• Journal of Periodontal and Implant Science
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• v.23 no.2
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• pp.243-259
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• 1993

The bone resorbing activity of $PGE_2$ and elevated level of prostaglandins(PGs) and thromboxanes (TXs) in inflamed gingiva which are cyclooxygenase(C) metabolites have been well documented. Nonsteroidal anti-inflammatory drugs(NSAIDs) have been known to suppress gingival inflammation and bone resorption through the specific inhibitory action on the C pathway thereby decrease of various C metabolites. Recent studies provide unequivocal results that gingival tissue metabolizes arachidonic acid(AA) mainly through lipoxygenase(L) pathway. And the results of our previous experiments suggest that indomethacin may have inhibitory action on L as well as C. Thus we started this study to show the influences of several C inhibitors on the L activity at therapeutic and toxic dosage. Periodontal tissue samples were obtained from patients with advanced periodontitis and incubated with $^{14}C-AA(0.2{\mu}Ci)$ and various enzyme inhibitors. The tissue lipid extracts were separated by means of thin layer chromatography(TLC) and analyzed by means of autoradiography and TLC analyzer. Our results showed that aspirin inhibited C more selectively than L, however at higher concentration it also decreased HETEs production significantly. Indomethacin showed dose-dependent inhibition of L as well as C and all of the L metabolites were decreased to the same degree by high concentration of indomethacin. AA-861, which is an experimental tool of selective L inhibitor, showed inhibition of HETEs production but no effect on the production of $TXB_2$, PGs and $LTB_4$. Various propionic acid derivatives NSAIDs(ibuprofen, flurbiprofen, naproxen) showed the same patterns of effect on AA metabolism each other that was profound inhibition of PGs production, to the less degree HETEs and $TXB_2$ production, and of no effect on the $LTB_4$ production.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.4
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• pp.393-402
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• 1997

In the present study, we characterized the angiotensin II (AII)-induced relaxations in the phenylephrine-precontracted rabbit mesenteric arteries with endothelium. 1) AII-induced relaxation was consistently observed in the rabbit mesenteric arteries with and without endothelium, but not in the aortic segment with endothelium. 2) AII-induced endothelium-dependent relaxation was markedly inhibited by $N^w-nitro-L-arginine$ (L-NNA, $100\;{\mu}M$), methylene blue ($10\;{\mu}M$) and LY83583 ($10\;{\mu}M$), respectively. 3) Inhibition of cyclooxygenase with indomethacin ($10\;{\mu}M$) strongly decreased the vasorelaxant response to AII irrespective of the presence of endothelium. 4) 7-Ethoxyresorufin ($1\;{\mu}M$) and clotrimazole ($1\;{\mu}M$), inhibitors of cytochrome P-450-dependent arachidonic acid metabolism, greatly attenuated the vasodilator response to AII. 5) Carbacyclin, arachidonic acid and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) caused concentration-dependent relaxations in the mesenteric artery with endothelium, which were inhibited by L-NNA and methylene blue. 6) AII and $PGF_{2{\alpha}}$ significantly stimulated cyclic GMP formation in the mesenteric arteries with endothelium, which was inhibited by L-NNA and methylene blue, respectively. 7) AII enhanced synthesis of $PGF_{2{\alpha}}$ and 6-keto $PGF_{1{\alpha}}$ from the arterial segments with endothelium, which was inhibitable by indomethacin, but not by L-NNA. In conclusion, the vasorelaxant responses to AII of the rabbit mesenteric artery with endothelium are subserved by arachidonic acid and its metabolites produced via activation of cyclooxygenase and cytochrome P-450 enzyme as well as by nitric oxide.

• Animal cells and systems
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• v.1 no.1
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• pp.81-86
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• 1997

We studied the mechanism of arachidonic acid on the secretion of a neurotransmitter in rat pheochromocytoma PC12 cells. Arachidonic acid inhibited the 70 mM $K^+$-induced secretion of norepinephrine. Arachidonic acid also inhibited the 70 mM $K^+$-induced $Ca^{2+}$ mobilization which is due to the opening of the voltage-sensitive $Ca^{2+}$ channels (VSCC). Both the half maximal inhibitory concentration ($IC_{50}$) of the norepinephrine secretion and VSCC coincided at 30 uM. The major oxidized metabolites of arachidonic acid, prostaglandins did not mimic the inhibitory effect of arachidonic acid. Nordihydroguaiaretic acid (NDGA) and indomethacin which are inhibitors of lipoxygenase and cyclooxygenase, respectively, did not block the inhibitory effect of arachidonic acid. The results suggest that arachidonic acid serves as a signal itself, not in the form of metabolites. The pretreatment of various $K^+$ channel blockers such as 4-aminopyridine, tetraethylarnmonium, glipizide, or glibenclamide also did not show any effect on the inhibitory effect of arachidonic acid. Through these results we suggest that arachidonic acid regulates VSCC directly and affects the secretion of neurotransmitters.

• Nutrition Research and Practice
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• v.11 no.4
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• pp.265-274
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• 2017

BACKGROUND/OBJECTIVES: Nelumbo leaves have been used in traditional medicine to treat bleeding, gastritis, hemorrhoids, and halitosis. However, their mechanisms have not been elucidated. MATERIALS/METHODS: The present study prepared two Nelumbo leaf extracts (NLEs) using water or 50% ethanol. Inflammatory response was induced with LPS treatment, and expression of pro-inflammatory mediators (inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin (IL)-$1{\beta}$, and IL-6 and nitric oxide (NO) and prostaglandin $E_2$ ($PGE_2$) productions were assessed. To determine the anti-inflammatory mechanism of NLEs, we measured nuclear factor-${\kappa}B$ (NF-${\kappa}B$) activity. Major metabolites of NLEs were also analyzed and quantified. RESULTS: NLEs effectively reduced the expression and productions of pro-inflammatory mediators such as IL-$1{\beta}$, IL-6, TNF-${\alpha}$, $PGE_2$, and NO. NLEs also reduced NF-${\kappa}B$ activity by inhibiting inhibitor of NF-${\kappa}B$ phosphorylation. Both extracts contained catechin and quercetin, bioactive compounds of NLEs. CONCLUSIONS: In this study, we showed that NLEs could be used to inhibit NF-${\kappa}B$-mediated inflammatory responses. In addition, our data support the idea that NLEs can ameliorate disease conditions involving chronic inflammation.

• Biomedical Science Letters
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• v.27 no.4
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• pp.223-230
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• 2021

Tumor necrosis factor alpha (TNF-α) is a principal regulator of inflammation and immunity. The proinflammatory properties of TNF-α can be attributed to its ability to activate the enzyme cytosolic phospholipase A₂ (cPLA₂), which generates potent inflammatory lipid mediators, eicosanoids. L-glutamine (Gln) plays physiologically important roles in various metabolic processes. We have reported that Gln has a potent anti-inflammatory activity via rapid upregulation of mitogen-activated protein kinases (MAPKs) phosphatase (MKP)-1, which preferentially dephosphorylates the key proinflammatory enzymes, p38 MAPK and cytosolic phospholipase A₂ (cPLA₂). In this study, we have investigated whether Gln could inhibit TNF-α-induced cPLA₂ activation. Gln inhibited TNF-α-induced increases in cPLA₂ phosphorylation in the lungs and blood levels of the cPLA₂ metabolites, leukotrine B4 (LTB4) (lipoxygenase metabolite) and prostaglandin E2 (PGE2) (cyclooxygenase metabolite). TNF-α increased p38 and cPLA₂ phosphorylation and blood levels of LTB4 and PGE2, which were blocked by the p38 inhibitor SB202190. Gln inhibited TNF-α-induced p38 and cPLA₂ phosphorylation and production of the cPLA₂ metabolites. Such inhibitory activity of Gln was no longer observed in MKP-1 small interfering RNA-pretreated animals. Our data indicate that Gln inhibited TNF-α-induced cPLA₂ phosphorylation through MKP-1 induction/p38 inhibition, and suggest that the utility of Gln in inflammatory diseases in which TNF-α plays a major role in their pathogenesis.

• YAKHAK HOEJI
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• v.56 no.2
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• pp.80-85
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• 2012

Previously, we have reported that arachidonic acid (AA) appears to be involved in the induction of apoptosis in HepG2 human hepatoblastoma cells. In this study we investigated the possible role of the NADPH oxidase, a membranebound enzyme generating reactive oxygen species (ROS), in the mechanism of AA-induced apoptosis in HepG2 cells. Apoptotic cell death induced by AA was significantly suppressed by various inhibitors of the NADPH oxidase, diphenylene iodonium (DPI), apocynin (Apo) and neopterine (NP). In addition, these inhibitors of the NADPH oxidase completely blunted the AA-induced ROS elevation. Next, we investigated the implication of metabolic pathway of AA in these AA actions. Both apoptosis and ROS production induced by AA were not significantly altered by treatment with indomethacin (Indo) or nordihydroguaiaretic acid (NDGA), selective inhibitors of cyclooxygenase (COX) and lipoxygenase (LOX), respectively, suggesting that AA metabolites produced by COX or LOX may not have an essential role in the AA-induced apoptosis and ROS generation. Collectively, these results suggest that the NADPH oxidase may be a key player in the mechanism of AA-induced apoptosis in HepG2 cells. These results further suggest that NADPH oxidase may be a good target for the management of human hepatomas.

• Natural Product Sciences
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• v.21 no.4
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• pp.268-272
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• 2015

Sesquiterpene-quinone is a class of secondary metabolites frequently encountered from marine sponge. The present study was designed to examine the anti-inflammatory action of sponge-derived dactyloquinone B (DQB) and cyclospongiaquinone-1 (CSQ1) mixture using lipopolysaccharide (LPS)-induced inflammatory responses. We measured the production of nitric oxide (NO), tumor necrosis factor-alpha ($TNF-{\alpha}$), $interleukin-1{\beta}$ ($IL-1{\beta}$), and interleukin-6 (IL-6) and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein. $TNF-{\alpha}$, $IL-1{\beta}$, and IL-6 production, which increased by treatment with LPS, were significantly inhibited by DQB and CSQ1 mixture. It also decreased the production of NO production, and iNOS and COX-2 expression. Furthermore, it reduced 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced ear edema of ICR mice. These results demonstrate that sesquiterpene-quinone, DQB and CSQ1 mixture, might serve as a chemical pipeline for the development of anti-inflammatory agent.

• Biomolecules & Therapeutics
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• v.23 no.5
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• pp.414-420
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• 2015

Flavonoids, such as fisetin (3,7,3',4'-tetrahydroxyflavone), are plant secondary metabolites. It has been reported that fisetin is able to perform numerous pharmacological roles including anti-inflammatory, anti-microbial, and anti-cancer activities; however, the exact anti-inflammatory mechanism of fisetin is not understood. In this study, the pharmacological action modes of fisetin in lipopolysaccharide (LPS)-stimulated macrophage-like cells were elucidated by using immunoblotting analysis, kinase assays, and an overexpression strategy. Fisetin diminished the release of nitric oxide (NO) and reduced the mRNA levels of inducible NO synthase (iNOS), tumor necrosis factor (TNF)-${\alpha}$, and cyclooxygenase (COX)-2 in LPS-stimulated RAW264.7 cells without displaying cytotoxicity. This compound also blocked the nuclear translocation of p65/nuclear factor (NF)-${\kappa}B$. In agreement, the upstream phosphorylation events for NF-${\kappa}B$ activation, composed of Src, Syk, and I${\kappa}B{\alpha}$, were also reduced by fisetin. The phospho-Src level, triggered by overexpression of wild-type Src, was also inhibited by fisetin. Therefore, these results strongly suggest that fisetin can be considered a bioactive immunomodulatory compound with anti-inflammatory properties through suppression of Src and Syk activities.

• Korean Journal of Oriental Medicine
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• v.8 no.1
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• pp.65-74
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• 2002

Inflammation is a disease that continues to afflict large numbers of people and may cause other diseases, for example, rheumatoid arthritis, colon cancer, etc. prostaglandins(PGs), one of arachidonic acid metabolites, are major chemical mediators in the process of inflammation. In traditional herbal medicine, many kinds of herbal drugs have been widely used for the treatment of inflammation. So, we analyzed many publications until 2001 which worked on inhibition of $PGE_2$ synthesis by cyclooxygenase-2 (COX-2) with herbs and herb oriented single compounds. And then we tried to make interpretations of herbal traditional prescriptions for inflammation. There are significant correlations between herbal medicine prescribed and inhibitions of COX-2 activity. From our efforts and further researches, we expect to develop new-inflammatory herbal drugs which have more efficacy and fewer side effects.

• The Korea Journal of Herbology
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• v.28 no.2
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• pp.1-7
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• 2013

Objectives : Sesamin, a major lignan in sesame seeds, has been reported to have neuroprotective effects against in vitro ischemia and in vivo MCAo-reperfusion cerebral ischemia model, however, there is no reports in an in vivo global cerebral ischemia model. The purpose of the study was to investigate the neuroprotective effect of sesamin in global cerebral ischemia induced by four-vessel occlusion (4-VO) in rats through inhibition of microglial activation in this model. Methods : The neuroprotective effects were investigated using a 10 min of 4-VO ischemia rat model by measuring intact pyramidal neurons in the CA1 region of the hippocampus using Nissle staining. The antiinflammatory or reducing neurotoxicity effect was investigated using immunohistochemisty, RT-PCR and western blot analysis of inflammatory or neurotoxic mediators. Results : Intraperitoneal injection of sesamin at doses of 0.3, 1.0, 3.0, and 10.0 mg/kg at 0 min and 90 min after ischemia conferred 26.6%, 30.1%, 42.5%, and 30.5% neuroprotection, respectively, compared to the vehicle-treated control group. A 3.0 mg/kg dose of sesamin inhibited microglia activation and consequently, cyclooxygenase-2, inducible nitric oxide, and interleukine-$1{\beta}$ expressions at 48 h after reperfusion. Conclusions : Sesamin protects neuronal cell death through inhibition of microglial activation or the production of neurotoxic metabolites and proinflammatory mediators by microglia such as COX-2, iNOS and IL-$1{\beta}$ in global cerebral ischemia.