• Biomolecules & Therapeutics
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• v.14 no.3
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• pp.143-147
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• 2006

In the mouse leukemic monocyte cell line RAW 264.7, the vacuolar-type $(H^+)$-ATPase (V-ATPase) inhibitor bafilomycin $A_1$ at 10 and 100 nM decreased cell growth and survival as determined by 3-(4,5-dimethyl(thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in a concentration-dependent manner. At such concentrations, bafilomycin $A_1$ induced nitric oxide (NO) production through the expression of inducible nitric oxide synthase (iNOS). The bafilomycin $A_1$-induced NO production was inhibited by the NOS inhibitor $N^G$-monomethyl-L-arginine acetate (L-NMMA). Our findings suggest that the V-ATPase inhibitor bafilomycin $A_1$ induces NO production through the expression of iNOS protein.

• BMB Reports
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• v.41 no.1
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• pp.79-85
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• 2008

The source of nitric oxide (NO) in plants is unclear and it has been reported NO can be produced by nitric oxide synthase (NOS) like enzymes and by nitrate reductase (NR). Here we used wild-type, Atnos1 mutant and nia1, nia2 NR-deficient mutant plants of Arabidopsis thaliana to investigate the potential source of NO production in response to Verticillium dahliae toxins (VD-toxins). The results revealed that NO production is much higher in wild-type and Atnos1 mutant than in nia1, nia2 NR-deficient mutants. The NR inhibitor had a significant effect on VD-toxins-induced NO production; whereas NOS inhibitor had a slight effect. NR activity was significantly implicated in NO production. The results indicated that as NO was induced in response to VD-toxins in Arabidopsis, the major source was the NR pathway. The production of NOS-system appeared to be secondary.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.427-434
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• 2013

2R,3R-Butanediol, a volatile compound produced by certain rhizobacteria, is involved in induced drought tolerance in Arabidopsis thaliana through mechanisms involving stomatal closure. In this study, we examined the involvement of nitric oxide and hydrogen peroxide in induced drought tolerance, because these are signaling agents in drought stress responses mediated by abscisic acid (ABA). Fluorescence-based assays showed that systemic nitric oxide and hydrogen peroxide production was induced by 2R,3R-butanediol and correlated with expression of genes encoding nitrate reductase and nitric oxide synthase. Co-treatment of 2R,3R-butanediol with an inhibitor of nitrate reductase or an inhibitor of nitric oxide synthase lowered nitric oxide production and lessened induced drought tolerance. Increases in hydrogen peroxide were negated by co-treatment of 2R,3R-butanediol with inhibitors of NADPH oxidase, or peroxidase. These findings support the volatile 2R,3R-butanediol synthesized by certain rhizobacteria is an active player in induction of drought tolerance through mechanisms involving nitric oxide and hydrogen peroxide production.

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.481-484
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• 1998

In activated macrophages the inducible form of nitric oxide synthase (i-NOS) generates high amounts of toxic mediator, nitric oxide (NO) which contributes to the circulatory failure associated with septic shock. A sesquiterpene lactone compound (yomogin) isolated from medicinal plant Artemisia princeps Pampan inhibited the production of NO in LPS-activated RAW 264.7 cells by suppressing i-NOS enzyme expression. Thus, yomogin may be a useful candidate for the development of new drugs to treat endotoxemia and inflammation accompanied by the overproduction of NO.

• Korean Journal of Pharmacognosy
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• v.30 no.2
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• pp.173-176
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• 1999

Bioassay-guided fractionation of a $H_2O$ extract of the roots of Gentiana scabra has furnished 5-(hydroxymethyl)-2-furfural (1) as an inhibitory compound for nitric oxide (NO) production in murine macrophage RAW 264.7 cells stimulated with $interferon-{\gamma}$ plus lipopolysaccharide. Compound 1 showed the moderate inhibition of NO production with $IC_{50}$ value of $803\;{\mu}M$.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.5
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• pp.283-287
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• 2003

While nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is beneficial for host survival, it is also detrimental to the host. Thus, regulation of iNOS gene expression may be an effective therapeutic strategy for the prevention of unwanted reactions at various pathologic conditions. During the screening process for the possible iNOS regulators, we observed that esculetin is a potent inhibitor of cytokine-induced iNOS expression. The treatment of 3T3-L1 adipocytes with the tumor necrosis factor-${\alpha}$ (TNF) induced iNOS expression, leading to enhanced NO production. TNF-induced NO production was inhibited by esculetin in a dose-dependent manner. Esculetin inhibited the TNF-induced NO production at the transcriptional level through suppression of iNOS mRNA and subsequent iNOS protein expression. These results suggest esculetin, a component of natural products, as a naturally occurring, nontoxic means to attenuate iNOS expression and NO-mediated cytotoxicity.

• Biomolecules & Therapeutics
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• v.7 no.3
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• pp.210-215
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• 1999

Nitric oxide (NO) can mediate numerous physiological processes, including vasodilation, neurotransmission, cytotoxicity, secretion and inflammatory response. The regulation of NO production by inducible NO synthase (iNOS) is considered to be the possible target of the development of anti-inflammatory agent, based on the observation that NO can activate cyclooxygenase, which results in the synthesis of prostaglandins. In an effort to screen new inhibitor of NO production from about 352 species of herbal extracts, we found 9 species with 50% or more inhibitory effect on NO production. Especially, the dose-dependent inhibition of NO production in lipopolysaccharide-treated macrophages by two of the herbal extracts (Artemisiae asiaticae Herba and Saussureae Radix) was due to the decrease in the expression of iNOS.

• Natural Product Sciences
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• v.16 no.3
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• pp.143-147
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• 2010

The chromatographic separation of a methanol extract of Artemisia princes led to the isolation of two sesquiterpene lactones, artecanin (1) and canin (2), together with a flavonoid, eupatilin (3). Their structures were determined by 1D, 2D-NMR and MS data analysis. All of the isolates were evaluated for their potential to inhibit the LPS-induced production of nitric oxide in murine macrophage RAW 264.7 cells. Compounds 1 - 3 inhibited nitric oxide production with $IC_{50}$ values of 19.5, 20.4 and 25.1 ${\mu}M$, respectively.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.511-519
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• 1998

This study investigated the role of nitric oxide on the oxidative damage in gastric mucosa of rats which received ischemia/reperfusion and its relation to mucus. Nitric oxide synthesis modulators such as L-arginine and $N^G-nitro-L-arginine$ methyl ester, and sodium nitroprusside, a nitric oxide donor, were injected intraperitoneally to the rats 30 min prior to ischemia/reperfusion which was induced by clamping the celiac artery and the superior mesenteric artery for 30 min and reperfusion for 1 h. Lipid peroxide production, the contents of glutathione and mucus, and glutathione peroxidase activities of gastric mucosa were determined. Histological observation of gastric mucosa was performed by using hematoxylin-eosin staining and scanning electron microscopy. The result showed that ischemia/reperfusion increased lipid peroxide production and decreased the contents of glutathione and mucus as well as glutathione peroxidase activities of gastric mucosa. Ischemia/reperfusion induced gastric erosion and gross epithelial disruption of gastric mucosa. Pretreatment of L-arginine, a substrate for nitric oxide synthase, and sodium nitroprusside prevented ischemia/reperfusion-induced alterations of gastric mucosa. However, $N^G-nitro-$ L- arginine methyl ester, a nitric oxide synthase inhibitor, deteriorated oxidative damage induced by ischemia/reperfusion. In conclusion, nitric oxide has an antioxidant defensive role on gastric mucosa by maintaining mucus, glutathione, and glutathione peroxidase of gastric mucosa.

• YAKHAK HOEJI
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• v.42 no.5
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• pp.540-543
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• 1998

The nitric oxide (NO) produced in large amounts by inducible nitric oxide synthase is known to be responsible for the vasodilation and hypotension observed in septic shock. We have found that 8-epi-xanthatin from Xanthium strumarium L. inhibited the production of NO in LPS-activated RAW 264.7 cells ($IC_{50}$ value was 1.5 ${\mu}$M). This activity was resulted from the suppressing of inducible nitric oxide synthase enzyme expression.