7-Methoxy-(9H-β-Carbolin-1-il)-(E)-1-Propenoic Acid, a β-Carboline Alkaloid From Eurycoma longifolia, Exhibits Anti-Inflammatory Effects by Activating the Nrf2/Heme Oxygenase-1 Pathway.

Eurycoma longifolia is an herbal medicinal plant popularly used in Southeast Asian countries. In the present study, we show that 7-methoxy-(9H-β-carbolin-1-il)-(E)-1-propenoic acid (7-MCPA), a β-carboline alkaloid isolated from E. longifolia, exerted anti-inflammatory effects by activating the nuclear factor-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. 7-MCPA inhibited lipopolysaccharide (LPS)-induced production of nitric oxide (NO), prostaglandin E2 (PGE2 ), and interleukin-6 (IL-6) in RAW264.7 cells and rescued C57BL/6 mice from LPS-induced lethality in vivo. LPS-induced expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and IL-6 was also significantly suppressed by treatment of 7-MCPA in RAW264.7 cells. 7-MCPA induced nuclear translocation of Nrf2 and increased transcription of its target genes, such as HO-1. Treating RAW264.7 cells with 7-MCPA increased the intracellular level of reactive oxygen species (ROS) and the phosphorylation level of p38 mitogen-activated protein kinase (MAPK); however, co-treatment with the antioxidant N-acetyl-cysteine (NAC) blocked 7-MCPA-induced p38 MAPK phosphorylation. Moreover, NAC or SB203580 (p38 MAPK inhibitor) blocked 7-MCPA-induced nuclear translocation of Nrf2, suggesting that 7-MCPA activated Nrf2 via a ROS-dependent p38 pathway. 7-MCPA induced HO-1 protein and mRNA expression and knockdown of Nrf2 with siRNA or SB203580 blocked 7-MCPA-mediated induction of HO-1 expression. Inhibiting Nrf2 or HO-1 abrogated the anti-inflammatory effects of 7-MCPA in LPS-stimulated RAW264.7 cells. We also demonstrated that 7-MCPA suppressed LPS-induced nuclear factor κB (NF-κB) activation. These results provide the first evidence that 7-MCPA exerts its anti-inflammatory effect by modulating the Nrf2 and NF-κB pathways and may be a potential Nrf2 activator to prevent or treat inflammatory diseases.

Nguyen HD ，Choo YY ，Nguyen TD ，Nguyen HN ，Chau VM ，Lee JH ... -  《-》

A prenylated flavonoid, 10-oxomornigrol F, exhibits anti-inflammatory effects by activating the Nrf2/heme oxygenase-1 pathway in macrophage cells.

Prenylated flavonoids are a unique class of naturally occurring flavonoids that have various pharmacological activities. In the present study, we investigated the anti-inflammatory effect in murine macrophages of a prenylated flavonoid, 10-oxomornigrol F (OMF), which was isolated from the twigs of Morus alba (Moraceae). OMF inhibited the lipopolysaccharide (LPS)-induced production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 in RAW264.7 cells, as well as in mouse bone marrow-derived macrophages (BMMs). OMF also rescued LPS-induced septic mortality in ICR mice. LPS-induced expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α and IL-6 was also significantly suppressed by OMF treatment in RAW264.7 cells. Treatment of RAW264.7 cells with OMF induced heme oxygenase (HO)-1 mRNA and protein expression and increased the nuclear translocation of the nuclear factor-E2-related factor 2 (Nrf2) as well as the expression of Nrf2 target genes, such as NAD(P)H:quinone oxidoreductase 1 (NQO1). Treatment of RAW264.7 cells with OMF increased the intracellular level of reactive oxygen species (ROS) and the phosphorylation levels of p38 mitogen-activated protein kinase (MAPK); co-treatment with the antioxidant N-acetyl-cysteine (NAC) blocked this OMF-induced p38 MAPK phosphorylation. Moreover, NAC, or SB203580 (a p38 MAPK inhibitor), blocked the OMF-induced nuclear translocation of Nrf2 and HO-1 expression, suggesting that OMF induces HO-1 expression by activating Nrf2 through the p38 MAPK pathway. Consistent with the notion that the Nrf2/HO-1 pathway has anti-inflammatory properties, inhibiting HO-1 significantly abrogated the anti-inflammatory effects of OMF in LPS-stimulated RAW264.7 cells. Taken together, these findings suggest that OMF exerts its anti-inflammatory effect by activating the Nrf2/HO-1 pathway, and may be a potential Nrf2 activator to prevent or treat inflammatory diseases.

Tran PL ，Tran PT ，Tran HNK ，Lee S ，Kim O ，Min BS ，Lee JH ... -  《-》

Anti-inflammatory activity of the water extract of Chloranthus serratus roots in LPS-stimulated RAW264.7 cells mediated by the Nrf2/HO-1, MAPK and NF-κB signaling pathways.

Chloranthus serratus is a traditional Chinese medicine for treating arthritis and bruises. To investigate the dose-effect relationship and molecular mechanisms of the water extract of C. serratus roots (WECR) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The cell viability was detected by CCK-8 method. One-step method, DCFH-DA fluorescence probe method and immunofluorescence method were used to detect nitric oxide (NO), reactive oxygen species (ROS) and p65 nuclear transcription, respectively. Interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and prostaglandin E2 (PGE2) were detected by enzyme linked immunosorbent assay. Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA were detected by quantitative real-time PCR. Western blotting was taken to determine the contents of the relevant proteins in the nuclear transcription factor E2 related factor 2/heme oxygenase-1 (Nrf2/HO-1), mitogen-activated protein kinases (MAPK) and nuclear factor-kappa B (NF-κB) pathways. The concentrations of 3, 30 and 300 μg/mL were optimized as low, medium and high concentrations of the WECR, respectively, and 1 μg/mL was selected as the optimal concentration of LPS to activate macrophages. The dose of the positive drug dexamethasone was 0.13 mg/mL. The WECR could not only inhibit LPS-induced cell differentiation and the overexpression of NO, IL-6, TNF-α, PGE2 and ROS but also promote the expression of Nrf2 and HO-1, and down-regulate the phosphorylation levels of ERK, JNK, p38 and p65. After the WECR treatment, the expression levels of iNOS and COX-2 mRNA and nuclear translocation of p65 were all inhibited. The WECR exerts its anti-inflammatory activity by inhibiting the MAPK and NF-κB pathways, activating the Nrf2/HO-1 pathway and down-regulating inflammatory factor levels in a dose-dependent manner.

Sun S ，Zhang J ，Li H ，Du Y ，Li S ，Li A ，Suo X ，Wang Y ，Sun Q ... -  《-》

Sappanone A exhibits anti-inflammatory effects via modulation of Nrf2 and NF-κB.

Homoisoflavonoids constitute a small class of natural products. In the present study, we investigated the anti-inflammatory effect of sappanone A (SPNA), a homoisoflavanone that is isolated from the heartwood of Caesalpinia sappan (Leguminosae), in murine macrophages. SPNA inhibited the production of nitric oxide (NO), prostaglandin E2 (PGE2) and interleukin-6 (IL-6) as well as the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and IL-6 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Moreover, SPNA protected C57BL/6 mice from LPS-induced mortality. Treatment of RAW264.7 cells with SPNA induced heme oxygenase (HO)-1 protein and mRNA expression and increased nuclear translocation of the nuclear factor-E2-related factor 2 (Nrf2) as well as the expression of Nrf2 target genes such as quinone oxidoreductase 1 (NQO1). Knockdown of Nrf2 by siRNA blocked SPNA-mediated HO-1 induction. SB203580, p38 mitogen-activated protein kinase (MAPK) inhibitor, blocked SPNA-induced HO-1 expression and nuclear translocation of Nrf2, suggesting that SPNA induces HO-1 expression by activating Nrf2 through the p38 MAPK pathway. Consistent with the notion that the Nrf2/HO-1 pathway has anti-inflammatory properties, inhibiting HO-1 significantly abrogated the anti-inflammatory effects of SPNA in LPS-stimulated RAW264.7 cells. Moreover, SPNA suppressed LPS-induced nuclear factor κB (NF-κB) activation via inhibiting Ser 536 phosphorylation and transcriptional activity of RelA/p65 subunit of NF-κB. Taken together, these findings suggest that SPNA exerts its anti-inflammatory effect by modulating the Nrf2 and NF-κB pathways, and may be a valuable compound to prevent or treat inflammatory diseases.

Lee S ，Choi SY ，Choo YY ，Kim O ，Tran PT ，Dao CT ，Min BS ，Lee JH ... -  《-》

Anti-inflammatory activity of Khayandirobilide A from Khaya senegalensis via NF-κB, AP-1 and p38 MAPK/Nrf2/HO-1 signaling pathways in lipopolysaccharide-stimulated RAW 264.7 and BV-2 cells.

Immunocytes-involved inflammation is considered to modulate the damage in various diseases. Herein, novel therapeutics suppressing over-activation of immunocytes could prove an effective strategy to prevent inflammation-related diseases. The objective of this study is to evaluate the anti-inflammatory activity of Khayandirobilide A (KLA), a new andirobin-type limonoid with modified furan ring isolated from the Khaya senegalensis (Desr.) A. Juss., and to explore its potential underlying mechanisms in LPS-stimulated inflammatory models. The structure of KLA was elucidated on the basis of 1D- and 2D-NMR spectroscopic data as well as HR-ESI-MS. As for its anti-inflammatory effect, the production of pro-inflammatory mediators and cytokines in LPS-stimulated RAW 264.7 and BV-2 cells were measured by Griess reagent, ELISA and qRT-PCR. The relevant proteins including nuclear factor κB (NF-κB), p-AKT, p-p38 and Nrf2/HO-1 were investigated by western blot. Nuclear localisations of NF-κB, activator protein-1 (AP-1) and Nrf2 were also examined by western blot and immunofluorescence. KLA could inhibit the production of LPS-induced NO with IC50 values of 5.04 ± 0.14 µM and 4.97 ± 0.5 µM in RAW 264.7 and BV-2 cells, respectively. KLA also attenuated interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein and mRNA levels. Further mechanistic studies demonstrated the activation of NF-κB and AP-1 were reduced by KLA. Moreover, KLA elevated expression of heme oxygenase-1(HO-1) via inducing Keap1 autophagic degradation and promoting Nrf2 nuclear translocation. Despite KLA induced the phosphorylation of mitogen-activated protein kinases (MAPKs) family, inhibiting the phosphorylation of p38 by its specific inhibitor SB203580 attenuated the degradation of KLA-induced Keap1, and then reduced KLA-induced Nrf2 nuclear translocation and HO-1 expression. Furthermore, SB203580, Brusatol (a Nrf2 specific inhibitor) and ZnPP (a HO-1 specific inhibitor) could partly reverse the suppressive effects of KLA on LPS-induced NO production and mRNA levels of pro-inflammatory genes. These data displayed that KLA possessed anti-inflammatory activity, which was attributed to inhibit the release of LPS-stimulated inflammatory mediators via suppressing the activation of NF-κB, AP-1, and upregulating the induction of p38 MAPK/Nrf2-mediated HO-1.

Zhou MM ，Zhang WY ，Li RJ ，Guo C ，Wei SS ，Tian XM ，Luo J ，Kong LY ... -  《-》