• Biomedical Science Letters
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• v.18 no.4
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• pp.420-427
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• 2012

Sprague-Dawley (SD) rats were orally administered with NG-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. We examined the effects of nitric oxide on some physiological changes such as blood pressure and heart rate, and confirms the apoptosis induced by the suppressed nitric oxide activity in the kidney. This study was performed to investigate correlation between the activities of nitric oxide and apoptosis by immunohistochemical changes of apoptotic control proteins with regulated chronic inhibition of nitric oxide. In the kidney from L-NAME-treated group, immunohistochemical reaction to the antigens of apoptosis inhibiting proteins such as bcl-2 and bcl-xL, exhibited a time-dependent reduction. The expression of apoptosis-inhibiting proteins such as bax and p53 increased expression in proportion to the duration of treatment. The most sensitive apoptosis regulating proteins to L-NAME were p53 in stimulation and bcl-2 in inhibition, respectively.

• Archives of Pharmacal Research
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• v.27 no.12
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• pp.1233-1237
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• 2004

The effects of four tanshinones isolated from Tanshen (the root of Salvia miltiorrhiza Bunge, Labiatae) were tested for their inhibition of nitric oxide production in macrophage cells, and the underlying molecular mechanisms studied. Of the four tanshinones used, 15, 16-dihydrotanshinone- I, tanshinone-IIA and cryptotanshinone, but not tanshinone I, demonstrated significant inhibition of the LPS-induced nitric oxide production in RAW 264.7 cells, with calculated $IC_{50}$ values of 5, 8, and 1.5 ${\mu}M$ , respectively. Tanshinones exerted inhibitory activities on the LPS-induced nitric oxide production only when applied concurrently with LPS, and tanshinone- IIA and cryptotanshinone were found to inhibit LPS-induced NF-$_KB$ mobilization and extracellular- regulated kinase (ERK) activation, respectively. These results suggest that tanshinones inhibit LPS-induced nitric oxide generation by interfering with the initial stage of LPS-induced expression of certain genes. NF-$_KB$ and ERK could be the molecular targets for tanshinones for the inhibition of LPS-induced nitric oxide production in macrophage cells.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.196-196
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• 1998

Nitric oxide is involved in various physiological processes. Among isoforms of nitric oxide synthase, iNOS is partly responsible for inflammation and septic shock. During our continual search for anti-inflammatory flavonoids, we have found that flavonoids, especially flavones, possessed the inihibitory activity of NO production by iNOS from LPS-activated RAW 264.7 cell. In this study, flavonoids from Scutellaria radix were investigated for their inhibitory activity of nitric oxide production. It was found that wogonin, among tested flavonoids including baicalein, oroxylin A, skullcapflavone II, showed the strongest inhibition of nitric oxide production (IC$\sub$50/ = 17 uM). And this inhibition was, at least partly, due to down-regulation of iNOS enzyme induction, not due to direct inhibition of iNOS enzyme activity.

• 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.

• Biomolecules & Therapeutics
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• v.7 no.4
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• pp.315-321
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• 1999

Since it has been known that hypoxia increases inducible nitric oxide synthase (iNOS) gene expression through hypoxia responsive element, it was possible to establish the hypothesis that nitric oxide could be a mediator of hypoxia to inhibit Cyplal promoter activity. In order to test this hypothesis, we have undertaken the study to examine the effects of hypoxia and nitric oxide on Cyplal promoter activity in Hepa I cells. Mouse Cyplal 5'flanking DNA, 1.6 Kb was cloned into pGL3 expression vector in order to construct pmCyplal-Luc. Hepa I cells were transfected with pmCyplal-Luc and were treated with $10^{-9}$ M TCDD and nitric oxide producing agents, such as lipopolysaccharide(LPS), sodium nitroprusside (SNP). Luciferase activity of reporter gene was measured from pmCyplal-Luc transfected Hepa I cell lysate which contains 2 g total protein using luciferin as a substrate. Nitric oxide producing agents, such as lipopolysaccharide (LPS), sodium nitroprusside(SNP) showed inhibition of luciferase activity that was induced by $10^{-9}$M TCDD treatment with dose dependent manner. Concomitant treatment of 1mM $N^G$-nitro-ι-arginine with $10^{-6}$~$10^{-4}$M sodium nitro-prusside recovered luciferase activity from the TCDD induced luciferase activity that was inhibited by nitric oxide producing agents. These demonstrated that nitric oxide could be a mediator of inhibitors on dioxin induced Cyplal expression in Hepa I cells.

• The Korean Journal of Pharmacology
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• v.32 no.2
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• pp.211-219
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• 1996

The inhibitory effect of cyclosporin A (CsA) on nitric oxide production is not related to the immunosuppressive action of the drug, but to the renal toxicity and arterial hyper-tension. In this study the experimental interventions to reverse the inhibition of nitric oxide production by cyclosporin A in rat aortic smooth muscle cells were examined. CsA inhibited the accumulation of nitrite, the stable end product of nitric oxide, in culture media in a concentration $(0.1{\sim}100{\mu}g/ml)-dependent$ manner. The inhibitory effect of CsA on nitrite accumulation were not antagonized by arginine (10 mM), a substrate of nitric oxide synthase, nor by calcium ionophore A23187 $(7{\mu}M)$. Forskolin, an activator of adenylate cyclase, which enhanced iNOS induction at transcriptional level, completely reversed the inhibitory action of CsA on nitrite accumulation. However, PMA (2 nM) and PDB (50 nM), PKC activators, increased the inhibitory action of CsA on nitrite accumulalion. From these results, it is suggested that cyclic AMP-elevating agents may be candidates of therapeutic agents in prevention and treatment of renal toxicity and arterial hypertension induced by CsA. Among conventional antihypertensive drugs, calcium channel blockers and ${\alpha}-blockers$ are preferred to ${\beta}-blockers$.

• 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.

• YAKHAK HOEJI
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• v.50 no.6
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• pp.367-371
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• 2006

Phellinus pini (Hymenocaetaceae) has been used for the immunomodulating activity hypolipidemic effect, gastric cancer non-insulin dependant diabetes, diarrhea, and menstrual irregularity. From the screening of each fraction for the inhibitory activity of NO production in lipopolysaccaride (LPS) activated RAW 264.7 cells, methanol extract of Phellinus pini and hexane soluble fraction exhibited inhibition of NO production compared with LPS control without toxicity. The hexane soluble fraction showed dose dependent inhibition of NO production. According to activity guided fractionation, the active hexane fr. was repeatedly chromatographed over silica gel, ergosta-4,6,8(14),22- tetraen-3-one was isolated. The compound inhibited NOS activation (IC$_{50}$ = 29.7 uM) and NO production of activated macrophage at 30 uM.

• Natural Product Sciences
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• v.25 no.1
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• pp.34-37
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• 2019

Phytochemical studies were performed to identify the active principles of Phryma leptostachya var. asiatica (Phyrymaceae) for anti-inflammation. The anti-inflammatory activity was assessed by measuring the inhibition rate on nitric oxide (NO) formation in lipopolysaccharide (LPS)-activated macrophage 264.7 cells. Of the five compounds including ursolic acid, phrymarolin I, harpagide, haedoxancoside A, and acteoside isolated from this plant, ursolic acid showed the most prominent inhibition of NO formation. Therefore, ursolic acid may be the anti-inflammatory principle of Phryma leptostachya var. asiatica.

• Biomolecules & Therapeutics
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• v.9 no.3
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• pp.183-187
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• 2001

Nitric oxide (NO) produced in large amounts by the inducible nitric oxide synthase (iNOS) is known to be responsible for the vasodilation and hypotension observed in septic shock and inflammation. The inhibitors of iNOS, thus, may be useful candidate for the treatment of inflammatory diseases accompanied by the overproduction of NO. We prepared alcoholic extracts of Chinese medicinal plants and screened their inhibitory activity against NO production in lipopolysaccharide (LPS)-activated macrophages. Among the 80 kinds of extracts of herbal drugs, 15 extracts showed potent inhibitory activity of NO production above 80% at the concentration o$50\mu\textrm{g}/ml$. These potent extracts showed dose dependent inhibition of NO production of LPS-activated macrophages at the concentration of 50, 30,$10\mu\textrm{g}/ml$. Especially, Rhus chinensis, Senecio scandens and Wikstroemia indica showed most potent inhibition above 50% at the concentration of $10\mu\textrm{g}/ml$. These plants are promising candidates for the study of the activity-guided purification of active compounds and would be useful for the treatment of inflammatory diseases and endotoxemia accompanying the overproduction of NO.