Proanthocyanidin‐rich Pinus radiata bark extract inhibits mast cell‐mediated anaphylaxis‐like reactions

Mast cells play a critical role in the effector phase of immediate hypersensitivity and allergic reactions. Pinus radiata bark extract exerts multiple biological effects and exhibits immunomodulatory and antioxidant properties. However, its role in mast cell‐mediated anaphylactic reactions has not been thoroughly investigated. In this study, we examined the effects of proanthocyanidin‐rich water extract (PAWE) isolated from P. radiata bark on compound 48/80‐induced or antidinitrophenyl (DNP) immunoglobulin E (IgE)‐mediated anaphylaxis‐like reactions in vivo. In addition, we evaluated the mechanism underlying the inhibitory effect of PAWE on mast cell activation, with a specific focus on histamine release, using rat peritoneal mast cells. PAWE attenuated compound 48/80‐induced or anti‐DNP IgE‐mediated passive cutaneous anaphylaxis‐like reactions in mice, and it inhibited histamine release triggered by compound 48/80, ionophore A23187, or anti‐DNP IgE in rat peritoneal mast cells in vitro. Moreover, PAWE suppressed compound 48/80‐elicited calcium uptake in a concentration‐dependent manner and promoted a transient increase in intracellular cyclic adenosine‐3′,5′‐monophosphate levels. Together, these results suggest that proanthocyanidin‐rich P. radiata bark extract effectively inhibits anaphylaxis‐like reactions.     

Neohesperidin suppresses IgE‐mediated anaphylactic reactions and mast cell activation via Lyn‐PLC‐Ca2+ pathway

Mast cells play an essential role in IgE‐FcεR1‐mediated allergic diseases. Citrus aurantium is a prolific source of flavonoids with various biological activities, including anti‐inflammatory, antioxidant, and anti‐tumor efficacies. Neohesperidin is a novel flavonoid isolated from the leaves of C. aurantium. In this study, the anti‐allergic and anti‐inflammatory potentials of neohesperidin were investigated along with its molecular mechanism. The anti‐anaphylactic activity of neohesperidin was evaluated through hind paw extravasation study in mice. Calcium imaging was used to assess intracellular Ca²⁺ mobilization. The levels of cytokines and chemokines were measured using enzyme immunoassay kits. Western blotting was used to explore the related molecular signaling pathways. Neohesperidin suppressed IgE‐induced mast cell activations, including degranulation and secretion of cytokines and eicosanoids through inhibiting phosphorylation of Lyn kinase. Neohesperidin inhibited the release of histamine and other proinflammatory cytokines through a mast cell‐dependent passive cutaneous anaphylaxis animal model. Histological studies demonstrated that neohesperidin substantially inhibited IgE‐induced cellular infiltration and attenuated mast cell activation in skin tissue. In conclusion, our study revealed that neohesperidin could inhibit allergic responses in vivo and in vitro, and the molecule may be regarded as a novel agent for preventing mast cell‐immediate and delayed allergic diseases.     

Paeoniflorin inhibits MRGPRX2‐mediated pseudo‐allergic reaction via calcium signaling pathway

Mas‐related G protein‐coupled receptor‐X2 (MRGPRX2) expressed on mast cells (MCs) has been shown to be a pivotal target for pseudo‐allergic diseases. Therefore, MRGPRX2 might be a therapeutic target for allergic contact dermatitis, atopic dermatitis, and red man syndrome. Paeoniflorin (PF) was reported to have an antiinflammatory effect in neuroinflammation, enteritis, and so forth. In this study, we investigated the anti‐pseudo‐allergic effect of PF and the underlying molecular mechanisms. Our results showed that PF can suppress compound 48/80 (C48/80)‐induced PCA and MCs degranulation in vivo, in a dose‐dependent manner. Moreover, PF can reduce C48/80‐induced calcium influx and suppress MC degranulation and chemokines release in vitro. PF can downregulate the phosphorylation levels of key kinases in PLCγ‐regulated calcium influx and subsequent cytokine synthesis pathways. Our study revealed that PF could inhibit C48/80‐induced allergic responses both in vivo and in vitro. As such, it may be regarded as a novel inhibitor for preventing MRGPRX2‐mediated allergic diseases.     

Lipid‐soluble components of honeybee‐collected pollen exert antiallergic effect by inhibiting IgE‐mediated mast cell activation in vivo

It was shown previously that bee‐collected pollen (bee pollen, BP), inhibited in vitro murine mast cell activation. This study further analysed the antiallergic effect of BP in vivo by measuring cutaneous mast cell activation using a passive cutaneous anaphylaxis reaction. Daily oral administration of BP to mice, dose‐dependently reduced the cutaneous mast cell activation elicited by IgE and specific antigens. Administration of BP also reduced the plasma concentration of malondialdehyde (MDA), an indicator of lipid peroxidation. The inhibitory effect of BP was mostly in a lipid‐ but not in water‐soluble fraction. The HPLC analysis of isoflavones in BP revealed that genistein was a major isoflavone. However, administration of genistein alone at the concentration found in BP, did not show an inhibitory effect as observed in whole BP, suggesting that component(s) other than genistein would be responsible for the inhibitory effect of BP. These results first reveal that lipid‐soluble components of BP exert an antiallergic action by inhibiting the FcåRI‐mediated cutaneous mast cell activation. Copyright © 2009 John Wiley & Sons, Ltd.     

Inhibition of immediate-type allergic reaction by Rosa davurica Pall. in a murine model

We studied the effect of Rosa davurica Pall. (Rosaceae) fruits (RdF) on immediate-type allergic reactions. RdF completely inhibited compound 48/80-induced systemic anaphylactic shock at the dose of 1 g/kg. When RdF was given as pretreatment, at concentrations ranging from 0.0001 to 1 g/kg, the serum histamine levels induced by compound 48/80 were reduced in a dose-dependent manner. RdF inhibited the passive cutaneous anaphylaxis activated by anti-dinitrophenyl (DNP) IgE antibody dose dependently. RdF also inhibited the histamine release induced by compound 48/80 or anti-DNP IgE from the rat peritoneal mast cells (RPMC). Moreover, RdF had a significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-alpha production from RPMC. These results indicate that RdF may contain compounds with actions that inhibit mast cell degranulation in the rat.     

Effect of Vitex rotundifolia on immediate-type allergic reaction

We investigated the effect of aqueous extract of Vitex rotundifolia (L.) (Verbenaceae) fruits (VRFE) on the immediate-type allergic reactions in vivo and in vitro. VRFE (10(-4)-1.0 g/kg) dose-dependently inhibited systemic allergic reaction induced by compound 48/80. When VRFE was employed in a systemic allergic reaction test, the plasma histamine levels were reduced in a dose-dependent manner. VRFE (5x10(-1) and 1.0 g/kg) inhibited passive cutaneous anaphylaxis activated by anti-dinitrophenyl (DNP) IgE. VRFE (10(-3)-1.0 mg/ml) also dose-dependently inhibited the histamine release from the rat peritoneal mast cells (RPMC) by compound 48/80 or anti-DNP IgE. Moreover, VRFE (10(-3) mg/ml) had a significant inhibitory effect on anti-DNP IgE-induced tumor necrosis factor-alpha production from RPMC. These results suggest that VRFE may be beneficial in the regulation of immediate-type allergic reaction.     

The anti‐anaphylactoid effects of Piperine through regulating MAS‐related G protein‐coupled receptor X2 activation

Mast cells play an important role in inflammatory and allergic diseases. MAS‐related G protein‐coupled receptor X2 (MRGPRX2) is a novel G protein‐coupled receptor in mast cells that mediates drug‐induced anaphylactoid reactions. Piperine has been reported to have anti‐inflammatory and anti‐allergic pharmacological activities. However, whether the pharmacological effects are regulated by MRGPRX2 has not yet been reported. The purpose of this study was to assess the anti‐anaphylactoid effect of Piperine and to explore its potential mechanism. The anti‐anaphylactoid effect of Piperine was assessed by an in vivo mouse hindpaw extravasation model. Mast cell intracellular calcium mobilization was measured by a calcium imaging assay. An enzyme immunoassay was used to evaluate the release of pro‐inflammatory factors from stimulated mast cells. Activated mast cell related signals were assessed by western blot. A cell membrane chromatography assay was used to determine the binding characteristics of Piperine and MRGPRX2. The results showed that Piperine suppressed mast cell intracellular Ca²⁺ mobilization, inhibited cytokines and chemokines release, and down‐regulated the phosphorylation level of phospholipase Cγ1, protein kinase C, inositol 1,4,5‐triphate receptor, P38, protein kinase B, and ERK. Meanwhile, Piperine can bind to MRGPRX2 as a specific antagonist. Hence, Piperine can be served as a novel therapeutic drug candidate for MRGPRX2‐mediated anaphylactoid reactions.     

Effect of Korean folk medicine ‘Chung-Dae-San' on mast cell-dependent anaphylactic reaction

We investigated the effect of the herbal formulation ‘Chung-Dae-San’ (CDS) on anaphylactic reactions. CDS inhibited compound 48/80-induced anaphylactic shock 100% with the dose of 10⁰ g/kg body weight (BW). When CDS was given as pretreatment at concentrations ranging from 10⁻⁴ to 10⁰ g/kg BW, the serum histamine levels induced by compound 48/80 were reduced in a dose-dependent manner. We also investigated the effect of CDS on mast cell-dependent passive cutaneous anaphylaxis (PCA) activated by anti-dinitrophenyl (DNP) IgE antibody. CDS potently inhibited PCA when administered orally, topically, intraperitoneally or intradermally. However, it did not show inhibitory activity when administered intravenously. CDS dose-dependently inhibited the histamine release from the rat peritoneal mast cells (RPMC) by compound 48/80 and anti-DNP IgE. Moreover, the level of cAMP in RPMC, when CDS was added, significantly increased about 4-fold at 4 min compared with that of basal cells. These results indicate that CDS may possess strong antianaphylactic activity and also suggest the differential activity follwing administration routes may be caused by difference in bioavailability.     

Inhibitory Effects of French Pine Bark Extract,Pycnogenol®, on Alveolar Bone Resorption and on the Osteoclast Differentiation

Pycnogenol^® (PYC) is a standardized bark extract from French maritime pine (Pinus pinaster Aiton). We examined the inhibitory effects of PYC on alveolar bone resorption, which is a characteristic feature of periodontitis, induced by Porphyromonas gingivalis (P. gingivalis) and osteoclast differentiation. In rat periodontitis model, rats were divided into four groups: group A served as the non‐infected control, group B was infected orally with P. gingivalis ATCC 33277, group C was administered PYC in the diet (0.025%: w/w), and group D was infected with P. gingivalis and administered PYC. Administration of PYC along with P. gingivalis infection significantly reduced alveolar bone resorption. Treatment of P. gingivalis with 1 µg/ml PYC reduced the number of viable bacterial cells. Addition of PYC to epithelial cells inhibited adhesion and invasion by P. gingivalis. The effect of PYC on osteoclast formation was confirmed by tartrate‐resistant acid phosphatase staining. PYC treatment significantly inhibited osteoclast formation. Addition of PYC (1–100 µg/ml) to purified osteoclasts culture induced cell apoptosis. These results suggest that PYC may prevent alveolar bone resorption through its antibacterial activity against P. gingivalis and by suppressing osteoclastogenesis. Therefore, PYC may be useful as a therapeutic and preventative agent for bone diseases such as periodontitis. Copyright © 2014 John Wiley & Sons, Ltd.     

Anti‐allergic Effect of Pleuran (β‐glucan from Pleurotus ostreatus) in Children with Recurrent Respiratory Tract Infections

Recurrent respiratory tract infections (RRTIs) present a very important problem in paediatric praxis. As true immunodeficiencies are rare, one of the most important factors assumed to contribute to increased respiratory morbidity is atopy. Several preparations of natural origin have been used for the prevention of RRTIs, and some of the most effective immunomodulators are biologically active polysaccharides – e.g. ß‐glucans. In our randomised, double‐blind, placebo‐controlled study, we investigated the prevalence of atopy in a group of children with RRTIs and the potential anti‐allergic effect of pleuran (ß‐glucan isolated from Pleurotus ostreatus) on basic laboratory markers of allergic inflammation. We confirmed that atopy may be an important factor contributing to the increased respiratory morbidity in children with RRTIs. The active treatment with pleuran resulted in a significant reduction of peripheral blood eosinophilia and stabilised the levels of total IgE in serum. This was more evident in atopic subjects. Pleuran showed a potential anti‐allergic effect. This previously non‐described effect could expand the application of this natural immunomodulator also as a complementary adjuvant therapy in allergic patients. Copyright © 2013 John Wiley & Sons, Ltd.     

Phlomis umbrosa root inhibits mast cell-dependent allergic reactions and inflammatory cytokine secretion

The effect of an aqueous extract of Phlomis umbrosa Turcz. (Labiatae) root (PUAE) on mast cell-dependent allergic reactions and inflammatory cytokine secretion were investigated. PUAE (0.01-1 g/kg) inhibited compound 48/80-induced systemic allergic reaction. When PUAE was employed in a systemic allergic reaction test, the plasma histamine levels were reduced in a dose-dependent manner. PUAE (0.1 and 1 g/kg) also significantly inhibited the local allergic reaction activated by anti-dinitrophenyl (DNP) IgE. PUAE (0.001-1 mg/mL) dose-dependently inhibited the histamine release from rat peritoneal mast cells activated by compound 48/80 or anti-DNP IgE. PUAE (0.01-1 mg/mL) inhibited the secretion of interleukin (IL)-1beta in phorbol 12-myristate 13-acetate plus calcium ionophore A23187-stimulated human mast cell line (HMC-1) cells. PUAE (1 mg/mL) inhibited the gene expression and production of the main inflammatory cytokine, TNF-alpha, in HMC-1 cells. These results provide evidence that PUAE may be beneficial in the treatment of allergic diseases.     

Anti‐platelet Activity of Erythro‐(7S,8R)‐7‐acetoxy‐3,4,3′,5′‐tetramethoxy‐8‐O‐4′‐neolignan from Myristica fragrans

Platelets play a critical role in pathogenesis of cardiovascular disorders and strokes. The inhibition of platelet function is beneficial for the treatment and prevention of these diseases. In this study, we investigated the anti‐platelet activity of erythro‐(7S,8R)‐7‐acetoxy‐3,4,3′,5′‐tetramethoxy‐8‐O‐4′‐neolignan (EATN), a neolignan isolated from Myristica fragrans, using human platelets. EATN preferentially inhibited thrombin‐ and platelet‐activating factor (PAF)‐induced platelet aggregation without affecting platelet damage in a concentration‐dependent manner with IC₅₀ values of 3.2 ± 0.4 and 3.4 ± 0.3 μM, respectively. However, much higher concentrations of EATN were required to inhibit platelet aggregation induced by arachidonic acid. EATN also inhibited thrombin‐induced serotonin and ATP release, and thromboxane B₂ formation in human platelets. Moreover, EATN caused an increase in cyclic AMP (cAMP) levels and attenuated intracellular Ca²⁺ mobilization in thrombin‐activated human platelets. Therefore, we conclude that the inhibitory mechanism of EATN on platelet aggregation may increase cAMP levels and subsequently inhibit intracellular Ca²⁺ mobilization by interfering with a common signaling pathway rather than by directly inhibiting the binding of thrombin or PAF to their receptors. This is the first report of the anti‐platelet activity of EATN isolated from M. fragrans. Copyright © 2013 John Wiley & Sons, Ltd.     

Ramalin Isolated from Ramalina Terebrata Attenuates Atopic Dermatitis‐like Skin Lesions in Balb/c Mice and Cutaneous Immune Responses in Keratinocytes and Mast Cells

Atopic dermatitis (AD) is a chronic inflammatory skin disease that involves eczematous skin lesions with pruritic erythematous papules. In this study, we investigated the mitigating effects of ramalin, a component of the Antarctic lichen Ramalina terebrata against AD in vivo and in vitro. Oral administration of ramalin lessened scratching behaviors and significantly reduced both serum immunoglobulin E and IL‐4 levels, and mRNA levels of IL‐4 and IL‐10 in AD‐induced Balb/c mice. In vitro, treatment with ramalin produced significantly less inflammatory chemokines and cytokines, including TARC, MCP‐1, RANTES, and IL‐8 in TNF‐α‐stimulated HaCaT cells. In addition, ramalin inhibited the activation of nuclear factor‐kappa B as well as the phosphorylation of mitogen‐activated protein kinases (MAPK). Furthermore, ramalin treatment resulted in decreased production of β‐hexosaminidase and proinflammatory cytokines IL‐4, IL‐6, and TNF‐α in 2,4 dinitrophenyl‐human serum albumin‐stimulated RBL‐2H3 cells through blocking MAPK signaling pathways. The results suggest that ramalin modulates the production of immune mediators by inhibiting the nuclear factor‐kappa B and MAPK signaling pathways. Taken together, ramalin effectively attenuated the development of AD and promoted the mitigating effects on Th2 cell‐mediated immune responses and the production of inflammatory mediators in mast cells and keratinocytes. Thus, ramalin may be a potential therapeutic agent for AD. Copyright © 2016 John Wiley & Sons, Ltd.     

The evaluation of antianaphylactic effect of Oryza sativa L. in rats.

This study was carried out to examine the effect of methanol extract of Oryza sativa L. (Dong-Jin in Korean, abbreviate as Os-DJ hereafter) on anaphylaxis. Os-DJ (10(-5) to 1 g/kg) dose-dependently inhibited systemic anaphylaxis induced by compound 48/80 in rats. When Os-DJ was pretreated at concentration ranging from 10(-5) to 1 g/kg, the serum histamine levels were reduced in a dose-dependent manner. Os-DJ (1 g/kg) also significantly inhibited local anaphylaxis activated by anti-dinitrophenyl (DNP) IgE. Moreover, Os-DJ dose-dependently inhibited the histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. These results indicate that Os-DJ possess antianaphylactic activity by inhibition of histamine release from mast cells in vivo and in vitro.     

Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis

A nettle (Urtica dioica) extract shows in vitro inhibition of several key inflammatory events that cause the symptoms of seasonal allergies. These include the antagonist and negative agonist activity against the Histamine‐1 (H₁) receptor and the inhibition of mast cell tryptase preventing degranulation and release of a host of pro‐inflammatory mediators that cause the symptoms of hay fevers. The nettle extract also inhibits prostaglandin formation through inhibition of Cyclooxygenase‐1 (COX‐1), Cyclooxygenase‐2 (COX‐2), and Hematopoietic Prostaglandin D₂ synthase (HPGDS), central enzymes in pro‐inflammatory pathways. The IC₅₀ value for histamine receptor antagonist activity was 251 (±13) µg mL^?1 and for the histamine receptor negative agonist activity was 193 (±71) µg mL^?1. The IC₅₀ values for inhibition of mast cell tryptase was 172 (±28) µg mL^?1, for COX‐1 was 160 (±47) µg mL^?1, for COX‐2 was 275 (±9) µg mL^?1, and for HPGDS was 295 (±51) µg mL^?1. Through the use of DART TOF‐MS, which yields exact masses and relative abundances of compounds present in complex mixtures, bioactives have been identified in nettle that contribute to the inhibition of pro‐inflammatory pathways related to allergic rhinitis. These results provide for the first time, a mechanistic understanding of the role of nettle extracts in reducing allergic and other inflammatory responses in vitro. Copyright © 2009 John Wiley & Sons, Ltd.     

Houttuynia cordata Thunb. Volatile Oil Exhibited Anti‐inflammatory Effects In Vivo and Inhibited Nitric Oxide and Tumor Necrosis Factor‐α Production in LPS‐stimulated Mouse Peritoneal Macrophages In Vitro

Houttuynia cordata Thunb. (HC) is a medicinal herb that generally used in traditional Chinese medicine for treating allergic inflammation. The present study investigated the inhibitory effect of the volatile oil from HC Thunb. on animal models of inflammation and the production of inflammatory mediators in vivo and in vitro. In vivo, xylene‐induced mouse ear edema, formaldehyde‐induced paw edema and carrageenan‐induced mice paw edema were significantly decreased by HC volatile oil. HC volatile oil showed pronounced inhibition of prostaglandin (PG) E₂ and malondialdehyde production in the edematous exudates. In vitro exposure of mouse resident peritoneal macrophages to 1, 10, 100 and 1000 µg/mL of HC volatile oil significantly suppressed lipopolysaccharide (LPS)‐stimulated production of NO and tumor necrosis factor‐α (TNF‐α) in a dose‐dependent manner. Exposure to HC volatile oil had no effect on cell viability and systemic toxicity. Furthermore, HC volatile oil inhibited the production of NO and TNF‐α by down‐regulating LPS‐stimulated iNOS and TNF‐α mRNA expression. Western blot analysis showed that HC volatile oil attenuated LPS‐stimulated synthesis of iNOS and TNF‐α protein in the macrophages, in parallel. These findings add a novel aspect to the biological profile of HC and clarify its anti‐inflammatory mechanism. Copyright © 2012 John Wiley & Sons, Ltd.     

Glycyrrhiza uralensis Flavonoids Present in Anti‐Asthma Formula,ASHMITM, Inhibit Memory Th2 Responses in Vitro and in Vivo

Allergic asthma is associated with Th2‐mediated inflammation. Several flavonoids were isolated from Glycyrrhiza uralensis, one of the herbs in the anti‐asthma herbal medicine intervention. The aim of this investigation was to determine whether Glycyrrhiza uralensis flavonoids have inhibitory effects on memory Th2 responses in vitro and antigen‐induced Th2 inflammation in vivo. The effects of three Glycyrrhiza uralensis flavonoids on effector memory Th2 cells, D10.G4.1 (D10 cells), were determined by measuring Th2 cytokine production. Isoliquiritigenin, 7, 4′‐dihydroxyflavone (7, 4′‐DHF) and liquiritigenin significantly suppressed IL‐4 and IL‐5 production in a dose‐dependent manner, 7, 4′‐DHF being most potent. It was also evaluated for effects on D10 cell proliferation, GATA‐3 expression and IL‐4 mRNA expression, which were suppressed, with no loss of cell viability. Chronic treatment with 7, 4′‐DHF in a murine model of allergic asthma not only significantly reduced eosinophilic pulmonary inflammation, serum IgE levels, IL‐4 and IL‐13 levels, but also increased IFN‐γ production in lung cell cultures in response to antigen stimulation. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of Korean folk medicine 'Chung-Dae-San' on mast cell-dependent anaphylactic reaction

We investigated the effect of the herbal formulation 'Chung-Dae-San' (CDS) on anaphylactic reactions. CDS inhibited compound 48/80-induced anaphylactic shock 100% with the dose of 10(0) g/kg body weight (BW). When CDS was given as pretreatment at concentrations ranging from 10(-4) to 10(0) g/kg BW, the serum histamine levels induced by compound 48/80 were reduced in a dose-dependent manner. We also investigated the effect of CDS on mast cell-dependent passive cutaneous anaphylaxis (PCA) activated by anti-dinitrophenyl (DNP) IgE antibody. CDS potently inhibited PCA when administered orally, topically, intraperitoneally or intradermally. However, it did not show inhibitory activity when administered intravenously. CDS dose-dependently inhibited the histamine release from the rat peritoneal mast cells (RPMC) by compound 48/80 and anti-DNP IgE. Moreover, the level of cAMP in RPMC, when CDS was added, significantly increased about 4-fold at 4 min compared with that of basal cells. These results indicate that CDS may possess strong antianaphylactic activity and also suggest the differential activity following administration routes may be caused by difference in bioavailability.