Yeong-Jong Ko

Anti-inflammatory effect of essential oil and its constituents from fingered citron (Citrus medica L. var. sarcodactylis) through blocking JNK, ERK and NF-κB signaling pathways in LPS-activated RAW 264.7 cells

We investigated the composition of essential oil from fingered citron (Citrus medica L. var. sarcodactylis) (FCEO) peels by GC-MS and its anti-inflammatory effects on lipopolysaccharide (LPS) - stimulated mouse macrophage (RAW 264.7) cells. Fifteen compounds, representing 98.97% of the essential oil, were tentatively identified; the main constituents were limonene (52.44%) and γ-terpinene (28.41%). FCEO significantly inhibited nitric oxide (NO) and prostaglandin E2 (PGE2) by suppressing the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, respectively. Additionally, FCEO suppressed the production of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6. FCEO attenuated LPS-induced nuclear factor-κB (NF-κB) activation via inhibition of inhibitor κB-α phosphorylation. Furthermore, FCEO blocked activation of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) but not that of p38 mitogen-activated protein kinase. These results indicate that FCEO inhibits LPS-stimulated inflammation by blocking the NF-κB, JNK, and ERK pathways in macrophages, and demonstrate that FCEO possesses anti-inflammatory properties.

Anti-inflammatory effects of trans-1,3-diphenyl-2,3-epoxypropane-1-one mediated by suppression of inflammatory mediators in LPS-stimulated RAW 264.7 macrophages

To assess the potential therapeutic properties of trans-1,3-diphenyl-2,3-epoxypropane-1-one (DPEP), its anti-inflammatory effects were investigated in lipopolysaccharide (LPS)-stimulated mouse macrophage (RAW 264.7) cells. DPEP induced dose-dependent reduction of the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and concomitant reduction in the production of NO and prostaglandin E(2) (PGE(2)). Additionally, DPEP suppressed the production of inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6. We investigated the mechanism by which DPEP inhibits NO and PGE(2) by examining the level of nuclear factor-κB (NF-κB) activation within the mitogen-activated protein kinase (MAPK) pathway, which is an inflammation-induced signaling pathway in RAW 264.7 cells. DPEP inhibited LPS-induced phosphorylation of ERK, JNK, and p38. Furthermore, DPEP inhibited the LPS-induced phosphorylation of inhibitor κB (IκB)-α and NF-κB p50. Taken together, the results of this study demonstrate that DPEP inhibits LPS-stimulated inflammation by blocking the NF-κB and MAPK pathways in macrophages.

Sargachromanol G inhibits osteoclastogenesis by suppressing the activation NF-κB and MAPKs in RANKL-induced RAW 264.7 cells

Inflammatory cytokines play a major role in osteoclastogenesis, leading to the bone resorption that is frequently associated with osteoporosis. Sargachromanol G (SG), isolated from the brown alga Sargassum siliquastrum, inhibits the production of inflammatory cytokines. In the present study, we determined the effect of SG on receptor activator of NF-κB ligand (RANKL)-induced osteoclast formation. SG inhibited RANKL-induced osteoclast differentiation from RAW264.7 cells without signs of cytotoxicity. Additionally, the expression of osteoclastic marker genes, such as tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), matrix metalloproteinase 9 (MMP9), and calcitonin receptor (CTR), was strongly inhibited. SG inhibited RANKL-induced activation of NF-κB by suppressing RANKL-mediated IκB-α degradation. Furthermore, SG inhibited RANKL-induced phosphorylation of mitogen activated protein kinases (p38, JNK, and ERK). This study identified SG as an inhibitor for osteoclast formation and provided evidence that natural compounds, such as SG, are an alternative medicines for preventing and treating osteolysis.

Anti-inflammatory effect and mechanism of action of Lindera erythrocarpa essential oil in lipopolysaccharide-stimulated RAW264.7 cells

The aim of this study was to investigate the chemical constituents of Lindera erythrocarpa essential oil (LEO) by gas chromatography-mass spectrometry and evaluate their inhibitory effect on the expression of pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Fifteen compounds, accounting for 63.7 % of the composition of LEO, were identified. The main compounds were nerolidol (18.73 %), caryophyllene (14.41 %), α-humulene (7.73 %), germacrene-D (4.82 %), and α-pinene (4.47 %). LEO significantly inhibited the expression of inducible nitric oxide (NO) synthase and cyclooxygenase-2, and subsequent production of NO and prostaglandin E2. In addition, it reduced the release of pro-inflammatory cytokines in LPS-activated RAW264.7 cells. The molecular mechanism underlying the effect of LEO was associated with inhibition of the phosphorylation of mitogen-activated protein kinase (MAPK). Furthermore, LEO inhibited LPS-induced phosphorylation and degradation of inhibitor of kappa B-α, which is required for the activation of the p50 and p65 nuclear factor (NF)-κB subunits in RAW264.7 cells. Taken together, these data suggest that LEO exerted its anti-inflammatory effect by downregulating LPS-induced production of pro-inflammatory mediators through the inhibition of NF-κB and MAPK signaling in RAW264.7 cells.

6-7-Dimethoxy-4-methylcoumarin suppresses pro-inflammatory mediator expression through inactivation of the NF-κB and MAPK pathways in LPS-induced RAW 264.7 cells.

In this study, we investigated the ability of 6,7-dimethoxy-4-methylcoumarin (DMC) to inhibit lipopolysaccharide (LPS)-induced expression of pro-inflammatory mediators in mouse macrophage (RAW 264.7) cells, and the molecular mechanism through which this inhibition occurred. Our results indicated that DMC downregulated LPS-induced nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, thereby reducing the production of NO and prostaglandin E2 (PGE2) in LPS-activated RAW 264.7 cells. Furthermore, DMC suppressed LPS-induced production of pro-inflammatory cytokines such as interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α. To elucidate the mechanism underlying the anti-inflammatory activity of DMC, we assessed its effects on the mitogen-activated protein kinase (MAPK) pathway and the activity and expression of nuclear transcription factor kappa-B (NF-κB). The experiments demonstrated that DMC inhibited LPS-induced phosphorylation of extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinase (JNK), and p38. In addition, it attenuated LPS-induced NF-κB activation via the inhibition of IκB-α phosphorylation. Taken together, these data suggest that DMC exerts its anti-inflammatory effects in RAW 264.7 cells through the inhibition of LPS-stimulated NF-κB and MAPK signaling, thereby downregulating the expression of pro-inflammatory mediators.

Effect of Dendrobium moniliforme on Melanogenic Protein Expression in B16F10 Melanoma Cells

Abstract The Dendrobium moniliforme extract (DME) was successively partitioned using n-hexane, CH2Cl2, EtOAc, BuOH, and water. The results indicate that the Dendrobium moniliforme fraction extracted using CH2Cl2 (DMC) was an effective inhibitor of melanogenesis in murine melanoma cells (B16F10). To elucidate the mechanism of the effect of DME on melanogenesis, we performed western blotting of the melanogenic proteins. DME inhibited tyrosinase and, tyrosinase-related protein-1 (TRP-1) and TRP-2 expressions. Futher, we confirmed that DME decreased the protein level of melanocyte-specific isoform of microphthalmia-associated transcription factor (MITF) proteins, which decreased tyrosinase and related genes in B16F10 melanoma cells. On the basis of the results, we suggest that D. moniliforme is effective against hyperpigmentation disorders and that it be considered a possible anti-melanogenic agent in topical application.