Curcumin, a constituent of curry, suppresses IgE-mediated allergic response and mast cell activation at the level of Syk

Effects of Dietary Components on Mast Cells: Possible Use as Nutraceuticals for Allergies?

Allergic diseases affect an estimated 30 percent of the world's population. Mast cells (MC) are the key effector cells of allergic reactions by releasing pro-inflammatory mediators such as histamine, lipid mediators, and cytokines/chemokines. Components of the daily diet, including certain fatty acids, amino acids, and vitamins, as well as secondary plant components, may have effects on MC and thus may be of interest as nutraceuticals for the prevention and treatment of allergies. This review summarizes the anti-inflammatory effects of dietary components on MC, including the signaling pathways involved, in in vitro and in vivo models. Butyrate, calcitriol, kaempferol, quercetin, luteolin, resveratrol, curcumin, and cinnamon extract were the most effective in suppressing the release of preformed and de novo synthesized mediators from MC or in animal models. In randomized controlled trials (RCT), vitamin D, quercetin, O-methylated epigallocatechin gallate (EGCG), resveratrol, curcumin, and cinnamon extract improved symptoms of allergic rhinitis (AR) and reduced the number of inflammatory cells in patients. However, strategies to overcome the poor bioavailability of these nutrients are an important part of current research.

Curcumin inhibits the pruritus in mice through mast cell MrgprB2 receptor

BACKGROUND

Curcumin is a diketone compound extracted from the rhizomes of some plants in the Zingiberaceae and Araceae family. It possesses a variety of biological activities, including antioxidant, anti-inflammatory and anti-cancer properties. However, the cellular and molecular antipruritic mechanisms of curcumin remain to be explored.

OBJECTIVE

Our objective was to study the role of curcumin in pruritus and determine whether its antipruritic effect is related to MrgprB2 receptor.

METHODS

The effect of curcumin on pruritus in mice was examined by scratching behavior test. The antipruritic mechanism of curcumin was explored by using transgenic mice (MrgprB2^-/- mice, MrgprB2Cre^Td/tomato mice), histological analysis, western blot and immunofluorescence. In addition, the relationship between curcumin and MrgprB2/X2 receptor was studied in vitro by using calcium imaging, plasmid transfection and molecular docking RESULTS: In the current study, we found that curcumin had obvious antipruritic effect. Its antipruritic effect was related to the regulation of MrgprB2 receptor activation and mast cells tryptase release. In vitro, mouse peritoneal mast cells activated by compound 48/80 could be inhibited by curcumin. In addition, curcumin was also found to suppress the calcium flux in MrgprX2 or MrgprB2-overexpression HEK cells induced by compound 48/80, substance P, and PAMP 9-20, displaying the specific relation with the MrgprB2/X2 receptor. Moreover, molecular docking results showed that curcumin had affinity to MrgprX2 protein.

CONCLUSIONS

Overall, these results indicated that curcumin has the potential to treat pruritus induced by mast cell MrgprB2 receptor.

Therapeutic potency of curcumin for allergic diseases: A focus on immunomodulatory actions

In light of increasing research evidence on the molecular mechanisms of allergic diseases, the crucial roles of innate and acquired immunity in the disease's pathogenesis have been well highlighted. In this respect, much attention has been paid to the modulation of unregulated and unabated inflammatory responses aiming to suppress pathologic immune responses in treating allergic diseases. One of the most important natural compounds with a high potency of immune modulation is curcumin, an active polyphenol compound derived from turmeric, Curcuma longa L. Curcumin's immunomodulatory action mainly arises from its interactions with an extensive collection of immune cells such as mast cells, eosinophils, epithelial cells, basophils, neutrophils, and lymphocytes. Up to now, there has been no detailed investigation of curcumin's immunomodulatory actions in allergic diseases. So, the present review study aims to prepare an overview of the immunomodulatory effects of curcumin on the pathologic innate immune responses and dysregulated functions of T helper (T_H) subtypes, including T_H1, T_H2, T_H17, and regulator T cells (Tregs) by gathering evidence from several studies of In-vitro and In-vivo. As the second aim of the present review, we also discuss some novel strategies to overcome the limitation of curcumin in clinical use. Finally, this review also assesses the therapeutic potential of curcumin regarding its immunomodulatory actions in allergic diseases.

The Complex Interplay between Immunonutrition, Mast Cells, and Histamine Signaling in COVID-19

There is an ongoing need for new therapeutic modalities against SARS-CoV-2 infection. Mast cell histamine has been implicated in the pathophysiology of COVID-19 as a regulator of proinflammatory, fibrotic, and thrombogenic processes. Consequently, mast cell histamine and its receptors represent promising pharmacological targets. At the same time, nutritional modulation of immune system function has been proposed and is being investigated for the prevention of COVID-19 or as an adjunctive strategy combined with conventional therapy. Several studies indicate that several immunonutrients can regulate mast cell activity to reduce the de novo synthesis and/or release of histamine and other mediators that are considered to mediate, at least in part, the complex pathophysiology present in COVID-19. This review summarizes the effects on mast cell histamine of common immunonutrients that have been investigated for use in COVID-19.

Steering Mast Cells or Their Mediators as a Prospective Novel Therapeutic Approach for the Treatment of Hematological Malignancies

Tumor cells require signaling and close interaction with their microenvironment for their survival and proliferation. In the recent years, Mast cells have earned a greater importance for their presence and role in cancers. It is known that mast cells are attracted towards tumor microenvironment by secreted soluble chemotactic factors. Mast cells seem to exert a pro-tumorigenic role in hematological malignancies with a few exceptions where they showed anti-cancerous role. This dual role of mast cells in tumor growth and survival may be dependent on the intrinsic characteristics of the particular tumor, differences in tumor microenvironment according to tumor type, and the interactions and heterogeneity of mediators released by mast cells in the tumor microenvironment. In many studies, Mast cells and their mediators have been shown to affect tumor survival and growth, prognosis, inflammation, tumor vascularization and angiogenesis. Modulating mast cell accumulation, viability, activity and mediator release patterns may thus be important in controlling these malignancies. In this review, we emphasize on the role of mast cells in lymphoid malignancies and discuss strategies for targeting and steering mast cells or their mediators as a potential therapeutic approach for the treatment of these malignancies.

Inhibition of c-Fos expression attenuates IgE-mediated mast cell activation and allergic inflammation by counteracting an inhibitory AP1/Egr1/IL-4 axis

Background

Activator protein-1 (AP1), a c-Fos–JUN transcription factor complex, mediates many cytobiological processes. c-Fos has been implicated in immunoglobulin (Ig)E activation of mast cells (MCs) via high-affinity IgE Fc receptor (FcεRI) binding. This study examined c-Fos involvement in MC activation and tested the effects of the c-Fos/AP1 inhibitor T-5224 on MCs activation and allergic responses.

Methods

In vitro studies were conducted with two MC model systems: rat basophilic leukemia cells (RBLs) and mouse bone marrow derived mast cells (BMMCs). MC degranulation and effector functions were examined with β-hexosaminidase release and cytokine secretion assays. c-Fos/AP1 was inhibited with T-5224. c-Fos activity was suppressed with short hairpin RNA targeting c-Fos (shFos). In vivo immune responses were evaluated in passive cutaneous anaphylaxis (PCA) and ovalbumin-induced active systemic anaphylaxis (ASA) models, as well as in an oxazolone (OXA)-induced model of atopic dermatitis, a common allergic disease.

Results

c-Fos expression was elevated transcriptionally and translationally in IgE-stimulated MCs. c-Fos binding of the Egr1 (early growth response 1) promoter upregulated Egr1 transcription, leading to production of interleukin (IL)4. T-5224 reduced FcεRI-mediated MC degranulation (evidenced by β-hexosaminidase activity and histamine levels) and diminished EGR1 and IL4 expression. T-5224 attenuated IgE-mediated allergic responses in PCA and ASA models, and it suppressed MC-mediated atopic dermatitis in mice.

Conclusion

IgE binding can activate MCs via a c-Fos/Egr1/IL-4 axis. T-5224 suppresses MC activation in vitro and in vivo and thus represents a promising potential strategy for targeting MC activation to treat allergic diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02932-0.

Fine particulate matter (PM2.5) promotes IgE-mediated mast cell activation through ROS/Gadd45b/JNK axis

BACKGROUND

Mast cells play an important role in allergic responses and persistently exposure to environmental fine particulate matter (PM2.5) exacerbates allergic diseases,but the details remained elucidative.

OBJECTIVES

To investigate the effect of PM2.5 on IgE-mediated mast cell responses through an IgE-mediated mouse model and mast cell activation.

METHODS

The β-hexosaminidase release and a BALB/c model of passive cutaneous anaphylaxis (PCA) was used to test IgE-mediated mast cells activation in vitro and in vivo. RNA-Seq technique was conducted to study the gene expression profile. Reactive oxygen species (ROS) production was measured by flow-cytometry. RT-PCR,WB and ELISA were performed to examine targeting molecules expression.

RESULTS

PM2.5 facilitated IgE-mediated degranulation and increased cytokines expression in mast cells. Meanwhile, the Evan's blue extravasation as well as serum cytokines in mice was increased after treatment with PM2.5. Furthermore, PM2.5 treatment dramatically increased the expression of Gadd45b which is an oxidative stress molecule that directly activates down-stream pathway, such as MEKK4/JNK. PM2.5 treatment activated MEKK4, JNK1/2 but not ERK1/2 and p38. Meanwhile, Knockdown of Gadd45b significantly attenuated PM2.5-mediated JNK1/2 activation and expression of cytokines. In addition, a JNK1/2-specific inhibitor SP600125 blocked IgE-mediated mast cell activation and cytokine release in PCA model mice. Moreover, PM2.5 treatment increased the ROS level and ROS inhibitor dramatically blocked the PM2.5-induced ROS production and reversed the PM2.5-mediated gene expression in the mitochondrial respiratory chain.

CONCLUSIONS

PM2.5 regulates ROS production through Gadd45b/MEKK4/JNK pathway, facilitating IgE-mediated mast cell activation.

Protein Disulfide Isomerases Regulate IgE-Mediated Mast Cell Responses and Their Inhibition Confers Protective Effects During Food Allergy

The thiol isomerase, protein disulfide isomerase (PDI), plays important intracellular roles during protein folding, maintaining cellular function and viability. Recent studies suggest novel roles for extracellular cell surface PDI in enhancing cellular activation and promoting their function. Moreover, a number of food-derived substances have been shown to regulate cellular PDI activity and alter disease progression. We hypothesized that PDI may have similar roles during mast cell-mediated allergic responses and examined its effects on IgE-induced mast cell activity during cell culture and food allergy. Mast cells were activated via IgE and antigen and the effects of PDI inhibition on mast cell activation were assessed. The effects of PDI blockade in vivo were examined by treating mice with the irreversible PDI inhibitor, PACMA-31, in an ovalbumin-induced model of food allergy. The role of dietary PDI modulators was investigated using various dietary compounds including curcumin and quercetin-3-rutinoside (rutin). PDI expression was observed on resting mast cell surfaces, intracellularly, and in the intestines of allergic mice. Furthermore, enhanced secretion of extracellular PDI was observed on mast cell membranes during IgE and antigen activation. Insulin turbidimetric assays demonstrated that curcumin is a potent PDI inhibitor and pre-treatment of mast cells with curcumin or established PDI inhibitors such as bacitracin, rutin or PACMA-31, resulted in the suppression of IgE-mediated activation and the secretion of various cytokines. This was accompanied by decreased mast cell proliferation, FcεRI expression, and mast cell degranulation. Similarly, treatment of allergic BALB/c mice with PACMA-31 attenuated the development of food allergy resulting in decreased allergic diarrhea, mast cell activation, and fewer intestinal mast cells. The production of TH2-specific cytokines was also suppressed. Our observations suggest that PDI catalytic activity is essential in the regulation of mast cell activation, and that its blockade may benefit patients with allergic inflammation.

Mast Cell Regulation and Irritable Bowel Syndrome: Effects of Food Components with Potential Nutraceutical Use

Mast cells are key actors in inflammatory reactions. Upon activation, they release histamine, heparin and nerve growth factor, among many other mediators that modulate immune response and neuron sensitization. One important feature of mast cells is that their population is usually increased in animal models and biopsies from patients with irritable bowel syndrome (IBS). Therefore, mast cells and mast cell mediators are regarded as key components in IBS pathophysiology. IBS is a common functional gastrointestinal disorder affecting the quality of life of up to 20% of the population worldwide. It is characterized by abdominal pain and altered bowel habits, with heterogeneous phenotypes ranging from constipation to diarrhea, with a mixed subtype and even an unclassified form. Nutrient intake is one of the triggering factors of IBS. In this respect, certain components of the daily food, such as fatty acids, amino acids or plant-derived substances like flavonoids, have been described to modulate mast cells' activity. In this review, we will focus on the effect of these molecules, either stimulatory or inhibitory, on mast cell degranulation, looking for a nutraceutical capable of decreasing IBS symptoms.

Immune responses modulation by curcumin and allergen encapsulated into PLGA nanoparticles in mice model of rhinitis allergic through sublingual immunotherapy

The purpose of this study was the combination of curcumin and ovalbumin in free form or encapsulated into PLGA NPs (polylactic co-glycolic acid nanoparticles) to enhance their sublingual immunotherapy (SLIT) efficiency in mouse model of rhinitis allergic. PLGA NPs containing curcumin (CUR), ovalbumin (OVA) or both were prepared by emulsion-solvent evaporation method and characterized. After sensitization of BALB/C mice with ovalbumin, SLIT with free or encapsulated formulations was carried out and immunological profiles were evaluated. SLIT treatment with all synthesized PLGA formulations lead to significantly decreased total IgE. The combination immunotherapy in the present of free form of curcumin or ovalbumin with encapsulated forms of the another substance (P.OVA-CUR 10 and P.CUR 5-OVA), showed the highest level of IFN-γ:IL-4 compared to other target groups. On the other hands, a significant increasment was observed in this ratio between these optimal groups and treated group with subcutaneous administration of OVA as the most commonly used method for immunotherapy. The study of nasal lavage fluid (NALF) showed significant decreased levels of total and eosinophil cell count in the traeted nano-formulation groups. The histopathological results of NAL were also like normal with no cellular infiltration and no inflammation in the optimal formulations. Therefore, using curcumin and nanoparticles with allergen can be considerd as potential immune modulatory agents.

In vitro anti-inflammatory effects of curcumin on mast cell-mediated allergic responses via inhibiting FcεRI protein expression and protein kinase C delta translocation

Allergy is a hypersensitivity reaction when exposed to certain environmental substances. It shows high relation between immunoglobulin E (IgE) binding to a specific receptor (FcεRI), pro-inflammatory cytokines, and mediators with allergic inflammation responses. Curcumin is a yellow pigment isolated from the turmeric. Curcumin possesses antioxidant and anti-inflammatory properties as well as exhibits significant chemopreventive activity. This study was aimed to investigate the in vitro assessment of the regulation of curcumin on allergic inflammatory responses on rat basophil leukemia (RBL)-2H3 and human pre-basophils (KU812) cell lines. Curcumin showed the activity against histamine and β-hexosaminidase releases from both IgE-mediated and A23187-induced cells degranulation. The morphological observation also confirmed that curcumin inhibits cells degranulation. IgE-mediated allergic responses and significantly induced mast cells intracellular reactive oxygen species (ROS) production. Curcumin reduced ROS production from IgE-mediated or A23187-induced cells degranulation. Curcumin also successfully reduced FcεRI expressions and some pro-inflammatory cytokines, such as interleukin (IL)-4 and IL-13. Furthermore, curcumin inhibited protein kinase C (PKC)-δ translocation from cytosolic to particulate. These results suggested that curcumin can alleviate both the IgE-mediated and calcium ionosphere A23187-stimulated allergic responses through reducing the release of the allergic mediators.

Allium porrum Extract Decreases Effector Cell Degranulation and Modulates Airway Epithelial Cell Function

Allium genus plants, such as leek (Allium porrum), are rich sources of anti-inflammatory and anti-oxidant secondary metabolites; this is of interest because it demonstrates their suitability as pharmacological alternatives for inflammatory processes, including allergy treatment. The composition of methanolic leek extract (LE) was analyzed by GC–MS and LC–IT/MS, and the total phenolic content and antioxidant capacity were quantified by colorimetric methods. Its pharmacological potential was analyzed in human bronchial epithelial Calu-3 cells, human mast cells LAD2, and humanized rat basophiles RBL-2H3. LE exhibited a cytotoxic effect on Calu-3 cells and HumRBL-2H3 cells only at high concentrations and in a dose-dependent manner. Moreover, LE decreased the degranulation of LAD2 and HumRBL-2H3 cells. LE treatment also significantly prevented alterations in transepithelial electrical resistance values and mRNA levels of glutathione-S-transferase (GST), c-Jun, and NFκB after treatment with H₂O₂ in ALI-cultured Calu-3 cells. Finally, ALI-cultured Calu-3 cells treated with LE showed lower permeability to Ole e 1 compared to untreated cells. A reduction in IL-6 secretion in ALI-cultured Calu-3 cells treated with LE was also observed. In summary, the results obtained in this work suggest that A. porrum extract may have potential anti-allergic effects due to its antioxidant and anti-inflammatory properties. This study provides several important insights into how LE can protect against allergy.

Quantum chemical calculation and binding modes of H1R; a combined study of molecular docking and DFT for suggesting therapeutically potent H1R antagonist

Histamine-1 receptor (H1R) belongs to the family of rhodopsin-like G-protein-coupled receptors expressed in cells that mediates allergies and other pathophysiological diseases. For alleviation of allergic symptoms, H1R antagonists are therapeutic drugs; of which the most frequently prescribed are second generation drugs, such as; Cetirizine, Loratadine, Hydroxyzine, Desloratadine, Bepotastine, Acrivastine and Rupatadine. To understand their potency, binding affinity and interaction; we have employed molecular docking and quantum chemical study such as; Induced-fit docking and calculation of quantum chemical descriptors. This study also introduces the binding site characterization of H1R, with its known antagonists and Curcumin (our proposed alternative H1R antagonist); useful for future drug target site. The interactive binding site residues of H1R are found to be; Lys-191, Tyr-108, Asp-107, Tyr-100, Lys-179, Lys-191, Thr-194, Trp-428, Phe-432, Tyr-458, Hie-450, with most of these shown to be inhibited by naturally-occurring compound curcumin. Amongst the FDA approved drugs, Hydroxyzine showed best ligand binding affinity, calculated as - 141.491 kcal/mol and naturally occurring compound, Curcumin showed binding affinity of - 87.046 kcal/mol. The known antagonists of H1R has been used for hypothesizing curcumin as naturally occurring lead compound for the target using accurate molecular docking simulation study. Though the pharmacological action of known inhibitor is already established, they could differ from their reactivity, which we have also focused in our study for predicting drug reactivity.

Cellular and molecular mechanisms of curcumin in prevention and treatment of disease

Curcumin is a naturally occurring polyphenolic compound present in rhizome of Curcuma longa belonging to the family zingiberaceae. Growing experimental evidence revealed that curcumin exhibit multitarget biological implications signifying its crucial role in health and disease. The current review highlights the recent progress and mechanisms underlying the wide range of pharmacological effects of curcumin against numerous diseases like neuronal, cardiovascular, metabolic, kidney, endocrine, skin, respiratory, infectious, gastrointestinal diseases and cancer. The ability of curcumin to modulate the functions of multiple signal transductions are linked with attenuation of acute and chronic diseases. Numerous preclinical and clinical studies have revealed that curcumin modulates several molecules in cell signal transduction pathway including PI3K, Akt, mTOR, ERK5, AP-1, TGF-β, Wnt, β-catenin, Shh, PAK1, Rac1, STAT3, PPARγ, EBPα, NLRP3 inflammasome, p38MAPK, Nrf2, Notch-1, AMPK, TLR-4 and MyD-88. Curcumin has a potential to prevent and/or manage various diseases due to its anti-inflammatory, anti-oxidant and anti-apoptotic properties with an excellent safety profile. In contrast, the anti-cancer effects of curcumin are reflected due to induction of growth arrest and apoptosis in various premalignant and malignant cells. This review also carefully emphasized the pharmacokinetics of curcumin and its interaction with other drugs. Clinical studies have shown that curcumin is safe at the doses of 12 g/day but exhibits poor systemic bioavailability. The use of adjuvant like piperine, liposomal curcumin, curcumin nanoparticles and curcumin phospholipid complex has shown enhanced bioavailability and therapeutic potential. Further studies are warranted to prove the potential of curcumin against various ailments.

Tetrahydrocurcumin, a major metabolite of curcumin, ameliorates allergic airway inflammation by attenuating Th2 response and suppressing the IL-4Rα-Jak1-STAT6 and Jagged1/Jagged2 -Notch1/Notch2 pathways in asthmatic mice

BACKGROUND

Curcumin (Cur), derived from Curcuma species, exhibits anti-inflammatory, antioxidant, and anticancer effects. Although Cur has some beneficial effects on asthma, its clinical application is limited by its low bioavailability. Tetrahydrocurcumin (THC), the major active metabolite of Cur, has multiple biological functions, similarly to Cur, and importantly, it showed enhanced bioavailability in tissues and plasma. However, the effect of THC on asthma has not been reported.

OBJECTIVE

The current study sought to investigate the efficacy of dietary THC on allergic asthma compared to that of Cur in an animal model.

METHODS

The anti-inflammatory effects of Cur and THC were evaluated in an ovalbumin-induced asthmatic mouse model. The nasal symptoms, pathological alterations of the lung tissues, oxidants and antioxidants, cytokine production, T cell subsets, and Th2-related signalling pathway activity were assessed.

RESULTS

Both THC and Cur had beneficial effects on asthmatic mice with regard to nasal symptoms, pathological changes (eosinophils and mucus hyper-production), oxidative stress (malondialdehyde), cytokine production (IL-13), Th17 and cytotoxic T cell subsets, and Th2 signalling pathway (IL-4Rα-Jak1-STAT6 and Jagged1/Jagged2-Notch1/Notch2 axis) activity. THC was more effective than Cur in suppressing tissue eosinophilia, mucus production, and IL-4Rα/Jak1/STAT6 pathway activity. Furthermore, only THC inhibited peripheral eosinophil levels, Th2 cytokines (IL-4 and IL-5), and Th2 cell subsets and enhanced an antioxidant enzyme (glutathione).

CONCLUSION AND CLINICAL RELEVANCE

The above results demonstrated for the first time that THC was superior to Cur in modulating allergic asthmatic phenotypes, especially attenuating the Th2 response. THC might be a potentially effective agent for asthma treatment.

Repositioning of anti-cancer drug candidate, AZD7762, to an anti-allergic drug suppressing IgE-mediated mast cells and allergic responses via the inhibition of Lyn and Fyn

Mast cells are critical effector cells in IgE-mediated allergic responses. The aim of this study was to investigate the anti-allergic effects of 3-[(aminocarbonyl)amino]-5-(3-fluorophenyl)-N-(3S)-3-piperidinyl-2-thiophenecarboxamide (AZD7762) in vitro and in vivo. AZD7762 inhibited the antigen-stimulated degranulation from RBL-2H3 (IC₅₀, ∼27.9 nM) and BMMCs (IC₅₀, ∼99.3 nM) in a dose-dependent manner. AZD7762 also inhibited the production of TNF-α and IL-4. As the mechanism of its action, AZD7762 inhibited the activation of Syk and its downstream signaling proteins, such as Linker of activated T cells (LAT), phospholipase (PL) Cγ1, Akt, and mitogen-activated protein (MAP) kinases (Erk1/2, p38, and JNK) in mast cells. In in vitro protein kinase assay, AZD7762 inhibited the activity of Lyn and Fyn kinases, which are important for the activation of Syk in mast cells. Furthermore, AZD7762 also suppressed the degranulation of LAD2 human mast cells (IC₅₀, ∼49.9 nM) and activation of Syk in a dose-dependent manner. As observed in experiments with mast cells in vitro, AZD7762 inhibited antigen-mediated passive cutaneous anaphylaxis in mice (ED₅₀, ∼35.8 mg/kg). Altogether, these results suggest that AZD7762 could be used as a new therapeutic agent for mast cell-mediated allergic diseases.

Inhibitory Activities of Compounds from the Marine Actinomycete Williamsia sp. MCCC 1A11233 Variant on IgE-Mediated Mast Cells and Passive Cutaneous Anaphylaxis

The compounds of the deep-sea-derived marine Williamsia sp. MCCC 1A11233 (CDMW) were isolated, which are secondary metabolites of the actinomycetes. In this study, seven kinds of CDMW were found to decrease degranulation and histamine release in immunoglobulin E (IgE)-mediated rat basophilic leukemia (RBL)-2H3 cells. The production of cytokines (tumor necrosis factor-α, interleukin-4) was inhibited by these CDMW in RBL-2H3 cells, and their chemical structures were established mainly based on detailed analysis of their NMR spectra. CDMW-3, CDMW-5, and CDMW-15 were further demonstrated to block mast cell-dependent passive cutaneous anaphylaxis in IgE-sensitized mice. Bone marrow mononuclear cells (BMMCs) were established to clarify the effect of CDMW-3, CDMW-5, and CDMW-15 on mast cells. The seven kinds of CDMW decreased the degranulation and histamine release of BMMCs. Furthermore, flow cytometry results indicated that CDMW-3, CDMW-5, and CDMW-15 increased the annexin⁺ cell population of BMMCs. In conclusion, CDMW-3, CDMW-5, and CDMW-15 have obvious antiallergic activity due to induction of the apoptosis of mast cells.

Immunosuppressive Effects of Natural α,β-Unsaturated Carbonyl-Based Compounds, and Their Analogs and Derivatives, on Immune Cells: A Review

The immune system is complex and pervasive as it functions to prevent or limit infections in the human body. In a healthy organism, the immune system and the redox balance of immune cells maintain homeostasis within the body. The failure to maintain the balance may lead to impaired immune response and either over activity or abnormally low activity of the immune cells resulting in autoimmune or immune deficiency diseases. Compounds containing α,β-unsaturated carbonyl-based moieties are often reactive. The reactivity of these groups is responsible for their diverse pharmacological activities, and the most important and widely studied include the natural compounds curcumin, chalcone, and zerumbone. Numerous studies have revealed the mainly immunosuppressive and anti-inflammatory activities of the aforesaid compounds. This review highlights the specific immunosuppressive effects of these natural α,β-unsaturated carbonyl-based compounds, and their analogs and derivatives on different types of immune cells of the innate (granulocytes, monocytes, macrophages, and dendritic cells) and adaptive (T cells, B cells, and natural killer cells) immune systems. The inhibitory effects of these compounds have been comprehensively studied on neutrophils, monocytes and macrophages but their effects on T cells, B cells, natural killer cells, and dendritic cells have not been well investigated. It is of paramount importance to continue generating experimental data on the mechanisms of action of α,β-unsaturated carbonyl-based compounds on immune cells to provide useful information for ensuing research to discover new immunomodulating agents.

Degranulation Inhibitors from Medicinal Plants in Antigen-Stimulated Rat Basophilic Leukemia (RBL-2H3) Cells

Mast cells and basophils play important roles in both immediate- and late-phase reactions of type 1 allergy. Histamine, which is released from mast cells and basophils stimulated by an antigen or degranulation inducers, is usually determined as a degranulation marker in experiments on immediate allergic reactions in vitro. β-Hexosaminidase is also stored in secretory granules of the cells and is released concomitantly with histamine when the cells are immunologically activated, and recently this enzyme activity in the medium has been used as a marker of the degranulation. In this paper, we review our studies on the search for degranulation inhibitors, such as flavonoids, stilbenes, and curcuminoids, from medicinal plants using rat basophilic leukemia (RBL-2H3) cells.

Can curcumin modulate allergic rhinitis in rats?

OBJECTIVES

This study aimed to explore the effects of curcumin on experimental allergic rhinitis in rats.

METHODS

Twenty-eight male Wistar albino rats were randomly divided into four groups: a control group; a group in which allergic rhinitis was induced and no treatment given; a group in which allergic rhinitis was induced followed by treatment with azelastine hydrochloride on days 21-28; and a group in which allergic rhinitis was induced followed by treatment with curcumin on days 21-28. Allergy symptoms and histopathological features of the nasal mucosa were examined.

RESULTS

The sneezing and nasal congestion scores were higher in the azelastine and curcumin treatment groups than in the control group. Histopathological examination showed focal goblet cell metaplasia on the epithelial surface in the azelastine group. In the curcumin group, there was a decrease in goblet cell metaplasia in the epithelium, decreased inflammatory cell infiltration and vascular proliferation in the lamina propria.

CONCLUSION

Curcumin is an effective treatment for experimentally induced allergic rhinitis in rats.

Antioxidant activities of curcumin in allergic rhinitis

We investigated the antioxidant effects of curcumin in an experimental rat model of allergic rhinitis (AR). Female Wistar albino rats (n = 34) were divided randomly into four groups: healthy rats (control group, n = 8), AR with no treatment (AR + NoTr group, n = 10), AR with azelastine HCl treatment (AR + Aze group, n = 8), and AR with curcumin treatment (AR + Curc group, n = 8). On day 28, total blood IgE levels were measured. For measurement of antioxidant activity, the glutathione (GSH) level and catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities were measured in both inferior turbinate tissue and serum. Malondialdehyde (MDA) levels were measured only in inferior turbinate tissue, and paraoxonase (PON) and arylesterase (ARE) activities were measured only in serum. Statistically significant differences were found for all antioxidant measurements (GSH levels and CAT, SOD, GSH-Px activities in the serum and tissue, MDA levels in the tissue, and PON and ARE activities in the serum) between the four groups. In the curcumin group, serum SOD, ARE, and PON and tissue GSH values were higher than the control group. Moreover, tissue GSH levels and serum GSH-Px activities in the curcumin group were higher than in the AR + NoTr group. In the azelastine group, except MDA, antioxidant measurement values were lower than in the other groups. Curcumin may help to increase antioxidant enzymes and decrease oxidative stress in allergic rhinitis. We recommend curcumin to decrease oxidative stress in allergic rhinitis.

Molecular mechanisms of curcumin and its semisynthetic analogues in prostate cancer prevention and treatment

Primary prostate cancer, also known as prostate adenocarcinoma (PCa), is a devastating cancer in men worldwide. Europe and developing countries of Asia have fewer reported cases of prostate cancer compared to increasing cases in the United States with higher incidence in Black men. Risk factors associated with prostate cancer are aging, genetics, lifestyle, high body mass index as well as carcinogenic exposure to carbon-containing fuels, tobacco, and charbroiled meats. Hormone therapy and radical prostatectomy are commonly implemented treatments. The >20.000 prostate cancer deaths of 2013 suggest that there exists a need for enhanced chemopreventive and therapeutic agents for prostate cancer treatment. Fruits, vegetables, and red wines contain high levels of polyphenolic levels. Consumption of these products may provide chemoprevetion of PCa. Curcumin, the major compound from the turmeric rhizome Curcuma longa has long been used for medicinal purposes as an antiseptic and wound healing. This review focuses on curcumin's therapeutic effectiveness in vitro and in vivo in prostate cancer models. The review will highlight the mechanisms of actions of curcumin in the signaling pathways of prostate cancer.

Turmeric (Curcuma longa) attenuates food allergy symptoms by regulating type 1/type 2 helper T cells (Th1/Th2) balance in a mouse model of food allergy

ETHNOPHARMACOLOGICAL RELEVANCE

Turmeric (Curcuma longa) has traditionally been used to treat pain, fever, allergic and inflammatory diseases such as bronchitis, arthritis, and dermatitis. In particular, turmeric and its active component, curcumin, were effective in ameliorating immune disorders including allergies. However, the effects of turmeric and curcumin have not yet been tested on food allergies.

MATERIALS AND METHODS

Mice were immunized with intraperitoneal ovalbumin (OVA) and alum. The mice were orally challenged with 50mg OVA, and treated with turmeric extract (100mg/kg), curcumin (3mg/kg or 30 mg/kg) for 16 days. Food allergy symptoms including decreased rectal temperature, diarrhea, and anaphylaxis were evaluated. In addition, cytokines, immunoglobulins, and mouse mast cell protease-1 (mMCP-1) were evaluated using ELISA.

RESULTS

Turmeric significantly attenuated food allergy symptoms (decreased rectal temperature and anaphylactic response) induced by OVA, but curcumin showed weak improvement. Turmeric also inhibited IgE, IgG1, and mMCP-1 levels increased by OVA. Turmeric reduced type 2 helper cell (Th2)-related cytokines and enhanced a Th1-related cytokine. Turmeric ameliorated OVA-induced food allergy by maintaining Th1/Th2 balance. Furthermore, turmeric was confirmed anti-allergic effect through promoting Th1 responses on Th2-dominant immune responses in immunized mice.

CONCLUSION

Turmeric significantly ameliorated food allergic symptoms in a mouse model of food allergy. The turmeric as an anti-allergic agent showed immune regulatory effects through maintaining Th1/Th2 immune balance, whereas curcumin appeared immune suppressive effects. Therefore, we suggest that administration of turmeric including various components may be useful to ameliorate Th2-mediated allergic disorders such as food allergy, atopic dermatitis, and asthma.

Cassia tora Seed Extract and Its Active Compound Aurantio-obtusin Inhibit Allergic Responses in IgE-Mediated Mast Cells and Anaphylactic Models

Cassia tora seed is widely used due to its various biological properties including anticancer, antidiabetic, and anti-inflammatory effects. However, there has been no report of the effects of C. tora seed extract (CTE) on immunoglobulin E (IgE)-mediated allergic responses. In this research, we demonstrated the effects of CTE and its active compound aurantio-obtusin on IgE-sensitized allergic reactions in mast cells and passive cutaneous anaphylaxis (PCA). CTE and aurantio-obtusin suppressed degranulation, histamine production, and reactive oxygen species generation and inhibited the production and mRNA expression of tumor necrosis factor-α and interleukin-4. CTE and aurantio-obtusin also suppressed the prostaglandin E2 production and expression of cyclooxygenase 2. Furthermore, CTE and aurantio-obtusin suppressed IgE-mediated FcεRI signaling such as phosphorylation of Syk, protein kinase Cμ, phospholipase Cγ, and extracellular signal-regulated kinases. CTE and aurantio-obtusin blocked mast cell-dependent PCA in IgE-mediated mice. These results suggest that CTE and aurantio-obtusin are a beneficial treatment for allergy-related diseases.

Anti-inflammatory effect of curcumin on mast cell-mediated allergic responses in ovalbumin-induced allergic rhinitis mouse

Curcumin has commonly been used for the treatment of various allergic diseases. However, its precise anti-allergic rhinitis effect and mechanism remain unknown. In the present study, the effect of curcumin on allergic responses in ovalbumin (OVA)-induced allergic rhinitis mouse was investigated. We explored the effect of curcumin on the release of allergic inflammatory mediators, such as histamine, OVA-specific IgE, and inflammatory cytokines. Also, we found that curcumin improved rhinitis symptoms, inhibited the histopathological changes of nasal mucosa, and decreased the serum levels of histamine, OVA-specific IgE and TNF-α in OVA-induced allergic rhinitis mice. In addition, curcumin suppressed the production of inflammatory cytokines, such as TNF-α, IL-1β, IL-6 and IL-8. Moreover, curcumin significantly inhibited PMA-induced p-ERK, p-p38, p-JNK, p-Iκ-Bα and NF-κB. These findings suggest that curcumin has an anti-allergic effect through modulating mast cell-mediated allergic responses in allergic rhinitis, at least partly by inhibiting MAPK/NF-κB pathway.

Curcumin Ingestion Inhibits Mastocytosis and Suppresses Intestinal Anaphylaxis in a Murine Model of Food Allergy

IgE antibodies and mast cells play critical roles in the establishment of allergic responses to food antigens. Curcumin, the active ingredient of the curry spice turmeric, has anti-inflammatory properties, and thus may have the capacity to regulate Th2 cells and mucosal mast cell function during allergic responses. We assessed whether curcumin ingestion during oral allergen exposure can modulate the development of food allergy using a murine model of ovalbumin (OVA)-induced intestinal anaphylaxis. Herein, we demonstrate that frequent ingestion of curcumin during oral OVA exposure inhibits the development of mastocytosis and intestinal anaphylaxis in OVA-challenged allergic mice. Intragastric (i.g.) exposure to OVA in sensitized BALB/c mice induced a robust IgE-mediated response accompanied by enhanced OVA-IgE levels, intestinal mastocytosis, elevated serum mMCP-1, and acute diarrhea. In contrast, mice exposed to oral curcumin throughout the experimental regimen appeared to be normal and did not exhibit intense allergic diarrhea or a significant enhancement of OVA-IgE and intestinal mast cell expansion and activation. Furthermore, allergic diarrhea, mast cell activation and expansion, and Th2 responses were also suppressed in mice exposed to curcumin during the OVA-challenge phase alone, despite the presence of elevated levels of OVA-IgE, suggesting that curcumin may have a direct suppressive effect on intestinal mast cell activation and reverse food allergy symptoms in allergen-sensitized individuals. This was confirmed by observations that curcumin attenuated the expansion of both adoptively transferred bone marrow-derived mast cells (BMMCs), and inhibited their survival and activation during cell culture. Finally, the suppression of intestinal anaphylaxis by curcumin was directly linked with the inhibition of NF-κB activation in curcumin-treated allergic mice, and curcumin inhibited the phosphorylation of the p65 subunit of NF-κB in BMMCs. In summary, our data demonstrates a protective role for curcumin during allergic responses to food antigens, suggesting that frequent ingestion of this spice may modulate the outcome of disease in susceptible individuals.

Mast cell stabilisers

Mast cells play a critical role in type 1 hypersensitivity reactions. Indeed, mast cell mediators are implicated in many different conditions including allergic rhinitis, conjunctivitis, asthma, psoriasis, mastocytosis and the progression of many different cancers. Thus, there is intense interest in the development of agents which prevent mast cell mediator release or which inhibit the actions of such mediators once released into the environment of the cell. Much progress into the design of new agents has been made since the initial discovery of the mast cell stabilising properties of khellin from Ammi visnaga and the clinical approval of cromolyn sodium. This review critically examines the progress that has been made in the intervening years from the design of new agents that target a specific signalling event in the mast cell degranulation pathway to those agents which have been developed where the precise mechanism of action remains elusive. Particular emphasis is also placed on clinically used drugs for other indications that stabilise mast cells and how this additional action may be harnessed for their clinical use in disease processes where mast cells are implicated.

An indoxyl compound 5-bromo-4-chloro-3-indolyl 1,3-diacetate, CAC-0982, suppresses activation of Fyn kinase in mast cells and IgE-mediated allergic responses in mice

Mast cells, constituents of virtually all organs and tissues, are critical cells in IgE-mediated allergic responses. The aim of this study was to investigate the effect and mechanism of an indoxyl chromogenic compound, 5-bromo-4-chloro-3-indolyl 1,3-diacetate, CAC-0982, on IgE-mediated mast cell activation and allergic responses in mice. CAC-0982 reversibly suppressed antigen-stimulated degranulation in murine mast cells (IC50, ~3.8μM) and human mast cells (IC50, ~3.0μM). CAC-0982 also inhibited the expression and secretion of IL-4 and TNF-α in mast cells. Furthermore, CAC-0982 suppressed the mast cell-mediated allergic responses in mice in a dose-dependent manner (ED50 27.9mg/kg). As for the mechanism, CAC-0982 largely suppressed the phosphorylation of Syk and its downstream signaling molecules, including LAT, Akt, Erk1/2, p38, and JNK. Notably, the tyrosine kinase assay of antigen-stimulated mast cells showed that CAC-0982 inhibited Fyn kinase, one of the upstream tyrosine kinases for Syk activation in mast cells. Taken together, these results suggest that CAC-0982 may be used as a new treatment for regulating IgE-mediated allergic diseases through the inhibition of the Fyn/Syk pathway in mast cells.

Spiraeoside inhibits mast cells activation and IgE-mediated allergic responses by suppressing phospholipase C-γ-mediated signaling

Mast cells are responsible for IgE-mediated allergic responses through the secretion of various inflammatory cytokines and mediators. Therefore, the pharmacological regulation of mast cell activation is an important goal in the development of novel anti-allergic drugs. In this study, we found that spiraeoside (SP) inhibits mast cell activation and allergic responses in vivo. SP dose-dependently inhibited the degranulation induced by IgE-antigen (Ag) stimulation in RBL-2H3 mast cells without cytotoxic effects. At the molecular level, SP reduced the Ag-induced phosphorylation and subsequent activation of phospholipase C-γ2 (PLC-γ2). Moreover, SP inhibited the phosphorylation of spleen tyrosine kinase (Syk), linker for activation of T cells (LAT), and downstream MAPKs, such as ERK1/2, p38, and JNK, eventually attenuating expression of TNF-α and IL-4. Finally, we found that SP significantly inhibited IgE-mediated passive cutaneous anaphylaxis (PCA) in mice. Taken together, our results strongly suggest that SP suppresses IgE-mediated mast cell activation and allergic responses by inhibiting Lyn-induced PLC-γ2/MAPK signaling in mast cells.

Twenty-first century mast cell stabilizers

Mast cell stabilizing drugs inhibit the release of allergic mediators from mast cells and are used clinically to prevent allergic reactions to common allergens. Despite the relative success of the most commonly prescribed mast cell stabilizer, disodium cromoglycate, in use for the preventative treatment of bronchial asthma, allergic conjunctivitis and vernal keratoconjunctivitis, there still remains an urgent need to design new substances that are less expensive and require less frequent dosing schedules. In this regard, recent developments towards the discovery of the next generation of mast cell stabilizing drugs has included studies on substances isolated from natural sources, biological, newly synthesized compounds and drugs licensed for other indications. The diversity of natural products evaluated range from simple phenols, alkaloids, terpenes to simple amino acids. While in some cases their precise mode of action remains unknown it has nevertheless sparked interest in the development of synthetic derivatives with improved pharmacological properties. Within the purely synthetic class of inhibitors, particular attention has been devoted to the inhibition of important signalling molecules including spleen TK and JAK3. The statin class of cholesterol-lowering drugs as well as nilotinib, a TK inhibitor, are just some examples of clinically used drugs that have been evaluated for their anti-allergic properties. Here, we examine each approach under investigation, summarize the test data generated and offer suggestions for further preclinical evaluation before their therapeutic potential can be realized.

Aceriphyllum rossii extract and its active compounds, quercetin and kaempferol inhibit IgE-mediated mast cell activation and passive cutaneous anaphylaxis

Aceriphyllum rossii contains an abundant source of natural flavonoids with potential antioxidant, anticancer and anti-inflammatory properties. However, the effect of A. rossii extract (ARE) on immunoglobulin E(IgE)-mediated allergic responses remains unknown. In the present study, the effects of ARE and its active compounds, quercetin and kaempferol, on IgE-mediated rat basophilic leukemia mast cell activation and passive cutaneous anaphylaxis (PCA) were investigated. ARE, quercetin, and kaempferol inhibited secretion of β-hexosaminidase and histamine, and reduced the production and mRNA expression of interleukin-4 and tumor necrosis factor-α. ARE also decreased the production of prostaglandin E2 and leukotriene B4 and expression of cyclooxygenase 2 and 5-lipoxygenase. Furthermore, ARE, quercetin, and kaempferol inhibited IgE-mediated phosphorylation of Syk, phospholipase Cγ, protein kinase C (PKC)μ, and the mitogen-activated protein kinases, extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase. ARE, quercetin, and kaempferol markedly suppressed mast cell-dependent PCA in IgE-sensitized mice. These results indicate that ARE and its active constituents, quercetin and kaempferol, may be a useful therapy for immediate-type hypersensitivity.

Curcumin ameliorates TNF-α-induced ICAM-1 expression and subsequent THP-1 adhesiveness via the induction of heme oxygenase-1 in the HaCaT cells

Adhesion molecules such as ICAM-1 are important in the infiltration of leukocytes into the site of inflammation. In this study, we investigated the inhibitory effects of curcumin on ICAM-1 expression and monocyte adhesiveness as well as its underlying action mechanism in the TNF-α-stimulated keratinocytes. Curcumin induced expression of heme oxygenase-1 (HO-1) in the human keratinocyte cell line HaCaT. In addition, curcumin induced Nrf2 activation in dose- and time-dependent manners in the HaCaT cells. Curcumin suppressed TNF-α- induced ICAM-1 expression and subsequent monocyte adhesion, which were reversed by the addition of tin protoporphyrin IX (SnPP), a specific inhibitor of HO-1, or HO-1 knockdown using siRNA. Furthermore, Nrf2 knockdown using siRNA reversed the inhibitory effect of curcumin on the TNF-α-induced ICAM-1 expression and adhesion of monocytes to keratinocytes. These results suggest that curcumin may exert its anti-inflammatory activity by suppressing the TNF-α-induced ICAM-1 expression and subsequent monocyte adhesion via expression of HO-1 in the keratinocytes. [BMB Reports 2013;46(8): 410-415]

Curcumin inhibits the activation of immunoglobulin e-mediated mast cells and passive systemic anaphylaxis in mice by reducing serum eicosanoid and histamine levels

Curcumin is naturally occurring polyphenolic compound found in turmeric and has many pharmacological activities. The present study was undertaken to evaluate anti-allergic inflammatory activity of curcumin, and to investigate its inhibitory mechanisms in immunoglobulin E (IgE)/Ag-induced mouse bone marrow-derived mast cells (BMMCs) and in a mouse model of IgE/Ag-mediated passive systemic anaphylaxis (PSA). Curcumin inhibited cyclooxygenase-2 (COX-2) dependent prostaglandin D₂ (PGD₂) and 5-lipoxygenase (5-LO) dependent leukotriene C₄ (LTC₄) generation dose-dependently in BMMCs. To probe the mechanism involved, we assessed the effects of curcumin on the phosphorylation of Syk and its downstream signal molecules. Curcumin inhibited intracellular Ca²⁺ influx via phospholipase Cγ1 (PLCγ1) activation and the phosphorylation of mitogen-activated protein kinases (MAPKs) and the nuclear factor-κB (NF-κB) pathway. Furthermore, the oral administration of curcumin significantly attenuated IgE/Ag-induced PSA, as determined by serum LTC₄, PGD₂, and histamine levels. Taken together, this study shows that curcumin offers a basis for drug development for the treatment of allergic inflammatory diseases.

Immunomodulation of mast cells by nutrients

In the past decades an increasing prevalence of allergic disorders was observed in industrialized countries. Thus, it is necessary to develop adequate therapeutic and preventive strategies. Many of the conservative strategies possess diverse harmful side effects. Therefore agents with fewer side effects and a better compliance among afflicted patients would be of interest. Especially substances with natural origin acting immunomodulatory on mast cells - the key effector cells of allergic diseases - could be used. Among them there are components of the daily diet such as distinct fatty acids and amino acids as well as a range of secondary plant substances such as carotenoids, flavonoids and spices. These nutritional substances could be applied as nutraceuticals in the therapy of mast cell associated diseases. Many of these substances show inhibitory influences on the release of prestored mast cell mediators such as histamine or de novo expression of mast cell mediators such as cytokines and eicosanoids which are involved in the pathogenesis of mast cell associated inflammatory conditions like allergic reactions.

A multimodal Darwinian strategy for alleviating the atherosclerosis pandemic

The conflict between our 'primitive' genes and 'modern' lifestyle probably lies at the root of several disorders that afflict modern man. Atherosclerosis, which is relatively unknown among contemporary hunter-gatherer populations, has reached pandemic proportions in recent times. Being an evolutionary problem with several inter-related pathologies, current therapeutic strategy for treating atherosclerosis has inherent limitations. Reviewing evolution-linked risk factors suggests that there are four aspects to the etiology of atherosclerosis namely, decreased intestinal parasitism, oversensitivity of evolutionarily redundant mast cells, chronic underactivation of AMPK (cellular energy sensor) and a deficiency of vitamin D. A combination of these four causes appear to have precipitated the atherosclerosis pandemic in modern times. Man and worms co-existed symbiotically in the past. Massive de-worming campaigns could have disrupted this symbiosis, increasing nutritional availability to man (pro-obesity) at the cost of decreased immunotolerance (pro-atherogenicity). A reduction in helminth-induced chronic TH2 activation could also have enhanced TH1 polarization, eventually disrupting the reciprocal regulation of TH1/TH2 balance and resulting in atherosclerosis. The riddance of helminth infestations may have rendered mast cells immunologically redundant, making them oversensitive to inflammatory stimuli, thereby playing a pro-atherogenic role. AMPK activation exerts pleiotropic anti-atherogenic effects, such as suppression of fatty acid, cholesterol, protein synthesis, reduction of vascular smooth muscle proliferation, etc. As energy deficit is the chief stimulus for AMPK activation, the over-nourished modern man appears to be suffering from chronic underactivation of AMPK, legitimising the unrivalled supremacy of metformin, the oldest prescribed antidiabetic drug. The fact that humans evolved in the sunny tropics suggests that humans are selected for high vitamin D levels. Vitamin D deficiency is now linked to several conditions including increased risk of CV disorders, diabetes, etc. The manifold decrease in vitamin D levels in modern man justifies a need for supplementation. We therefore hypothesize that a judicious combination of mast cell stabilization, AMPK activation, vitamin D supplementation, and moderation in hygiene practices could be an evolution-based multimodal strategy for both preventing and mitigating the pandemic of atherosclerosis.

Therapeutic potential of curcumin in experimentally induced allergic rhinitis in guinea pigs

In the present experiments, the possible role of curcumin in ovalbumin induced allergic rhinitis in guinea pig model was investigated. Various allergic rhinitis symptoms viz sneezing, rubbing frequencies, lacrimation and nasal congestion at various humidity conditions as well as on repeated sensitization were studied. The biochemical changes like serum IgE, IL-4 and nitric oxide (NO) in nasal lavage and eosinophil peroxidase activity in nasal homogenates were determined in allergic rhinitis. Curcumin treatment significantly reduced the symptoms (sneezing, rubbing frequencies, lacrimation and nasal congestion) and improved the histopathological alterations (reduction in inflammatory cells infiltration) of nasal mucosa in allergic rhinitis. Furthermore, curcumin treatment prevented significantly elevation of serum IgE, IL-4, NO in nasal lavage and eosinophil peroxidase in nasal homogenate. In the present experimental findings, we suggest that curcumin is a promising anti-allergic agent that may be useful in the clinical management of allergic rhinitis.

Anti-inflammatory activity of hexane extracts from bones and internal organs of Anguilla japonica suppresses cyclooxygenase-2-dependent prostaglandin D₂ generation in mast cells and anaphylaxis in mice

The purpose of this study is to investigate the effects of n-hexane extracts from bones and internal organs of Japanese eel, Anguilla japonica (HEE), on cyclooxygenase-2 (COX-2)-dependent prostaglandin D₂(PGD₂) generation in stem cell factor (SCF), IL-10, plus LPS-induced mouse bone marrow-derived mast cells (BMMCs) and on passive cutaneous anaphylaxis (PCA) in mice. HEE suppressed SCF/IL-10/LPS-induced PGD₂ generation, and concomitantly reduced COX-2 protein expression dose-dependently. To understand the mechanistic basis for the inhibition of PGD₂ generation by HEE, we examined the effects of HEE on upstream signaling pathways essential for COX-2 induction. HEE was found to inhibit the translocation of nuclear factor-κB (NF-κB) p65 subunit to the nucleus and its DNA-binding ability through the inhibition of TAK1, IKK and IκB phosphorylation. Furthermore, HEE also attenuated mitogen-activated protein kinase (MAPK)-mediated regulation of DNA binding of activator protein-1 (AP-1). Moreover, oral administration of HEE inhibited anti-dinitrophenyl (DNP) IgE-induced PCA in a dose dependent manner. Taken together, the present study provides new insights into the anti-inflammatory activity of HEE, which could be a promising candidate to be used for an inflammatory therapy.

Enhanced bioavailability and efficiency of curcumin for the treatment of asthma by its formulation in solid lipid nanoparticles

Curcumin has shown considerable pharmacological activity, including anti-inflammatory, but its poor bioavailability and rapid metabolization have limited its application. The purpose of the present study was to formulate curcumin-solid lipid nanoparticles (curcumin-SLNs) to improve its therapeutic efficacy in an ovalbumin (OVA)-induced allergic rat model of asthma. A solvent injection method was used to prepare the curcumin-SLNs. Physiochemical properties of curcumin-SLNs were characterized, and release experiments were performed in vitro. The pharmacokinetics in tissue distribution was studied in mice, and the therapeutic effect of the formulation was evaluated in the model. The prepared formulation showed an average size of 190 nm with a zeta potential value of -20.7 mV and 75% drug entrapment efficiency. X-ray diffraction analysis revealed the amorphous nature of the encapsulated curcumin. The release profile of curcumin-SLNs was an initial burst followed by sustained release. The curcumin concentrations in plasma suspension were significantly higher than those obtained with curcumin alone. Following administration of the curcumin-SLNs, all the tissue concentrations of curcumin increased, especially in lung and liver. In the animal model of asthma, curcumin-SLNs effectively suppressed airway hyperresponsiveness and inflammatory cell infiltration and also significantly inhibited the expression of T-helper-2-type cytokines, such as interleukin-4 and interleukin-13, in bronchoalveolar lavage fluid compared to the asthma group and curcumin-treated group. These observations implied that curcumin-SLNs could be a promising candidate for asthma therapy.

Inhibitory effect of eriodictyol on IgE/Ag-induced type I hypersensitivity

Mast cells are the principal effector cells involved in the allergic response, through the release of histamine. We investigated the effect of eriodictyol, derived from the painted maple and yerba santa, on mast cell degranulation and on an allergic response in an animal model. We also investigated its effect on the expression of the ceramide kinase (CERK) involved in calcium-dependent degranulation, and on ceramide activation by multiple cytokines. Eriodictyol suppressed the release of beta-hexosaminidase, a marker of degranulation, and the expression of interleukin (IL)-4 mRNA. It inhibited the expression of CERK mRNA, reduced the ceramide concentration in antigen-stimulated mast cells, and suppressed the passive cutaneous anaphylaxis (PCA) reaction in mice in a dose-dependent manner. These results suggest that eriodictyol can inhibit mast cell degranulation through inhibition of ceramide kinase, and that it might potentially serve as an anti-allergic agent.

Antiallergic activity of novel isoflavone methyl-glycosides from Cordyceps militaris grown on germinated soybeans in antigen-stimulated mast cells

Isoflavones are known to possess immunomodulating and antiallergic activities. Previously we identified novel isoflavone methyl-glycosides (daidzein 7-O-β-d-glucoside 4″-O-methylate (CDGM), glycitein 7-O-β-D-glucoside 4″-O-methylate (CGLM), genistein 7-O-β-D-glucoside 4″-O-methylate (CGNMI) and genistein 4'-O-β-D-glucoside 4″-O-methylate (CGNMII)) from Cordyceps militaris grown on germinated soybeans (GSC). The biological activity of novel isoflavone methyl-glycosides, however, remains unknown. In this study, CGNMII showed the strongest inhibition of degranulation. Additionally, the release of interleukin (IL)-4 and tumor necrosis factor (TNF)-α was decreased by CGNMII in antigen-stimulated RBL-2H3 cells. To elucidate the antiallergic mechanism of CGNMII, we examined whether it affected levels of signaling molecules responsible for degranulation. The levels of activated Lyn, Syk, PLCγ1 and LAT proteins were reduced in CGNMII treated RBL-2H3 cells. CGNMII also inhibited the activation of AKT and ERK1/2 proteins. These results suggest that CGNMII might be used as a therapeutic agent for allergic diseases.