Imidazole propionate ameliorates atopic dermatitis-like skin lesions by inhibiting mitochondrial ROS and mTORC2.

Background: Imidazole propionate (IMP) is a histidine metabolite produced by some gut microorganisms in the human colon. Increased levels of IMP are associated with intestinal inflammation and the development and progression of cardiovascular disease and diabetes. However, the anti-inflammatory activity of IMP has not been investigated. This study aimed to elucidate the role of IMP in treating atopic dermatitis (AD). Methods: To understand how IMP mediates immunosuppression in AD, IMP was intraperitoneally injected into a Dermatophagoides farinae extract (DFE)/1-chloro-2,4 dinitrochlorobenzene (DNCB)-induced AD-like skin lesions mouse model. We also characterized the anti-inflammatory mechanism of IMP by inducing an AD response in keratinocytes through TNF-α/IFN-γ or IL-4 stimulation. Results: Contrary to the prevailing view that IMP is an unhealthy microbial metabolite, we found that IMP-treated AD-like skin lesions mice showed significant improvement in their clinical symptoms, including ear thickness, epidermal and dermal thickness, and IgE levels. Furthermore, IMP antagonized the expansion of myeloid (neutrophils, macrophages, eosinophils, and mast cells) and Th cells (Th1, Th2, and Th17) in mouse skin and prevented mitochondrial reactive oxygen species production by inhibiting mitochondrial energy production. Interestingly, we found that IMP inhibited AD by reducing glucose uptake in cells to suppress proinflammatory cytokines and chemokines in an AD-like in vitro model, sequentially downregulating the PI3K and mTORC2 signaling pathways centered on Akt, and upregulating DDIT4 and AMPK. Discussion: Our results suggest that IMP exerts anti-inflammatory effects through the metabolic reprogramming of skin inflammation, making it a promising therapeutic candidate for AD and related skin diseases.

Nepetin, a natural compound from Inulae flos, suppresses degranulation and eicosanoid generation through PLCγ1 and Akt signaling pathways in mast cells.

Nepetin derived from the flowers of Inula japonica, Inulae flos, has been reported to exert several biological activities, including anti-inflammatory responses. In this study, we evaluated the anti-allergic property of nepetin with its molecular mechanisms in bone marrow-derived mast cells (BMMC) and mice. In this in vitro study, we investigated the inhibitory effects of nepetin on degranulation and generation of leukotriene C4 (LTC4) and prostaglandin D2 (PGD2) in IgE/antigen (Ag)-stimulated BMMC. The effect of nepetin on passive cutaneous anaphylaxis (PCA) reaction was also studied in mice. Nepetin reduced degranulation and LTC4 generation in BMMC. The IgE/Ag-mediated signaling pathway demonstrated that nepetin suppressed intracellular Ca2+ level and activation of PLCγ1 and cPLA2. However, MAPKs were not affected by nepetin in BMMC. In addition, nepetin treatment reduced PGD2 production and suppressed cyclooxygenase-2 protein expression via the inhibition of the Akt and nuclear factor-κB signaling pathways. With respect to the local allergic response in vivo, oral administration of nepetin suppressed mast cell-dependent PCA reaction in a dose-dependent manner. The results of this study suggest that nepetin might have an anti-allergic potential related to mast cell-mediated inflammatory diseases.

Anti-inflammatory Effects of KOTMIN13: A Mixed Herbal Medicine in LPS-stimulated RAW 264.7 Cells and Mouse Edema Models.

BACKGROUND: A Korean herbal medicine, KOTMIN13, composed of Inula japonica Thunberg, Trichosanthes kirilowii Maximowicz var. japonica kitamura, Peucedanum praeruptorum Dunn, and Allium macrostemon Bge, has been used for anti-allergic and anti-asthmatic treatment in oriental clinics, but its activity has not been investigated. MATERIALS AND METHODS: To evaluate the anti-inflammatory activity of KOTMIN13 for in vitro study, LPS-stimulated RAW 264.7 cells were used to induce the production and expression of inflammatory mediators and its mechanisms. 12-O-Tetradecanoylphorobol-13 aceate (TPA)-induced ear edema and carrageenan-induced paw edema models were also used to evaluate the effect of KOTMIN13 on acute inflammation in vivo. RESULTS: KOTMIN13 reduced the release of inflammatory mediators [nitric oxide, prostaglandin E2, interleukin (IL)-1ß, and IL-6] and the protein expression of inducible nitric oxide synthase and cyclooxygenase-2 in LPS-stimulated RAW 264.7 cells. Mechanism studies showed the attenuation of LPS-induced NF-κB activation by KOTMIN13 via IκBα degradation abrogation and a subsequent decrease in nuclear p65 levels. Activation of mitogen-activated protein kinases (ERK, JNK, and p38) was also suppressed. Furthermore, KOTMIN13 ameliorated the development of TPA-induced ear edema and carrageenan-induced paw edema in acute inflammatory edema mouse models. CONCLUSION: Our study demonstrates that KOTMIN13 inhibits inflammatory mediators through the inhibitions of NF-κB and MAPK activities in LPS-induced RAW 264.7 cells, as well as acute inflammation in edema models, indicating that KOTMIN13 is an effective suppressor for anti-inflammatory activities. SUMMARY: KOTMIN13 decrease the production of No, PGE2, and proinflammatory cytokine (TNF-∝, IL-1ß,IL-6).KOTMIN13 Suppressed the degradation of NF-kß and IKßα and the phosorylation of MAP Kinases.Topical application of KOTMIN13 reduced mouse ear edema.Oral administration of KOTMIN13 decreased carrageenan-induced paw edema. Abbreviations used: NO: nitric oxide; PGE2: prostaglandin E2; iNOS: inducible NO synthase; COX-2: cyclooxygenase-2; TNF-α: tumor necrosis factor-α; IL: interleukin; NF-κB: nuclear factor kappaB; MAPK: mitogen-activated protein kinases; ERK: extracellular signal regulated kinase; JNK: c-jun N terminal kinase; TPA: 12-O-tetradecanoylphorbol-13-acetate.

KOTMIN13, a Korean herbal medicine alleviates allergic inflammation in vivo and in vitro.

BACKGROUND: The ethanol extract of KOTMIN13, composed of Inula japonica Flowers, Trichosanthes kirilowii Semen, Peucedanum praeruptorum Radix, and Allium macrostemon Bulbs, was investigated for its anti-asthmatic and anti-allergic activities. METHODS: The anti-asthmatic effects of KOTMIN13 were evaluated on ovalbumin (OVA)-induced murine asthma model. Anti-allergic properties of KOTMIN13 in bone-marrow derived mast cells (BMMC) and passive cutaneous anaphylaxis (PCA) in vivo were also examined. RESULTS: In asthma model, KOTMIN13 effectively suppressed airway hyperresponsiveness induced by aerosolized methacholine when compared to the levels of OVA-induced mice. KOTMIN13 treatment reduced the total leukocytes, eosinophil percentage, and Th2 cytokines in the bronchoalveolar lavage fluids in OVA-induced mice. The increased levels of eotaxin and Th2 cytokines in the lung as well as serum IgE were decreased by KOTMIN13. The histological analysis shows that the increased inflammatory cell infiltration and mucus secretion were also reduced. In addition, the degranulation and leukotriene C4 production were inhibited in BMMC with IC50 values of 3.9 µg/ml and 1.7 µg/ml, respectively. Furthermore, KOTMIN13 treatment attenuated mast-mediated PCA reaction. CONCLUSIONS: These results demonstrate that KOTMIN13 has anti-asthmatic and anti-allergic effects in vivo and in vitro models.

Britanin attenuates ovalbumin-induced airway inflammation in a murine asthma model.

We previously demonstrated the alleviation of ovalbumin (OVA)-induced airway inflammation by Inulae flos. In the present study, the effects of britanin, a sesquiterpene compound isolated from Inulae flos, were evaluated in an in vivo animal model for anti-asthma activity through observation of airway hyperresponsiveness (AHR), eosinophil recruitment, Th2 cytokine and IgE levels, and lung histopathology. Britanin administration effectively reduced AHR induced by aerosolized methacholine, airway eosinophilia, Th2 cytokines in bronchoalveolar lavage fluids and the supernatant of cultured splenocytes compared with OVA-induced mice. Histological studies showed that increased inflammatory cell infiltration and mucus secretion were reduced by britanin administration. Thus, britanin may have therapeutic potential for treating allergic asthma.

Anti-inflammatory effects of Juncus effusus extract (JEE) on LPS-stimulated RAW 264.7 cells and edema models.

CONTEXT: Juncus effusus L. var. decipiens BUCHEN. f. leschenaultii GAY has been used in traditional medicine for the treatment of anxiety and insomnia. OBJECTIVE: The objective of this study was to evaluate the effects of ethanol extract from the pith of Juncus effusus (JEE) on anti-inflammatory activities in RAW 264.7 cells. MATERIALS AND METHODS: The production of inflammatory mediators and the underlying mechanisms using 3.1, 6.3, and 12.5 µg/mL concentrations of JEE were investigated. In addition, the topical anti-inflammatory effects of JEE (0.5, 1, and 2 mg/mL) on 12-O-tetradecanoylphorobol-13 acetate (TPA)-induced ear edema and oral administration of JEE (50, 100, and 200 mg/kg) on carrageenan-induced paw-edema were studied in mice. RESULTS: JEE reduced the release of nitric oxide (NO, IC50 value = 1.98 µg/mL), prostaglandin E2 (IC50 value = 5.5 µg/mL), and pro-inflammatory cytokines, IL-1ß (IC50 value = 4.74 µg/mL) and IL-6 (IC50 value = 20.48 µg/mL). JEE also suppressed the protein expression of inducible NO synthase and cyclooxygenase-2 in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Mechanism studies showed attenuation of LPS-induced activation of NF-κB by JEE via abrogation of IκBα degradation and a subsequent decrease in nuclear p65 level. Phosphorylation of all three MAP kinases (ERK, JNK, and p38) in LPS-stimulated RAW 264.7 cells was also suppressed in a dose-dependent manner. In acute inflammation models of mice, topical application (1 and 2 mg) and oral administration (50, 100, and 200 mg/kg) of JEE ameliorated TPA-induced ear edema and carrageenan-induced paw edema, respectively, in dose-dependent manners. DISCUSSION AND CONCLUSION: These results indicate that JEE exhibited anti-inflammatory activities by suppressing the production of inflammatory mediators in LPS-stimulated RAW 264.7 cells and by attenuating edema in mice.

Potential Wound Healing Activities of Galla Rhois in Human Fibroblasts and Keratinocytes.

Wound healing is a complex process orchestrated by the regeneration of the epithelium and the remodeling of the extracellular matrix through processes like collagen deposition. Galla Rhois has been widely used in traditional Korean medicine for its various pharmacological effects, including an anticoccidial effect, however, little is known about its healing activity. The purpose of this study was to determine the effects of Galla Rhois ethanol extract (GRE) on wound healing activities, including H2O2-induced oxidative stress, cell migration, and lactate dehydrogenase (LDH) release assays using human keratinocyte (HaCaT) and dermal fibroblasts (CCD-986SK). In addition, total soluble collagen deposition and collagen gene expression for Type I and III collagen were evaluated in CCD-986SK. Total tannin and flavonoid contents for GRE were measured. GRE induced a significant increase in the number and migration of cells, along with a decrease in cell death and LDH release. In addition, it also induced the over-expression of collagen Type I and III mRNA and caused increased synthesis of total soluble collagen. The contents of total tannin and flavonoid for GRE were 55.7% ([Formula: see text][Formula: see text]mg/g) and 62.9% ([Formula: see text][Formula: see text]mg/g), respectively. The results suggest that GRE can cause accelerated wound healing by increasing cell survival, proliferation, migration, and collagen synthesis along with a potential anti-oxidant property. This evidence provides novel insight into natural therapy for tissue injury.

Imperatorin Suppresses Degranulation and Eicosanoid Generation in Activated Bone Marrow-Derived Mast Cells.

Imperatorin has been known to exert many biological functions including anti-inflammatory activity. In this study, we investigated the inhibitory effects of imperatorin on the production of inflammatory mediators in mouse bone marrow-derived mast cells (BMMC). Imperatorin inhibited degranulation and the generation of eicosanoids (leukotriene C4 (LTC4) and prostaglandin D2 (PGD2)) in IgE/antigen (Ag)-stimulated BMMC. To elucidate the molecular mechanism involved in this process, we investigated the effect of imperatorin on intracellular signaling in BMMC. Biochemical analyses of the IgE/Ag-mediated signaling pathway demonstrated that imperatorin dramatically attenuated degranulation and the production of 5-lipoxygenase-dependent LTC4 and cyclooxygenase-2-dependent PGD2 through the inhibition of intracellular calcium influx/phospholipase Cγ1, cytosolic phospholipase A2/mitogen-activated protein kinases and/or nuclear factor-κB pathways in BMMC. These results suggest that the effects of imperatorin on inhibition of degranulation and eicosanoid generation through the suppression of multiple steps of IgE/Ag-mediated signaling pathways would be beneficial for the prevention of allergic inflammation.

Anti-Inflammatory Activity of Heterocarpin from the Salt Marsh Plant Corydalis heterocarpa in LPS-Induced RAW 264.7 Macrophage Cells.

The inhibitory effect of three chromones 1-3 and two coumarins 4-5 on the production of nitric oxide (NO) was evaluated in LPS-induced RAW 264.7 macrophage cells. Among the compounds tested heterocarpin (1), a furochromone, significantly inhibited its production in a dose-dependent manner. In addition, heterocarpin suppressed prostaglandin E2 (PGE2) production and expression of cytokines such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6).

Suppressive effects of britanin, a sesquiterpene compound isolated from Inulae flos, on mast cell-mediated inflammatory responses.

Mast cells are central players in immediate-type hypersensitvity and inflammatory responses. In the present study, the effects of britanin on the passive cutaneous anaphylaxis (PCA) reaction in mice and on the phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-induced production of pro-inflammatory cytokines in human mast cell line (HMC-1) were evaluated. The oral administration of britanin (10-20 mg/kg) decreased the mast cell-mediated PCA reaction in IgE-sensitized mice. In the activity and mechanism of britanin in vitro assay, britanin suppressed the gene expression and secretion of pro-inflammatory cytokines in a dose-dependent manner in HMC-1. In addition, britanin attenuated PMACI-induced activation of NF-κB as indicated by the inhibition of the degradation of IκBα, nuclear translocation of NF-κB, NF-κB/DNA binding activity assay, and blocked the phosphorylation of p38 MAP kinase, in a dose-dependent manner. We conclude that britanin may have potential as a treatment for allergic-inflammatory diseases.

Suppressive effect of tomentosin on the production of inflammatory mediators in RAW264.7 cells.

In this study, tomentosin, a sesquiterpene lactone was isolated from Inulae flos and its biological activities were investigated. The effects of tomentosin on the production of inflammatory mediators as well as on nuclear factor (NF)-κB and mitogen-activated protein (MAP) kinase activation were evaluated in RAW264.7 cells. Tomentosin decreased the production of nitric oxide (NO) and prostaglandin E2 (PGE2) by suppressing the protein expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2, respectively. Additionally, tomentosin reduced the release of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Tomentosin not only attenuated lipopolysaccharide (LPS)-induced NF-κB activation via the abrogation of inhibitory (I)κBα degradation and caused a subsequent decrease in nuclear p65 level, but it also suppressed the phosphorylation of MAP kinases (p38 and c-Jun N terminal kinase (JNK)). These results indicate that tomentosin exerts anti-inflammatory activities through the inhibition of inflammatory mediators (NO, iNOS, PGE2, COX-2, TNF-α, and IL-6) by regulating NF-κB activation and phosphorylation of p38/JNK kinases in macrophages, thus suggesting that tomentosin could be a potential agent for the treatment of inflammatory diseases.

Anti-allergic effect of a Korean traditional medicine, Biyeom-Tang on mast cells and allergic rhinitis.

BACKGROUND: Biyeom-Tang, a medicine prescribed by oriental clinics, has been used for the treatment of the allergic rhinitis (AR). In the present study, an ethanol extract of Biyeom-Tang (EBT) was investigated for anti-allergic properties on bone-marrow derived mast cells (BMMC) and in vivo models. METHODS: The anti-allergic properties of EBT were evaluated by measuring ß-Hex release and the production of prostaglandin D2 (PGD2) and leukotriene C4 (LTC4) on BMMC in vitro and PCA and OVA-induced AR models in vivo. RESULTS: EBT strongly inhibited a degranulation reaction in a dose dependent manner with an IC50 value of 35.6 µg/ml. In addition, the generation of PGD2 and LTC4 was inhibited in BMMC in a concentration-dependent manner with IC50 values of 7.0 µg/ml and 10.9 µg/ml, respectively. When administrated orally, EBT ameliorated the mast cell-mediated PCA reaction. In the OVA-induced AR model, the increased levels of IgE were reduced by EBT. The levels of cytokines, such as IL-4, IL-5, IL-10, and IL-13 decreased in the splenocytes of EBT-treated mice. The histological analysis shows that the infiltration of inflammatory cells increased by OVA-sensitization was also reduced. CONCLUSIONS: Taken together, these results suggested that EBT has anti-allergic and anti-inflammatory effects in vitro and in vivo models.

Britanin suppresses LPS-induced nitric oxide, PGE2 and cytokine production via NF-κB and MAPK inactivation in RAW 264.7 cells.

Little is known about the biological properties of britanin, which is isolated from the flowers of Inula japonica (Inulae Flos). Based on our previous studies that Inulae Flos had anti-inflammation and anti-asthmatic activities, we tried to find the bioactive compounds from it. In this study, the anti-inflammatory effects of britanin on the inflammatory mediators as well as on nuclear factor (NF)-кB and mitogen-activated protein (MAP) kinase activation were evaluated in RAW 264.7 cells. Britanin inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) along with the expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. In addition, britanin reduced the release of pro-inflammatory cytokines, such as TNF-α, IL-1ß, and IL-6. Furthermore, the phosphorylations of MAP kinases (p38 and JNK) in LPS-stimulated RAW 264.7 cells were suppressed by britanin. Moreover, britanin inhibited the NF-κB activation induced by LPS, which was associated with the abrogation of IκBα degradation and subsequent decreases in nuclear p65 levels. This study suggests that the anti-inflammatory activities of britanin might be attributed to the inhibition of iNOS and COX-2 and cytokine expression at least in part, through the attenuation of the phosphorylations of MAP kinases and NF-κB activation via IκBα degradation in macrophages. We conclude that britanin may have potential for the treatment of inflammatory diseases through the down-regulation of MAP kinases and NF-κB mediated activation of macrophages.

Inula japonica extract inhibits mast cell-mediated allergic reaction and mast cell activation.

ETHNOPHARMACOLOGICAL RELEVANCE: The flowers of Inula japonica (Inulae Flos) have long been used in traditional medicine for the treatment of bronchitis, digestive disorders, and inflammation. However, the mechanisms underlying its anti-inflammatory effects remain yet to be elucidated. The objectives of this study were 1) to assess the anti-allergic activity of the ethanol extract of flowers of Inula japonica extract (IFE) in vivo, 2) to investigate the mechanism of its action on mast cells in vitro, and 3) to identify its major phytochemical compositions. MATERIALS AND METHODS: The anti-allergic activity of IFE was evaluated using mouse bone marrow-derived mast cells (BMMCs) in vitro and a passive cutaneous anaphylaxis (PCA) animal model in vivo. The effects of IFE on mast cell activation were evaluated in terms of degranulation, eicosanoid generation, Ca(2+) influx, and immunoblotting of various signaling molecules. RESULTS: IFE inhibited degranulation and the generation of eicosanoids (PGD(2) and LTC(4)) in stem cell factor (SCF)-stimulated BMMCs. Biochemical analysis of the SCF-mediated signaling pathways demonstrated that IFE inhibited the activation of multiple downstream signaling processes including mobilization of intracellular Ca(2+) and phosphorylation of the mitogen-activated protein kinases (MAPKs), PLCγ1, and cPLA(2) pathways. When administered orally, IFE attenuated the mast cell-mediated PCA reaction in IgE-sensitized mice. Its major phytochemical composition included three sesquiterpenes, 1-O-acetylbritannilactone, britanin and tomentosin. CONCLUSIONS: This study suggests that IFE modulates eicosanoids generation and degranulation through the suppression of SCF-mediated signaling pathways that would be beneficial for the prevention of allergic inflammatory diseases. Anti-allergic activity of IFE may be in part attributed particularly to the presence of britanin and tomentosin as major components evidenced by a HPLC analysis.

The effect of macrolides on myofibroblast differentiation and collagen production in nasal polyp-derived fibroblasts.

BACKGROUND: Macrolides are known to have anti-inflammatory, immunomodulatory, and tissue reparative effects. The purpose of this study was to determine the effect of macrolides (erythromycin [EM] and roxithromycin [RXM]) on the differentiation of fibroblasts into myofibroblasts and extracellular matrix accumulation in transforming growth factor (TGF) beta1-induced nasal polyp-derived fibroblasts (NPDFs) and to determine if NADPH oxidase (Nox) 4 and reactive oxygen species (ROS) are involved in the aforementioned processes. METHODS: Nasal polyps of six patients (three women and three men; 32.3 ± 5.2 years of age) were acquired during surgery and NPDFs were isolated from surgical tissues. NPDFs were pretreated with macrolides for 2 hours before differentiation induction by TGF-beta1. The mRNA expressions of alpha-smooth muscle actin (SMA), collagen types I and III, and Nox4 were determined by reverse-transcription-polymerase chain reaction, and the expression of alpha-SMA protein was determined by immunocytochemical staining. The amount of total collagen production was analyzed by SirCol collagen dye-binding assay. ROS activity was measured by nitroblue tetrazolium reduction assay and was visualized by fluorescent microscopy. RESULTS: In TGF-beta1-induced NPDFs, EM, and RXM significantly inhibited expressions of alpha-SMA and collagen types I and III mRNA and reduced alpha-SMA and collagen protein levels at concentrations of 5 and 10 µg/mL. EM and RXM also inhibited TGF-ß1-induced ROS production and Nox4 mRNA expression at the same concentrations. CONCLUSION: These results suggest the possibility that EM and RXM may play an important role in inhibiting the development of nasal polyps through their antioxidant effect.

Increased expression of pigment epithelium-derived factor in allergic rhinitis.

OBJECTIVES: To investigate the expression of messenger RNA (mRNA) of the gene for pigment epithelium-derived factor (PEDF) (OMIM *172860) and PEDF protein and to localize the PEDF protein in the nasal mucosa of patients with allergic rhinitis and of control subjects. DESIGN: Investigation of PEDF mRNA and PEDF protein expression in the nasal mucosa using reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemical staining. PARTICIPANTS: We used inferior turbinate mucosal samples from 10 patients with allergic rhinitis and 10 matched healthy control subjects. INTERVENTIONS: We extracted PEDF mRNA from the inferior turbinate mucosa samples and performed reverse transcription-polymerase chain reaction analysis. We used Western blotting to analyze differences in expression levels of PEDF protein between patients with allergic rhinitis and healthy controls, and the PEDF protein was localized immunohistochemically. RESULTS: The expression levels of PEDF mRNA and PEDF protein in the nasal mucosa were significantly increased in patients with allergic rhinitis compared with those in nonallergic controls. The PEDF protein was expressed in the epithelium and submucosal glands. CONCLUSIONS: We found that PEDF protein is expressed in the human nasal mucosa, and its expression is increased in allergic rhinitis. These results suggest a possible contribution of PEDF to the chronic inflammation of the nasal mucosa in allergic rhinitis.

Flavonoids inhibit histamine release and expression of proinflammatory cytokines in mast cells.

Mast cells participate in allergy and inflammation by secreting inflammatory mediators such as histamine and proinflammatory cytokines. Flavonoids are naturally occurring molecules with antioxidant, cytoprotective, and antiinflammatory actions. However, effect of flavonoids on the release of histamine and proinflammatory mediator, and their comparative mechanism of action in mast cells were not well defined. Here, we compared the effect of six flavonoids (astragalin, fisetin, kaempferol, myricetin, quercetin, and rutin) on the mast cell-mediated allergic inflammation. Fisetin, kaempferol, myricetin, quercetin, and rutin inhibited IgE or phorbol-12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-mediated histamine release in RBL-2H3 cells. These five flavonoids also inhibited elevation of intracellular calcium. Gene expressions and secretion of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, and IL-8 were assessed in PMACI-stimulated human mast cells (HMC-1). Fisetin, quercetin, and rutin decreased gene expression and production of all the proinflammatory cytokines after PMACI stimulation. Myricetin attenuated TNF-alpha and IL-6 but not IL-1beta and IL-8. Fisetin, myricetin, and rutin suppressed activation of NF-kappaB indicated by inhibition of nuclear translocation of NF-kappaB, NF-kappaB/DNA binding, and NF-kappaB-dependent gene reporter assay. The pharmacological actions of these flavonoids suggest their potential activity for treatment of allergic inflammatory diseases through the down-regulation of mast cell activation.

Allose gallates suppress expression of pro-inflammatory cytokines through attenuation of NF-kappaB in human mast cells.

Gallotannins are plant-derived, water-soluble polyphenols with wide-ranging biological activities. Mast cell-mediated allergic inflammation is known to cause many diseases such as asthma, sinusitis, and rheumatoid arthritis. Mast cells induce synthesis and production of pro-inflammatory cytokines including tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 with immune regulatory properties. Expression of inflammatory cytokines is mainly regulated by a transcription factor, nuclear factor (NF)-kappaB. In the present study, the effect of eight gallotannins on the level of pro-inflammatory cytokines and NF-kappaB activation was investigated in human mast cell line (HMC-1). HMC-1 cells were sensitized by phorbol 12-myristate 13-acetate (PMA) and calcium ionophore (A23187). Among the eight gallotannins from EUPHORBIA species, three gallotannins such as 1,2,3,4,6-penta- O-galloyl-beta-D-glucose, 1,2,6-tri-O-galloyl-beta-D-allopyanose, and 1,2,3,6-tetra-O-galloyl-beta-D-allopyranose suppressed the gene expression and secretion of pro-inflammatory cytokines in a dose-dependent manner. In addition, these three gallotannins blocked the activation of NF-kappaB as indicated by an NF-kappaB-dependent gene reporter assay. We conclude that these gallotannins may have potential for the treatment of inflammatory diseases through the down-regulation of NF-kappaB-mediated activation of mast cells.

Anti-inflammatory activity of fisetin in human mast cells (HMC-1).

Mast cells play an important role in the pathogenesis of allergic diseases through the release of inflammatory mediators such as histamine, cysteinyl leukotrienes, cytokines, and chemokines. Flavonoids, like fisetin are naturally occurring molecules with antioxidant, cytoprotective, and anti-inflammatory actions. The aim of our study was to examine whether fisetin modulates inflammatory reaction in stimulated human mast cells (HMC-1). Fisetin decreased phorbol-12-myristate 13-acetate plus calcium ionophore A23187 (PMACI)-stimulated gene expression and production of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-4, IL-6, and IL-8 in HMC-1 cells. Fisetin inhibited PMACI-induced phosphorylation of p38 mitogen-activated protein kinase, extracellular-regulated kinase, and c-Jun N-terminal kinase. In addition, fisetin suppressed nuclear factor (NF)-kappaB activation induced by PMACI, leading to expression of IkappaB-alpha phosphorylation and degradation. Fisetin suppressed powerful induction of NF-kappaB promoter-mediated luciferase activity. These pharmacological actions of fisetin produce new suggestion that fisetin is a potential medicine for treatment of inflammatory diseases through the down-regulation of mast cell activation.

The anti-anaphylactic effect of the gall of Rhus javanica is mediated through inhibition of histamine release and inflammatory cytokine secretion.

The immediate-type allergic reaction (anaphylaxis) is involved in many allergic diseases such as asthma, allergic rhinitis and sinusitis. We investigated the effect of the gall of Rhus javanica (GRJ) on the model of the immediate-type allergic reaction, and studied its possible mechanisms. GRJ inhibited compound 48/80-induced systemic reactions in mice. GRJ attenuated immunoglobulin (Ig) E-mediated local allergic reactions. In addition, GRJ dose dependently decreased histamine release from rat peritoneal mast cells activated by compound 48/80 or IgE. The decreasing effect of GRJ on the histamine release was mediated by the modulation of cAMP and [Ca2+]i in mast cells. Furthermore, GRJ decreased the phorbol 12-myristate 13-acetate plus calcium ionophore A23187-stimulated TNF-alpha and IL-6 secretion in human mast cells. The inhibitory effect of GRJ on the pro-inflammatory cytokine was c-Jun N-terminal kinase and nuclear factor-kappaB dependent. Our findings provide evidence that GRJ inhibits mast cell-derived immediate-type allergic reactions, and suggest the possible mechanisms of action.