An Arylbenzofuran, Stilbene Dimers, and Prenylated Diels-Alder Adducts as Potent Diabetic Inhibitors from Morus bombycis Leaves.

Morus bombycis has a long history of usage as a treatment for metabolic diseases, especially, diabetes mellitus (DM). Thus, we aimed to isolate and evaluate bioactive constituents derived from M. bombycis leaves for the treatment of DM. According to bioassay-guided isolation by column chromatography, eight compounds were obtained from M. bombycis leaves: two phenolic compounds, p-coumaric acid (1) and chlorogenic acid methyl ester (2), one stilbene, oxyresveratrol (3), two stilbene dimers, macrourin B (4) and austrafuran C (6), one 2-arylbenzofuran, moracin M (5), and two Diels-Alder type adducts, mulberrofuran F (7) and chalcomoracin (8). Among the eight isolated compounds, the anti-DM activity of 3-8 (which possess chemotaxonomic significance in Morus species) was evaluated by inhibition of α-glucosidase, protein tyrosine phosphatase 1B (PTP1B), human recombinant aldose reductase (HRAR), and advanced glycation end-product (AGE) formation as well as by scavenging peroxynitrite (ONOO-), which are crucial therapeutic targets of DM and its complications. Compounds 4 and 6-8 significantly inhibited α-glucosidase, PTP1B, and HRAR enzymes with mixed-type and non-competitive-type inhibition modes. Furthermore, the four compounds had low negative binding energies in both enzymes according to molecular docking simulation, and compounds 3-8 exhibited strong antioxidant capacity by inhibiting AGE formation and ONOO- scavenging. Overall results suggested that the most active stilbene-dimer-type compounds (4 and 6) along with Diels-Alder type adducts (7 and 8) could be promising therapeutic and preventive resources against DM and have the potential to be used as antioxidants, anti-diabetic agents, and anti-diabetic complication agents.

Inhibition Mechanism of Components Isolated from Morus alba Branches on Diabetes and Diabetic Complications via Experimental and Molecular Docking Analyses.

Previously, we reported the anti-diabetic effect of Morus alba root bark and the compounds therein. In our continuous study of other parts of this plant, the ability of the branch of Morus alba to inhibit α-glucosidase, protein tyrosine phosphatase 1B (PTP1B), and advanced glycation end products (AGEs) formation was evaluated. Moreover, there are no previous studies that have performed enzyme kinetics and molecular docking analyses, along with assessments of peroxynitrite (ONOO-) inhibitory activities. Since the Morus alba branch exhibited favorable inhibitory effects, repeated column chromatography was performed to obtain eight compounds, including four flavonoids (1, 3, 6, 8), one arylbenzofuran (2), one stilbene (5), one Diels-Alder-type adduct (7), and one sterol (4). Among them, compounds 1-3 and 5-7 were mixed-type inhibitors of α-glucosidase, sharing the same catalytic residues with acarbose and the same allosteric sites with (Z)-3-bytylidenephthalide. On the other hand, kuwanon C (1) and oxyresveratrol (5) interacted with residues of the allosteric site (α3 and α6 helices) of PTP1B, indicating their use as non-competitive inhibitors. Interestingly, kuwanon G (7) directly bound the catalytic site, or interrupted the binding between the substrate and the active site, as a mixed-type inhibitor. Moreover, most of the compounds exhibited greater activity against AGE formation and ONOO- than positive controls. The IC50 values required to inhibit ONOO- using compounds 1, 3, 5, 6, and 7 were reported for the first time, and range from 1.08 to 12.92 µM. Based on the structure-activity relationship, the presence of hydroxyl, resorcinol, and prenyl moieties was important in the prevention of diabetes' pathological mechanisms, and these findings have been further supported by molecular docking analysis. These computational and experimental results will be useful in the development of therapeutic candidates to prevent/treat diabetes and its complications.

Structural Bases for Hesperetin Derivatives: Inhibition of Protein Tyrosine Phosphatase 1B, Kinetics Mechanism and Molecular Docking Study.

In the present study, we investigated the structure-activity relationship of naturally occurring hesperetin derivatives, as well as the effects of their glycosylation on the inhibition of diabetes-related enzyme systems, protein tyrosine phosphatase 1B (PTP1B) and α-glycosidase. Among the tested hesperetin derivatives, hesperetin 5-O-glucoside, a single-glucose-containing flavanone glycoside, significantly inhibited PTP1B with an IC50 value of 37.14 ± 0.07 µM. Hesperetin, which lacks a sugar molecule, was the weakest inhibitor compared to the reference compound, ursolic acid (IC50 = 9.65 ± 0.01 µM). The most active flavanone hesperetin 5-O-glucoside suggested that the position of a sugar moiety at the C-5-position influences the PTP1B inhibition. It was observed that the ability to inhibit PTP1B is dependent on the nature, position, and number of sugar moieties in the flavonoid structure, as well as conjugation. In the kinetic study of PTP1B enzyme inhibition, hesperetin 5-O-glucoside led to mixed-type inhibition. Molecular docking studies revealed that hesperetin 5-O-glucoside had a higher binding affinity with key amino residues, suggesting that this molecule best fits the PTP1B allosteric site cavity. The data reported here support hesperetin 5-O-glucoside as a hit for the design of more potent and selective inhibitors against PTP1B in the search for a new anti-diabetic treatment.

Alterations of amygdala-prefrontal cortical coupling and attention deficit/hyperactivity disorder-like behaviors induced by neonatal habenula lesion: normalization by Ecklonia stolonifera extract and its active compound fucosterol.

Alterations of monoamine transmission in mesocorticolimbic regions have been suggested in the pathophysiology of attention deficit/hyperactivity disorder (ADHD). The habenula is an important brain area in regulation of monoamine transmission. In this study, we investigated behavioral and electrophysiological alterations induced by neonatal habenula lesion (NHL) in rats. In NHL rats, age-dependent behavioral alterations relevant to the ADHD symptoms, such as hyperlocomotion, impulsivity, and attention deficit, were observed. Local field potentials (LFPs) in mesocorticolimbic regions of anesthetized rats were examined with in vivo electrophysiological recordings. Abnormally enhanced synchronization of slow (delta) and fast (gamma) LFP oscillations between the amygdala (AMY) and prefrontal cortex (PFC) was found in juvenile, but not in adult, NHL rats. We further examined the effects of an extract and the active compound from the perennial large brown algae Ecklonia stolonifera (ES), which have previously been demonstrated to modulate monoamine transmission, on these NHL-induced alterations. One week of ES extract treatments normalized the NHL-induced behavioral alterations, whereas the active compound fucosterol improved attention deficit and impulsivity, but not hyperlocomotion, in NHL rats. Consistent with the behavioral effects, ES extract treatments also normalized augmented AMY-PFC coupling. These results suggest that altered limbic-cortical information processing may be involved in ADHD-like behavioral alterations induced by NHL, which could be ameliorated by the natural substance, such as ES that affects monoamine transmission.

Erratum to "Protective Effects of Ecklonia stolonifera Extract on Ethanol-Induced Fatty Liver in Rats" [Biomol.Ther. 24 (2016) 650-658].

The authors request to correct the figures of Table 4 from '11.80' to '118.00' on the serum free fatty acid of the 3rd column (ED) and from '10.30' to '103.00' on the serum fatty acid of the 5th column (ESL). Also, the authors request to correct all term 'liver index' from 'fatty liver index' on the 21th, 27th, 30th line of left column of page 654 and the 8th line of right column of page 656.

Protective Effects of Ecklonia stolonifera Extract on Ethanol-Induced Fatty Liver in Rats.

Chronic alcohol consumption causes alcoholic liver disease, which is associated with the initiation of dysregulated lipid metabolism. Recent evidences suggest that dysregulated cholesterol metabolism plays an important role in the pathogenesis of alcoholic fatty liver disease. Ecklonia stolonifera (ES), a perennial brown marine alga that belongs to the family Laminariaceae, is rich in phlorotannins. Many studies have indicated that ES has extensive pharmacological effects, such as antioxidative, hepatoprotective, and antiinflammatory effects. However, only a few studies have investigated the protective effect of ES in alcoholic fatty liver. Male Sprague-Dawley rats were randomly divided into normal diet (ND) (fed a normal diet for 10 weeks) and ethanol diet (ED) groups. Rats in the ED group were fed a Lieber-DeCarli liquid diet (containing 5% ethanol) for 10 weeks and administered ES extract (50, 100, or 200 mg/kg/day), silymarin (100 mg/kg/day), or no treatment for 4 weeks. Each treatment group comprised of eight rats. The supplementation with ES resulted in decreased serum levels of triglycerides (TGs), total cholesterol, alanine aminotransferase, and aspartate aminotransferase. In addition, there were decreases in hepatic lipid and malondialdehyde levels. Changes in liver histology, as analyzed by Oil Red O staining, showed that the ES treatment suppressed adipogenesis. In addition, the ES treatment increased the expression of fatty acid oxidation-related genes (e.g., PPAR-α and CPT-1) but decreased the expression of SREBP 1, which is a TG synthesis-related gene. These results suggest that ES extract may be useful in preventing fatty acid oxidation and reducing lipogenesis in ethanol-induced fatty liver.

PTP1B, α-glucosidase, and DPP-IV inhibitory effects for chromene derivatives from the leaves of Smilax china L.

Two new flavonoids, bismilachinone (11) and smilachinin (14), were isolated from the leaves of Smilax china L. together with 14 known compounds. Their structures were elucidated using spectroscopic methods. The PTP1B, α-glucosidase, and DPP-IV inhibitory activities of compounds 1-16 were evaluated at the molecular level. Among them, compounds 4, 7, and 10 showed moderate DPP-IV inhibitory activities with IC50 values of 20.81, 33.12, and 32.93 µM, respectively. Compounds 3, 4, 6, 11, 12, and 16 showed strong PTP1B inhibitory activities, with respective IC50 values of 7.62, 10.80, 0.92, 2.68, 9.77, and 24.17 µM compared with the IC50 value for the positive control (ursolic acid: IC50 = 1.21 µM). Compounds 2-7, 11, 12, 15, and 16 showed potent α-glucosidase inhibitory activities, with respective IC50 values of 8.70, 81.66, 35.11, 35.92, 7.99, 26.28, 11.28, 62.68, 44.32, and 70.12 µM. The positive control, acarbose, displayed an IC50 value of 175.84 µM. In the kinetic study for the PTP1B enzyme, compounds 6, 11, and 12 displayed competitive inhibition with Ki values of 3.20, 8.56, and 5.86 µM, respectively. Compounds 3, 4, and 16 showed noncompetitive inhibition with Ki values of 18.75, 5.95, and 22.86 µM, respectively. Molecular docking study for the competitive inhibitors (6, 11, and 12) radically corroborates the binding affinities and inhibition of PTP1B enzymes. These results indicated that the leaves of Smilax china L. may contain compounds with anti-diabetic activity.

Desmethylanhydroicaritin isolated from Sophora flavescens, shows antitumor activities in U87MG cells via inhibiting the proliferation, migration and invasion.

This study is the first report of the antitumor activities of desmethylanhydroicaritin (DMAI) isolated from Sophora flavescens on U87MG cells. Human glioblastoma is one of the most aggressive malignant type of brain tumors and highly diffuses to around normal brain tissues. DMAI showed anti-proliferation effects on U87MG cells at the concentration of 30µM, however did not affect to HEK-293 cells. DMAI induced anti-proliferation effects via ERK/MAPK, PI3K/Akt/mTOR signal pathway and G2/M phase cell cycle arrest. DMAI led to morphological change and inhibition of filapodia formation through regulation of Rac 1 and Cdc 42. In addition, migration and invasion of U87MG cells were inhibited by DMAI via down-regulation of matrix metalloproteinase (MMP) -2 and MMP -9 expressions and activities. Our results suggest that DMAI has a potential as a therapeutic agent against glioblastoma cells.

Anti-wrinkle effects of a tuna heart H2O fraction on Hs27 human fibroblasts.

With the increase in life expectancy, there is also growing interest in anti-aging treatments and technologies. The development of anti-aging functional drugs for the skin, and foods from natural sources, may offer solutions to this global matter. Aging involves structural, functional and biochemical changes that occur throughout cells and bodily tissues; the amount of hormones secreted from of all human organs, including the skin, decreases over time. Matrix metalloproteinase (MMP) genes (MMP-1 and -8) play an important role in the aging of skin fibroblasts. For example, an increased MMP expression causes accelerated aging and the degradation of skin elasticity-related genes. In the present study, we examined the anti-wrinkle effects of tuna heart extract which are mediated through the inhibition of MMPs in skin cells. Generally, tuna contains high concentrations of selenium and antioxidants, which serve to remove free radicals, and is known to delay skin and body aging. In addition, unsaturated fatty acids in tuna help to maintain the natural glossy look of skin, and increase skin elasticity, providing moisture for dry skin. A recent study confirmed the various bio-effects of boiled tuna extract and muscle. However, bioactivity studies using tuna heart are limited. Thus, in the present study, we obtained extracts and fractions of tuna heart, and examined their effects on Hs27 human fibroblast proliferation using an MTS assay. In addition, we measured procollagen type 1 levels and elastase activity, and performed ß-galactosidase staining. We then measured the expression levels of phosphatidylinositol 3-kinase/Akt and MMP-related genes by western blot analysis and RT-PCR. Our results revealed that tuna heart extract decreased MMP expression by upregulating tissue inhibitors of metalloproteinase-1 (TIMP-1) and decreasing elastase activity, thus exerting anti-aging and anti-wrinkle effects by increasing collagen synthesis and promoting skin fibroblast proliferation. Thus, our data suggest that tuna heart (TH)-H2O fractions exert anti-wrinkle effects on Hs27 cells.

Sargaquinoic acid attenuates inflammatory responses by regulating NF-κB and Nrf2 pathways in lipopolysaccharide-stimulated RAW 264.7 cells.

Myagropsis myagroides, a brown alga, showed strong anti-inflammatory activities in the previous studies. In this study, we isolated a strong anti-inflammatory compound, sargaquinoic acid (SQA), from M. myagroides and investigated the anti-inflammatory action using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. SQA suppressed the production of inducible nitric oxide synthase and cyclooxygenase-2 in LPS-stimulated cells as well as that of reactive oxygen species. As a result, SQA inhibited the production of NO, prostaglandin E2, and pro-inflammatory cytokines. LPS-induced transcriptional activation of nuclear factor-κB (NF-κB) was remarkably inhibited by SQA treatment through the prevention of inhibitor κB-α degradation. The regulation of NF-κB activation was also mediated by the phosphorylation of ERK and Akt in LPS-stimulated RAW 264.7 cells. Moreover, SQA induced the production of heme oxygenase 1 via activation of transcription factor Nrf2. These results indicate that SQA inhibits the LPS-induced expression of inflammatory mediators via suppression of ERK and Akt-mediated NF-κB pathway as well as up-regulation of Nrf2/HO-1 pathway, indicating that SQA has a potential therapeutic and preventive application in various inflammatory diseases.

Phlorofucofuroeckol B suppresses inflammatory responses by down-regulating nuclear factor κB activation via Akt, ERK, and JNK in LPS-stimulated microglial cells.

Microglial activation has been implicated in many neurological disorders for its inflammatory and neurotrophic effects. In this study, we investigated the effects of phlorofucofuroeckol B (PFF-B) isolated from Ecklonia stolonifera, on the production of inflammatory mediators in lipopolysaccharide (LPS)-stimulated microglia. PFF-B decreased secretion of pro-inflammatory cytokines including tumor necrosis factor α, interleukin (IL)-1ß, and IL-6 and the expression of pro-inflammatory proteins such as cyclooxygenase-2 and inducible nitric oxide synthase in LPS-stimulated BV-2 cells. Profoundly, PFF-B inhibited activation of nuclear factor kappaB (NF-κB) by preventing the degradation of inhibitor κB-α (IκB-α), which led to prevent the nuclear translocation of p65 NF-κB subunit. Moreover, PFF-B inhibited the phosphorylation of Akt, ERK, and JNK. These results indicate that the anti-inflammatory effect of PFF-B on LPS-stimulated microglial cells is mainly regulated by the inhibition of IκB-α/NF-κB and Akt/ERK/JNK pathways. Our study suggests that PFF-B can be considered as a therapeutic agent against neuroinflammation by inhibiting microglial activation.

Chemical Constituents of Euonymus alatus (Thunb.) Sieb. and Their PTP1B and α-Glucosidase Inhibitory Activities.

Phytochemical study on the corks of Euonymus alatus resulted in the isolation of a novel 3-hydroxycoumarinflavanol (23), along with ten triterpenoids (1-10), ten phenolic derivatives (11-20), and two flavonoid glycosides (21 and 22). Their structures were determined by extensive 1D and 2D-nuclear magnetic resonance spectroscopic and mass spectrometry data analysis. Furthermore, their inhibitory effects against the protein tyrosine phosphatases 1B (PTP1B) and α-glucosidase enzyme activity were evaluated. Compounds 6, 7, 9, 15, 19, and 23 were non-competitive inhibitors, exhibiting most potency with IC50 values ranging from 5.6 ± 0.9 to 18.4 ± 0.3 µm, against PTP1B. Compound 3 (competitive), compounds 5 and 15 (mixed-competitive) displayed potent inhibition with IC50 values of 15.1 ± 0.7, 23.6 ± 0.6 and 14.8 ± 0.9 µm, respectively. Moreover, compounds 15, 20, and 23 exhibited potent inhibition on α-glucosidase with IC50 values of 10.5 ± 0.8, 9.5 ± 0.6, and 9.1 ± 0.5 µm, respectively. Thus, these active ingredients may have value as new lead compounds for the development of new antidiabetic agents.

Selaginellin and biflavonoids as protein tyrosine phosphatase 1B inhibitors from Selaginella tamariscina and their glucose uptake stimulatory effects.

As part of an ongoing search for new antidiabetic agents from medicinal plants, the methanol extract of the aerial parts of Selaginella tamariscina was found to possess stimulatory effect on glucose uptake in 3T3-L1 adipocyte cells. Thus, bioassay-guided isolation of this active extract yielded two new compounds (1 and 2) along with five known biflavonoids (3-7). Their structures were elucidated by extensive analysis of spectroscopic and physicochemical data. The absolute configuration of compound 2 was determined by specific rotation and CD data analysis. All isolates exhibited potent inhibitory effects on PTP1B enzyme with IC50 values ranging from 4.5±0.1 to 13.2±0.8µM. Furthermore, the isolates (1-7) showed significant stimulatory effects on 2-NBDG uptake in 3T3-L1 adipocyte cells. Of these, compounds (1, 6, and 7) which exhibited mixed-competitive inhibition modes against PTP1B, showed potent stimulatory effects on 2-NBDG uptake. This result indicated the potential of these biflavonoids as lead molecules for development of antidiabetic agents and the beneficial use of S. tamariscina against hyperglycemia.

Toluhydroquinone from Aspergillus sp. suppress inflammatory mediators via nuclear factor-κB and mitogen-activated protein kinases pathways in lipopolysaccharide-induced RAW264.7 cells.

OBJECTIVES: The purpose of this study is to investigate anti-inflammatory effects of toluhydroquinone in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. METHODS: Toluhydroquinone was purified from a fungal strain, Aspergillus sp. We investigated that levels of nitric oxide (NO) using Griess reagent, production of prostaglandin E2 (PGE2 ) and pro-inflammatory cytokines using ELISA assay. We conducted Western blot analysis to investigate regulatory effects of toluhydroquinone on expression of inducible nitric oxide synthase (iNOS), cyclooxyganse-2 (COX-2), nuclear factor-κB (NF-κB), Akt and mitogen-activated protein kinases (MAPKs) in LPS-stimulated RAW264.7 cells. The translocation of NF-κB was detected by immunofluorescence staining. KEY FINDINGS: Toluhydroquinone inhibited production of NO and PGE2 via suppressing protein expression of iNOS and COX-2, respectively. Secretion and expression of inflammatory cytokines were down-regulated by toluhydroquinone as well. Toluhydroquinone reduced phosphorylation of Akt, NF-κB and MAPKs. Moreover, toluhydroquinone inhibited translocation of NF-κB from the cytosol into the nucleus. CONCLUSIONS: We revealed that inhibitory effects of toluhydroquinone on expression of inflammatory mediators are induced through inactivation of Akt, NF-κB and MAPKs. Thus, our results suggest that toluhydroquinone may be used for a potential anti-inflammatory reagent.

Insulin-mimetic selaginellins from Selaginella tamariscina with protein tyrosine phosphatase 1B (PTP1B) inhibitory activity.

As part of an ongoing search for new antidiabetic agents from medicinal plants, three new (2, 4, and 5) and two known selaginellin derivatives (1 and 3) were isolated from a methanol extract of Selaginella tamariscina. The structures of the new compounds were determined by spectroscopic data analysis. All isolates showed strong glucose uptake stimulatory effects in 3T3-L1 adipocyte cells at a concentration of 5 µM. Furthermore, these compounds were found to possess inhibitory effects on PTP1B enzyme activity with IC50 values ranging from 4.6 ± 0.1 to 21.6 ± 1.5 µM. Compound 2 showed the greatest potency, with an IC50 value of 4.6 ± 0.1 µM, when compared with the positive control (ursolic acid, IC50 = 3.5 ± 0.1 µM). Therefore, these selaginellin derivatives may have value as new lead compounds for the development of agents against type 2 diabetes.

Marine algal fucoxanthin inhibits the metastatic potential of cancer cells.

Metastasis is major cause of malignant cancer-associated mortality. Fucoxanthin has effect on various pharmacological activities including anti-cancer activity. However, the inhibitory effect of fucoxanthin on cancer metastasis remains unclear. Here, we show that fucoxanthin isolated from brown alga Saccharina japonica has anti-metastatic activity. To check anti-metastatic properties of fucoxanthin, in vitro models including assays for invasion, migration, actin fiber organization and cancer cell-endothelial cell interaction were used. Fucoxanthin inhibited the expression and secretion of MMP-9 which plays a critical role in tumor invasion and migration, and also suppressed invasion of highly metastatic B16-F10 melanoma cells as evidenced by transwell invasion assay. In addition, fucoxanthin diminished the expressions of the cell surface glycoprotein CD44 and CXC chemokine receptor-4 (CXCR4) which play roles in migration, invasion and cancer-endothelial cell adhesion. Fucoxanthin markedly suppressed cell migration in wound healing assay and inhibited actin fiber formation. The adhesion of B16-F10 melanoma cells to the endothelial cells was significantly inhibited by fucoxanthin. Moreover, in experimental lung metastasis in vivo assay, fucoxanthin resulted in significant reduction of tumor nodules. Taken together, we demonstrate, for the first time, that fucoxanthin suppresses metastasis of highly metastatic B16-F10 melanoma cells in vitro and in vivo.

Neferine isolated from Nelumbo nucifera enhances anti-cancer activities in Hep3B cells: molecular mechanisms of cell cycle arrest, ER stress induced apoptosis and anti-angiogenic response.

Hepatocellular carcinoma (HCC) is one of the most aggressive malignant diseases and is highly resistant to conventional chemotherapy. Neferine, a major bisbenzylisoquinoline alkaloid derived from the embryos of Nelumbo nucifera, has been reported a few physiological activities. However, the mechanisms of anticancer effects are not well understood and its detailed activities on Hep3B cells have not been determined. Our results suggest that neferine exhibited cytotoxicity against HCC Hep3B cells, but not against HCC Sk-Hep1 and THLE-3, a normal human liver cell line. In addition, consistent with the induction of G1/S phase cell population in flow cytometry, downregulation of c-Myc, cyclin D1, D3, CDK4, E2F-1, as well as dephosphorlyation of cdc2 by western blot analysis, as evidenced by the appearance of cell cycle arrest, were observed in Hep3B cells treated with neferine. Our results demonstrated neferine induced ER stress and apoptosis, acting through multiple signaling cascades by the activation of Bim, Bid, Bax, Bak, Puma, caspases-3, -6, -7, -8 and PARP, and the protein expression levels of Bip, calnexin, PDI, calpain-2 and caspase-12 were also upregulated dramatically by neferine treatment. Overexpression of GFP-LC3B by neferine resulted in a diffuse cytosolic GFP fluorescence and the strong fluorescent spots, representing autophagosomes. The significant reduction of the migration in Hep3B cells and the capillary tube-like formation of HUVECs by neferine were also determined. These observations reveal that the therapeutic potential of neferine in treating HCC Hep3B cells, containing copies of hepatitis B virus (HBV) genomes.

Anti-inflammatory effect of hexane fraction from Myagropsis myagroides ethanolic extract in lipopolysaccharide-stimulated BV-2 microglial cells.

OBJECTIVES: Microglial activation has been implicated in neurological disorders for its inflammatory and neurotrophic effects. We investigated the anti-inflammatory effect of the hexane fraction from Myagropsis myagroides (Mertens ex Turner) Fensholt ethanolic extract and its underlying molecular mechanism in lipopolysaccharide-stimulated microglia. METHODS: Various solvent fractions prepared from the ethanolic extract of M. myagroides were analysed for total phenolic content, 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity and inhibitory effect on nitric oxide (NO) production in activated BV-2 microglia. We measured prostaglandin E2 (PGE2 ) and pro-inflammatory cytokine levels by enzyme-linked immunosorbent assay. Expression of inflammatory enzymes was analysed by Western blot. Nuclear translocation and activation of nuclear factor-kappaB (NF-κB) were determined by immunofluorescence and reporter gene assay, respectively. KEY FINDINGS: Among the fractions, the hexane fraction (MMH), rich in fatty acid, showed the highest inhibitory activity on NO generation. Pretreatment with MMH decreased mRNA and protein levels of inducible NO synthase and cyclooxygenase-2, resulting in a decrease in NO and PGE2 in LPS-stimulated BV-2 cells. Furthermore, MMH inhibited the production of inducible pro-inflammatory cytokines at their transcriptional level via inactivation of NF-κB. MMH inhibited the activation of extracellular signal-regulated kinase and c-Jun N-terminal kinase. CONCLUSIONS: These results indicate that MMH has a strong anti-inflammatory activity in LPS-stimulated microglia, suggesting that MMH can be used as a therapeutic agent against neuroinflammatory diseases.

Anti-inflammatory activities of an ethanol extract of Ecklonia stolonifera in lipopolysaccharide-stimulated RAW 264.7 murine macrophage cells.

Ecklonia stolonifera is a brown alga that was shown to have antioxidant, anti-inflammatory, tyrosinase inhibitory, and chemopreventive activities. However, the molecular mechanisms underlying its anti-inflammatory activity remain unclear. In this study, we investigated the molecular mechanism of the anti-inflammatory action of E. stolonifera ethanolic extracts (ESE) using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. ESE inhibited LPS-induced nitric oxide (IC(50) = 72 ± 1.9 µg/mL) and prostaglandin E(2) (IC(50) = 98 ± 5.3 µg/mL) production in a dose-dependent manner and suppressed the expression of inducible nitric oxide synthase and cyclooxygenase-2 in RAW 264.7 cells. ESE also reduced the production of pro-inflammatory cytokines in LPS-stimulated RAW 264.7 cells. LPS-induced nuclear factor-κB (NF-κB) transcriptional activity and NF-κB translocation into the nucleus were significantly inhibited by ESE treatment through the prevention of the degradation of inhibitor κB-α. Moreover, ESE inhibited the activation of Akt, ERK, JNK1/2, and p38 MAPK in LPS-stimulated RAW 264.7 cells. The main components with anti-inflammatory activity in ESE were identified as phlorofucofuroeckol A and B based on the inhibition of NO production. Our results indicate that ESE can be considered as a potential source of therapeutic agents for inflammatory diseases.