Lian Yu Guo

Seoul National University, Seoul, Seoul, South Korea

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Publications (8)16.35 Total impact

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    ABSTRACT: The roots of Angelica tenuissima have been commonly used for the treatment of cardiovascular diseases and menstrual discomfort in Asian countries, such as China and Korea. The primary volatile flavor components are essential oil ingredients, phthalide lactones. In this study, (Z)-ligustilide was tested for its anti-inflammatory activities in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. We found that (Z)-ligustilide strongly inhibitis the induction of LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at both the mRNA and protein levels in a dose-dependent manner. The transcriptional activity of nuclear factor kappa B (NF-B) was also down-regulated in a concentration-dependent manner. Further study revealed that (Z)-ligustilide inhibited the phosphorylation and subsequent degradation of IBα, an inhibitor protein of NF-B. In addition, (Z)-ligustilide inhibited the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK) and c-Jun NH(2)-terminal kinase (JNK) in a dose-dependent manner. Taken together, these data suggest that (Z)-ligustilide can exert its antiinflammatory effects by regulating the NF-B and MAPK signal pathways.
    Archives of Pharmacal Research 03/2012; 35(4):723-32. · 1.54 Impact Factor
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    ABSTRACT: Cimiside E was isolated from the Cimicifuga heracleifolia Komarov extract, which has been previously demonstrated to possess apoptotic action on gastric cancer cells. The IC(50) value of cimiside E on gastric cancer cells for 24 h was 14.58 microM. The mechanism of apoptosis was further elucidated through western blot, RT-PCR, morphology, Annexin V-FITC/PI staining and cell cycle analysis. Cell cycle arrest was induced by cimiside E in S phase at a lower concentration (30 microM) and G2/M phase at higher concentrations (60 and 90 microM). Cimiside E mediated apoptosis through the induction of the caspase cascade for both the extrinsic and intrinsic pathways. These findings suggest that cimiside E may be an effective chemopreventive agent against cancer.
    Archives of Pharmacal Research 10/2009; 32(10):1385-92. · 1.54 Impact Factor
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    ABSTRACT: Schisandrin is the main active ingredient isolated from Schisandra chinensis Baill. Recent studies have demonstrated that schisandrin exhibits anti-inflammatory effects in vivo and in vitro. In this study, we examined whether the order of lipopolysaccharide (LPS) treatment affects the mechanism of schisandrin anti-inflammatory activity. We found that the antiinflammatory mechanisms are not the same depending on whether macrophages were treated with schisandrin before or after LPS. The main difference is that inhibitor kappaBα (IκBα) degradation was not inhibited when macrophages were pretreated by LPS before schisandrin and was weakly inhibited when macrophages were pretreated by schisandrin before LPS.
    Archives of Pharmacal Research 03/2009; 32(3):399-405. · 1.54 Impact Factor
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    ABSTRACT: The anti-inflammatory effects of glycyrol, a benzofuran coumarin isolated from Glycyrrhizae Radix, were studied. Glycyrol of 5, 25 and 50 microM dose-dependently inhibited nitric oxide (NO) production by down-regulating inducible nitric oxide synthase (iNOS), and alleviated cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW264.7 macrophages, in both the mRNA and the protein. Furthermore, glycyrol dose-dependently decreased the mRNA of the pro-inflammatory cytokines IL-1beta and IL-6. LPS-induced NF-kappaB activation was prevented in RAW264.7 macrophages by inhibition of I-kappaBalpha phosphorylation. In addition, administration of glycyrol (30 and 100 mg/kg, i.p) reduced the thickness of carrageenan-induced mouse-paw edema swelling. Taken together, our results indicate that glycyrol is an important anti-inflammatory constituent of Glycyrrhizae Radix, and that its anti-inflammatory effect is attributed to the inhibition I-kappaBalpha phosphorylation.
    International Immunopharmacology 08/2008; 8(11):1524-32. · 2.42 Impact Factor
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    ABSTRACT: Schisandrin is the main active ingredient isolated from the fruit of Schisandra chinensis Baill. Recent studies have demonstrated that schisandrin exhibits anti-oxidative effects in vivo. In the present study, the effect of schisandrin on plasma nitrite concentration in lipopolysaccharide (LPS)-treated mice was evaluated. It also significantly inhibited carrageenan-induced paw edema and acetic acid-induced vascular permeability in mice. Furthermore, schisandrin had a protective effect on lipopolysaccharide (LPS)-induced sepsis. In vitro, our results are the first that show that the anti-inflammatory properties of schisandrin result from the inhibition of nitric oxide (NO) production, prostaglandin E(2) (PGE(2)) release, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression, which in turn results from the inhibition of nuclear factor-kappaB (NF-kappaB), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) activities in a RAW 264.7 macrophage cell line.
    European Journal of Pharmacology 07/2008; 591(1-3):293-9. · 2.59 Impact Factor
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    ABSTRACT: The extracts or constituents from the bark of Magnolia (M.) obovata are known to have many pharmacological activities. 4-Methoxyhonokiol, a neolignan compound isolated from the stem bark of M. obovata, was found to exhibit a potent anti-inflammatory effect in different experimental models. Pretreatment with 4-methoxyhonokiol (i.p.) dose-dependently inhibited the dye leakage and paw swelling in an acetic-acid-induced vascular permeability assay and a carrageenan-induced paw edema assay in mice, respectively. In the lipopolysaccharide (LPS)-induced systemic inflammation model, 4-methoxyhonokiol significantly inhibited plasma nitric oxide (NO) release in mice. To identify the mechanisms underlying this anti-inflammatory action, we investigated the effect of 4-methoxyhonokiol on LPS-induced responses in a murine macrophage cell line, RAW 264.7. The results demonstrated that 4-methoxyhonokiol significantly inhibited LPS-induced NO production as well as the protein and mRNA expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Furthermore, 4-methoxyhonokiol inhibited LPS-mediated nuclear factor-kappaB (NF-kappaB) activation via the prevention of inhibitor kappaB (IkappaB) phosphorylation and degradation. 4-Methoxyhonokiol had no effect on the LPS-induced phosphorylation of extracellular signal-regulated kinase (ERK), whereas it attenuated the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun NH2-terminal kinase (JNK) in a concentration-dependent manner. Taken together, our data suggest that 4-methoxyhonokiol is an active anti-inflammatory constituent of the bark of M. obovata, and that its anti-inflammatory property might be a function of the inhibition of iNOS and COX-2 expression via down-regulation of the JNK and p38 MAP kinase signal pathways and inhibition of NF-kappaB activation in RAW 264.7 macrophages.
    European Journal of Pharmacology 06/2008; 586(1-3):340-9. · 2.59 Impact Factor
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    ABSTRACT: Demethoxycurcumin and bisdemethoxycurcumin are the main active ingredients isolated from Curcumae Longae Radix. Recent studies demonstrated that both compounds exhibit antioxidative and anti-inflammatory effects as well as effects on cancer cell lines. In this study, we compared the activities of demethoxycurcumin and bisdemethoxycurcumin, and both compounds were evaluated on lipopolysaccharide (LPS)-induced nitric oxide (NO) production, inducible nitric oxide synthase (iNOS), cycloxygenase-2 (COX-2) and nuclear factor-kappaB (NF-kappaB) activity in a RAW 264.7 macrophage cell line. The evaluation:results suggested that the anti-inflammatory properties of demethoxycurcumin and bisdemethoxycurcumin were attributed to the inhibition of iNOS and COX-2 expression, as initiated by the inhibition of NF-kappaB activity. Additionally, both of them significantly inhibited carrageenan-induced paw edema in mice. Taken together, all of the results showed that the suppressive effect of demethoxycurcumin was stronger than that of bisdemethoxycurcumin, indicating that the methoxy group had enhanced demethoxycurcumin's anti-inflammation effects.
    Archives of Pharmacal Research 05/2008; 31(4):490-6. · 1.54 Impact Factor
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    ABSTRACT: The fruits of Poncirus trifoliata (L.) are widely used in Oriental medicine as a remedy for allergic inflammation. As a part of our program to screen medicinal plants for potential anti-inflammatory compounds, 21alpha-methylmelianodiol (21alpha-MMD) and 21beta-methylmelianodiol (21beta-MMD), which are two isomers of 21-methylmelianodiol isolated from the fruits of P. trifoliata for the first time, were found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. 21alpha-MMD and 21beta-MMD attenuated LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein expressions as well as the mRNA levels of iNOS, COX-2, tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta). To investigate the mechanism involved, we examined the effect of 21alpha-MMD and 21beta-MMD on LPS-induced nuclear factor-kappaB (NF-kappaB) activation. Both 21alpha-MMD and 21beta-MMD significantly inhibited LPS-induced NF-kappaB transcriptional activity in RAW 264.7 macrophages. Moreover, the in vivo anti-inflammatory effect of 21alpha-MMD was examined in two mouse models of acute inflammation. In the carrageenan-induced paw edema model, administration of 21alpha-MMD (20 and 100 mg/kg, i.p.) dose-dependently reduced paw swelling. In addition, 21alpha-MMD significantly inhibited the dye leakage in an acetic acid-induced vascular permeability assay. Taken together, our data indicate that 21-methylmelianodiol is an important constituent of the fruit of P. trifoliata, and that the inhibition of iNOS and COX-2 expression by 21alpha-MMD and 21beta-MMD might be one of the mechanisms responsible for their anti-inflammatory effects.
    European Journal of Pharmacology 11/2007; 572(2-3):239-48. · 2.59 Impact Factor