• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.5
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• pp.1405-1410
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• 2005

Asthma is recognized today as an inflammatory disease of the lung characterized by acute non-specific airway hypersensitiveness in association with chronic pulmonary inflammation. Gamijihwang-tang(GJT), a fortified prescription of YMJHT, is applied for the treatments of chronic coughing and asthma, and post-delivery coughing and asthma in the gynecology. Also in the clinical practice, GJT is known to be very effective for controlling coughing and asthma as a cold sequoia. In this study, we investigated the effects of GJT on the lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) production, and on the level of inducible nitric oxide synthase (iNOS) and Cyclooxygenase-2 expression in murine macrophage RAW 264.7 cells. We found that GJT inhibited LPS-induced NO and $PGE_2$ production in a dose dependent manner. Furthermore, GJT inhibited the expression of LPS-induced iNOS and COX-2 protein and mRNA expression in RAW 264.7 macrophages. Treatment with GJT of RAW 264.7 cells transfected with a reporter construct indicated a reduced level of LPS-induced nuclear factor-KB (NF-kB) activity and effectively lowered NF-kB binding as measured by transient transfection assay. These results suggest that the main inhibitory mechanism of the GJT may be the reduction of iNOS and COX-2 gene expression through blocking of NF-kB activation.

• 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.

• Korean Journal of Veterinary Research
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• v.51 no.3
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• pp.185-191
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• 2011

Trimethyltin chloride (TMT) has been used as a neurotoxin for inducing brain dysfunction and neuronal death. Neuronal death in the hippocampus by TMT may generate excessive nitric oxide, but there are few studies about nitric oxide synthase enzyme involved in the synthesis of nitric oxide. The purpose of present study is to analyze the TMT toxicity in each region of rat hippocampus. To evaluate the involvement of nitric oxide, we analyzed the effects of aminoguanidine known as a selective inhibitor for inducible nitric oxide synthase on behavioral changes and the hippocampus of rat by TMT toxicity. 6-week-old male Sprague-Dawley rats were administered with a single dose of TMT (8 mg/kg b.w., i.p.) and the control group was similarly administered with distilled water. TMT + aminoguanidine-treated groups were administered with aminoguanidine (10 mg/kg or 100 mg/kg b.w., i.p.) for 3 days prior to TMT injection. The rats were sacrificed 2 days after TMT administration. In the TMT-treated group, a number of cell losses were seen in CA1, CA3 and the dentate gyrus. In the TMT + aminoguanidine-treated group, neuronal death was seen in CA1 and CA3, but reduced in the dentate gyrus compared to the TMT-treated group. Western blot analysis showed that cleaved caspase-3 expression was increased in the TMT-treated group compared to the control group. However, the expression significantly declined in the TMT + aminoguanidine-treated group. The present findings suggest that inducible nitric oxide synthase is involved in neuronal death induced by TMT.

• Archives of Pharmacal Research
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• v.25 no.2
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• pp.151-153
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• 2002

Three pseudoguaianolide type sesquiterpenes, bigelovin(1), 2,3-dihydroaromaticin (2), and ergolide (3) were isolated as inhibitory constituents against inducible nitric oxide synthase (iNOS) from the flowers of Inula britannica var. chinensis. Bigelovin (1) exhibited a highly potent inhibitory activity on lipopolysaccharide (LPS)-induced iNOS in murine macrophage RAW 264.7 cells with an $IC_{50}$ value of 0.46 mM, which is about 8 times more potent than the known selective inhibitor of iNOS, $L-N^6-(1-iminoethyl)Iysine{\;}(IC_{50}{\;}3.49{\;}{\mu}M)$. 2,3-Dihydroaromaticin (2) and ergolide (3) also exhibited potent inhibitory activities on LPS-induced iNOS with $IC_{50}$ values of 1.05 and $0.69{\;}{\mu}M$, respectively.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.91-91
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• 2003

Colon cancer is one of the most common malignancies in humans, and the search for effective chemopreventive agents is an important and urgent task. Expression levels of inflammation-related enzymes, cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) are elevated in colon cancers, and their products, prostaglandins and nitric oxide, are suggested to be involved in colon carcinogenesis.(omitted)

• Biomedical Science Letters
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• v.25 no.3
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• pp.267-274
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• 2019

Toll-like receptors (TLRs) are one of the families of pattern recognition receptors (PRR) to recognize pathogen-associated molecular patterns (PAMPs). PAMPs stimulate TLRs to initiate specific immunoactivity. The activation of TLRs signaling leads to the expression of pro-inflammatory gene products such as cytokines and inducible nitric oxide synthase (iNOS). To evaluate the therapeutic potential of dehydrocostus lactone (DHL), which is a natural sesquiterpene lactone derived from various medicinal plants, iNOS expression induced by LPS (TLR4 agonist), MALP-2 (TLR2 and TLR6 agonist), or Poly[I:C] (TLR3 agonist) were examined. DHL suppressed the iNOS expression induced by LPS, MALP-2, or Poly[I:C]. DHL also inhibited nitrite production induced by LPS, MALP-2, or Poly[I:C]. These results suggest that DHL can modulate TLRs signaling pathways resulting in anti-inflammatory effect.

• Preventive Nutrition and Food Science
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• v.14 no.4
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• pp.269-276
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• 2009

Overproduction of reactive oxygen species (ROS), including nitric oxide (NO), could be associated with the pathogenesis of various diseases such as cancer and chronic inflammation. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) are known to play key roles in the development of these diseases. Cedrela sinensis leaves have been used in Asian countries as a traditional remedy for enteritis, dysentery and itching. In the present study, we investigated the anti-inflammatory effects of Cedrela sinensis leaves in lipopolysaccharide (LPS)- stimulated RAW 264.7 macrophages. Powder of C. sinensis leaves was extracted with 95% ethanol and fractionated with a series of organic solvents including n-hexane, dichloromethane, ethyl acetate, n-butanol, and water. The dichloromethane (DCM) fraction strongly inhibited NO production possibly by down-regulating iNOS and COX-2 expression, as determined by Western blotting. Hydrogen peroxide-induced generation of reactive oxygen species (ROS) was also effectively inhibited by the DCM fraction from C. sinensis leaves. In addition, C. sinensis inhibited LPS-mediated p65 activation via the prevention of IκB-$\alpha$ phosphorylation. Furthermore, mitogen-activated protein kinases (MAPKs) such as ERK 1/2 and p38 were found to affect the expression of iNOS and COX-2 in the cells. Taken together, our data suggest that leaves of C. sinensis could be used as a potential source for anti-inflammatory agents.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.375-382
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• 1999

Growing evidence indicates that enhanced generation or actions of nitric oxide (NO) are implicated in the pathogenesis of hypertension in spontaneously hypertensive rats and diabetic nephropathy in streptozotocin (STZ)-induced diabetic rats. We investigated whether inducible nitric oxide synthase (iNOS) expression in STZ-induced diabetic rats is responsible for the alterations of vascular reactivity. Diabetic state was confirmed 28 days after injection of STZ (i.p) in rats by measuring blood glucose. In order to evaluate whether short term (4 weeks) diabetic state is related with altered vascular reactivity caused by iNOS expression, isometric tension experiments were performed. In addition, plasma nitrite/nitrate (NOx) levels and expression of iNOS in the lung and aorta of control and STZ-treated rats were compared by using Griess reagent and Western analysis, respectively. Results indicated that STZ-treated rats increased the maximal contractile response of the aorta to phenylephrine (PE), and high $K^+,$ while the sensitivity remained unaltered. Endothelium-dependent relaxation, but not SNP-mediated relaxation, was reduced in STZ-treated rats. Plasma nitrite/nitrates are significantly increased in STZ-treated rats compared to controls. The malondialdehyde (MDA) contents of liver, serum, and aorta of diabetic rats were also significantly increased. Furthermore, nitrotyrosine, a specific foot print of peroxynitrite, was significantly increased in endothelial cells and smooth muscle layers in STZ-induced diabetic aorta. Taken together, the present findings indicate that enhanced release of NO by iNOS along with increased lipid peroxidation in diabetic conditions may be responsible, at least in part, for the augmented contractility, possibly through the modification of endothelial integrity or ecNOS activity of endothelium in STZ-diabetic rat aorta.

• Preventive Nutrition and Food Science
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• v.12 no.2
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• pp.74-78
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• 2007

Fucoidan, that is high-molecular-weight sulfated polysaccharides extracted from brown seaweeds has been shown to elicit various biological activities. Here, we investigated the effects of fucoidan on cell proliferation and nitric oxide (NO) production in neuronal blastoma cell (SH-SY5Y). In the present study, we demonstrated that fucoidan treatment resulted in increase of cell proliferation and NO production. When cells were treated with amyloid-${\beta}$ (A${\beta}$) in the absence or presence of fucoidan, fucoidan recovered the cell viability decreased by A${\beta}$ peptides. To further determine whether nitric oxide synthase (NOS) is involved in proliferative effect of fucoidan, cells were treated with NOS inhibitors in the absence or presence of fucoidan. Selective constitutive nitric oxide synthase (cNOS) inhibitor, diphenylene iodonium chloride (DPI), caused a decrease of cell viability, whereas cell viability was increased by specific inducible nitric oxide synthase (iNOS) inhibitor, S-methylisothiourea (SMT), in the fucoidan-untreated cells. Treatment with fucoidan inhibited the cell viability decreased in DPI-exposed cells. In contrast, fucoidan had no effect on cell growth in SMT-treated cells, indicating that cNOS may not play a role in the proliferation of fucoidan-treated cells. The present data suggest that fucoidan has proliferative and neuroprotective effects and these effects may be associated with iNOS.

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.1081-1095
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• 2005

본 연구는 치주질환 주요 병인균주 중의 하나인 Porphyromonas gingivalis의 세균내독소가 마우스 대식 세포주인 RAW264.7 세포에서의 nitric oxide의 생성과 iNOS의 발현에 미치는 영향을 분석하고 그 기전을 규명하기 위해 수행되었다. Butanol추출법과 phenol-water법에 의해 P. gingivalis 381로부터 세균내독소를 추출하였으며, NO의 생성은 배양 상층액 내의 nitrite 농도를 측정하여 결정하였다. 또한, iNOS의 western blot 분석과 reverse transcription (RT)-PCR 산물의 분석을 수행하였다. P. gingivalis의 세균내독소는 부가적인 자극이 없는 상태에서도 iNOS의 발현과 NO 생성을 유발하였으며, NF- ${\kappa}B$, microtubule polymerization, protein tyrosine kinase, 그리고 protein kinase C 등이 P. gingivalis 세균내독소에 의한 NO 생성에 간여하는 것으로 여겨진다. 또한, P. gingivalis 세균내독소에 의한 NO 생성에는 L-arginine이 요구되었다. P. gingivalis 세균내독소에 의한 NO 생성은 염증성 치주질환의 발병과 진행에 있어 중요한 역할을 하는 것으로 여겨진다.