Dong-Hwan Sohn

Isoliquiritigenin, from Dalbergia odorifera, up-regulates anti-inflammatory heme oxygenase-1 expression in RAW264.7 macrophages.

Abstract.Objectives:Isoliquiritigenin (ISL), one of the major constituents of Dalbergia odorifera T. Chen (Leguminosae), is reported to exert anti-inflammatory effects, but the relevant anti-inflammatory mechanisms are not completely understood. Heme oxygenase-1 (HO-1) has been proven to be involved in the resolution of inflammatory responses. In this study, we investigated whether ISL could induce HO-1 expression in RAW264.7 macrophages, and if so, whether HO-1 could mediate the anti-inflammatory effects of ISL.Methods:The protein expression of inducible nitric oxide synthase and HO-1 was analyzed by western blot analysis. The production of nitric oxide (NO) and interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) was assayed by Griess and ELISA, respectively. The TNF-α and HO-1 mRNA expression was analyzed by northern blot analysis.Results:ISL markedly suppressed LPS-induced NO, IL-1β, and TNF-α production. ISL induced HO-1 expression through the extracellular signal-regulated kinase1/2 pathway in RAW264.7 macrophages. The effects of ISL on LPS-induced NO and TNF-α production were reversed by the HO-1 inhibitor, tin protoporphyrin.Conclusions:ISL is an effective HO-1 inducer capable of inhibiting macrophage-derived inflammation.

Antibacterial activity of Ecklonia cava against methicillin-resistant Staphylococcus aureus and Salmonella spp.

Ecklonia cava is a brown alga (Laminariales, Phaeophyta) growing on the subtidal rocky shores of Korea. It has antioxidant, antidiarrhea, and anticoagulant effects. In this study, the antimicrobial activity of E. cava EtOH extract and its fractions (n-hexane, CH2Cl2, EtOAc, n-BuOH, and H2O) were investigated against methicillin-resistant Staphylococcus aureus and Salmonella spp. The E. cava EtOAc fraction showed good antibacterial activity against all bacteria. Eckol isolated from E. cava EtOAc fraction showed antimicrobial activity against all the tested strains. The minimum inhibitory concentration of eckol against S. aureus strains ranged from 125 to 250 microg/mL and 125 to 250 microg/mL for Salmonella strains. The fraction inhibitory concentration index of eckol in combination with ampicillin ranged from 0.31 to 0.5, indicating remarkable synergism against S. aureus. However, against Salmonella gallinarum ATCC 9184 and Salmonella typhimurium, it ranges from 0.75 to 1.0. The combinations of eckol + ampicillin exhibited improved inhibition of S. aureus and Salmonella with synergy or additive effect. We suggest that eckol ingredients of the E. cava against S. aureus and Salmonella have antibacterial activity.

Costunolide inhibits production of tumor necrosis factor-α and interleukin-6 by inducing heme oxygenase-1 in RAW264.7 macrophages

Abstract.Objectives:Heme oxygenase (HO)-1 expression via nuclear factor-erythroid 2-related factor 2 (Nrf2) activation has an ability to inhibit tumor necrosis factor (TNF)-α and interleukin (IL)-6 production. Costunolide has been reported to inhibit IL-1 production, but whether other cytokines could be inhibited remains to be confirmed. We investigated the effects of costunolide and its components (α-methylene-γ-butyrolactone; CH2-BL, α-methyl-γ-butyrolactone; CH3-BL, and γ-butyrolactone; BL) on HO-1 expression as well as TNF-α and IL-6 production in RAW264.7 macrophages.Methods:HO-1 expression and Nrf2 nuclear accumulation were analyzed by Western blot analysis. The production of TNF-α and IL-6 in RAW264.7 macrophages stimulated with lipopolysaccharide (LPS) was assayed by ELISA.Results:Costunolide and CH2-BL induced HO-1 expression and Nrf2 nuclear accumulation, whereas CH3-BL and BL did not. Pre-incubation with costunolide inhibited LPS-induced production of TNF-α and IL-6. The inhibitory effects of costunolide on TNF-α and IL-6 production were abrogated by tin protoporphyrin, an HO inhibitor.Conclusions:Costunolide is an effective HO-1 inducer capable of inhibiting macrophage-derived pro-inflammatory cytokines. CH2-BL moiety of costunolide is essential for Nrf2 activation leading to HO-1 expression.

An isocoumarin with hepatoprotective activity in Hep G2 and primary hepatocytes from Agrimonia pilosa.

Phytochemical investigation of the aqueous extract of the roots of Agrimonia pilosa Ledeb. (Rosaceae), as guided by hepatoprotective activityin vitro, furnished two isocoumarins, agrimonolide (1) and agrimonolide 6-O-β-D-glucoside (3), and (+)-catechin (2). Compound 1 showed hepatoprotective effects on both tacrine-induced cytotoxicity in human liver-derived Hep G2 cells andtert-butyl hydroperoxide-induced cytotoxicity in rat primary hepatocytes with EC50 values of 88.2 ± 2.8 and 37.7 ± 1.6 μM, respectively.

In Vitro hepatoprotective compounds from Suaeda glauca

Bioassay-guided fractionation of the MeOH extract of Suaeda glauca yielded four phenolic compounds, methyl 3,5-di-O-caffeoyl quinate (1) and 3,5-di-O-caffeoyl quinic acid (2), isorhamnetin 3-O-β-D-galactoside (3), and quercetin 3-O-β-D-galactoside (4). Compounds 1 and 2 were hepatoprotective against tacrine-induced cytotoxicity in human liver-derived Hep G2 cells with the EC50 values of 72.7±6.2 and 117.2±10.5 μM, respectively. Silybin as a positive control showed an EC50 value of 82.4±4.1 μM.

Salvia miltiorrhiza Bunge and its active component cryptotanshinone protects primary cultured rat hepatocytes from acute ethanol-induced cytotoxicity and fatty infiltration.

Alcoholic liver disease involves hepatocellular injury induced by the acute or chronic consumption of ethanol. Fatty infiltration is usually followed by inflammation and focal necrosis, which can lead to cirrhosis if not treated properly in the initial stage. There have been many attempts to develop effective therapies for the disease, using natural products derived from medicinal plants. In this study, we report that the standardized fraction of Salvia miltiorrhiza Bunge (Sm-SF) and its active component, cryptotanshinone, were able to protect hepatocytes from lipopolysaccharide- and ethanol-induced cell death. They also suppressed ethanol-induced lipid accumulation as evidenced by the Nile red binding assay. The ethanol-induced activation and nuclear translocation of sterol regulatory element-binding protein-1 and the consequent transactivation of the target genes involved in fatty acid biosynthesis were inhibited by Sm-SF and cryptotanshinone in a dose-dependent manner. Cryptotanshinone, an active component of S. miltiorrhiza, has the potential to ameliorate alcoholic liver disease by blocking hepatic cell death and fatty acid synthesis.

Cytoprotective constituent of hoveniae lignum on both hep G2 cells and rat primary hepatocytes

A phytochemical investigation of the EtOH extract of Hoveniae Lignum yielded four phenolic compounds, phloretin (1), 5-(4′-hydroxyphenyl)-γ-valerolactone (2), (-)-epiafzelechin (3), and maesopsin (4). Compound1 was hepatoprotective against tacrine-induced cytotoxicity in human liver-derived Hep G2 cells with an EC50 value of 37.55 ± 0.42 μM. Compound1 (0.4-200 μM) also significantly reduced tert-butyl hydroperoxide-induced cytotoxicity in rat primary hepatocytes as measured by the cellular leakage of lactate dehydrogenase and the level of aspartate transaminase.

A new monoterpene glycoside and antibacterial monoterpene glycosides fromPaeonia suffruticosa

Antibacterial activity-guided fractionation of the CHCl3−MeOH (1∶1) extract ofPaeonia suffruticosa root bark furnished three monoterpene glycosides, 6-O-vanillyoxypaeoniflorin (1), mudanpioside-H (2), and galloyl-oxypaeoniflorin (3). Of the isolated compounds, compound1 is a new compound. All isolated compounds showed broad, but moderate, antibacterial activity with minimum inhibitory concentration (MIC) values in the range of 100 to 500 μg/mL against eighteen pathogenic microorganisms of concern for public health or zoonosis.

Modulation of Atg5 expression by globular adiponectin contributes to autophagy flux and suppression of ethanol-induced cell death in liver cells

Globular adiponectin (gAcrp) protects liver cells from ethanol-induced apoptosis via induction of autophagy. However, the underlying mechanisms are unknown. The present study aims to investigate the potential role of autophagy-related protein 5 (Atg5), an essential Atg for the elongation of autophagosomes, in suppression of ethanol-induced cytotoxicity by gAcrp. Here, we demonstrated that suppression of Atg5 expression by ethanol was restored by pretreatment with gAcrp both in primary rat hepatocytes and human hepatoma cell line (HepG2). Moreover, ethanol-induced accumulation of p62 (sequestosome1), a marker of autophagic flux, was restored by gAcrp treatment, implying that gAcrp modulates autophagic flux in liver cells. Further, Atg5 silencing prevented p62 degradation by gAcrp, suggesting that Atg5 plays a critical role in induction of autophagic flux by gAcrp. Interestingly, gene silencing of Atg5 by siRNA abrogated restoration of autophagosome formation by gAcrp in ethanol-treated cells. Finally, protection of liver cells by gAcrp from ethanol-induced apoptosis was also significantly attenuated by knocking-down of Atg5 expression, suggesting an important role of Atg5 in autophagy induction and cellular apoptosis modulated by gAcrp. Taken together, our data demonstrated that Atg5 expression, at least in part, is implicated in gAcrp-induced autophagy and subsequent anti-apoptotic effects in ethanol-treated liver cells.

DA-9601 inhibits activation of the human mast cell line HMC-1 through inhibition of NF-κB

Mast cell-mediated allergic inflammation is involved in many diseases such as asthma, sinusitis, and rheumatoid arthritis. Mast cells induce synthesis and production of pro-inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 with immune regulatory properties. The formulated ethanol extract of Artemisia asiatica Nakai (DA-9601) has been reported to have antioxidative and anti-inflammatory activities. In this report, we investigated the effect of DA-9601 on the expression of pro-inflammatory cytokines by the activated human mast cell line HMC-1 and studied its possible mechanisms of action. DA-9601 dose-dependently decreased the gene expression and production of TNF-α, IL-1β, and IL-6 on phorbol 12-myristate 13-acetate (PMA)- and calcium ionophore A23187-stimulated HMC-1 cells. In addition, DA-9601 attenuated PMA- and A23187-induced activation of NF-κB as indicated by inhibition of degradation of IκBα, nuclear translocation of NF-κB, NF-κB/DNA binding, and NF-κB-dependent gene reporter assay. Our in vitro studies provide evidence that DA-9601 might contribute to the treatment of mast cell-derived allergic inflammatory diseases.