• Biomolecules & Therapeutics
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• 제12권4호
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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.

• Mycobiology
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• 제31권4호
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• pp.209-213
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• 2003

Aspergillus flavus K-03 isolated from poultry forming soil in Korea was studied for its ability to produce extracellular proteases on basal medium containing 2%(w/v) chicken feathers. The fungus was observed to be a potent producer of such enzymes. Keratinolytic enzyme secretion was the best at 15 days of incubation period at pH 9 and temperature $40^{\circ}C$. No relationship existed between the enzyme yield and increase of biomass. Enzyme production was suppressed by exogenous sugars in descending order arabinose>maltose>mannose>fructose. But glucose did not influence the enzyme activity. The keratinolytic enzyme released by the fungus demonstrated the ability to decompose keratin substrates as chicken feather when exogenous glucose was present. The keratinolytic activity was inhibited by $HgCl_2$ and serine-protease inhibitors such as phenymethylsulfonyl fluoride(100%), chymostain(88%), crystalline soybean trypsin inhibtor(80%), antipain(45%) and aprotinin(40%), and was not by cystein-protease and aspartyl-protease inhibitors. The enzyme activity is only partially inhibited by metallo-protease inhibitor. Thus, the enzyme secreted by A. flavus K-03 belongs to the alkaline serine-type protease.

• BMB Reports
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• 제30권2호
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• pp.89-94
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• 1997

In this study, during the activation of neutrophil responses by sodium fluoride. involvement of protein tyrosine kinase was studied. Respiratory burst lysosomal enzyme release and elevation of $[Ca^{2+}]_i$stimulated by sodium fluoride in neutrophils were inhibited by protein kinase inhibitors, genistein and tyrphostin. The inhibitory effect of genistein and tyrphostin on superoxide and $H_{2}O_{2}$ production was less than that of protein kinase C inhibitors, staurosporine and H-7. Staurosporine and H-7 had little or no effect on the release of myeloperoxidase and acid phosphatase stimulated by sodium fluoride. EGTA and verapamil inhibited the elevation of $[Ca^{2+}]_i$ evoked by sodium fluoride. The inhibitory effect of staurosporine on the elevation of $[Ca^{2+}]_i$ was less than that of genistein. Phorbol 12-myristate 13-acetate (PMA)-stimulated superoxide production, which is sensitive to staurosporine, was further enhanced by genistein, whereas the stimulatory action of PMA on myeloperoxidase release was inhibited by genistein. A pretreatment of neutrophils with PMA signifcantly attenuated sodium fluoride-evoked elevation of $[Ca^{2+}]_i$ These results suggest that protein tyrosine kinase may be involved in the activation process of neutrophil responses due to direct stimulation of guanine nucleotide regulatory proteins. In neutrophil responses, PMA-stimulated neutrophils appear to show a different type of inhibition of protein tyrosine kinase.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1763-1768
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• 2014

In the course of our program to search for antithrombotic and anti-inflammatory agents from plants, twelve phenolics (1-12) were isolated from the stems of Parthenocissus tricuspidata. Their structures were elucidated on the basis of spectroscopic (1D and 2D NMR, and MS) data analyses, and comparison with published data. At the concentration of $100{\mu}g/ml$, compounds 2, 4, 6 and 10 possessed potential effects on anti-blood coagulation, with inhibitory percentage of 216, 174, 148 and 225%, respectively; while aspirin used as positive control showed 181% inhibition at the same concentration. Furthermore, the anti-inflammatory activity of isolated compounds (1-12) was investigated on lipopolysaccharide (LPS)-induced murine macrophage cells (RAW264.7). Compounds 2, 4 and 6 also potential inhibited the production of nitric oxide, with $IC_{50}$ values of $11.9{\pm}0.3$, $2.9{\pm}0.2$ and $29.0{\pm}0.6{\mu}M$, respectively. Celastrol, the positive control used, gave an $IC_{50}$ value of $1.0{\pm}0.1{\mu}M$.

• Archives of Pharmacal Research
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• 제27권9호
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• pp.937-943
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• 2004

Recent investigations have shown that certain flavonoids, especially flavone derivatives, inhibit nitric oxide (NO) production by inducible NO synthase (iNOS) in macrophages, which contrib-ute their anti-inflammatory action. For the purpose of finding the optimized chemical structures of flavonoids that inhibit NO production, various A- and B-ring substituted flavones were syn-thesized and evaluated for their inhibitory activity using lipopolysaccharide-treated RAW 264.7 cells. It was found that the optimal chemical structures were A-ring 5,7-dihydroxyflavones hav-ing the B-ring 2＇,3＇-dihydroxy or 3＇,4＇-dihydroxy or 3＇,4＇-hydroxy/methoxy (methoxy/hydroxy) groups. These structurally optimized compounds were revealed to be down-regulators of iNOS induction, but not direct iNOS inhibitors. Of these derivatives that were evaluated, 2＇,3＇,5,7-tet-rahydroxyflavone and 3＇,4＇,5,7-tetrahydroxyflavone (Iuteolin) showed the strongest inhibition. The $IC_{50}$/ values for these compounds were 19.7 and 17.1 11M, respectively. Therefore, these compounds may have a potential as new anti-inflammatory agents.

• 약학회지
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• 제51권6호
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• pp.430-434
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• 2007

The anti-inflammatory activity of fruit body of Phellinus pini was investigated by activity-guided fractionation. From the screening of each fraction for the inhibitory activity of NO production in lipopolysaccaride (LPS) activated RAW 264.7 cells, methanol extract and its hexane soluble fraction of Phellinus pini exhibited inhibition of NO production compared with LPS control without toxicity. The hexane soluble fraction showed dose-dependent inhibition of NO production. The active hexane fraction was repeatedly chromatographed over silica gel, ergosta-7,24(28)-dien-3-ol(1) and ergosterol peroxide (2) were isolated and identified. Ergosterol derivatives were inhibited NOS activation, $IC_{50}$ of them were $18.9{\pm}3.9{\mu}M$ (1) and $20.4{\pm}4.5{\mu}M$ (2).

• Natural Product Sciences
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• 제18권3호
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• pp.183-189
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• 2012

It is well known that inflammation is associated with neurodegenerative disorders, including Alzheimer' disease, Parkinson's disease and ischemia. Nitric oxide (NO), a pro-inflammatory mediator, is produced by inducible NO synthase (iNOS) in microglia as well as macrophages and appears to account for neurodegeneration. In this study, we aimed to isolate NO inhibitors from Pyrus pyrifolia by activity guided purification. As a result, we identified daucosterol and ${\beta}$-sitosterol, which have not been isolated from this plant before. This article also describes NO inhibitory activities of the methanol extract of Pyrus pyrifolia fruit and the isolated compounds from this, which are lupeol, betulin, betulinic acid, ${\beta}$-sitosterol and daucosterol, in LPS-activated RAW 264.7 and BV2 cell lines. Western blot analysis was performed to clarify the underlying mechanism of NO inhibition in the two cell lines.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.102-102
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• 2003

The inhibitors of prostaglandin biosynthesis and nitric oxide production by corresponding inducible isozyme have been considered as potential anti-inflammatory and cancer chemopreventive agents. In our continuous search for cancer chemopreventive agents from natural products, we have evaluated the inhibitory potential of PGE$_2$and NO production in lipopolysaccharide (LPS)-induced mouse macrophage RAW264.7 cells. As a result, pinosylvin (3,5-dihydroxy-trans-stilbene), a stilbenoid, mainly found from the heartwood and leaves of the Pinus sylvestris, showed potential inhibitory activity of LPS-induced PGE$_2$and NO production in a dose-dependent manner. Pinosylvin also suppressed the LPS-induced iNOS protein expression. Further study revealed that pinosylvin exhibited antioxidant activity by the DPPH free radical scavenging potential and inhibitory effect of xanthine oxidase activity. In addition, pinosylvin inhibited COX -2 overexpressed human colon cancer cell (HT-29) growth in a time- and dose-dependent manner. These findings suggest that pinosylvin might be a promising candidate for developing cancer chemopreventive agent.

• Animal Bioscience
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• 제34권12호
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• pp.2023-2033
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• 2021

Objective: The present study was conducted to assess the effect of urease inhibitor (hydroquinone [HQ]) and nitrification inhibitor (dicyandiamide [DCD]) on nitrogen (N) use efficiency of pig slurry for perennial ryegrass regrowth yield and its environmental impacts. Methods: A micro-plot experiment was conducted using pig slurry-urea ¹⁵N treated with HQ and/or DCD and applied at a rate of 200 kg N/ha. The flows of N derived from the pig slurry urea to herbage regrowth and soils as well as soil N mineralization were estimated by tracing pig slurry-urea ¹⁵N, and the N losses via ammonia (NH₃), nitrous oxide (N₂O) emission, and nitrate (NO₃^-) leaching were quantified for a 56 d regrowth of perennial ryegrass (Lolium perenne) sward. Results: Herbage dry matter at the final regrowth at 56 d was significantly higher in the HQ and/or DCD applied plots, with a 24.5% to 42.2% increase in ¹⁵N recovery by herbage compared with the control. Significant increases in soil ¹⁵N recovery were also observed in the plots applied with the inhibitors, accompanied by the increased N content converted to soil inorganic N (NH₄⁺+NO₃^-) (17.3% to 28.8% higher than that of the control). The estimated loss, which was not accounted for in the herbage-soil system, was lower in the plots applied with the inhibitors (25.6% on average) than that of control (38.0%). Positive effects of urease and/or nitrification inhibitors on reducing N losses to the environment were observed at the final regrowth (56 d), at which cumulative NH₃ emission was reduced by 26.8% (on average 3 inhibitor treatments), N₂O emission by 50.2% and NO₃^- leaching by 10.6% compared to those of the control. Conclusion: The proper application of urease and nitrification inhibitors would be an efficient strategy to improve the N use efficiency of pig slurry while mitigating hazardous environmental impacts.

• Journal of Ginseng Research
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• 제22권3호
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• pp.181-187
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• 1998

Nitric Oxide (NO), derived from L-arginine, is produced by two types (constitutive and inducible) of nitric oxide synthase (NOS). The NO produced in large amounts by the inducible NOS is known to be responsible for the vasodilation and hypotension observed in septic shock. We have found three polyacetylene compounds which inhibited the production of NO in LPS-activated RAW 264.7 cells. Their structures were identified as panauynol, ginsenoyne A and PQ-6 by the spec- troscopic analysis (IC50 values were 32.3 $\mu$M, 2.3 $\mu$M, 1.5 $\mu$M, respectively). These polyacetylenes may be useful candidates for the development of new drug to treat endotoxemia and inflammation accompanied by the overproduction of NO.