Isoliquiritigenin, from Dalbergia odorifera, up-regulates anti-inflammatory heme oxygenase-1 expression in RAW264.7 macrophages.
OBJECTIVE
Isoliquiritigenin (ISL), one of the major constituents of Dalbergia odorifera T. Chen (Leguminosae), is reported to exert anti-inflammatory effects, but the relevant anti-inflammatory mechanisms are not completely understood. Heme oxygenase-1 (HO-1) has been proven to be involved in the resolution of inflammatory responses. In this study, we investigated whether ISL could induce HO-1 expression in RAW264.7 macrophages, and if so, whether HO-1 could mediate the anti-inflammatory effects of ISL.


METHODS
The protein expression of inducible nitric oxide synthase and HO-1 was analyzed by western blot analysis. The production of nitric oxide (NO) and interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) was assayed by Griess and ELISA, respectively. The TNF-alpha and HO-1 mRNA expression was analyzed by northern blot analysis.


RESULTS
ISL markedly suppressed LPS-induced NO, IL-1beta, and TNF-alpha production. ISL induced HO-1 expression through the extracellular signal-regulated kinase1/2 pathway in RAW264.7 macrophages. The effects of ISL on LPS-induced NO and TNF-alpha production were reversed by the HO-1 inhibitor, tin protoporphyrin.


CONCLUSIONS
ISL is an effective HO-1 inducer capable of inhibiting macrophage-derived inflammation.
Lee
S H
SH
Institute of Pharmaceutical Research and Development, College of Pharmacy, Wonkwang University, Iksan, Jeonbuk, Republic of Korea.
Kim
J Y
JY
Seo
G S
GS
Kim
Y-C
YC
Sohn
D H
DH
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000378:metabolism; D002460:Cell Line; D047188:Chalcones / Q000737:chemistry / Q000494:pharmacology*; D035782:Dalbergia / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology; D051379:Mice; D015394:Molecular Structure; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
D000893:Anti-Inflammatory Agents; D047188:Chalcones; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; C040920:isoliquiritigenin; D052247:Nitric Oxide Synthase Type II; D051547:Heme Oxygenase-1; D048049:Extracellular Signal-Regulated MAP Kinases