• Biomolecules & Therapeutics
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• v.22 no.5
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• pp.390-399
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• 2014

Chalcones (1,3-diaryl-2-propen-1-ones), a flavonoid subfamily, are widely known for their anti-inflammatory properties. Propenone moiety in chalcones is known to play an important role in generating biological responses by chalcones. In the present study, we synthesized chalcone derivatives structurally modified in propenone moiety and examined inhibitory effect on nitric oxide (NO) production and its potential mechanisms. Among the chalcone derivatives used for this study, TI-I-174 (3-(2-Hydroxyphenyl)-1-(thiophen-3-yl)prop-2-en-1-one) most potently inhibited lipopolysaccharide (LPS)-stimulated nitrite production in RAW 264.7 macrophages. TI-I-174 treatment also markedly inhibited inducible nitric oxide synthase (iNOS) expression. However, TI-I-174 did not significantly affect production of IL-6, cyclooxygenase-2 (COX-2) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), implying that TI-I-174 inhibits production of inflammatory mediators in a selective manner. Treatment of macrophages with TI-I-174 significantly inhibited transcriptional activity of activator protein-1 (AP-1) as determined by luciferase reporter gene assay, whereas nuclear factor-${\kappa}B$ (NF-${\kappa}B$) activity was not affected by TI-I-1744. In addition, TI-I-174 significantly inhibited activation of c-Jun-N-Terminal kinase (JNK) without affecting ERK1/2 and p38MAPK, indicating that down-regulation of iNOS gene expression by TI-I-174 is mainly attributed by blockade of JNK/AP-1 activation. We also demonstrated that TI-I-174 treatment led to an increase in heme oxygenase-1 (HO-1) expression both at mRNA and protein level. Transfection of siRNA targeting HO-1 reversed TI-I-174-mediated inhibition of nitrite production. Taken together, these results indicate that TI-I-174 suppresses NO production in LPS-stimulated RAW 264.7 macrophages via induction of HO-1 and blockade of AP-1 activation.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.9-19
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• 2005

Both nitric oxide (NO) and interleukin-6 (IL-6) have been thought to have a role in the pathogenesis of inflammatory periodontal disease as it does in other inflammatory diseases, and the inhibitors of NO and IL-6 production have been considered as potential anti-inflammatory agents. In this study, we evaluated methanol extract of Sophorae Flos for inhibition of NO and IL-6 production in Prevotella intermedia LPS-induced mouse macrophages RAW264.7 cells. Dried Sopharae Flos was sliced, and extracted with 100% methanol. LPS from p. intermedia ATCC 25611 was prepared by the standard hot phenol-water method. NO production was assayed by measuring the accumulation of nitrite in culture supematants and IL-6 was measured using mouse IL-6 ELISA kit. Western blot analysis of iNOS and analysis of reverse transcription (RT)-PCR products were carried out. The methanol extract of Sophorae Flos concentration-dependently reduced the production of NO and the expression of iNOS protein and mRNA in RAw264.7 cells treated with P. intermedia LPS. Sophorae Flos also suppressed IL-6 production and the expression of IL-6 mRNA in RAw264.7 cells stimulated by P. intermedia LPS. The inhibition of NO and IL-6 production by Sophorae Flos may be useful in the therapy of inflammatory diseases such as periodontitis. This hypothesis, however, remains to be tested.

• Biomedical Science Letters
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• v.24 no.1
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• pp.50-54
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• 2018

N-nitroso-N-methylurea (NMU) and N-nitroso-N-ethylurea (NEU), direct alkylating chemical mutagens and carcinogens, are shown to be the upregulators of cellular $NF-{\kappa}B$, regulating various genes that mediate tumorigenesis and carcinogenesis. Nitric oxide (NO), a toxic reactive radical gas, has been known to induce programmed cell death or apoptosis in various cells. Therefore, the assessment of NO production was examined to elucidate the possible contribution of NO release to the chemical carcinogenic potency of NMU and NEU in human skin cells. NMU and NEU did not alter the NO production, but they caused a significant downregulation of the NO generation on lipopolysaccharide (LPS)-induced NO production at concentrations ranging from $2{\sim}5{\mu}M$. The degree of downregulation of NO by NMU and NEU decreased up to 15% and 20%, respectively, compared to the control. These results demonstrate that the LPS-inducible keratinocytes NO synthase is involved in modulating carcinogenic potency by NMU and NEU, and the regulation of the cellular $NF-{\kappa}B$ activity by NMU and NEU is negatively correlated with the level of LPS-induced NO production in human skin cells. The findings of this study suggest the hypothesis that NMU and NEU-induced carcinogenesis may be associated with the downregulation of NO production, and the inducible NO may play an important role in NMU and NEU-induced carcinogenicity in human epidermal keratinocytes.

• The Journal of Internal Korean Medicine
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• v.20 no.1
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• pp.73-82
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• 1999

Nitric oxide (NO) is now recognized as a mediator of several biological and immunological functions, but unlike classical neurotransmitters. NO simply diffuse of the postsynaptic cells and around affecting cells. Taraxacum officinale (Compositae) has been used for maintenance of vitality, and they still occupy an important place in the traditional Korean medicine. We have examined that the effect of Taraxacum officinale water extract on NO synthesis in microglial cells of murine's brain, using the Griess method. And this study was evident that Taraxacum officinale did not induce NO production without recombinant interferon gamma ($rIFN-{\gamma}$), whereas Taraxacum officinale (10-1000 g/ml) with $rIFN-{\gamma}$ effectively produced NO in microglial cells of brain. As result. NO production in microglial cells increased most significantly in dose of 100 g/ml of the Taraxacum officinale and the production of NO was dependent on the dose of Taraxacum officinale, NG-monomethyl-L-arginine, competitive inhibitor of NO synthase, reduced the NO production by Taraxacum officinale stimulation with $rIFN-{\gamma}$ in microglial cells of murine. The effect of Taraxacum officinale was mainly dependent on Taraxacum officinale-induced tumor necrosis factor- secretion. Conclusively, this study suggested that Taraxacum officinale stimulate NO production at microglial cells in brain, which may be an important factor for mediating immune and neuroendocrinologic regulation in nervous system.

• Food Science and Preservation
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• v.24 no.1
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• pp.116-124
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• 2017

In this study, we compared the antioxidant and immuno-modulatory effects of water (HR, HL, HS), 70% ethanol (ER, EL, ES), and 70% methanol (MR, ML, MS) extracts of different parts (root, leaf, and seed) from Glehnia Radix. Yields were 17.40-30.17% for water extract, 11.47-28.67% for 70% ethanol extract, and 10.73-30.57% for 70% methanol extract, respectively. The total polyphenol and flavonoid contents of EL were 10.79 g/100 g and 2.01 g/100 g, respectively. The DPPH and ABTS radical scavenging activities of EL at $1,000{\mu}g/mL$ were 84.70% and 57.64%, respectively. The superoxide radical scavenging and ferric-reducing antioxidant power of EL at $1,000{\mu}g/mL$ were 84.05% and $975.28{\mu}M$, respectively. Moreover, 70% ethanol and 70% methanol extracts of root from Glehnia Radix significantly inhibited production of NO in LPS-stimulated macrophage RAW 264.7 cells without cytotoxicity. These results suggest that 70% ethanol and 70% methanol extracts of Glehnia Radix leaf may be a useful functional food material in the food industry.

• Biomedical Science Letters
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• v.16 no.1
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• pp.25-32
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• 2010

Sprague-Dawley(SD) rats were orally administered with $N^G$-nitro-L-arginine methyl ester(L-NAME) which inhibits or blocks the production of nitric oxide from L-arginine in vascular endothelial cells and vessel tissue to statistically examine the effects of nitric oxide on some physiological changes such as blood pressure and heart rate, and to confirm the apoptosis induced by the suppressed nitric oxide activity in some related organs under light microscope. Systolic blood pressure significantly increased 28.5% by the chronic treatment of L-NAME for 8 weeks (P<0.001), no significant difference, however, was observed in heart rate between the control group and the L-NAME-treated group regardless of their age. Hematoxylin-eosin staining showed some histological alterations only in kidney among the examined organs; heart, liver, pancreas, and adrenal gland from the L-NAME-treated group. TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) test showed a strong positive reaction, representing that the chronic treatment of L-NAME facilitates apoptosis, in the cortex and medulla of kidney, but not any significance detectable in the other organs. These results conclude that chronic treatment of L-NAME significantly increases blood pressure, and that the followed inhibition of nitric oxide synthesis occurs a typical inducement of apoptosis in kidney.

• 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.

• Biomedical Science Letters
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• v.25 no.2
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• pp.196-200
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• 2019

Effect of retinoids, i.e., all-trans retinoic acid and 13-cis retinoic acid, on the activity of nitric oxide synthase (NOS) was evaluated in human malignant keratinocytes to examine the possible correlation of retinoids with NOS activities. All-trans retinoic acid and 13-cis retinoic acid did not alter the nitric oxide (NO) production. However, in the presence of lipopolysaccharide (LPS, $1{\mu}g/mL$), they significantly increased NO release in a dose-dependent manner until 48 h at concentrations of $50{\sim}100{\mu}M$. The degree of upregulation of NO by all-trans retinoic acid and 13-cis retinoic acid increased up to 35% and 37%, respectively, compared to that by the control, which demonstrated the upregulation of LPS-inducible nitric oxide synthase (iNOS)-dependent generation of NO as well as showing a crucial link between retinoids-induced activity and NOS. Findings of this study now suggest that the upregulation of LPS-iNOS activity may be associated with modulation of retinoids-induced control of cellular developmental processes, which may produce new therapeutics of retinoids in the complexity of how NO affects human keratinocytes.

• Biomolecules & Therapeutics
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• v.12 no.4
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• pp.209-214
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• 2004

Lead has long been considered as a toxic environmental pollutant that severely damages the central nervous system. In various neurogenerative diseases, actrocytes become activated by proinflammatory cytokines. In the present study, we investigated whether lead (Pb$^{2+}$) affects inducible nitric oxide synthase (iNOS) expression in activated glial cells. Rat primary glial cells were stimulated with lipopolysaccharide (LPS, 1 ${\mu}$g/ml) plus IFN$_{\gamma}$(100 U/ml). Pre-treatment of Pb$^{2+}$ increased nitric oxide (NO) production in LPS/IFN$_{\gamma}$-stimulated glial cells. Lead itself, however, suppressed the basal production of NO in control glial cells. Addition of the iNOS inhibitors L-NAME (1 mM) and L-NNA (800 ${\mu}$M) prevented the Pb$^{2+}$-induced increase in NO production. Western blot analysis showed that pre-treatment of Pb$^{2+}$ augmented LPS/IFN$_{\gamma}$-induced increase in iNOS immunoreactivity, which was well correlated with the increased NO production. In addition, pre-treatment of Pb$^{2+}$ synergistically increased the iNOS mRNA expression induced by LPS and IFN${\gamma}$. The present results indicate that lead intoxication adversely affect brain function by potentiating iNOS expression and NO production in activated glial cells observed in various neurodegenerative diseases.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.691-696
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• 2002

Doxorubicin (DOX) is an active and broad spectrum chemotherapeutic agent. Increased inducible nitric oxide synthase (NOS) expression and/or activity have been reported in several human tumors. While the relationship between DOX treatment and the enzymatic activity of endothelial NOS has been well characterized, little is known about the effects of DOX on the expression of iNOS in human cancer cells. In the present study, we characterized the effects of DOX on the nitric oxide (NO) production by colorectal cancer cells, DLD-1. IFN-${\gamma}$/IL-1$\beta$ (CM) increased the production of NO, whereas pretreatment of DOX inhibited the production of NO in response to CM in a dose dependent manner. The increased expressions of iNOS mRNA and protein by CM were completely blocked by DOX without affecting the iNOS mRNA stability. However, DOX activated nuclear factor-kB (NF-kB) in response to CM. Furthermore, the expression of inhibitor kB$\alpha$ was reduced by DOX in a dose dependent manner. Collectively, DOX inhibited the production of NO by DLD-1 cells, which is not linked to well known transcription factor, NF-kB. Therefore, further studies on the possible mechanisms of inhibitory effects of NO production by DOX would be worth pursuing.