Anti-inflammatory and immunomodulatory properties of 2-amino-3H-phenoxazin-3-one.
Accumulating evidence suggests that nitric oxide (NO) and prostaglandin E(2) (PGE(2)) are involved in the pathogenesis of various chronic inflammatory diseases and cancer. During the course of a screening program to identify natural anti-inflammatory substances, we isolated the compound 2-amino-3H-phenoxazin-3-one (APO) from an extract of the edible brown mushroom Agaricus bisporus IMBACH. APO inhibited NO production by mouse peritoneal macrophages in response to the pro-inflammatory stimuli lipopolysaccharide (LPS) and interferon (IFN)-gamma (LPS/IFN-gamma) at low concentrations (IC(50)=1.5 microM) through reduced inducible NO synthase protein expression. PGE(2) production by LPS/IFN-gamma-stimulated macrophages was inhibited by APO at much lower concentrations (IC(50)=0.27 microM) than those required for the inhibition of NO production. Mechanistic analysis showed that APO inhibited both cyclooxygenase (COX)-1 and COX-2 enzyme activities with almost equal selectivity. Secretion of NO and the pro-inflammatory cytokine IL-6 by IFN-gamma-activated RAW264.7 cells, a murine macrophage-like cell line, was also dose-dependently reduced by APO. Furthermore, APO increased the secretion of the anti-inflammatory cytokine IL-4 by antigen-stimulated T cells and promoted the polarization of CD4(+) Th cells toward the anti-inflammatory Th2 phenotype at equimolar concentrations that inhibited NO production. Our results suggested that APO induced polarization toward the Th2 subset, at least in part through the down-regulation of IL-12 production. Thus, APO appears to have potent anti-inflammatory and immunoregulatory properties that may provide a promising therapeutic strategy for the treatment of T cell-mediated inflammatory autoimmune diseases as well as for bacteria-induced chronic-inflammatory diseases.
Kohno
Keizo
K
Biomedical Institute, Research Center, Hayashibara Biochemical Laboratories, Inc, 675-1 Fujisaki, Okayama 702-8006, Japan. kohnok@hayashibara.co.jp
Miyake
Masaki
M
Sano
Osamu
O
Tanaka-Kataoka
Mari
M
Yamamoto
Shigeto
S
Koya-Miyata
Satomi
S
Arai
Norie
N
Fujii
Mitsukiyo
M
Watanabe
Hikaru
H
Ushio
Shimpei
S
Iwaki
Kanso
K
Fukuda
Shigeharu
S
D000363:Agaricales / Q000737:chemistry; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000302:isolation & purification* / Q000494:pharmacology*; D047072:Aromatase Inhibitors / Q000494:pharmacology*; D015704:CD4 Antigens / Q000096:biosynthesis; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D015232:Dinoprostone / Q000096:biosynthesis; D005260:Female; D007155:Immunologic Factors / Q000302:isolation & purification* / Q000494:pharmacology*; D007202:Indicators and Reagents; D017737:Macrophages, Peritoneal / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis; D010078:Oxazines / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D018418:Th2 Cells / Q000187:drug effects
D000894:Anti-Inflammatory Agents, Non-Steroidal; D047072:Aromatase Inhibitors; D015704:CD4 Antigens; D016207:Cytokines; D007155:Immunologic Factors; D007202:Indicators and Reagents; D010078:Oxazines; C005512:3-aminophenoxazone; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone