of Food Science and Technology, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea.
Sung
Jeehye
J
Sung
Misun
M
Choi
Youngmin
Y
Jeong
Heon-Sang
HS
Lee
Junsoo
J
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D031202:Chrysanthemum / Q000737:chemistry*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D051547:Heme Oxygenase-1 / Q000187:drug effects / Q000378:metabolism; D007249:Inflammation / Q000188:drug therapy* / Q000473:pathology; D008070:Lipopolysaccharides; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000187:drug effects / Q000378:metabolism; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D008070:Lipopolysaccharides; D010936:Plant Extracts; D012333:RNA, Messenger; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D051547:Heme Oxygenase-1