Wonmin Ko

PTP1B inhibitory and anti-inflammatory effects of secondary metabolites isolated from the marine-derived fungus Penicillium sp. JF-55.

Protein tyrosine phosphatase 1B (PTP1B) plays a major role in the negative regulation of insulin signaling, and is thus considered as an attractive therapeutic target for the treatment of diabetes. Bioassay-guided investigation of the methylethylketone extract of marine-derived fungus Penicillium sp. JF-55 cultures afforded a new PTP1B inhibitory styrylpyrone-type metabolite named penstyrylpyrone (1), and two known metabolites, anhydrofulvic acid (2) and citromycetin (3). Compounds 1 and 2 inhibited PTP1B activity in a dose-dependent manner, and kinetic analyses of PTP1B inhibition suggested that these compounds inhibited PTP1B activity in a competitive manner. In an effort to gain more biological potential of the isolated compounds, the anti-inflammatory effects of compounds 1–3 were also evaluated. Among the tested compounds, only compound 1 inhibited the production of NO and PGE2, due to the inhibition of the expression of iNOS and COX-2. Penstyrylpyrone (1) also reduced TNF-α and IL-1β production, and these anti-inflammatory effects were shown to be correlated with the suppression of the phosphorylation and degradation of IκB-α, NF-κB nuclear translocation, and NF-κB DNA binding activity. In addition, using inhibitor tin protoporphyrin (SnPP), an inhibitor of HO-1, it was verified that the inhibitory effects of penstyrylpyrone (1) on the pro-inflammatory mediators and NF-κB DNA binding activity were associated with the HO-1 expression. Therefore, these results suggest that penstyrylpyrone (1) suppresses PTP1B activity, as well as the production of pro-inflammatory mediators via NF-κB pathway, through expression of anti-inflammatory HO-1.

The Neoflavonoid Latifolin Isolated from MeOH Extract of Dalbergia odorifera Attenuates Inflammatory Responses by Inhibiting NF-κB Activation via Nrf2-Mediated Heme Oxygenase-1 Expression

In Korea and China, the heartwood of Dalbergia odorifera T. Chen is an important traditional medicine used to treat blood disorders, ischemia, swelling, and epigastric pain. In this study, we investigated the inhibitory effects of latifolin, a major neoflavonoid component isolated from the MeOH extract of D. odorifera, on the inflammatory reaction of thioglycollate‐elicited peritoneal macrophages exposed to lipopolysaccharide, with a particular focus on heme oxygenase‐1 (HO‐1) expression and nuclear factor‐κB (NF‐κB) signaling. Latifolin significantly inhibited the protein and mRNA expression of inducible nitric oxide synthase and COX‐2, reduced NO, prostaglandins E2, tumor necrosis factor‐α, and interleukin‐1β production in primary murine peritoneal macrophages exposed to lipopolysaccharide. Latifolin also suppressed inhibitor κB‐α levels, NF‐κB nuclear translocation, and NF‐κB DNA‐binding activity. Furthermore, latifolin upregulated HO‐1 expression via nuclear transcription factor‐E2‐related factor 2 (Nrf2) nuclear translocation. In addition, using inhibitor tin protoporphyrin IX (SnPP), an inhibitor of HO‐1, it was verified that the inhibitory effects of latifolin on the proinflammatory mediators and NF‐κB DNA‐binding activity were associated with the HO‐1 expression. These results suggested that the latifolin‐mediated up‐regulation of HO‐1 expression played a critical role in anti‐inflammatory effects in macrophages. This study therefore identified potent therapeutic effects of latifolin, which warrants further investigation as a potential treatment for inflammatory diseases. Copyright

The Cytoprotective Effect of Sulfuretin against tert-Butyl Hydroperoxide-Induced Hepatotoxicity through Nrf2/ARE and JNK/ERK MAPK-Mediated Heme Oxygenase-1 Expression

Sulfuretin is one of the major flavonoid components in Rhus verniciflua Stokes (Anacardiaceae) isolates. In this study, we investigated the protective effects of sulfuretin against tert-butyl hydroperoxide (t-BHP)-induced oxidative injury. The results indicated that the addition of sulfuretin before t-BHP treatment significantly inhibited cytotoxicity and reactive oxygen species (ROS) production in human liver-derived HepG2 cells. Sulfuretin up-regulated the activity of the antioxidant enzyme heme oxygenase (HO)-1 via nuclear factor E2-related factor 2 (Nrf2) translocation into the nucleus and increased the promoter activity of the antioxidant response element (ARE). Moreover, sulfuretin exposure enhanced the phosphorylation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase 1/2 (ERK1/2), which are members of the mitogen-activated protein kinase (MAPK) family. Furthermore, cell treatment with a JNK inhibitor (SP600125) and ERK inhibitor (PD98059) reduced sulfuretin-induced HO-1 expression and decreased its protective effects. Taken together, these results suggest that the protective effect of sulfuretin against t-BHP-induced oxidative damage in human liver-derived HepG2 cells is attributable to its ability to scavenge ROS and up-regulate the activity of HO-1 through the Nrf2/ARE and JNK/ERK signaling pathways. Therefore, sulfuretin could be advantageous as a bioactive source for the prevention of oxidative injury.

Tanzawaic acid derivatives from a marine isolate of Penicillium sp. (SF-6013) with anti-inflammatory and PTP1B inhibitory activities

Chemical investigation of a marine-derived fungus Penicillium sp. SF-6013 resulted in the discovery of a new tanzawaic acid derivative, 2E,4Z-tanzawaic acid D (1), together with four known analogues, tanzawaic acids A (2) and D (3), a salt form of tanzawaic acid E (4), and tanzawaic acid B (5). Their structures were mainly determined by analysis of NMR and MS data, along with chemical methods. Preliminary screening for anti-inflammatory effects in lipopolysaccharide (LPS)-activated microglial BV-2 cells showed that compounds 1, 2, and 5 inhibited the production of nitric oxide (NO) with IC50 values of 37.8, 7.1, and 42.5 μM, respectively. Compound 2 also inhibited NO production in LPS-stimulated RAW264.7 murine macrophages with an IC50 value of 27.0 μM. Moreover, these inhibitory effects correlated with the suppressive effect of compound 2 on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW264.7 and BV2 cells. In addition, compounds 2 and 5 significantly inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with the same IC50 value (8.2 μM).

Anti-neuroinflammatory effect of aurantiamide acetate from the marine fungus Aspergillus sp. SF-5921: Inhibition of NF-κB and MAPK pathways in lipopolysaccharide-induced mouse BV2 microglial cells

In the course of a search for anti-neuroinflammatory metabolites from marine fungi, aurantiamide acetate (1) was isolated from marine-derived Aspergillus sp. as an anti-neuroinflammatory component. Compound 1 dose-dependently inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in BV2 microglial cells. It also attenuated inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and other pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). In a further study designed to elucidate the mechanism of its anti-neuroinflammatory effect, compound 1 was shown to block the activation of nuclear factor-kappa B (NF-κB) in lipopolysaccharide (LPS)-induced BV2 microglial cells by inhibiting the phosphorylation of the inhibitor kappa B-α (IκB)-α. In addition, compound 1 decreased the phosphorylation levels of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (MAPKs). These results suggest that compound 1 has an anti-neuroinflammatory effect on LPS stimulation through its inhibition of the NF-κB, JNK and p38 pathways.

Penicillinolide A: A New Anti-Inflammatory Metabolite from the Marine Fungus Penicillium sp. SF-5292

In the course of studies on bioactive metabolites from marine fungi, a new 10-membered lactone, named penicillinolide A (1) was isolated from the organic extract of Penicillium sp. SF-5292 as a potential anti-inflammatory compound. The structure of penicillinolide A (1) was mainly determined by analysis of NMR and MS data and Mosher’s method. Penicillinolide A (1) inhibited the production of NO and PGE2 due to inhibition of the expression of iNOS and COX-2. Penicillinolide A (1) also reduced TNF-α, IL-1β and IL-6 production, and these anti-inflammatory effects were shown to be correlated with the suppression of the phosphorylation and degradation of IκB-α, NF-κB nuclear translocation, and NF-κB DNA binding activity. In addition, using inhibitor tin protoporphyrin (SnPP), a competitive inhibitor of HO activity, it was verified that the inhibitory effects of compound 1 on the production of pro-inflammatory mediators and NF-κB DNA binding activity were partially associated with HO-1 expression through Nrf2 nuclear translocation.

Anti-Inflammatory Effect of Methylpenicinoline from a Marine Isolate of Penicillium sp. (SF-5995): Inhibition of NF-κB and MAPK Pathways in Lipopolysaccharide-Induced RAW264.7 Macrophages and BV2 Microglia

In the course of a search for anti-inflammatory metabolites from marine-derived fungi, methylpenicinoline (1) was isolated from a marine isolate of Penicillin sp. Compound 1 inhibited lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production by suppressing the expression of inducible NO synthase (iNOS) in RAW264.7 macrophages and BV2 microglia. It also attenuated prostaglandin E2 (PGE2) production by suppressing cyclooxygenase-2 (COX-2) expression in a concentration-dependent manner (from 10 μM to 80 μM) without affecting cell viability. In addition, compound 1 reduced the production of the pro-inflammatory cytokine interleukin-1β (IL-1β). In a further study designed to elucidate the mechanism of its anti-inflammatory effects, compound 1 was shown to block nuclear factor-kappa B (NF-κB) activation in LPS-induced RAW264.7 macrophages and BV2 microglia by inhibiting the phosphorylation of inhibitor kappa B-α (IκB-α), thereby suppressing the nuclear translocation of NF-κB dimers, namely p50 and p65, that are known to be crucial molecules associated with iNOS and COX-2 expression. In addition, compound 1 inhibited the activation of mitogen-activated protein kinase (MAPK) pathways. Taken together, the results suggest that compound 1 might be a valuable therapeutic agent for the treatment of anti-inflammatory and anti-neuroinflammatory diseases.

Inhibitory effects of alternaramide on inflammatory mediator expression through TLR4-MyD88-mediated inhibition of NF-кB and MAPK pathway signaling in lipopolysaccharide-stimulated RAW264.7 and BV2 cells.

Alternaramide (1), a novel lipophilic depsipeptide, has been isolated from the extract of the marine-derived fungus Alternaria sp. SF-5016. In the course of extensive biological evaluation of 1, its anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated RAW264.7 and BV2 cells were observed. In our initial study of the anti-inflammatory effects of 1, the compound suppressed production of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated RAW264.7 and BV2 cells. Suppression of NO and PGE2 production was correlated with the inhibitory effect of 1 on expression of LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein level in RAW264.7 and BV2 cells. In addition, 1 reduced production of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-12 in LPS-stimulated RAW264.7 and BV2 cells. In the evaluation of the molecular mechanisms underlying the anti-inflammatory effects of 1, the compound was found to suppress the nuclear factor-kappa B (NF-κB) signaling pathway in RAW264.7 and BV2 cells stimulated with LPS. This suppression was mediated by disruption of phosphorylation and degradation of IκBα, an inhibitor of NF-κB, in the cytoplasm, and blocking of nuclear translocation of the NF-κB p50-p65 heterodimer. Furthermore, 1 inhibited phosphorylation of c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinase (MAPK), demonstrating its capacity to inhibit MAPK signaling. Finally, 1 markedly reduced expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) at the mRNA and protein levels in LPS-stimulated RAW264.7 and BV2 cells. Taken together, the results of the present study suggest that 1 modulates several TLR4-mediated inflammatory pathways, demonstrating its potential in the treatment of inflammatory and neuroinflammatory conditions.

Cudarflavone B Provides Neuroprotection against Glutamate-Induced Mouse Hippocampal HT22 Cell Damage through the Nrf2 and PI3K/Akt Signaling Pathways

Oxidative cell damage contributes to neuronal degeneration in many central nervous system (CNS) diseases such as Alzheimer’s disease, Parkinson’s disease, and ischemia. Nrf2 signaling-mediated heme oxygenase (HO)-1 expression acts against oxidants that are thought to play a key role in the pathogenesis of neuronal diseases. Cudraflavone B is a prenylated flavone isolated from C. tricuspidata which has shown anti-proliferative activity, mouse brain monoamine oxidase (MAO) inhibitory effects, apoptotic actions in human gastric carcinoma cells and mouse melanoma cells, and hepatoprotective activity. In this study, cudraflavone B showed neuroprotective effects and reactive oxygen species (ROS) inhibition against glutamate-induced neurotoxicity by inducing the expression of HO-1 in mouse hippocampal HT22 cells. Furthermore, cudraflavone B caused the nuclear accumulation of nuclear factor-E2-related factor 2 (Nrf2) and increased the promoter activity of antioxidant response elements (ARE) in mouse hippocampal HT22 cells. In addition, we found that the Nrf2-midiated HO-1 expression by cudraflavone B is involved in the cell protective response and ROS reductions, and cudraflavone B-induced expression of HO-1 was mediated through the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in HT22 cells. Our results demonstrated the potential application of naturally occurring cudraflavone B as a therapeutic agent from neurodegenerative disease.

Inhibitory Effects of Benzaldehyde Derivatives from the Marine Fungus Eurotium sp. SF-5989 on Inflammatory Mediators via the Induction of Heme Oxygenase-1 in Lipopolysaccharide-Stimulated RAW264.7 Macrophages

Two benzaldehyde derivatives, flavoglaucin (1) and isotetrahydro-auroglaucin (2), were isolated from the marine fungus Eurotium sp. SF-5989 through bioassay- and 1H NMR-guided investigation. In this study, we evaluated the anti-inflammatory effects of these compounds in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. We demonstrated that compounds 1 and 2 markedly inhibited LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production by suppressing inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression without affecting cell viability. We also demonstrated that the compounds reduced the secretion of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). Furthermore, compounds 1 and 2 inhibited LPS-induced nuclear factor-κB (NF-κB) activation by suppressing phosphorylation of IkappaB (IκB). These results indicated that the anti-inflammatory effects of these benzaldehyde derivatives in LPS-stimulated RAW264.7 macrophages were due to the inactivation of the NF-κB pathway. In addition, compounds 1 and 2 induced heme oxygenase-1 (HO-1) expression through the nuclear transcription factor-E2–related factor 2 (Nrf2) translocation. The inhibitory effects of compounds 1 and 2 on the production of pro-inflammatory mediators and on NF-κB binding activity were reversed by HO-1 inhibitor tin protoporphyrin (SnPP). Thus, the anti-inflammatory effects of compounds 1 and 2 also correlated with their ability of inducing HO-1 expression.