• Title/Summary/Keyword: Chemical-induced inhibition

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Inhibition of Osteoclast Differentiation by Wheat Bran Butanol Fraction (밀기울 부탄올 분획물이 파골세포의 분화억제에 미치는 효과)

  • Moon, Jung Sun;Moon, Seung-Hee;Shim, Bo Won;Kang, Tae Jin;Lee, Sookyeon;Yim, Dongsool
    • Korean Journal of Pharmacognosy
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    • v.44 no.3
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    • pp.257-262
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    • 2013
  • Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis, the bone mineral density is reduced, bone microarchitecture deteriorates, and the amount and variety of proteins in bone are altered. $It^{\circ}{\emptyset}s$ caused by the imbalance between born resorption and born formation. Recently natural products from plants have been extensively studied as therapeutic drugs to treat and prevent various diseases. Wheat bran is the hard outer layers of wheat grain and produced as a by-product of milling in the production of refined grains. In oriental medicines, Bu So Maek (Tritici Immaturi Semen) with wheat bran has been used as bronchitis, sedatives and anti-sweating effects. However effects of wheat bran butanol fraction (WBB, 50 ${\mu}g/ml$) in osteoclast differentiation remains unknown yet. Thus we investigated the effects of WBB on RANKL induced osteoclast differentiation. WBB inhibited osteoclast differentiation by downregulating the RANKL-induced activations of MAP kinases. Moreover mRNA expression of osteoclast-mediating molecules such as c-Fos, NFATc1 and DC-STAMP were attenuated by WBB during osteoclast differentiation. The finding of this study show that WBB and its components might prevent osteoclast-related bone loss.

PKC Downstream of PI3-Kinase Regulates Peroxynitrite Formation for Nrf2-Mediated GSTA2 Induction

  • Kim, Sang-Geon;Kim, Sun-Ok
    • Archives of Pharmacal Research
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    • v.27 no.7
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    • pp.757-762
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    • 2004
  • The protective adaptive response to electrophiles and reactive oxygen species is mediated by the induction of phase II detoxifying genes including glutathione S-transferases (GSTs). NF-E2-related factor-2 (Nrf2) phosphorylation by protein kinase C (PKC) is a critical event for its nuclear translocation in response to oxidative stress. Previously, we have shown that peroxynitrite plays a role in activation of Nrf2 and Nrf2 binding to the antioxidant response element (ARE) via the pathway of phosphatidylinositol 3-kinase (PI3-kinase) and that nitric oxide synthase in hepatocytes is required for GSTA2 induction. In view of the importance of PKC and Pl3-kinase in Nrf2-mediated GST induction, we investigated the role of these kinases in peroxynitrite formation for GSTA2 induction by oxidative stress and determined the relationship between PKC and PI3-kinase. Although PKC activation by phorbol 12-myristate-13-acetate (PMA) did not increase the extents of constitutive and inducible GSTA2 expression, either PKC depletion by PMA or PKC inhibition by staurosporine significantly inhibited GSTA2 induction by tert-butylhydroquinone (t-SHa) a prooxidant chemical. Therefore, the basal PKC activity is req- uisite for GSTA2 induction. 3-Morpholinosydnonimine (SIN-1), which decomposes and yields peroxynitrite, induced GSTA2, which was not inhibited by PKC depletion, but slightly enhanced by PKC activation, suggesting that PKC promotes peroxynitrite formation for Nrf2-mediated GSTA2 induction. Treatment of cells with S-nitroso-N-acetyl-penicillamine (SNAP), an exogenous NO donor, in combination with t-BHQ may produce peroxynitrite. GSTA2 induction by SNAP + t-BHQ was not decreased by PKC depletion, but rather enhanced by PKC activation, showing that the activity of PKC might be required for peroxynitrite formation. LY294002 a P13-kinase inhibitor blocked GSTA2 induction by t-BHQ, which was reversed by PMA-induced PKC activation. These results provide evidence that PKC may playa role in formation of peroxynitrite that activates Nrf2 for GSTA2 induction and that PKC may serve an activator for GSTA2 induction downstream of PI3-kinase.

Pharmacological Effects of ginseng Saponins on Receptor Stimulation-responses

  • Eiichi Tachikawa;Kenzo Kudo;Kazuho Harada;Takeshi Kashimoto;KatsuroFurumachi;Yoshikazu Miyate;Atsushi Kakizaki;Eiji Takahashi
    • Proceedings of the Ginseng society Conference
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    • 1998.06a
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    • pp.40-46
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    • 1998
  • We investigated the influence of the root of Panax ginseng C. A. Meyer on the secretion of catecholamines from bovine adrenal chromaffin cells, which are used as a model of nervous systems. In two major parts extracted from the ginseng root, the crude saponin fraction, but not the non-saponin fraction, reduced the secretion from the cells, stimulated by acetylcholine (ACh). Ginseng saponins (ginsenosides) are classified into three groups, the panaxadiol, the panaxatriol and the oleanolic acid groups, on the basis of the chemical structures of their saponins. Both the panaxadiol and the panaxatriol saponins, excluding only one oleanolic acid saponin ginsenoside-Ro, generally reduced the ACh-evoked secretion. The inhibitory effects of the panaxatriol were much stronger than those of the panaxadiol. However, ginsenoside-Rg, and -Rh3 in the panaxadiol saponins were the potent inhibitors comparable to the panaxatriol saponins. Ginsenoside-Rg2 in the panaxatriol was the most effective. It is probable that the ginsenoside inhibition of the catecholamine secretion is due to the suppression of the function of the nicotinic ACh receptor-cation channels. On the other hand, ginsenoside-Rg2 did not affect the angiotensin II-, the bradykinin-, the histamine- and the neurotensin- induced catecholamine secretions from the chromaffin cells and the muscarine- and the histamine- induced contraction of the ileum in guinea-pigs. Ginsenoside-Rbl, a panaxadiol saponin, and ginsenoside-Ro had no or only a slight effect on them. On the contrary, ginsenoside-Rg3 not only competitively inhibited the muscarine-induced ileum contraction but also reduced the angiotensin R -, the bradykinin-, the histamine- and the neurotensin-induced catecholamine secretions. Thus, the ginseng root contains active ingredients, namely some ginsensides, which suppress the responses induced by receptor stimulation. The inhibitory effects of ginseng saponins may be one of the action mechanisms for the pharmacological effects of the Panax ginseng root.

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Anti-inflammatory Effects of Amentoflavone on Modulation of Signal Pathways in LPS-stimulated RAW264.7 Cells

  • Lee, Eun-Jung;Shin, So-Young;Kim, Jin-Kyoung;Woo, Eun-Rhan;Kim, Yang-Mee
    • Bulletin of the Korean Chemical Society
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    • v.33 no.9
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    • pp.2878-2882
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    • 2012
  • Amentoflavone is naturally occurring bioflavonoid that is found in a number of plants. In this paper, the anti-inflammatory activity of amentoflavone in LPS-stimulated macrophages and its mode of action were examined. Using LPS-stimulated RAW264.7 macrophage cells, we found that amentoflavone exerted anti-inflammatory activities through inhibition of nitric oxide (NO) production and tumor necrosis factor (TNF)-${\alpha}$ and macrophage inflammatory protein (MIP)-2 secretion. Amentoflavone (1.0-20 ${\mu}M$) gradually inhibited nitrite production without cytotoxicity. Amentoflavone (1.0 and 10 ${\mu}M$) effectively suppressed both TNF-${\alpha}$ and MIP-2 cytokine release from LPS-stimulated RAW264.7 cells. The expression of mIL-$1{\beta}$ and mMIP-2 cytokine mRNAs was completely inhibited while expression of mMIP-1 was effectively suppressed and mTNF-${\alpha}$ expression was slightly inhibited by 10 ${\mu}M$ amentoflavone. We also demonstrated that the innate immune response to amentoflavone involves the toll-like receptor (TLR) and mitogen-activated protein kinase (MAPK) pathways. LPS-induced upregulation of p38 MAPK phosphorylation was significantly reduced by 10 ${\mu}M$ amentoflavone. These results suggest that amentoflavone exhibits effective anti-inflammatory activities through regulation of TLR4 and phosphorylation of p38 MAPKs.

Pharmacological Studies of Zizyphus Seed Extract on Central Nervous System and Blood Pressure (산조인의 중추신경 및 심혈관계에 대한 약리작용)

  • Ahn, Y.S.;Kim, K.H.;Cho, T.S.;Kim, W.J.;Hong, S.S.
    • The Korean Journal of Pharmacology
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    • v.18 no.1
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    • pp.17-22
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    • 1982
  • Zizyphus seed(Zizyphus vulgaris Lamark var. Spinosus Bunge) has long been used as hypnotics and sedatives in oriental medicine, and it is reported that the Zizyphus seed elicited a variety of pharmacologic actions besides CNS depression. Present study was undertaken to investigate the effects of Zizyphus seed on the central nervous system and on the blood pressure. The effect of Zizyphus seed on the central nervous system was measured by the influence of thiopental sleeping time and by inhibition of chemical convulsion (strychnine and pentylenetetrazol induced). Blood pressure changes by Zizyphus extract and its mode of action were investigated. The ground Zizyphus seed was extracted with hexane and methanol, consecutively and the supernatants were discarded. The precipitate was re-extracted with distilled water and the supernatant was evaporated to a dark-brownish sticky liquid, which was used as Zizyphus seed extract in this study after dissolving in saline prior to experiment. The results are as follows. 1) Zizyphus seed extract caused marked prolongation of the thiopental sleeping time in mice. 2) The chemical convulsion by strychnine and pentylenetetrazol, and the mortality by them in chicks were not affected by pretreatment of Zizyphus seed extract. 3) Zizyphus seed extract produced transient fall of blood pressure in the cat, and this hypotentive effect was blocked partially by atropine but not affected by bilateral vagotomy and/or hexamethonium, nor propranolol and, chlorpheniramine and/or cimetidine. With the above results, it may be suggested that the water extract of Zizyphus seeds contains components producing CNS depression and hypotension. Furthermore it is felt that the cholinergic effect, but not the adrenergic or histaminergic, is partly responsible for the hypotensive effect of Zizyphus seed extract.

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Euchromatin histone methyltransferase II (EHMT2) regulates the expression of ras-related GTP binding C (RRAGC) protein

  • Hwang, Supyong;Kim, Soyoung;Kim, Kyungkon;Yeom, Jeonghun;Park, Sojung;Kim, Inki
    • BMB Reports
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    • v.53 no.11
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    • pp.576-581
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    • 2020
  • Dimethylation of the histone H3 protein at lysine residue 9 (H3K9) is mediated by euchromatin histone methyltransferase II (EHMT2) and results in transcriptional repression of target genes. Recently, chemical inhibition of EHMT2 was shown to induce various physiological outcomes, including endoplasmic reticulum stress-associated genes transcription in cancer cells. To identify genes that are transcriptionally repressed by EHMT2 during apoptosis, and cell stress responses, we screened genes that are upregulated by BIX-01294, a chemical inhibitor of EHMT2. RNA sequencing analyses revealed 77 genes that were upregulated by BIX-01294 in all four hepatic cell carcinoma (HCC) cell lines. These included genes that have been implicated in apoptosis, the unfolded protein response (UPR), and others. Among these genes, the one encoding the stress-response protein Ras-related GTPase C (RRAGC) was upregulated in all BIX-01294-treated HCC cell lines. We confirmed the regulatory roles of EHMT2 in RRAGC expression in HCC cell lines using proteomic analyses, chromatin immune precipitation (ChIP) assay, and small guide RNA-mediated loss-of-function experiments. Upregulation of RRAGC was limited by the reactive oxygen species (ROS) scavenger N-acetyl cysteine (NAC), suggesting that ROS are involved in EHMT2-mediated transcriptional regulation of stress-response genes in HCC cells. Finally, combined treatment of cells with BIX-01294 and 5-Aza-cytidine induced greater upregulation of RRAGC protein expression. These findings suggest that EHMT2 suppresses expression of the RRAGC gene in a ROS-dependent manner and imply that EHMT2 is a key regulator of stress-responsive gene expression in liver cancer cells.

Discovery of Epinastine-NSAID Hybrids as Potential Anti-inflammatory Agents: Synthesis and In Vitro Nitric Oxide Production Inhibitory Activity Study

  • Woo, Hyeong Ryeol;Damodar, Kongara;Lee, Yeontaek;Lim, Soon-sung;Jeon, Sung Ho;Lee, Jeong Tae
    • Journal of the Korean Chemical Society
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    • v.64 no.2
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    • pp.79-83
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    • 2020
  • A novel pharmacophore with epinastine (1) and NSAID moieties (2-5) was designed by molecular hybridization approach. The hybrid compounds 6-9 were synthesized by EDCI/HOBt or HATU-mediated coupling of 1 with salicylic acid (2), mefenamic acid (3), indomethacin (4) and naproxen (5), respectively, and were assessed for their inhibitory effect against NO production in LPS-induced RAW-264.7 macrophages in vitro. The Hybrids were found to exhibit significant NO production inhibitory effects with half-maximal inhibitory concentration (IC50) values ranging in between 15.96 ± 1.32 and 36.68 ± 2.53 μM and were non-cytotoxic to macrophages. Comparing the inhibition concentration (IC50), cytotoxicity concentration (CC50) and in vitro efficacy index (iEI), 6 (IC50 = 17.97 ± 1.92 μM; iEI = 11.13) and 9 (IC50 = 15.96 ± 1.32 μM; iEI = 12.53) were better suited than other hybrids as well as their parent compound. Our findings signify that hybrids 6 and 9 may serve as platforms for continued investigations for the development of more efficient anti-inflammatory agents.

Studies on Pyrocatechase from a Soil Bacterium (Ⅰ). Purification and Characterization of Pyrocatechase (토양 박테리아로부터의 Pyrocatechase 에 관한 연구 (제1보). 효소정제와 특성연구)

  • Yeon-Bo Chung;Hyun-Jae Lee
    • Journal of the Korean Chemical Society
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    • v.24 no.1
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    • pp.25-33
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    • 1980
  • Pyrocatechase as a phenolytic dioxygenase was extracted from the benzoate-induced cells of a soil bacterium, a member of Pseudomonadaceae, and purified partially by DEAE-cellulose ion-exchange chromatography and Sephadex G-75 gel filtration. Final preparation of the enzyme yielding 200 fold purification over the crude extracts showed a specific activity of about 40 ${\mu}moles$ per minute per mg protein based on catechol as the substrate. The enzyme showed a very limited substrate specificity towards catechol for its catalytic activity. Based on the inhibition study with the substrate analogues, it was assumed that ortho dihydroxy groups on the aromatic ring may participate in the enzyme-substrate binding. The $K_m$ value for catechol was obtained as $1.9{\times}10^{-6}M$, and the optimum activity of the enzyme was obtained at the pH range of 7∼10 and $35^{\circ}C$. With SH-group blocking agents the enzyme was inhibited seriously. The activity of enzyme was also inhibited by the addition of some heavy metals, $Ag^+$ and $Cu^{2+}$, but was not affected by EDTA. General property of the enzyme was characterized and the possible nature of the enzyme active center was also discussed.

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Induction of Sesquiterpene Cyclase During Integrated Extraction of Sesquiterpenes from Hairy Root Cultures of Hyoscyamus muticus (Hyoscyamus muticus의 모상근배양으로부터 Sesquiterpene 화합물의 Intergration 추출시 Sesquiterpene Cyclase의 유도)

  • BACK, Kyoungwhan;SHIN, Dong Hyun;KIM, Kil Ung;De HAAS, Cynthia R.;CHAPPELL, Joseph;CURTIS Wayne R.
    • Korean Journal of Plant Tissue Culture
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    • v.24 no.5
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    • pp.273-277
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    • 1997
  • The sesquiterpene cyclase (SC) was induced and its products were accumulated in the culture media of Hyoscyamus muticus hairy roots by addition of Rhizoctonia solani extracts. The cumulative production of solavetivone was nearly doubled by integrated extraction of the products from the media during the 24 h accumulation period. Western blots with monoclonal antibodies against SC show that the enzyme levels are the same for both extracted and non-extracted cultures. SC activities measured in vitro with radioactive substrate are not significantly different. These results suggest that productivity is controlled by substrate availability within the terpenoid pathway, and feedback regulation precedes the branch-point enzyme sesquiterpene cyclase.

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Synthesis and SAR of N-Chlorophenyl Substituted Piperrazinylethyl-aminomethylpyrazoles as 5-HT3A Inhibitors

  • Lee, Byung-Hwan;Choi, In-Sung;Rhim, Hye-Whon;Choi, Kyung-Il;Nah, Seung-Yeol;Nam, Ghil-Soo
    • Bulletin of the Korean Chemical Society
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    • v.30 no.11
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    • pp.2707-2712
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    • 2009
  • 5-$HT_{3}$ receptor;5-$HT_{3A}$ receptor channel activity;Novel 5-$HT_{3}$ receptor channel current blockers;Chlorophenyl substituted piperazinylethylaminomethylpyrazoles; The 5-$HT_{3A}$ receptors are one of ligand-gated ion channels and are known to be involved in visceral pain, anxiety, or anticancer agent-induced nausea and vomiting. In present study, we designed novel skeletons based on the developed 5-$HT_{3}$ receptor antagonists and evaluated their effects on 5-$HT_{3A}$ receptor channel currents ($I_{5-HT}$) of a series of pyrazole derivatives having N-chlorophenylpiperazine functionality (6-9). We found that most of N-p-chlorophenyl substituted piperazinyl-pyrazole derivatives (7b, 7c, 7e and 7h) exhibited the high potency for the inhibition of $I_{5-HT}$, whereas the compound without chloride (6) or with m-chlorophenyl group (a serious of 8 and 9) showed the low potency. These result indicate that p-chlorophenyl group is might play an important role for increasing the inhibitory potency on $I_{5-HT}$.