Neuroinflammation activated by microglia affects inflammatory pain development. This study aimed to explore the anti-inflammatory properties and mechanisms of 1,6,7-trihydroxy-2-(1,1-dimethyl-2-propenyl)-3-methoxyxanthone (THMX) from Cudrania tricuspidata in microglia activation-mediated inflammatory pain. In RAW 264.7 and BV2 cells, THMX has been shown to reduce lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and pro-inflammatory mediators and cytokines, including nitric oxide (NO), prostaglandin (PG) E2, interleukin (IL)-6, and tumor necrosis factor alpha (TNF-α). THMX also decreased LPS-induced phosphorylation of mitogen-activated protein kinase (MAPK) and the activation of p65 nuclear factor kappa B (NF-κB). Interestingly, THMX also activated heme oxygenase (HO)-1 expression. These findings suggest that THMX is a promising biologically active compound against inflammation through preventing MAPKs and NF-ĸB and activating HO-1 signaling pathways.

The present study aimed to evaluate the anti-obesity effect of the ethanolic extract of Korean Curcuma longa (CLE) on 3T3-L1 adipocytes and high-fat diet (HFD)-induced obesity in mouse. CLE treatment suppressed lipid accumulation and restored the differentiation-induced changes in adipogenesis- and lipolysis-related proteins by recovering phosphorylation of AMP-activated protein kinase (AMPK). Moreover, in CLE-administered HFD-induced mouse model, body weight and lipid accumulation were reduced, and the changes in factors related to adipogenesis and lipolysis were regulated in the adipose and liver tissues, confirming that these effects were due to a restoration in the phosphorylation of AMPK. In summary, these results provide important insights into the anti-obesity role of CLE by demonstrating its anti-obesity effects on adipocytes and obese mouse models, thereby suggesting the potential application of CLE as a preventive agent for obesity.

Glabridin is a polyphenolic compound with reported anti-inflammatory and anti-oxidative effects. In the previous study, we synthesized glabridin derivatives—HSG4112, (S)-HSG4112, and HGR4113—based on the structure–activity relationship study of glabridin to improve its biological efficacy and chemical stability. In the present study, we investigated the anti-inflammatory effects of the glabridin derivatives in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. We found that the synthetic glabridin derivatives significantly and dose-dependently suppressed the production of nitric oxide (NO) and prostaglandin E2 (PGE2), and decreased the level of inducible nitric oxygen synthase (iNOS) and cyclooxygenase-2 (COX-2) and the expression of pro-inflammatory cytokines interleukin-1β (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α). The synthetic glabridin derivatives inhibited the nuclear translocation of the NF-κB by inhibiting phosphorylation of the inhibitor of κB alpha (IκB-α), and distinctively inhibited the phosphorylation of ERK, JNK, and p38 MAPKs. In addition, the compounds increased the expression of antioxidant protein heme oxygenase (HO-1) by inducing nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) through ERK and p38 MAPKs. Taken together, these results indicate that the synthetic glabridin derivatives exert strong anti-inflammatory effects in LPS-stimulated macrophages through MAPKs and NF-κB pathways, and support their development as potential therapeutics against inflammatory diseases.

Microglia play a significant role in immune defense and tissue repair in the central nervous system (CNS). Microglial activation and the resulting neuroinflammation play a key role in the pathogenesis of neurodegenerative disorders. Recently, inflammation reduction strategies in neurodegenerative diseases have attracted increasing attention. Herein, we discovered and evaluated the anti-neuroinflammatory potential of compounds from the Antarctic fungi strain Aspergillus sp. SF-7402 in lipopolysaccharide (LPS)-stimulated BV2 cells. Four metabolites were isolated from the fungi through chemical investigations, namely, 5-methoxysterigmatocystin (1), sterigmatocystin (2), aversin (3), and 6,8-O-dimethylversicolorin A (4). Their chemical structures were elucidated by extensive spectroscopic analysis and HR-ESI-MS, as well as by comparison with those reported in literature. Anti-neuroinflammatory effects of the isolated metabolites were evaluated by measuring the production of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in LPS-activated microglia at non-cytotoxic concentrations. Sterigmatocystins (1 and 2) displayed significant effects on NO production and mild effects on TNF-α and IL-6 expression inhibition. The molecular mechanisms underlying this activity were investigated using Western blot analysis. Sterigmatocystin treatment inhibited NO production via downregulation of inducible nitric oxide synthase (iNOS) expression in LPS-stimulated BV2 cells. Additionally, sterigmatocystins reduced nuclear translocation of NF-κB. These results suggest that sterigmatocystins present in the fungal strain Aspergillus sp. are promising candidates for the treatment of neuroinflammatory diseases.

Mecasin, a traditional medicine, contains nine herbal constituents: Curcuma longa, Salvia miltio rhiza, Gastrodia elata, Chaenomeles sinensis, Polygala tenuifolia, Paeonia japonica, Glycyrrhiza uralensis, Atractylodes japonica and processed Aconitum carmichaeli. Several biological effects of mecasin have been described both in vivo and in vitro. Previous studies have demonstrated that mecasin has anti-inflammatory effects. The purpose of the present study was to determine anti-inflammatory effects of mecasin and its natural product constituents on lipopolysaccharide (LPS)-stimulated BV2 cells by measuring nitrite and nitric oxide contents. Nitrite production levels in LPS-stimulated BV2 cells incubated with mecasin and each individual constituent of mecasin were measured. The results suggested that C. longa, P. tenuifolia and P. japonica inhibited nitrite production in a pattern similar to that of mecasin. The effect of mecasin was likely a result of synergistic effects of its natural herb constituents.

Aging is associated with immune disregulation and oxidative stress which lead to inflammation and neurodegenerative diseases. We have tried to identify the anti-neuroinflammatory and anti-inflammatory components of Coreopsis lanceolata L. The dried flowers of C. lanceolata were extracted with 70% EtOH, and the obtained extract was divided into CH2Cl2, EtOAc, n-BuOH, and H2O fractions. The CH2Cl2 fraction was separated using silica gel and C-18 column chromatography to yield phenylheptatriyne (1), 2′-hydroxy-3,4,4′-trimethoxychalcone (2), and 4′,7-dimethoxyflavanone (3). Additionally, the EtOAc fraction was subjected to silica gel, C-18, and Sephadex LH-20 column chromatography to yield 8-methoxybutin (4) and leptosidin (5). All the compounds isolated from C. lanceolata inhibited the production of nitric oxide (NO) in LPS-induced BV2 and RAW264.7 cells. In addition, phenylheptatriyne and 4′,7-dimethoxyflavanone reduced the secretion of inflammatory cytokines, tumor necrosis factor alpha (TNF-α), and interleukin (IL)-6. Among them, phenylheptatriyne was significantly downregulated in the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). Subsequently, phenylheptatriyne also effectively inhibited nuclear factor-kappa B (NF-κB) activation in LPS-stimulated BV2 and RAW264.7 cells. Based on these results, the anti-neuroinflammatory effect of phenylheptatriyne isolated from C. lanceolata was confirmed, which may exert a therapeutic effect in treatment of neuroinflammation-related diseases.

OBJECTIVE:The prenylated xanthones compounds, macluraxanthone B (MCXB) was isolated from the MeOH extracts of Cudrania tricuspidata. In this study, we investigated the effect of MCXB on inflammatory response. MATERIALS AND METHODS:Anti-inflammatory effects of MCXB were examined in lipopolysaccharide (LPS)-stimulated RAW264.7 and BV2 cells. We observed their anti-inflammatory effects by ELISA, western blot analysis, and immunofluorescence. RESULTS:MCXB significantly inhibited the LPS-stimulated production of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-6 (IL-6), and tumor necrosis factor (TNF)-α in RAW264.7 and BV2 cells. MCXB also reduced the LPS-induced expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 proteins. Incubating cells with MCXB prevented subsequent activation of the nuclear factor kappa B (NF-κB) signaling pathway by inhibiting the nuclear localization and DNA-binding activity of the p65 subunit induced by LPS. MCXB inhibited the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 mitogen-activated protein kinases (MAPKs) in RAW264.7 and BV2 cells. MCXB induced the expression of heme oxygenase (HO)-1 protein, and the inhibitory effect of MCXB on nitric oxide production was partially reversed by a selective HO-1 inhibitor. DISCUSSION AND CONCLUSIONS:Our results suggested that the anti-inflammatory effect of MCXB is partly regulated by HO-1 induction. In conclusion, MCXB could be a useful candidate for the development of therapeutic and preventive agents to treat inflammatory diseases.

Chemical investigation of the Antarctic fungi Pleosporales sp. SF-7343 revealed four known secondary fungal metabolites: alternate C (1), altenusin (2), alternariol (3), and altenuene (4). The compound structures were identified primarily by NMR and MS analyses. Atopic dermatitis, an inflammatory disease, is driven by the abnormal activation of T helper (Th) 2 cells and barrier dysfunction. We attempted to identify the anti-inflammatory components of SF-7343. Initial screening showed that compounds 1 and 3 inhibited the secretion of interleukin-8 and -6 in tumor necrosis factor-α/interferon-γ-treated HaCaT cells, and these compounds also showed inhibitory effects on CCL5 and CCL22. Compounds 1 and 3 also downregulated the protein expression levels of intercellular adhesion molecule-1 and upregulated the expression of filaggrin and involcurin. The mechanism study results showed that compounds 1 and 3 inhibited nuclear translocation of nuclear factor-kappa B p65 and the phosphorylation of STAT1 and STAT3. Compound 1, but not compound 3, significantly promoted the expression of heme oxygenase (HO)-1. The effects of compound 1 were partly reversed by co-treatment with a HO-1 inhibitor, tin protoporphyrin IX. Taken together, this study demonstrates the potential value of Antarctic fungal strain SF-7343 isolates as a bioresource for bioactive compounds to prevent skin inflammation.

Sargassum horneri is used as a traditional medicinal agent and exhibits various pharmacological effects. In this study, we found that the 70% EtOH extract contained 34.37 ± 0.75 μg/mg fucosterol. We tested the antioxidant activities of the 70% EtOH extracts and their fractions. The CH2Cl2-soluble fraction showed the strongest DPPH and ABTS radical scavenging activities. Next, we evaluated the anti-neuroinflammatory effects of S. horneri on lipopolysaccharide (LPS)-stimulated BV2 cells. Pretreatment with the extract and fractions suppressed LPS-induced production of nitric oxide (NO) in BV2 cells. The 70% EtOH, CH2Cl2-soluble fraction, and water-soluble fraction inhibited the production of prostaglandin E2, interleukin-6, and tumor necrosis factor-α, as well as markedly blocking LPS-induced expression of inducible NO synthase and cyclooxygenase-2 via inactivation of the nuclear factor-kappa B pathway. In addition, the CH2Cl2-soluble fraction showed the most remarkable heme oxygenase (HO)-1 expression effects and increased nuclear erythroid 2-related factor translocation in the nucleus. In HT22 cells, the CH2Cl2-soluble fraction inhibited cell damage and ROS production caused by glutamate via the regulation of HO-1. Therefore, CH2Cl2-soluble fractions of S. horneri can attenuate oxidative action and neuroinflammatory responses via HO-1 induction, demonstrating their potential in the treatment of neuroinflammatory diseases.

The root bark of Cudrania tricuspidata has been reported to have anti-sclerotic, anti-inflammatory, antioxidant, neuroprotective, hepatoprotective, and cytotoxic activities. In the present study, the effect of 16 compounds from C. tricuspidata on tumor necrosis factor-α+interferon-γ-treated HaCaT cells were investigated. Among these 16 compounds, 11 decreased IL-6 production and 15 decreased IL-8 production. The six most effective compounds, namely, steppogenin (2), cudraflavone C (6), macluraxanthone B (12), 1,6,7-trihydroxy-2-(1,1-dimethyl-2-propenyl)-3- methoxyxanthone (13), cudraflavanone B (4), and cudratricusxanthone L (14), were selected for further experiments. These six compounds decreased the expression levels of chemokines, such as regulated on activation, normal T cell expressed and secreted (RANTES) and thymus and activation-regulated chemokine (TARC), and downregulated the protein expression levels of intercellular adhesion molecule-1. Compounds 2, 6, 12, 4, and 14 inhibited nuclear factor-kappa B p65 translocation to the nucleus; however, compound 13 showed no significant effects. In addition, extracellular signal regulatory kinase-1/2 phosphorylation was only inhibited by compound 14, whereas p38 phosphorylation was inhibited by compounds 13 and 4. Taken together, the compounds from C. tricuspidata showed potential to be further developed as therapeutic agents to suppress inflammation in skin cells.

Acanthopanax sessiliflorus (Araliaceae) have been reported to exhibit many pharmacological activities. Our preliminary study suggested that A. sessiliflorus fruits include many bioactive 3,4-seco-triterpenoids. A. sessiliflorus fruits were extracted in aqueous EtOH and fractionated into EtOAc, n-BuOH, and H2O fractions. Repeated column chromatographies for the organic fractions led to the isolation of 3,4-seco-triterpenoid glycosides, including new compounds. Ultra-high-performance liquid chromatography (UPLC) mass spectrometry (MS) systems were used for quantitation and quantification. BV2 and RAW264.7 cells were induced by LPS, and the levels of pro-inflammatory cytokines and mediators and their underlying mechanisms were measured by ELISA and Western blotting. NMR, IR, and HR-MS analyses revealed the chemical structures of the nine noble 3,4-seco-triterpenoid glycosides, acanthosessilioside G–O, and two known ones. The amounts of the compounds were 0.01–2.806 mg/g, respectively. Acanthosessilioside K, L, and M were the most effective in inhibiting NO, PGE2, TNF-α, IL-1β, and IL-6 production and reducing iNOS and COX-2 expression. In addition, it had inhibitory effects on the LPS-induced p38 and ERK MAPK phosphorylation in both BV2 and RAW264.7 cells. Nine noble 3,4-seco-triterpenoid glycosides were isolated from A. sessiliflorus fruits, and acanthosessilioside K, L, and M showed high anti-inflammatory and anti-neuroinflammatory effects.

We previously investigated the methanolic extract of Morus alba bark and characterized 11 compounds from the extract: kuwanon G (1), kuwanon E (2), kuwanon T (3), sanggenon A (4), sanggenon M (5), sanggenol A (6), mulberofuran B (7), mulberofuran G (8), moracin M (9), moracin O (10), and norartocarpanone (11). Herein, we investigated the anti-inflammatory effects of these compounds on microglial cells (BV2) and macrophages (RAW264.7). Among them, 3 and 4 markedly inhibited the lipopolysaccharide (LPS)-induced production of nitric oxide in these cells, suggesting the anti-inflammatory properties of these two compounds. These compounds inhibited the production of prostaglandin E2, interleukin-6, and tumor necrosis factor-α, and the expression of inducible nitric oxide synthase and cyclooxygenase-2 following LPS stimulation. Pretreatment with 3 and 4 inhibited the activation of the nuclear factor kappa B signaling pathway in both cell types. The compounds also induced the expression of heme oxygenase (HO)-1 through the activation of nuclear factor erythroid 2-related factor 2. Suppressing the activity of HO-1 reversed the anti-inflammatory effects caused by pretreatment with 3 and 4, suggesting that the anti-inflammatory effects were regulated by HO-1. Taken together, 3 and 4 are potential candidates for developing therapeutic and preventive agents for inflammatory diseases.

Heme oxygenase (HO)-1 is a detoxifying phase II enzyme that plays a role in both inflammatory and oxidative stress responses. Curdrania tricuspidata is widespread throughout East Asia and is used as a therapeutic agent in traditional medicine. We investigated whether treatment with sixteen flavonoid or xanthone compounds from C. tricuspidata could induce HO-1 expression in HT22 hippocampal cells, RAW264.7 macrophage, and BV2 microglia. In these compounds, kuwanon C showed the most remarkable HO-1 expression effects. In addition, treatment with kuwanon C reduced cytoplasmic nuclear erythroid 2-related factor (Nrf2) expression and increased Nrf2 expression in the nucleus. Significant inhibition of glutamate-induced oxidative injury and induction of reactive oxygen species (ROS) occurred when HT22 hippocampal cells were pretreated with kuwanon C. The levels of inflammatory mediator and cytokine, which increased following lipopolysaccharide (LPS) stimulation, were suppressed in RAW264.7 macrophage and BV2 microglia after kuwanon C pretreatment. Kuwanon C also attenuated p65 DNA binding and translocation into the nucleus in LPS-induced RAW264.7 and BV2 cells. The anti-inflammatory, anti-neuroinflammatory, and neuroprotective effects of kuwanon C were reversed when co-treatment with HO-1 inhibitor of tin protoporphyrin-IX (SnPP). These results suggest that the neuroprotective and anti-inflammatory effects of kuwanon C are regulated by HO-1 expression.

A prenylated flavonoid, cudraflavanone B, is isolated from Cudrania tricuspidata. In this study, we investigated its anti-inflammatory and anti-neuroinflammatory effects in lipopolysaccharide (LPS)-induced RAW264.7 and BV2 cells. In our initial study of the anti-inflammatory effects of cudraflavanone B the production of nitric oxide and prostaglandin E2 was attenuated in LPS-stimulated RAW264.7 and BV2 cells. These inhibitory effects were related to the downregulation of inducible nitric oxide synthase and cyclooxygenase-2. In addition, cudraflavanone B suppressed the production of pro-inflammatory cytokines such as interleukin-6 and tumor necrosis factor-α in LPS-induced RAW264.7 and BV2 cells. Moreover, the evaluation of the molecular mechanisms underlying the anti-inflammatory effects of cudraflavanone B revealed that the compound attenuated the nuclear factor-kappa B signaling pathway in LPS-induced RAW264.7 and BV2 cells. In addition, cudraflavanone B inhibited the phosphorylation of extracellular signal-regulated kinase mitogen-activated protein kinase signaling pathways in these LPS-stimulated cells. Thus, cudraflavanone B suppressed nuclear factor-κB, and extracellular signal-regulated kinase mitogen-activated protein kinase mediated inflammatory pathways, demonstrating its potential in the treatment of neuroinflammatory conditions.

 Mahaenggamsuk-tang (MHGS) has been widely used in Korea and China for the treatment of various diseases. MHGS was constituted the Ephedrea Herba, Armenicae Semen, Glycyrrhizae Radix and Gypsum Fibrosum. In this study, we have made three different solvents extract as MHGS water extract (MHGS-W), MHGS 50% EtOH extract (MHGS-50E), and MHGS 100% EtOH extract (MHGS-100E). The MHGS-W, MHGS-50E and MHGS-100E showed the discernible difference patterns on HPLC analysis. Furthermore, MHGS-50E and MHGS-100E significantly increased the DPPH and ABTS radical scavenging effects than MHGS-W. In addition, the MHGS-50E and MHGS-100E also inhibited significantly nitric oxide (NO) and prostaglandin E2 (PGE 2 ) production, and inducible nitric oxide synthase (iNOS) cyclooxygenase-2 (COX-2) protein expression in RAW264.7. On the other hand, MHGS-50E and MHGS-W showed remarkable protection on the HT22 cell via heme oxygenase (HO)-1, but MHGS-100E did not show. The results of this study proved that MHGS-50E has greater potential therapeutic uses by exerting antioxidant, anti-inflammatory and neuroprotective effects compared to MHGS-100E, MHGS-W. Our study suggests that the different solvent might be affected the biological activities when make the traditional herbal medicines including MHGS.

The extract of Sappan Lignum, the heartwood of Caesalpinia sappan L., has been used in medicine to improve blood circulation. Recently, the application of microwave extraction methods has been a major focus of research into the extraction of components from natural sources. In this experiment, we compared the anti‑inflammatory effects of Sappan Lignum prepared by heat‑70% EtOH extraction (CSE‑H‑70E) and microwave‑70% EtOH extraction (CSE‑MW‑70E). High‑performance liquid chromatography analysis was used to identify the compounds in these extracts. The heat‑70% EtOH and microwave‑70% EtOH extracts of Sappan Lignum had different chromatograms. CSE‑MW‑70E significantly inhibited the protein expression of iNOS and COX‑2, PGE2, TNF‑α, and reduced NO and IL‑1β production in macrophages exposed to LPS, whereas, only high concentrations of CSE‑H‑70E (20 µg/ml) resulted in any effects. Furthermore, CSE‑MW‑70E upregulated heme oxygenase‑1 (HO‑1) expression. In addition, the use of tin protoporphyrin, an inhibitor of HO‑1, confirmed the inhibitory effects of CSE‑MW‑70E on pro‑inflammatory mediators. These results suggested that the CSE‑MW‑70E‑mediated upregulation of HO‑1 played an important role in the anti‑inflammatory effects of macrophages. Therefore, these findings showed that microwave extraction can be utilized to improve the extraction efficiency and biological activity of Sappan Lignum.

Brain cell damage that results from oxidative toxicity contributes to neuronal degeneration. The transcription factor nuclear factor-E2-related factor 2 (Nrf2) regulates the expression of heme oxygenase (HO)-1 and glutathione (GSH), and serves a key role in the pathogenesis of neurological diseases. Brassica rapa is a turnip that is unique to Ganghwa County, and is used mainly for making kimchi, a traditional Korean food. In the current study, brassicaphenanthrene A (BrPA) from B. rapa was demonstrated to exhibit protective effects against neurotoxicity induced by glutamate via Nrf2-mediated HO-1 expression. Similarly, BrPA increased the expression of cellular glutathione and glutamine-cysteine ligase genes. Furthermore, BrPA caused the nuclear translocation of Nrf2 and increased antioxidant response element (ARE) promoter activity. Nrf2 also mediated HO-1 induction by BrPA through the PI3K/Akt and JNK regulatory pathways. The results of the present study indicated the neuroprotective effect of BrPA, a natural food component from B. rapa.

Objective: The isochroman-type fungal metabolite 3,7-dimethyl-1,8-hydroxy-6-methoxyisochroman (DMHM) was isolated from the extracts of a marine-derived fungal strain of Penicillium sp. SF-6013. In this study, we investigated the effect of DMHM on inflammatory response. Materials and methods: Anti-inflammatory effects of DMHM were examined in lipopolysaccharide (LPS)-stimulated RAW264.7 and BV2 cells. We observed their anti-inflammatory effects by ELISA, qRT-PCR, and western blot analysis. Results: DMHM revealed that it suppressed the production of prostaglandin E2 (PGE2), nitric oxide (NO), cyclooxygenase-2 (COX-2), and inducible NO synthase (iNOS) in LPS-stimulated RAW264.7 and BV2 cells. Furthermore, DMHM decreased the mRNA expression of pro-inflammatory cytokines including interleukin (IL)-1β and IL-6. Therefore, DMHM was further investigated to elucidate the mechanisms of its anti-inflammatory properties; the results indicated that its effect was mediated by the suppression of the nuclear factor (NF)-κB and c-Jun N-terminal kinase (JNK) MAPK pathways. Furthermore, the anti-inflammatory activity of DMHM correlated with its induction of heme oxygenase-1 (HO)-1 expression via activation of the nuclear factor erythroid 2-like 2 (Nrf2) pathway. Discussion and conclusions: Collectively, the results of this study suggest that DMHM inhibited several inflammatory pathways including the NF-κB and MAPK pathways, and induced Nrf2-mediated HO-1 expression, demonstrating its potential usefulness for treating inflammatory and neuroinflammatory diseases.

Dalbergia odorifera T. Chen (Leguminosae) grows in Central and South America, Africa, Madagascar, and Southern Asia. D. odorifera possesses many useful pharmacological properties, such as antioxidative and anti-inflammatory activities in various cell types. 4-Methoxydalbergione (MTD) and 4'-hydroxy-4-methoxydalbergione (HMTD) were isolated from the EtOH extract of D. odorifera by several chromatography methods. The chemical structures were elucidated by nuclear magnetic resonance (NMR) and mass spectrum (MS). Anti-inflammatory and cytoprotective effects were examined using BV2 microglial cells and murine hippocampus. MTD and HMTD were demonstrated to induce heme oxygenase (HO)-1 protein levels through the nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) in BV2 microglial cells, while only MTD upregulated HO-1 in HT22 cells. MTD and HMTD induced HO-1 expression through JNK MAPK pathway in BV2 cells, whereas only MTD activated the ERK and p38 pathways in HT22 cells. MTD was also shown to activated MTD and HMTD suppressed lipopolysaccharide-stimulated nitric oxide (NO) and prostaglandin E2 production by inhibiting inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in a dose-dependent manner. Furthermore, MTD and HMTD attenuated pro-inflammatory cytokine productions. These anti-inflammatory effects were found to be mediated through the nuclear factor-kappa B (NF-κB) pathway. MTD exhibited neuroprotective effects on glutamate-induced neurotoxicity by promoting HO-1 in HT22 cells. The anti-inflammatory and cytoprotective effects of MTD and HMTD were partially reversed by an HO inhibitor tin protoporphyrin IX. In addition, MTD and HMTD inhibited pro-inflammatory cytokines and NF-κB pathway in primary rat microglia. These findings suggest that MTD and HMTD have therapeutic potential against neurodegenerative diseases accompanied by microglial activation and/or oxidative cellular injury.

Context: Cudrania tricuspidata Bureau (Moraceae) is an important source of traditional Korean and Chinese medicines used to treat neuritis and inflammation. Objective: The anti-neuroinflammatory effects of cudraflavanone A isolated from a chloroform fraction of C. tricuspidata were investigated in LPS-induced BV2 cells. Materials and methods: Cudraflavanone A was isolated from the root of C. tricuspidata, and its structure was determined by MS and NMR data. Cytotoxicity of the compound was examined by MTT assay, indicating no cytotoxicity at 5-40 mu M of cudraflavanone A. NO concentration was measured by the Griess reaction, and the levels of PGE(2), cytokines and COX-2 enzyme activity were measured by each ELISA kit. The mRNA levels of cytokines were analysed by quantitative-PCR. The expression of iNOS, COX-2, HO-1, NF-kappa B, MAPKs and Nrf2 was detected by Western blot. Results: Cudraflavanone A had no major effect on cell viability at 40 mu M indicating 91.5% viability. It reduced the production of NO (IC50 = 22.2 mu M), PGE2 (IC50 = 20.6 mu M), IL-1 beta (IC50 = 24.7 mu M) and TNF-alpha (IC50 = 33.0 mu M) in LPS-stimulated BV2 cells. It also suppressed iNOS protein, IL-1b and TNF-alpha mRNA expression. These effects were associated with the inactivation of NF-kappa B, JNK and p38 MAPK pathways. This compound mediated its anti-neuroinflammatory effects by inducing HO-1 protein expression via increased nuclear translocation of Nrf2. Discussion and conclusions: The present study suggests a potent effect of cudraflavanone A to prevent neuroinflammatory diseases. Further investigation is necessary to elucidate specific molecular mechanism of cudraflavanone A.