Inhibitory effects of butanol fraction of the aqueous extract of Forsythia koreana on the nitric oxide production by murine macrophage-like RAW 264.7 cells

The aim of this study was to investigate the effect of butanol fraction of the aqueous extract of Forsythia koreana fruits on the nitric oxide (NO) production and inducible nitric oxide synthesis (iNOS) gene expression in murine macrophage-like RAW 264.7 cells. Butanol fraction alone affected neither NO production nor iNOS gene expression in macrophage-like RAW 264.7 cells. However, the butanol fraction inhibited NO production and iNOS gene expression in RAW 264. 7 cells stimulated with interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS). These findings suggest that inhibition of NO production by this butanol fraction in RAW 264.7 cells stimulated with IFN-gamma plus LPS was due to the suppression of iNOS gene expression.     

Ethanol extract of propolis inhibits nitric oxide synthase gene expression and enzyme activity

Propolis obtained from honeybee hives has been used in Oriental folk medicine as an anti-inflammatory, anti-carcinogenic, or immunomodulatory agent. However, the molecular basis for anti-inflammatory properties of propolis has not yet been established. Since nitric oxide (NO) synthesized by inducible nitric oxide synthase (iNOS) has been known to be involved in inflammatory and autoimmune-mediated tissue destruction, modulation of NO synthesis or action represents a new approach to the treatment of inflammatory and autoimmune diseases. The present study, therefore, examined effects of ethanol extract of propolis (EEP) on iNOS expression and activity of iNOS enzyme itself. Treatment of RAW 264.7 cells with EEP significantly inhibited NO production and iNOS protein expression induced by lipopolysaccharide (LPS) plus interferon-gamma (IFN-γ). EEP also inhibited iNOS mRNA expression and nuclear factor-kappa B (NF-κB) binding activity in a concentration-dependent manner. Furthermore, transfection of RAW 264.7 cells with iNOS promoter linked to a chloramphenicol acetyltransferase (CAT) reporter gene, revealed that EEP inhibited the iNOS promoter activity induced by LPS plus IFN-γ through the NF-κB sites of the iNOS promoter. In addition, EEP directly interfered with the catalytic activity of murine recombinant iNOS enzyme. These results suggest that EEP may exert its anti-inflammatory effect by inhibiting the iNOS gene expression via action on the NF-κB sites in the iNOS promoter and by directly inhibiting the catalytic activity of iNOS.     

A combined extract of Cinnamomi Ramulus, Anemarrhenae Rhizoma and Alpiniae Officinari Rhizoma suppresses production of nitric oxide by inhibiting NF-kappaB activation in RAW 264.7 cells

An herbal mixture prepared with Cinnamomi Ramulus, Anemarrhenae Rhizoma and Alpiniae Officinari Rhizoma (CAA) is used in oriental medicine for treating several ailments. The purpose of this study was to determine the mechanisms by which CAA elicits an antiinflammatory effect on nitric oxide (NO) production in the mouse macrophage cell line RAW 264.7 cells. The results indicated that lipopolysaccharide (LPS)-induced NO production was inhibited by CAA in a dose-dependent manner. Western blotting and RT-PCR analysis demonstrated that CAA decreased LPS-induced inducible nitric oxide synthase (iNOS) protein and gene expression in RAW 264.7 cells. Furthermore, CAA inhibited the LPS-induced DNA binding activity of nuclear factor-kappa B (NF-kappaB) and this effect was mediated through inhibiting the degradation of inhibitory factor-kappaBalpha (IkappaBalpha). Therefore, the results demonstrate that CAA inhibits LPS-induced production of NO and expression of iNOS by blocking NF-kappaB activation. CAA might be a potential therapeutic candidate for treating inflammatory diseases such as arthritis.     

Effects of bee venom on the pro-inflammatory responses in RAW264.7 macrophage cell line

The purpose of this study is to elucidate the molecular mechanism of anti-inflammatory effect of bee venom (BV), which has been used for the treatment of various inflammatory diseases in oriental medicine. With this aim, we examined the effects of BV on the nitric oxide (NO) production by lipopolysaccharide (LPS) or sodium nitroprusside in RAW264.7 macrophages. We further investigated the effects of BV on the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor-kappaB (NF-kappaB) and mitogen-activated protein kinase (MAPK) with RT-PCR in LPS-stimulated RAW264.7 cells. BV suppressed the NO production and decreased the levels of iNOS, COX-2, NF-kappaB and MAPK mRNA in a dose-dependent manner. These results suggest that BV has an anti-inflammatory effect by inhibiting iNOS and COX-2 expression, possibly through suppression of NF-kappaB and MAPK expression.     

Acanthopanax senticosus inhibits nitric oxide production in murine macrophages in vitro and in vivo

Excess nitric oxide (NO) production has been implicated in inflammatory diseases. The present study investigated the inhibitory effect of the stem bark extract of Acanthopanax senticosus (A. senticosus) on NO production in murine macrophages in vitro and in vivo. In vitro exposure of RAW264.7 cells to 1, 10, 50, 100, 250, 500 and 1000 microg/mL of A. senticosus extract significantly suppressed NO production induced by lipopolysaccharide (LPS) and interferon gamma (IFN-gamma) in a dose-dependent manner. In vitro exposure of mouse resident peritoneal macrophages to 1, 10, 100 and 1000 microg/mL of A. senticosus extract significantly suppressed NO production induced by LPS and IFN-gamma in a dose-dependent manner. In vivo administration of A. senticosus extract (50, 100 and 200 mg/kg) to KM mice dose-dependently inhibited LPS and IFN-gamma induced production of NO in isolated mouse peritoneal macrophages ex vivo. Exposure to A. senticosus extract had no effect on cell viability and systemic toxicity. The results demonstrated that the stem bark extract of A. senticosus extract inhibits NO production in murine macrophages in vitro and in vivo.     

Phellinus linteus inhibits inflammatory mediators by suppressing redox-based NF-kappaB and MAPKs activation in lipopolysaccharide-induced RAW 264.7 macrophage

The mushroom Phellinus linteus has been known to exhibit potent biological activity. In contrast to the immuno-potentiating properties of Phellinus linteus, the anti-inflammatory properties of Phellinus linteus have rarely been investigated. Recently, ethanol extract and n-BuOH fractions from Phellinus linteus were deemed most effective in anti-inflammatory activity in RAW 264.7 macrophages. The regulatory mechanisms of Phellinus linteus butanol fractions (PLBF) on the pharmacological and biochemical actions of macrophages involved in inflammation have not been clearly defined yet. In the present study, we tested the role of PLBF on anti-inflammation patterns in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. To investigate the mechanism by which PLBF inhibits NO and PGE2 production as well as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, we examined the activation of IkappaB and MAPKs in LPS-activated macrophages. PLBF clearly inhibited nuclear translocation of NF-kappaB p65 subunits, which correlated with PLBF's inhibitory effects on IkappaBalpha phosphorylation and degradation. PLBF also suppressed the activation of mitogen-activated protein (MAP) kinases including p38 and stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK). Furthermore, macrophages stimulated with LPS generated ROS via activation of membrane-bound NADPH oxidase, and ROS played an important role in the activation of nuclear factor-kappaB (NF-kappaB) and MAPKs. We demonstrated that PLBF directly blocked intracellular accumulation of reactive oxygen species in RAW 264.7 cells stimulated with LPS much as the NADPH oxidase inhibitors, diphenylene iodonium, and antioxidant pyrrolidine dithiocarbamate did. The suppression of NADPH oxidase also inhibited NO production and iNOS protein expression. Cumulatively, these results suggest that PLBF inhibits the production of NO and PGE2 through the down-regulation of iNOS and COX-2 gene expression via ROS-based NF-kappaB and MAPKs activation. Thus, PLBF may provide a potential therapeutic approach for inflammation-associated disorders.     

Protective effect of Acanthopanax senticosus extract against endotoxic shock in mice

AIM OF THE STUDY: In this study, we evaluated protective effect of Acanthopanax senticosus extract (ASE) and a possible signaling pathway involved during endotoxic shock induced by intraperitoneal injection lipopolysaccharide (LPS) and D-galactosamine (D-GalN) in BALB/c mice. MATERIALS AND METHODS: Mice were intraperitoneal administrated with ASE (100, 200 or 400mg/kg) prior to injection of 50 microg/kg LPS and 1g/kg D-GalN. The levels of tumor necrosis-alpha (TNF-alpha) and interleukin-10 (IL-10) in serum and liver. Nitric oxide (NO) production in serum and inducible nitric oxide synthase (iNOS) protein level were investigated. Nuclear factor-kappa B (NF-kappaB) activation in liver was determined. Furthermore, we evaluated the effect of ASE pretreatment on infiltration of inflammatory cells into the heart, liver and lung of mice. RESULTS: Treatment of mice with ASE prior to LPS/D-GalN injection significantly improved the survival rate. ASE pretreatment inhibited the elevation of TNF-alpha in serum and liver. ASE also decreased iNOS level in liver and the overproduction of nitric oxide (NO) in serum. In addition, IL-10 levels in serum and liver were markedly enhanced. ASE pretreatment inhibited NF-kappaB activation in liver of mice. Moreover, infiltration of inflammatory cells into the heart, liver and lung of mice was also attenuated by ASE pretreatment. CONCLUSIONS: These results suggested that ASE protected mice against LPS/D-GalN-induced endotoxic shock involving inhibition of NF-kappaB activation, which caused down-regulation of TNF-alpha and involved up-regulation of IL-10. Acanthopanax senticosus may thus prove beneficial in the prevention of endotoxic shock.     

Shikonin derivatives inhibited LPS-induced NOS in RAW 264.7 cells via downregulation of MAPK/NF-kappaB signaling

AIM OF THE STUDY: Shikonin/alkannin (SA) derivatives, analogs of naphthoquinone pigments, are the major components of root extracts of the Chinese medicinal herb (Lithospermum erythrorhizon; LE) and widely distributed in several folk medicines. In the present study, the effect and the underline molecular mechanism of shikonin derivatives isolated from root extracts of Lithospermum euchroma on lipopolysaccharide (LPS)-induced inflammatory response were investigated. MATERIALS AND METHODS: Effects of five SA derivatives, including SA, acetylshikonin, beta,beta-dimethylacrylshikonin, 5,8-dihydroxy-1.4-naphthoquinone, and 1,4-naphthoquinone on LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in mouse macrophage RAW264.7 cells were examined. RESULTS: Data suggested that SA derivatives inhibited LPS-induced NO and PGE(2) production, and iNOS protein expression. RT-PCR analysis showed that SA derivatives diminished LPS-induced iNOS mRNA expression. Moreover, the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 in LPS-stimulated RAW 264.7 cells was concentration-dependently suppressed by SA derivatives. SA inhibited NF-kappaB activation by prevention of the degradation of inhibitory factor-kappaB and p65 level in nuclear fractions induced by LPS. CONCLUSIONS: Taken together, these results suggest that the anti-inflammatory properties of SA derivatives might result from inhibition of iNOS protein expression through the downregulation of NF-kappaB activation via suppression of phosphorylation of ERK, in LPS-stimulated RAW 264.7 cells.     

芪麝丸体外抗炎的机制

目的:考察芪麝丸体外对小鼠RAW264.7巨噬细胞炎症模型的抗炎机制.方法:干扰素γ(1×104 U·mL-1)和脂多糖(100μg·L-1)协同诱导小鼠RAW264.7巨噬细胞(1×105/mL)24 h造成炎症模型;Griess反应测定细胞上清液中一氧化氮(NO)产量;Western blot检测诱导型一氧化氮合酶(iNOS)、环氧合酶(COX-2)的蛋白表达及丝裂原活化蛋白激酶(MAPK)信号转导通路的活化情况.结果:芪麝丸(250,500,1000 mg·L-1)呈剂量依赖性抑制细胞上清液中NO含量,且无细胞毒性.较模型组,经芪麝丸500,1000 mg·L-1剂量处理后,iNOS蛋白表达从(1.00±0.06)下调至(0.61±0.07)和(0.02±0.15),(P＜0.01),COX-2蛋白表达从(0.56±0.03)下调至(0.42±0.02),(0.30±0.03),(P＜0.01).胞外信号调节激酶(ERK)磷酸化水平从(1.04±0.04)下调至(0.79±0.06),(0.73 ±0.10),(P＜0.01).p38磷酸化水平从(0.51±0.06)下调至(0.39 ±0.07),(0.29±0.15),(P＜0.05),c-Jun氨基末端激酶(JNK)磷酸化水平从(1.05±0.03)下调至(0.65 ±0.02),(0.66±0.033),(P＜0.01).结论:芪麝丸部分通过抑制MAPK信号转导通路活化过程中关键蛋白胞外信号调节激酶(ERK)、JNK和p38丝裂原活化蛋白激酶(p38)磷酸化,下调iNOS基因和蛋白的表达从而减少NO的产量,同时下调COX-2蛋白表达,而发挥其抗炎效果.     

青蒿琥酯对内毒素诱导的一氧化氮合成的抑制作用

目的 :探讨青蒿琥酯对内毒素诱导的巨噬细胞一氧化氮 (NO)合成的影响。方法 :①用内毒素 (LPS)或LPS合并γ 干扰素作为巨噬细胞 (RAW 264.7)的NO合成诱导剂 ,加入不同浓度的青蒿琥酯 ,培养后取上清液 ,用Griess试剂测定NO产生量。②Balb/c小鼠肌肉注射青蒿琥酯 5 0mg·kg^-1·d^-1×3d ,收集腹腔巨噬细胞 ,测定LPS对细胞的NO诱生能力。结果 :LPS 1.0 ,0.2μg·ml^-1或γ-干扰素 100u合并LPS 1.0 ,0.2 ,0.04μg·ml^-1作用于RAW 264.7细胞 ,均可诱导大量NO合成。青蒿琥酯对LPS或LPS合并干扰素诱导的NO合成均有明显的抑制作用 ,其抑制作用具有明显的量效关系。经青蒿琥酯治疗后的小鼠 ,其腹腔巨噬细胞对LPS的反应性降低 ,其受LPS刺激后产生的NO量明显降低。结论 :青蒿琥酯可降低LPS诱导的炎性因子的产生 ,减轻炎症反应。     

Polygonum tinctorium extract suppresses nitric oxide production by activated macrophages through inhibiting inducible nitric oxide synthase expression

Despite its beneficial role in host defense mechanisms, excessive nitric oxide (NO) production by activated macrophages has been implicated in several inflammatory diseases. To clarify the mechanisms of anti-inflammatory activities of Polygonum tinctorium, we evaluated whether extracts of P. tinctorium could modulate the production of NO by activated macrophages. An AcOEt extract of P. tinctorium markedly inhibited NO synthesis by interferon-gamma (IFN-gamma)/lipopolysaccharide (LPS)-stimulated murine peritoneal macrophages and the macrophage-like cell line RAW 264.7 in a dose-dependent manner. Inhibition of NO synthesis was achieved by reducing inducible NO synthase (iNOS) expression at protein and mRNA levels. However, the AcOEt extract of P. tinctorium failed to inhibit NO synthesis when iNOS was already expressed following stimulation with IFN-gamma and LPS. The AcOEt extract also exhibited inhibitory activity on iNOS expression in human lung epithelial A549 cells stimulated with a combination of IFN-gamma, TNF-alpha and IL-1 beta without affecting the expression of constitutive isoforms of NOS. Furthermore, in vivo injection of the AcOEt extract of P. tinctorium into LPS-treated mice significantly reduced NO synthesis by peritoneal exudate cells under ex vivo conditions. These results suggest that P. tinctorium extract may be a potential therapeutic modulator of NO synthesis in various pathological conditions.     

藏药十八味党参丸提取物对脂多糖诱导的RAW264.7细胞Akt/p38MAPK信号通路及M1/M2极化影响的探究

目的探究藏药十八味党参丸(TEP)的提取物调控脂多糖(LPS)诱导小鼠巨噬细胞RAW 264.7的炎性反应及M1/M2极化分型的探究。方法 Alarmarblue法评价RAW 264.7活力;荧光酶标定量分析细胞活性氧(reactive oxygen species, ROS)水平;Griess法检测上清液中细胞一氧化氮(NO)的分泌情况;流式细胞术检测表面标志物CD206和CCR7蛋白的表达;RT-qPCR法检测细胞白介素(IL)-1β、IL-6、趋化因子2(CCL2)、一氧化氮合酶(iNOS)、精氨酸酶(ARG)-1和肿瘤坏死因子α(TNF-α)基因表达的情况;Western blot法检测TEP调控细胞合成iNOS、蛋白激酶B(Akt)和p38丝裂原活化激酶(p38MAPK)信号通路相关蛋白的表达情况。结果与模型组相比,TEP组一定程度上提高了RAW 264.7的细胞活性,同时抑制了LPS诱导的细胞内ROS水平的升高。经过LPS刺激后,模型组NO表达量显著升高,在24 h后表达量达到最高,而TEP组NO表达显著降低。模型组的CCR7表达升高,CD206表达下降,TEP干预后CCR7表达下降,CD206表达升高,且趋势呈现浓度依赖。与模型组相比,TEP组的IL-1β、IL-6、CCL2、iNOS、ARG和TNF-α基因表达以及iNOS、Akt和p38MAPK蛋白表达水平均显著降低。结论 TEP能够抑制细胞内ROS水平,降低NO分泌和炎性基因的表达水平,抑制细胞的M1表型,促进M2表型,其机制可能与细胞内iNOS、Akt和p38MAPK信号通路蛋白表达被抑制有关。     

藏药十八味党参丸提取物对脂多糖诱导的RAW264.7细胞Akt/p38MAPK信号通路及M1/M2极化影响的探究

目的探究藏药十八味党参丸(TEP)的提取物调控脂多糖(LPS)诱导小鼠巨噬细胞RAW 264.7的炎性反应及M1/M2极化分型的探究。方法 Alarmarblue法评价RAW 264.7活力;荧光酶标定量分析细胞活性氧(reactive oxygen species, ROS)水平;Griess法检测上清液中细胞一氧化氮(NO)的分泌情况;流式细胞术检测表面标志物CD206和CCR7蛋白的表达;RT-qPCR法检测细胞白介素(IL)-1β、IL-6、趋化因子2(CCL2)、一氧化氮合酶(iNOS)、精氨酸酶(ARG)-1和肿瘤坏死因子α(TNF-α)基因表达的情况;Western blot法检测TEP调控细胞合成iNOS、蛋白激酶B(Akt)和p38丝裂原活化激酶(p38MAPK)信号通路相关蛋白的表达情况。结果与模型组相比,TEP组一定程度上提高了RAW 264.7的细胞活性,同时抑制了LPS诱导的细胞内ROS水平的升高。经过LPS刺激后,模型组NO表达量显著升高,在24 h后表达量达到最高,而TEP组NO表达显著降低。模型组的CCR7表达升高,CD206表达下降,TEP干预后CCR7表达下降,CD206表达升高,且趋势呈现浓度依赖。与模型组相比,TEP组的IL-1β、IL-6、CCL2、iNOS、ARG和TNF-α基因表达以及iNOS、Akt和p38MAPK蛋白表达水平均显著降低。结论 TEP能够抑制细胞内ROS水平,降低NO分泌和炎性基因的表达水平,抑制细胞的M1表型,促进M2表型,其机制可能与细胞内iNOS、Akt和p38MAPK信号通路蛋白表达被抑制有关。     

Suppressive effect of inducible nitric oxide synthase (iNOS) expression by the methanol extract of Actinodaphne lancifolia

Nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) has played a crucial role in various pathophysiological processes including inflammation and carcinogenesis. Therefore, the inhibitors of NO synthesis or iNOS gene expression have been considered as potential anti-inflammatory and cancer chemopreventive agents. In our continuous search for iNOS inhibitors from natural products we have evaluated indigenous Korean plant extracts using an assay for inhibition of nitric oxide formation on lipopolysaccharide (LPS)-activated mouse macrophage RAW 264.7 cells. As a result, the methanolic stem extract of Actinodaphne lancifolia showed an inhibitory activity of NO production in a dose-dependent manner (IC50 = 2.5 microg/ml). Additional study demonstrated that the extract of Actinodaphne lancifolia significantly suppressed the iNOS protein and gene expression in a dose-dependent manner. These results suggest that Actinodaphne lancifolia could be a potential candidate for developing an iNOS inhibitor from natural products. Further elucidation of active principles for development of new cancer chemopreventive and/or anti-inflammatory agents could be warranted.     

The anti-inflammatory effects of Pyrolae herba extract through the inhibition of the expression of inducible nitric oxide synthase (iNOS) and NO production

The extract of Pyrolae herba (PH), which has been used as an anti-inflammatory folk remedy in Korea and China, was investigated for its anti-inflammatory action using arachidonic acid, 12-O-tetradecanoylphorbol 13-acetate or carrageenan-induced edema assays. The anti-nociceptive activity of PH was also tested in mice using the acetic acid-induced writhing model. PH showed dose-dependent and significant (P<0.05 at 100-400mg/kg) anti-inflammatory and anti-nociceptive activities in the animal assays. The mechanism of the activities of PH was examined by testing the extract to determine if it inhibits the expression of inducible nitric oxide synthase (iNOS) and the production of nitric oxide (NO) from the murine macrophages, RAW 264.7 cells. Similar to the in vivo activities, both the iNOS expression and NO production were significantly suppressed by PH in a dose-dependent manner. PH also inhibited the activating phosphorylation of p38 MAP kinase and NF-kappaB in these cells. These results provide a scientific basis to explain the effects of PH as an anti-inflammatory folk remedy in Asian countries.     

Echinacea increases arginase activity and has anti-inflammatory properties in RAW 264.7 macrophage cells,indicative of alternative macrophage activation

Ethnopharmacological relevance

The genus Echinacea is a popular herbal immunomodulator. Recent reports indicate that Echinacea products inhibit nitric oxide (NO) production in activated macrophages.

Aim of the study

In the present study we determined the inhibitory effects of alcohol extracts and individual fractions of alcohol extracts of Echinacea on NO production, and explored the mechanism underlying the pharmacological anti-inflammatory activity.

Materials and methods

Alcohol extracts of three medicinal Echinacea species, Echinacea angustifolia, Echinacea pallida and Echinacea purpurea, were prepared using Soxhlet apparatus and fractionated using HPLC. NO production by LPS activated RAW 264.7 macrophage cells was measured using a Griess reagent and iNOS detected using immunoblotting. In addition, effects on arginase activity were measured in RAW 264.7 cells stimulated with 8-bromo-cAMP +/− LPS.

Results

Alcohol extracts of all three Echinacea species significantly inhibited NO production by lipopolysaccharide (LPS)-activated the RAW 264.7 macrophage cell line; among them Echinacea pallida was the most active. The Echinacea-mediated decrease in NO production was unlikely due to a direct scavenging of NO because the extracts did not directly inhibit NO released from an NO donor, sodium nitroprusside. An immunoblotting assay demonstrated that the extract of Echinacea pallida inhibited inducible nitric oxide synthase (iNOS) protein expression in LPS-treated macrophages. The enzymes iNOS and arginase metabolize a common substrate, l-arginine, but produce distinct biological effects. While iNOS is involved in inflammatory response and host defense, arginase participates actively in anti-inflammatory activation. Arginase activity of RAW 264.7 cells stimulated with 8-bromo-cAMP was significantly increased by alcohol extracts of all three Echinacea species. The polar fraction containing caffeic acid derivatives enhanced arginase activity, while the lipophilic fraction containing alkamides exhibited a potential of inhibiting NO production and iNOS expression.

Conclusions

These results suggest that the anti-inflammatory activity of Echinacea might be due to multiple active metabolites, which work together to switch macrophage activation from classical activation towards alternative activation.