Chung Mu Park

Luteolin and chicoric acid synergistically inhibited inflammatory responses via inactivation of PI3K-Akt pathway and impairment of NF-κB translocation in LPS stimulated RAW 264.7 cells

Synergistic anti-inflammatory effects of luteolin and chicoric acid, two abundant constituents of the common dandelion (Taraxacum officinale Weber), were investigated in lipopolysaccharide (LPS) stimulated RAW 264.7 cells. Co-treatment with luteolin and chicoric acid synergistically reduced cellular concentrations of nitric oxide (NO) and prostaglandin E2 (PGE2) and also inhibited expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In addition, co-treatment reduced the levels of proinflammatory cytokines, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β. Both luteolin and chicoric acid suppressed oxidative stress, but they did not exhibit any synergistic activity. Luteolin and chicoric acid co-treatment inhibited phosphorylation of NF-κB and Akt, but had no effect on extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38. This anti-inflammatory signaling cascade coincides with that affected by luteolin treatment alone. These results suggest that luteolin plays a central role in ameliorating LPS-induced inflammatory cascades via inactivation of the NF-κB and Akt pathways, and that chicoric acid strengthens the anti-inflammatory activity of luteolin through NF-κB attenuation.

Taraxacum officinale Weber extracts inhibit LPS-induced oxidative stress and nitric oxide production via the NF-κB modulation in RAW 264.7 cells.

ETHNOPHARMACOLOGICAL RELEVANCE The common dandelion (Taraxacum officinale G.H. Weber ex Wiggers, Asteraceae) has been widely used in folklore medicine to treat dyspepsia, heartburn, and spleen and liver disorders. AIM OF THE STUDY To compare the antioxidative and anti-inflammatory activities of Taraxacum officinale methanol extract (TOME) and water extract (TOWE) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and assess their constitutional differences, including luteolin, chicoric acid, and total phenol content. MATERIALS AND METHODS Antioxidative enzyme activities, nitric oxide (NO) production, and inducible NO synthase (iNOS) and nuclear factor (NF)-κB expression were estimated by biochemical analysis, the Griess reaction, reverse transcription-polymerase chain reaction, western hybridization, and electrophoretic mobility shift assay. High-performance liquid chromatography and the Folin-Ciocalteau method were used to analyze functional phytochemicals and total phenol content. RESULTS TOME and TOWE significantly reduced NO production with an IC(50) of 79.9 and 157.5 μg/mL, respectively, without cytotoxicity. Depleted glutathione (GSH) and antioxidative enzyme activities, including superoxide dismutase, catalase, GSH-peroxidase, and GSH-reductase, were restored by dandelion extracts. Both extracts inhibited LPS-stimulated iNOS gene expression and that of its transcription factor, NF-κB, in parallel with nitrite reduction. TOME showed more potent antioxidative and anti-inflammatory capacities than TOWE, which was attributable to its high total phenol, luteolin, and chicoric acid content. CONCLUSIONS These results indicate that TOME and TOWE inhibit oxidative stress and inflammatory responses through elevated de novo synthesis of antioxidative enzymes and suppression of iNOS expression by NF-κB inactivation.

TOP1 and 2, polysaccharides from Taraxacum officinale, attenuate CCl4-induced hepatic damage through the modulation of NF-κB and its regulatory mediators.

In this work, we estimate the inhibitory effect of two polysaccharides from Taraxacum officinale (TOP) on CCl(4)-induced oxidative stress and inflammation in Sprague-Dawley rats. TOP1 and 2 (304, 92 mg/kg bw) were administered for 7 days via a stomach sonde, and hepatitis was induced by a single dose of CCl(4) (50% CCl(4)/olive oil; 0.5 mL/kg bw) administration. CCl(4) significantly elevated serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities. Histopathological observation further revealed that CCl(4)-induced moderate levels of inflammatory cell infiltration, centrilobular fatty change, apoptosis, and necrosis. However, TOPs pretreatment markedly decreased AST and ALT activities as well as hepatic lesions. TOPs also increased free radical scavenging activity, as exhibited by a lowered TBARS concentration. TOPs pretreatment also reversed other hepatitis-associated symptoms, including GSH depletion, inhibited anti-oxidative enzyme activities, up-regulation of NF-kappaB and increased expression of its regulatory inflammatory mediators, such as inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-1beta. These results suggest that TOPs have a hepatoprotective effect by modulating inflammatory responses and ameliorating oxidative stress.

Amelioration of oxidative stress by dandelion extract through CYP2E1 suppression against acute liver injury induced by carbon tetrachloride in Sprague-Dawley rats.

The protective effects of common dandelion leaf water extract (DLWE) were investigated by carbon tetrachloride (CCl4) induced hepatitis in Sprague‐Dawley rats. The animals were divided into five groups: normal control, DLWE control, CCl4 control, and two DLWE groups (0.5 and 2 g/kg bw). After 1 week of administering corresponding vehicle or DLWE, a single dose of CCl4 (50% CCl4/olive oil; 0.5 mL/kg bw) was administered 24 h before killing in order to produce acute liver injury. The DLWE treatment significantly decreased CCl4‐induced hepatic enzyme activities (AST, ALT and LDH) in a dose dependent manner. Also, the obstructed release of TG and cholesterol into the serum was repaired by DLWE administration. Hepatic lipid peroxidation was elevated while the GSH content and antioxidative enzyme activities were reduced in the liver as a result of CCl4 administration, which were counteracted by DLWE administration. Furthermore, the hepatocytotoxic effects of CCl4 were confirmed by significantly elevated Fas and TNF‐? mRNA expression levels, but DLWE down‐regulated these expressions to the levels of the normal control. Highly up‐regulated cytochrome P450 2E1 was also lowered significantly in the DLWE groups. These results indicate that DLWE has a protective effect against CCl4‐induced hepatic damage with at least part of its effect being attributable to the attenuation of oxidative stress and inflammatory processes resulting from cytochrome P450 activation by CCl4. Copyright

Methionine Supplementation Accelerates Oxidative Stress and Nuclear Factor κB Activation in Livers of C57BL/6 Mice

The present study was designed to investigate whether hyperhomocysteinemia (HHcy) induced by methionine supplementation promotes oxidative stress and nuclear factor kappaB (NFkappaB) activation in livers of C57BL/6 mice when fed a 2% methionine and low folate (1 mg/kg) diet for 12 weeks. Plasma homocysteine concentrations of mice fed methionine were found to be 49 micromol/L by 12 weeks of feeding, which was five times higher than that of controls. HHcy induced by methionine feeding significantly increased oxidative stress, as measured by thiobarbituric acid-reactive substances (P < .05) in livers. This was further confirmed by lower levels of hepatic glutathione (P < .05) and elevated mRNA expressions of hepatic antioxidative enzymes, such as Cu,Zn-superoxide dismutase, catalase, glutathione reductase, and L-gulonolactone oxidase in methionine-fed animals (P < .05). Hepatic function of mice fed methionine seems to be normal, while hepatic triglyceride concentration was lowered by methionine feeding. NFkappaB nuclear binding activities of livers were higher in the methionine group than in the control group. The above results suggest that HHcy induced by methionine may promote disturbances in lipid peroxidation and antioxidant processes and be a pro-inflammatory mediator in livers of C57BL/6 mice.

Comparative effect of genistein and daidzein on the expression of MCP-1, eNOS, and cell adhesion molecules in TNF-α-stimulated HUVECs

We compared the effects of genistein and daidzein on the expression of chemokines, cell adhesion molecules (CAMs), and endothelial nitric oxide synthase (eNOS) in tumor necrosis factor (TNF)-α-stimulated human umbilical vascular endothelial cells (HUVECs). TNF-α exposure significantly increased expression of monocyte chemoattractant protein (MCP)-1, vascular adhesion molecule (VCAM)-1, and intercellular adhesion molecule-1. Genistein significantly decreased MCP-1 and VCAM-1 production in a dose-dependent manner, whereas CAM expression was not significantly lowered by genistein treatment. However, daidzein slightly decreased MCP-1 production. The effects of genistein and daidzein on MCP-1 secretion coincided with mRNA expression. Pre-treatment with either genistein or daidzein elevated eNOS expression and nitric oxide production disturbed by TNF-α exposure. A low concentration of isoflavones significantly inhibited nuclear factor (NF)κB activation, whereas a high dose slightly ameliorated these inhibitive effects. These results suggest that genistein had a stronger effect on MCP-1 and eNOS expression than that of daidzein. Additionally, NFκB transactivation might be partially related to the down-regulation of these mRNAs in TNF-α-stimulated HUVECs.

Fibrinolytic and Antiplatelet Aggregation Properties of a Recombinant Cheonggukjang Kinase

This study characterized the efficacy of recombinant Cheonggukjang kinase (CGK) 3-5-rich fraction as a thrombolytic agent, which we overexpressed in Bacillus licheniformis ATCC10716, a strain normally lacking fibrinolytic activity. We found that CGK3-5 is a plasmin-like protease that directly degrades fibrin clots and does not activate plasminogen during fibrin clot lysis and platelet-rich clot lysis assays. We also confirmed antiplatelet and antithrombotic activity by CGK3-5-rich fraction both in vitro and in vivo. CGK3-5-rich fraction inhibited collagen-induced platelet aggregation in platelet-rich plasma in a concentration-dependent manner. The concentration of 1.5 mg/mL CGK3-5-rich fraction completely inhibited collagen-induced platelet aggregation. Furthermore, injection of CGK3-5-rich fraction into tail veins dose-dependently protected mice from death by pulmonary embolism induced by collagen and epinephrine. The survival rates were 30%, 70%, and 100%, respectively, with doses of 130 mg/kg, 260 mg/kg, and 520 mg/kg. These findings suggest that CGK3-5 holds promise as a treatment to mitigate the potentially effects of stroke and heart failure.

Luteolin inhibits inflammatory responses by downregulating the JNK, NF-κB, and AP-1 pathways in TNF-α activated HepG2 cells

The inhibitory mechanism of luteolin on tumor necrosis factor (TNF)-α-induced inflammation was investigated in HepG2 cells. Luteolin significantly suppressed TNF-α-stimulated inducible nitric oxide synthase (iNOS) expression in a dose-dependent manner without cytotoxicity. Phosphorylation and nuclear translocation of both transcription factors, nuclear factor (NF)-κB and activator protein (AP)-1, were also inhibited by luteolin treatment. Additionally, luteolin suppressed TNF-α-induced c-Jun N-terminal kinase (JNK) phosphorylation, which is crucially related to regulating inflammation. SP600125, a JNK selective inhibitor, abolished the TNF-α triggered inflammatory signaling cascade. These results suggest that luteolin attenuates inflammatory responses by blocking NF-κB and AP-1 activation through suppressed JNK phosphorylation in TNF-α-stimulated HepG2 cells.

Identification of differentially expressed genes by 2,3,7,8-tetrachlorodibenzo-p-dioxin in human bronchial epithelial cells.

Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) is one of the most powerful environmental toxins and causes a variety of toxic effects in humans. Since it makes first contact with bronchial epithelial cells as an atmospheric contaminant, we identified differentially expressed genes (DEGs) in TCDD-treated human bronchial epithelial cells (HBE4-E6/E7) using an annealing control primer (ACP) system. Six genes, five upregulated and one downregulated, were isolated and their expression patterns were confirmed by reverse dot blot analysis. Their genomic sequences were used for identification, and the upregulated proteins were found to be acyl-coenzyme A dehydrogenase (VLCAD), S100 calcium binding protein A6 (S100A6), nuclear receptor co-repressor 2 (NCOR2), ribosomal protein, large, P1 (RPLP1), and tubulin α 1c, and the downregulated protein was shown to be tubulin β2. Among them, the expression of the S100A6 was further analysed by northern hybridization because of its relationship with TCDD. These results suggest that this new method was simple and convenient to identify DEGs regulated by a specific agent. Moreover, these isolated genes may provide important information to better understand the mechanisms of TCDD toxicity in human bronchial epithelial cells.