Biomedical subjects

Ae Ra Kim

Publications and source records attributed to Ae Ra Kim.

12 recordsLinked to original sources

PubMed2005

Flavonoids differentially modulate nitric oxide production pathways in lipopolysaccharide-activated RAW264.7 cells.

Naturally occurring flavonoids are known to modulate various inflammatory and immune processes. Based on structural property, in this study, molecular mechanism of flavonoids in modulating nitric oxide (NO) production and its signaling pathway were investigated using lipopolysaccharide (LPS)-activated RAW264.7 cells. Although flavonol-typed flavonoids (kaempferol and quercetin) more potently scavenged reactivity of nitric oxide (*NO) as well as peroxynitrite (ONOO-) than isoflavones (genistein and genistin), kaempferol, quercetin and genistein showed a little difference in inhibition of both inducible NO synthase expression and NO production, with IC50 values of 13.9, 20.1 and 26.8 microM. However, there was a striking pattern related to structural feature in modulation of LPS-mediated signaling pathways. Thus, flavonols only inhibited transcription factor AP-1 activation, whereas isoflavones suppressed the DNA binding activation of NF-kappaB and C/EBPbeta. Therefore, these data suggest that structural feature may be linked to decide drugs target molecule in LPS-mediated signaling pathways, rather than its potency.

Animals↗

PubMed2005

Hydroquinone modulates reactivity of peroxynitrite and nitric oxide production.

Peroxynitrite (ONOO(-)), a potent cytotoxic oxidant formed by the reaction of nitric oxide ((.-)NO) and superoxide radical ((.-)O(2)(-)), may be rapidly lethal in a cellular milieu due to oxidization and nitration processes. In the present study, hydroquinone displayed strong ONOO(-) scavenging activity and inhibitory effect on NO production in murine macrophage RAW264.7 cells. Hydroquinone strongly scavenged ONOO(-)induced dihydrorhodamine 123 oxidation in a dose-dependent manner compared with other reactive species such as (.-)O(2)(-) and (.-)NO. Hydroquinone also decreased levels of ONOO(-) induced nitrotyrosine of glutathione reductase and consequently prevented the enzyme from ONOO(-) induced damage. Furthermore, hydroquinone suppressed NO production, a cellular pathway for ONOO(-) formation, in lipopolysaccharide-activated RAW264.7 cells via inhibition of inducible NO synthase expression. The inhibitory effect by hydroquinone seems to be mediated by interruption of lipopolysaccharide-induced signalling such as activation of nuclear factor-kappaB and extracellular signalrelated kinases 1 and 2. The results suggest that hydroquinone may potently modulate reactivity of ONOO(-) and may therefore be a useful agent against ONOO(-) mediated diseases.

Animals↗

PubMed2004

Cytotoxic and pro-apoptotic activities of cynaropicrin, a sesquiterpene lactone, on the viability of leukocyte cancer cell lines.

Cynaropicrin, a sesquiterpene lactone from Saussurea lappa, has been reported to possess immunomodulatory effects on cytokine release, nitric oxide production and immunosuppressive effects. In this study, we have examined cytotoxic effect of cynaropicrin against several types of cell lines such as macrophages, eosinophils, fibroblasts and lymphocytes. Cynaropicrin potently inhibited the proliferation of leukocyte cancer cell lines, such as U937, Eol-1 and Jurkat T cells, but some other cells such as Chang liver cells and human fibroblast cell lines were not strongly suppressed by cynaropicrin treatment. The cytotoxic effect of cynaropicrin was due to inducing apoptosis and cell cycle arrest at G1/S phase, according to flow-cytometric, DNA fragmentation and morphological analyses using U937 cells. Evidence that combination treatment with l-cysteine and N-acetyl-l-cysteine, reactive oxygen species scavengers, or rottlerin (1-[6-[(3-acetyl-2,4,6-trihydroxy-5-methylphenyl)methyl]-5,7-dihydroxy-2, 2-dimethyl-2H-1-benzopyran-8-yl]-3-phenyl-2-propen-1-one), a specific protein kinase (PK) Cdelta inhibitor, abolished cynaropicrin-mediated cytotoxicity and morphological change, and that cynaropicrin-induced proteolytic cleavage of PKCdelta suggests that reactive oxygen species and PKCdelta may play an important role in mediating pro-apoptotic activity by cynaropicrin. Taken together, these results indicate that cynaropicrin may be a potential anticancer agent against some leukocyte cancer cells such as lymphoma or leukemia, through pro-apoptotic activity.

Antineoplastic Agents↗

PubMed2004

Cynaropicrin, a sesquiterpene lactone, as a new strong regulator of CD29 and CD98 functions.

Cynaropicrin is a sesquiterpene lactone displaying immunomodulatory effects on the production of cytokine and nitric oxide from macrophages/monocytes. In this study we have examined inhibitory effect of cynaropicrin on activation of major adhesion molecules [CD29 (beta1 integrins), CD43, and CD98] on the cells assessed by U937 (promonocytic cells) homotypic aggregation. Cynaropicrin potently blocked CD29 (beta1 integrins)- and CD98-induced homotypic aggregation with IC(50) values of 3.46 and 2.98 microM, respectively, without displaying cytotoxicity. Similarly, flow cytometric analysis exhibited that cynaropicrin down-regulated strikingly surface level of CD29 and CD147, a functional regulator of CD98, but not CD43. More importantly, cynaropicrin inhibition was linked to blockade of extracellular signal-related kinase (ERK) activation and distinct from other enzyme inhibitors including rottlerin, propranolol, forskolin, and chloroquine, but not cytochalasin B. Therefore, our finding is the first demonstration that cynaropicrin may be a potent functional regulator of CD29 and CD98 via interrupting ERK activation which may be linked to cytoskeleton rearrangement, suggesting further application to CD29- and CD98-mediated diseases such as virus-induced chronic inflammation, and invasion, migration, and metastasis of leukocyte cancer cells.

Antigens, CD↗

PubMed2004

Active components from Artemisia iwayomogi displaying ONOO(-) scavenging activity.

Peroxynitrite (ONOO(-)) is one of cytotoxic species produced by the reaction between superoxide (*O(2) (-)) and nitric oxide (NO). The main aim of this study was to identify ONOO(-) scavenging constituents from herbs. Methanolic extracts derived from one hundred thirty eight herbs were screened out for their ONOO(-) scavenging activities. Twenty herbs showed excellent ONOO(-) scavenging activity in a dose dependent manner. Of them, Artemisia iwayomogi, which showed the highest activity, was fractioned with several solvents. The ONOO(-) scavenging activity of fractions was in order of ethyl acetate (EtOAc) > n-butanol (BuOH) > dichloromethane (CH(2)Cl(2)) > water (H(2)O) fraction. The EtOAc and the n-BuOH fractions were further purified to isolate active principles by column chromatography. Apigenin 7-methylether (genkwanin), apigenin 7,4'-di-O methylether, jaceosidin, and scopoletin from the EtOAc fraction and chlorogenic acid, 2,4-dihydroxy 6-methoxy acetophenone 4-O-beta-D-glucoside, quebrachitol, and scopolin from the n-BuOH fraction were identified. The scavenging activities of chlorogenic acid (IC(50) = 0.52 +/- 0.04 microM), genkwanin (IC(50) = 1.01 +/- 0.10 microM), and scopoletin (IC(50) = 1.03 +/- 0.15 micro M) were higher than or comparable to a well-known ONOO(-) scavenger, penicillamine (IC(50) = 1.76 +/- 0.18 microM), suggesting that those compounds might be developed as effective ONOO(-) scavengers for, prevention of the ONOO(-)-involved diseases.

Artemisia↗

PubMed2004

Effects of dialkoxylphenyl compounds with oxime group on macrophage function and the proliferation of lymphocytes.

Dialkoxyphenyl compounds have been reported to possess anti-inflammatory activity through inhibition of phosphodieseterase (PDE) type IV. In this study, a series of derivatives of dialkoxyphenyl compounds with an oxime group, which is generally known to be one of the biologically active functional groups, were prepared and evaluated for their ability to inhibit the production of inflammatory mediators in activated macrophages and the proliferation of lymphocytes. The structure-activity relationship (SAR) study with 12 compounds on tumour necrosis factor (TNF)-alpha inhibition, analysed by the oxime geometry and different size of spacers between the oxime and phenyl group, indicated that there might be at least three possible hydrogen bonding sites in the inhibitor binding pocket of PDE IV. Of them, compound 6 clearly displayed the highest inhibitory effect on in-vitro TNF-alpha production from lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compound 6 also suppressed in-vivo TNF-alpha release from LPS-primed mice, a level comparable with that of the standard PDE IV inhibitor, rolipram. In addition, oxime compounds also significantly inhibited both nitric oxide production from activated RAW264.7 cells and T lymphocyte proliferation elicited by concanavalin A but not IL-2. The data suggest that the oxime group may act as a functional group, capable of interacting with the inhibitor-binding pocket of target PDE IV. Therefore, it is conceivable that compound 6 may have the potential either to be developed as a new anti-inflammatory drug or to be used to develop more potent analogues.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2003

In vitro anti-inflammatory and pro-aggregative effects of a lipid compound, petrocortyne A, from marine sponges.

(3 S,14 S)-Petrocortyne A, a lipid compound (a C(46) polyacetylenic alcohol), from marine sponges ( Petrosia sp.) is potently cytotoxic against several solid tumour cells. In this study, we investigated in vitro anti-inflammatory and pro-aggregative effects of petrocortyne A at non-cytotoxic concentrations on various cellular inflammatory phenomena using the macrophage and monocytic cell lines RAW264.7 and U937. Petrocortyne A blocked tumour necrosis factor-alpha (TNF-alpha) production strongly and concentration-dependently in lipopolysaccharide (LPS)-activated RAW264.7 cells and phorbol 12-myristate 13-acetate (PMA)/LPS-treated U937 cells. It also blocked NO production concentration-dependently in LPS- or interferon (IFN)-gamma-treated RAW264.7 cells. Among the migration factors tested, the compound selectively blocked the expression of hepatocyte growth factor/scatter factor (HGF/SF). On the other hand, as assessed by a cell-cell adhesion assay, petrocortyne A did not block the activation of adhesion molecules induced by aggregative antibodies to adhesion molecules, but suppressed PMA-induced cell-cell adhesion significantly. Intriguingly, petrocortyne A induced U937 homotypic aggregation following long exposure (2 and 3 days), accompanied by weak induction of pro-aggregative signals such as tyrosine phosphorylation of p132 and phosphorylation of extracellular signal-related kinase 1 and 2 (ERK 1/2). Petrocortyne A may thus inhibit cellular inflammatory processes and immune cell migration to inflamed tissue.

Acetylene↗

PubMed2003

In vitro peroxynitrite scavenging activity of diarylheptanoids from Curcuma longa.

Peroxynitrite is a cytotoxic intermediate produced by the reaction between the superoxide anion (O(2)) and nitric oxide (NO). The aim of this study was to investigate the scavenging effects of Curcuma longa L. on authentic peroxynitrite, and further studies are planned that will attempt to identify the active principles from the active fractions. The methanolic extract of C. longa showed 50% scavenging activity (IC(50)) at concentration of 1.7 +/- 0.08 micro g/ml, and was thus fractionated with several solvents. The peroxynitrite scavenging activity potential of the individual fraction was in the order of ethyl acetate > dichloromethane > water fraction. The ethyl acetate soluble fraction exhibiting strong scavenging activity was further purified by repeated silica gel column chromatography. Peroxynitrite scavenging diarylheptanoids, curcumin I (1), curcumin II (2), and curcumin III (3) were isolated as active principles. Compounds 1-3 showed the peroxynitrite scavenging activities with IC(50) values of 4.0 +/- 0.04, 6.4 +/- 0.30, and 29.7 +/- 1.29 micro M, respectively. Penicillamine as positive control exhibited IC(50) value of 2.38 +/- 0.34 micro M. The structure-activity relationship of diarylheptanoids on peroxynitrite was also discussed.

Curcuma↗

PubMed2002

Peroxynitrite scavenging activity of sinapic acid (3,5-dimethoxy-4-hydroxycinnamic acid) isolated from Brassica juncea.

Peroxynitrite (ONOO(-)), formed from a reaction of superoxide and nitric oxide, is one of the most potent cytotoxic species that are known to oxidize cellular constituents including essential proteins, lipids, and DNA. In this study, the ability of sinapic acid (3,5-dimethoxy-4-hydroxycinnamic acid), isolated from Brassica juncea, to scavenge ONOO(-) was investigated. The data obtained show that sinapic acid can efficiently scavenge native ONOO(-) as well as ONOO(-) derived from the peroxynitrite donor 3-morpholinosydnonimine hydrochloride (SIN-1). Spectrophotometric analyses revealed that sinapic acid suppressed the formation of ONOO(-)-mediated tyrosine nitration through an electron donation mechanism. In further studies, sinapic acid also showed a significant ability of inhibiting nitration of bovine serum albumin and low-density lipoprotein (LDL) in a dose-dependent manner. Sinapic acid decreased the LDL peroxidation induced by SIN-1-derived ONOO(-). The present study suggests that sinapic acid has an efficient ONOO(-) scavenging ability, which may well be a potent ONOO(-) oxidant scavenger for the protection of the cellular defense activity against the ONOO(-)-involved diseases.

Brassica↗

PubMed2002

In vitro antioxidant activity of some selected Prunus species in Korea.

In the course of the investigations of natural antioxidants, we examined the antioxidant activities of the methanol (MeOH) extracts of some selected Prunus species, including P buergeriana, P davidiana, P padus, P pendula for. ascendens, P. sargentii, P. serrulata var. spontanea and P. yedoensis by three methods as represented by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, total ROS (reactive oxygen species) and the peroxynitrite (ONOO-) scavenging activity tests. We also evaluated the activities of the organic solvent-soluble fractions, including the dichloromethane (CH2Cl2), ethyl acetate (EtOAc), n-butanol (n-BuOH) fractions and the water (H2O) layer of P serrulata var. spontanea leaves. By means of bioassay-directed fractionation, we isolated eleven known flavonoids (1-11) from the EtOAc soluble fraction of the MeOH extract of the Prunus serrulata var. spontanea leaves, exhibiting strong antioxidant activity and characterized as prunetin (1), genistein (2), quercetin (3), prunetin 4'-O-beta-glucopyranoside (4), kaempferol 3-O-alpha-arabinofuranoside (5), prunetin 5-O-beta-glucopyranoside (6), kaempferol 3-O-beta-xylopyranoside (7), genistin (8), kaempferol 3-O-beta-glucopyranoside (9), quercetin 3-O-beta-glucopyranoside (10) and kaempferol 3-O-beta-xylopyranosyl-(1-->2)-beta-glucopyranoside (11). Compounds 3 and 10 showed good activities in all tested model systems. Compounds 2 and 8 showed scavenging activities in the DPPH and ONOO- tests, while compounds 5, 7, 9 and 11 were active in the ONOO- and ROS tests. On the other hand, compounds 1, 4 and 6 did not show any activities in the tested model systems.

Animals↗

PubMed2002

Ginsenosides from Panax ginseng differentially regulate lymphocyte proliferation.

We have examined the immunosuppressive effects of representative ginsenosides (Rb1, Rb2, Re and Rg1) from Panax ginseng C. A. Meyer on CD4+ and CD8+ lymphocyte proliferation. Ginsenosides differentially modulated lymphocyte proliferation induced by concanavalin A (Con A), lipopolysaccharide (LPS), phytohemaglutinin (PHA) and interleukin-2 (IL-2). Thus, Rb1 and Re significantly enhanced Con A-induced lymphocyte proliferation, whereas Rg1 did not affect the proliferation. Interestingly, however, Rb2 strongly blocked Con A, LPS and PHA-induced lymphocyte proliferation with the IC50 values of 21.8, 29.0 and 24.0 microM, respectively. Moreover, Rb2 inhibited Con A-stimulated IL-2 production with an IC 50 of 13.3 microM. In the IL-2-stimulated CD8+ T cell (CTLL-2) proliferation assay, Re and Rg1 showed strong suppressive effects with IC50 values of 57.5 and 64.7 microM, respectively. In contrast, neither Rb1 nor Rb2 did inhibit CTLL-2 cell proliferation at tested concentrations. These results suggest that ginsenosides from P. ginseng may modulate lymphocyte proliferation in a different manner.

Animals↗

PubMed2002

Selective peroxynitrite scavenging activity of 3-methyl-1,2-cyclopentanedione from coffee extract.

It has been known that reactive oxygen and nitrogen species such as nitric oxide (NO), superoxide radical (*O2-) and their byproduct peroxynitrite (ONOO-) induce cellular and tissue injury, ultimately resulting in several human diseases. In this study, we examined scavenging effects of 3-methyl-1,2-cyclopentanedione (MCP) from coffee extract on the reactivity of those toxic molecules. MCP significantly inhibited both the oxidation of 2,7-dichlorodihydrofluorescein diacetate (H2DCFDA) by reactive oxygen species (ROS) (mainly *O2-) from kidney homogenate (41% at 100 microM) and the generation of fluorescent 4,5-diaminofluorescein (DAF-2) by NO from sodium nitroprusside (IC50 (concn producing 50% inhibition), 63.8 microM). More potently, however, MCP suppressed the oxidation of dihydrorhodamine 123 (DHR 123) to fluorescent rhodamine 123 mediated by authentic ONOO- with an IC50 value of 3.3 microM. The neutralizing effect of the reactivity of ONOO- by MCP was due to electron donation, not nitration of the compound. Additionally, MCP also decreased ONOO- formation of nitrotyrosine adducts of glutathione (GSH) reductase, and consequently protected the enzyme activity of GSH reductase against decreasing by ONOO-, indicating that MCP may prevent ONOO- -induced damage of GSH reductase. Furthermore, MCP only weakly suppressed NO production, which is one of the upstream sources of ONOO- in-vivo, suggesting that NO production may be not a pharmacological target for MCP. Taken together, our results suggest that MCP may be regarded as a selective regulator of ONOO- -mediated diseases via direct scavenging activity of ONOO-.

Blotting, Western↗