Effects of triterpenoid-rich extracts of Ganoderma tsugae on airway hyperreactivity and Th2 responses in vivo

Formononetin isolated from Sophorae flavescentis inhibits B cell-IgE production by regulating ER-stress transcription factor XBP-1

Rationale

IgE plays an important pathologic role in most, if not all, allergic conditions. We previously showed that ASHMI (anti-asthma herbal medicine intervention) suppressed IgE production in murine models of asthma and in asthma subjects. However, the active compounds in ASHMI responsible for the IgE suppression are still unknown.

Objective

We sought to identify the compound(s) in ASHMI that are responsible for IgE inhibition as well as investigate the mechanisms by which the identified compound(s) decreases IgE production.

Methods

The compounds in Sophorae Flavescentis were separated using Column chromatography and preparative-HPLC. The separated compounds were identified using LC-MS and ¹H-NMR. U266 cells, an IgE-producing plasma cell line, were cultured with various concentrations of identified compounds. The levels of IgE production by the U266 cell were measured by ELISA. Trypan blue exclusion was used to determine the cell viability. The gene expression of XBP-1 and IgE-heavy chain was determined by RT-PCR.

Results

A single compound identified as formononetin was isolated from Sophorae Flavescentis. Formononetin significantly and dose dependently decreased the IgE production in U266 cells across a concentration range of 2-20 µg/ml (p < 0.05-0.001 vs. untreated cells) with an IC50 value of 3.43 μg/ml. There was no cytotoxicity at any tested concentration. Formononetin significantly decreased XBP-1, and IgE-heavy chain gene expression compared with untreated cells (p < 0.001).

Conclusion

Formononetin decreased IgE production in human B cell line U266 cells in a dose-dependent fashion through the regulation of XBP-1 ER transcription. Formononetin may be a potential therapy for allergic asthma and other IgE-mediated diseases.

Time-dependent dual beneficial modulation of interferon-γ, interleukin 5, and Treg cytokines in asthma patient peripheral blood mononuclear cells by ganoderic acid B

Th2 cytokines play a dominant role in the pathogenesis of allergic asthma. Interferon gamma (IFN-γ), a Th1 cytokine, links to therapeutic mechanisms of allergic asthma. Interleukin (IL)-10, a regulatory cytokine, is involved in the induction of immune tolerance. We previously demonstrated that Anti-Asthma Simplified Herbal Medicine Intervention (ASHMI) suppressed Th2 and increased IFN-γ in patients with asthma and in animal models, but its bioactive compound is unknown. Ganoderic acid beta (GAB) was isolated from Ganoderma lucidum (one herb in ASHMI). Human peripheral blood mononuclear cells (PBMCs) from adult patients with asthma were cultured with GAB or dexamethasone (Dex) in the presence of environmental allergens. The cytokine levels of IL-10, IFN-γ, IL-5, transcription factors T-bet, Foxp-3, and GATA3 were measured. Following 3-day culture, GAB, but not Dex, significantly increased IL-10 and IFN-γ levels by allergic patients' PBMCs. Following 6-day treatment, GAB inhibited IL-5 production, but IL-10 and IFN-γ remained high. Dex suppressed production of all three cytokines. GAB suppressed GATA3 and maintained Foxp-3 and T-bet gene expression, while Dex significantly suppressed GATA3 and T-bet expression. GAB simultaneously increased IL-10, IFN-γ associated with induction of T-bet and Foxp3, while suppressing IL-5, which was associated with suppression of GATA3, demonstrating unique beneficial cytokine modulatory effect, which distinguishes from Dex's overall suppression.

Suppression on allergic airway inflammation of dehulled adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) in mice and anti-degranulation phytosterols from adlay bran

Adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) seeds have been used in Asia for thousands years to treat warts, chapped skin, rheumatism, and neuralgia. The anti-allergic activity of dehulled adlay (DA) seeds was identified, and the bran (AB) is regarded as the main functional constituent in the edible part. However, no study has focused on in vivo acute anti-allergic airway inflammation. In the present report, we investigated DA methanolic extract (DAM) reversed ovalbumin (OVA)/methacholine (Mch)-induced airway hypersensitivity, decreased interleukin (IL)-4, IL-5, and IL-13 levels from splenocytes, suppressed tumor necrosis factor (TNF)-α, IL-1β, and IL-13 levels and reduced eosinophil counts and eotaxin in bronchoalveolar lavage fluid (BALF), which imply that the modulatory effects of DA should involve allergic degranulation. Further, seven phytosterols were isolated from AB ethanolic extract (ABE); among them, 3-O-caffeoyl-5β-sitostan-3-ol, β-sitosterol 3-O-glucopyranoside and β-sitosterol inhibited β-hexosaminidase release from A23187-stimulated RBL-2H3 cells with percentages of 54.1%, 52.0% and 48.5%, respectively, at 50 μM. In addition, β-sitosterol reduced immunoglobulin (Ig)E-stimulated degranulation on RBL-2H3 cells in a dose-dependent manner. The phytosterols were the predominant components based on gas chromatography (GC) analysis. This is the first study to demonstrate that DA suppressed OVA/Mch-induced acute airway inflammation. The phytosterols in AB showed significant anti-degranulation activities, and may be regarded as the indicative components of AB for anti-allergy effects.

Advanced Molecular Knowledge of Therapeutic Drugs and Natural Products Focusing on Inflammatory Cytokines in Asthma

Asthma is a common respiratory disease worldwide. Cytokines play a crucial role in the immune system and the inflammatory response to asthma. Abnormal cytokine expression may lead to the development of asthma, which may contribute to pathologies of this disease. As cytokines exhibit pleiotropy and redundancy characteristics, we summarized them according to their biologic activity in asthma development. We classified cytokines in three stages as follows: Group 1 cytokines for the epithelial environment stage, Group 2 cytokines for the Th2 polarization stage, and Group 3 cytokines for the tissue damage stage. The recent cytokine-targeting therapy for clinical use (anti-cytokine antibody/anti-cytokine receptor antibody) and traditional medicinal herbs (pure compounds, single herb, or natural formula) have been discussed in this review. Studies of the Group 2 anti-cytokine/anti-cytokine receptor therapies are more prominent than the studies of the other two groups. Anti-cytokine antibodies/anti-cytokine receptor antibodies for clinical use can be applied for patients who did not respond to standard treatments. For traditional medicinal herbs, anti-asthmatic bioactive compounds derived from medicinal herbs can be divided into five classes: alkaloids, flavonoids, glycosides, polyphenols, and terpenoids. However, the exact pathways targeted by these natural compounds need to be clarified. Using relevant knowledge to develop more comprehensive strategies may provide appropriate treatment for patients with asthma in the future.

Petiveria alliacea Suppresses Airway Inflammation and Allergen-Specific Th2 Responses in Ovalbumin-Sensitized Murine Model of Asthma

OBJECTIVE

To examine the effect of metanol extract of Petiveria alliacea (PM) on airway inflflammation in a murine model of chronic asthma.

METHODS

Two-month-old male BALB/c mice (n=6-8/group) were sensitized on days 0 and 14 by intraperitoneal injection of 20 μg ovalbumin (OVA). On day 25, the mice received an airway challenge with OVA (3%, w/v, in phosphate buffered saline). PM was administered orally by oral gavage to mice at doses of 100, 200 and 400 mg/kg body weight once daily from days 18 to 23. Control mice were orally administered phosphate buffered saline (PBS) to induce a model of asthma. At the end of the test, respiratory reactivity was assayed, the total cell number, interleukin-4 (IL-4), IL-5, IL-13, tumor necrosis factor-alpha (TNF-α) and reactive oxygen species (ROS) in the bronchoalveolar lavage fluid (BALF) were determined and the levels of serum IgE, intercellular cell adhesion molecule 1 (ICAM-1) and eotoxin were measured. In addition, lung tissue was used to qualify the IL-4, IL-5, IL-13, TNF-α and transforming growth factor beta 1 (TGF-β1). Histologic examination was performed to observe inflammatory cellular infiltration.

RESULTS

The administration of PM in comparison with the OVA-only treated group signifificantly attenuated the infifiltration of eosinophils and other inflflammatory cells (P<0.01). Airway resistance (RI) in the OVA-only induced group was significantly higher than that of the PBS control group (P<0.01) when methacholine was added. TNF-α, IgE, TGF-β1 and cytokine levels IL-4, IL-5, IL-13 in the BALF decreased compared to control mice (P<0.01 or P<0.05). PM treatment also inhibited the production of chemokines, eotaxin and ICAM-1 in BALF (P<0.01), which improved lung function. Histopathological examination revealed that the sensitized treated PM groups had significant lower in inflammatory scores similar to dexamethasone treatments and the untreated group.

CONCLUSION

Administration of PM could inhibit airway inflammation, regulate cytokines, chemokines and enhance pulmonary conditions in allergic murine model of asthma.

Immune Homeostasis: Effects of Chinese Herbal Formulae and Herb-Derived Compounds on Allergic Asthma in Different Experimental Models

Allergic asthma is thought to arise from an imbalance of immune regulation, which is characterized by the production of large quantities of IgE antibodies by B cells and a decrease of the interferon-γ/interleukin-4 (Th1/Th2) ratio. Certain immunomodulatory components and Chinese herbal formulae have been used in traditional herbal medicine for thousands of years. However, there are few studies performing evidence-based Chinese medicine (CM) research on the mechanisms and effificacy of these drugs in allergic asthma. This review aims to explore the roles of Chinese herbal formulae and herb-derived compounds in experimental research models of allergic asthma. We screened published modern CM research results on the experimental effects of Chinese herbal formulae and herb-derived bioactive compounds for allergic asthma and their possible underlying mechanisms in English language articles from the PubMed and the Google Scholar databases with the keywords allergic asthma, experimental model and Chinese herbal medicine. We found 22 Chinese herb species and 31 herb-derived anti-asthmatic compounds as well as 12 Chinese herbal formulae which showed a reduction of airway hyperresponsiveness, allergen-specifific immunoglobulin E, inflflammatory cell infifiltration and a regulation of Th1 and Th2 cytokines in vivo, in vitro and ex vivo, respectively. Chinese herbal formulae and herbderived bioactive compounds exhibit immunomodulatory, anti-inflflammatory and anti-asthma activities in different experimental models and their various mechanisms of action are being investigated in modern CM research with genomics, proteomics and metabolomics technologies, which will lead to a new era in the development of new drug discovery for allergic asthma in CM.

Folate deficiency affects dendritic cell function and subsequent T helper cell differentiation

Insufficient folate status may be related to the increasing prevalence of immune- or inflammation-related chronic diseases. To investigate the effects of folate on immune regulation, we examined the impact of folate deficiency (FD) on dendritic cell (DC) maturation and function and, thus, T helper (Th) cells differentiation. First, bone marrow-derived DCs (BMDCs) were generated from BALB/c mice bone marrow cells cultured in folate-containing (F-BMDCs) or folate-deficient (FD-BMDCs) medium. FD-BMDC displayed more immature phenotype including reduced levels of major histocompatibility complex class II (MHC II), co-stimulatory molecules and characteristic of higher endocytic activity. FD-BMDC produced less IL-12p70 and proinflammatory cytokines in response to lipopolysaccharide. This aberrant DC maturation due to FD resulted in reduced BMDC-induced Th cell activity and lower IL-2, IFNγ, IL-13 and IL-10 productions. Further in vivo study confirmed significantly lower IFNγ and IL-10 productions by T cells and showed higher splenic naïve Th and lower memory T, effector T and regulatory T cell (Treg) percentages in mice fed with the FD diet for 13 weeks. To investigate the role of DCs on T cell activity, splenic DCs (spDC) from FD mice were cocultured with Th cells. The FD spDC had lower MHC II and CD80 expressions and subsequently impaired DC-induced Th differentiation, shown as decreased cytokine productions. This study demonstrated that folate deficiency impaired DC functions and, thus, Th differentiation and responses, suggesting that folate plays a crucial role in maintaining Th cells homeostasis.

Ethanol Extract of Perilla frutescens Suppresses Allergen-Specific Th2 Responses and Alleviates Airway Inflammation and Hyperreactivity in Ovalbumin-Sensitized Murine Model of Asthma

This study was to investigate the effects of different fractions of Perilla frutescens (Pf) leaves extracted by water or ethanol on asthma. BALB/c mice sensitized intraperitoneally and challenged with ovalbumin (OVA) were divided into six groups. Each group of mice was tube-feeding with 0 (control), 80 μg (PfWL), or 320 μg (PfWH) water extracts or 80 μg (PfEL) or 320 μg (PfEH) ethanol extracts of perilla leaves daily for 3 weeks. A negative control group (PBS) was neither sensitized nor treated with Pf. The effects of perilla leave extracts on allergic immune response were evaluated. The results showed that OVA-specific IL-5 and IL-13 secretions from OVA-stimulated splenocytes were significantly suppressed in the ethanol extract groups PfEL and PfEH. Serum level of anti-OVA IgE tended to be lower in the PfEH group. The inflammatory mediators, such as eotaxin and histamine, and total cells, particularly eosinophils in bronchoalveolar lavage fluid (BALF), were also decreased in the PfEL and the PfEH groups. Therefore, the PfEL and the PfEH groups had significantly lower methacholine-induced hyperresponsiveness (AHR). In conclusion, ethanol extracts, rather than water extract, of perilla leaves could significantly suppress Th2 responses and airway inflammation in allergic murine model of asthma.

Triterpenoids and Polysaccharide Fractions of Ganoderma tsugae Exert Different Effects on Antiallergic Activities

This study was to investigate antiallergic effects of triterpenoids (Gt-TRE) and polysaccharide (Gt-PS) extracts from Ganoderma tsugae, using mast cell line RBL-2H3, T cell line EL4, primary T cells, and transfected RAW264.7 macrophage cells. The results showed that histamine secreted from activated RBL-2H3 mast cells was significantly suppressed by Gt-TRE but not Gt-PS. Interleukin- (IL-) 4 secreted from activated EL4 cells was significantly suppressed by Gt-TRE but not Gt-PS. Further primary CD4⁺ T cells cultures also confirmed that Gt-TRE (5 ~ 50 µg/mL) significantly suppressed Th2 cytokines IL-4 and IL-5 secretions but had no effect on Th1 cytokines IL-2 and interferon (IFN)-γ. Gt-PS did not affect IL-4 and IL-5 secretions until higher doses (400, 500 µg/mL) and significantly suppressed IFNγ secretions but enhanced IL-2 at these high doses. The reporter gene assay indicated that Gt-TRE inhibited but Gt-PS enhanced the transcriptional activity of NF-κB in activated transfected RAW264.7 cells and transfected EL4 cells. IL-4 secreted by this transfected EL-4 cells was also significantly decreased by Gt-TRE but not by Gt-PS, suggesting that these two fractions may exert different effects on NF-κB related cytokines expression. These data suggested that triterpenoids fraction of Ganoderma tsugae might be the main constituents to alleviate allergic asthma.

Ganoderma formosanum polysaccharides attenuate Th2 inflammation and airway hyperresponsiveness in a murine model of allergic asthma

Allergic asthma is an inflammatory disease of the airways mediated by Th2 immune responses and characterized by airway hyperresponsiveness (AHR). Fungi of the genus Ganoderma are basidiomycetes that have been used in traditional Asian medicine for centuries. We recently found that PS-F2, a polysaccharide fraction purified from the submerged culture broth of Ganoderma formosanum, stimulates the activation of dendritic cells and primes a T helper 1 (Th1)-polarized adaptive immune response. This study was designed to investigate whether the Th1 adjuvant properties of PS-F2 could suppress the development of allergic asthma in a mouse model. BALB/c mice were sensitized by repeated immunization with chicken ovalbumin (OVA) and alum, followed by intranasal challenge of OVA to induce acute asthma. PS-F2 administration during the course of OVA sensitization and challenge effectively prevented AHR development, OVA-specific IgE and IgG1 production, bronchial inflammation, and Th2 cytokine production. Our data indicate that PS-F2 has a potential to be used for the prevention of allergic asthma.

Glycyrrhiza uralensis flavonoids present in anti-asthma formula, ASHMI™, 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.

Beta-escin has potent anti-allergic efficacy and reduces allergic airway inflammation

Background

Type I hypersensitivity is characterized by the overreaction of the immune system against otherwise innocuous substances. It manifests as allergic rhinitis, allergic conjunctivitis, allergic asthma or atopic dermatitis if mast cells are activated in the respective organs. In case of systemic mast cell activation, life-threatening anaphylaxis may occur. Currently, type I hypersensitivities are treated either with glucocorticoids, anti-histamines, or mast cell stabilizers. Although these drugs exert a strong anti-allergic effect, their long-term use may be problematic due to their side-effects.

Results

In the course of a routine in vitro screening process, we identified beta-escin as a potentially anti-allergic compound. Here we tested beta-escin in two mouse models to confirm this anti-allergic effect in vivo. In a model of the early phase of allergic reactions, the murine passive cutaneous anaphylaxis model, beta-escin inhibited the effects of mast cell activation and degranulation in the skin and dose-dependently prevented the extravasation of fluids into the tissue. Beta-escin also significantly inhibited the late response after antigen challenge in a lung allergy model with ovalbumin-sensitized mice. Allergic airway inflammation was suppressed, which was exemplified by the reduction of leucocytes, eosinophils, IL-5 and IL-13 in the bronchoalveolar lavage fluid. Histopathological examinations further confirmed the reduced inflammation of the lung tissue. In both models, the inhibitory effect of beta-escin was comparable to the benchmark dexamethasone.

Conclusions

We demonstrated in two independent murine models of type I hypersensitivity that beta-escin has potent anti-allergic properties. These results and the excellent safety profile of beta-escin suggest a therapeutic potential of this compound for a novel treatment of allergic diseases.

Efficacy and mechanisms of action of traditional Chinese medicines for treating asthma and allergy

BACKGROUND

Although corticosteroids and beta(2)-agonists are effective in managing asthma symptoms, a curative therapy for asthma is lacking. Traditional Chinese medicine (TCM), used in Asia for centuries, is beginning to play a role in Western health care as a complementary and alternative medicine modality. There is increasing scientific evidence supporting the use of TCM for asthma treatment.

OBJECTIVE

This review article discusses promising TCM interventions for asthma and explores their possible mechanisms of action.

METHODS

We first reviewed 5 clinical studies of antiasthma TCM herbal remedies published between 2005 and 2007. We then summarized possible mechanisms underlying their effects on the basis of data in the original articles, published abstracts, and available databases. Possible mechanisms include anti-inflammation, inhibition of airway smooth muscle contraction, and immunomodulation. Research on TCM herbal therapy for food allergy is rare, and we therefore focused on the effect and mechanism of action of food allergy herbal formula-2 on a murine model of peanut allergy and preliminary clinical study results.

CONCLUSION

Evidence from clinical studies supports beneficial effects of TCM herbal therapy on asthma. A number of mechanisms may be responsible for efficacy of these agents. Strong preclinical study data suggest the potential efficacy of food allergy herbal formula-2 for food allergy.

Anti-inflammatory activities of new succinic and maleic derivatives from the fruiting body of Antrodia camphorata

Six new compounds, trans-3-isobutyl-4-[4-(3-methyl-2-butenyloxy)phenyl]pyrrolidine-2,5-dione (1), trans-1-hydroxy-3-(4-hydroxyphenyl)-4-isobutylpyrrolidine-2,5-dione (2), cis-3-(4-hydroxyphenyl)-4-isobutyldihydrofuran-2,5-dione (3), 3-(4-hydroxyphenyl)-4-isobutyl-1H-pyrrole-2,5-dione (4), 3-(4-hydroxyphenyl)-4-isobutylfuran-2,5-dione (5), and dimethyl 2-(4-hydroxyphenyl)-3-isobutylmaleate (6), together with one known compound, 3-isobutyl-4-[4-(3-methyl-2-butenyloxy)phenyl]furan-2,5-dione (7), were isolated from the fruiting bodies of Antrodia camphorata. The structures of the compounds were elucidated by analysis of their spectroscopic data. To investigate the immunomodulatory potential of the compounds, RAW264.7 macrophage cells were treated with the compounds. Compound 1 significantly increased spontaneous TNF-alpha secretion from unstimulated RAW264.7 cells but suppressed IL-6 production [50% inhibition concentration value (IC50) = 10 microg/mL] in LPS-stimulated cells. Compounds 3, 4, and 6 also suppressed IL-6 production with IC50 values of 17, 18, and 25 microg/mL, respectively, suggesting that these four compounds may have an anti-inflammatory effect on macrophage-mediated responses. Of the six compounds, compound 1 was the most effective, exerting both immunostimulatory and anti-inflammatory effects.