Sceptridium ternatum extract exerts antiasthmatic effects by regulating Th1/Th2 balance and the expression levels of leukotriene receptors in a mouse asthma model

Aim of the study

Sceptridium ternatum Lyon (ST), a common Chinese herb, has been used in treatment of allergic asthma and whooping cough. In the present study, we investigated the Th1/Th2 ratio of peripheral blood and mRNA levels of leukotriene receptors after the treatment of ST in allergic asthma mouse model.

Materials and methods

Mouse asthma model was developed by ovalbumin (OVA) sensitization followed by the inhalation of aerosol allergen. Montelukast (10 mg/kg), as a positive control drug, and ST were administrated six days before the OVA sensitization for ten days. Airway responsiveness was evaluated by the Medlab 12.0 biological signal processing system. The ratio of Th1/Th2 cells was determined by flow cytometry. The expression level of Cyslt1 was measured by PCR. Pathological changes of lung tissues were examined by H&E staining.

Results

ST significantly reduced the airway responsiveness, elevated the ratio of Th1/Th2, and decreased Cyslt1 mRNA level in a dose-dependent manner. High-dose ST distinctly prevented the pathological changes of lung tissues.

Conclusion

High-dose ST had the same efficacy as Montelukast in a mouse asthma model, and ST could be a potential anti-asthmatic agent.     

Attenuation of airway hyperreactivity and T helper cell type 2 responses by coumarins from Peucedanum praeruptorum Dunn in a murine model of allergic airway inflammation

Ethnopharmacological relevance

The root of Peucedanum praeruptorum Dunn (PPD) is a commonly used traditional Chinese medicine for the treatment of asthma. Its major constituents, coumarins, were presumed to be responsible for its efficacy.

Aim of the study

The potential of coumarins from PPD (CPPD) as anti-asthma agent was investigated.

Materials and methods

Female BALB/c mice were sensitized and challenged with ovalbumin (OVA) to induce allergic airway inflammation. CPPD was administered intragastrically before every OVA challenge. Airway reactivity to the intravenous administration of acetylcholine chloride was measured 48 h after final OVA inhalation. Airway inflammation was evaluated by leukocyte counts of bronchoalveolar lavage fluid (BALF) and histopathological analysis of lung lesions. Levels of interleukin (IL)-4, IL-5, IL-10, IL-13 and IFN-γ in BALF and OVA-specific immunoglobulin (Ig) E in serum, and activity of eosinophil peroxidase (EPO) in lung was measured. The percentage of CD4⁺CD25⁺Foxp3⁺ regulatory T cells among CD4⁺ T cells in spleen was analyzed by flow cytometry.

Results

Compared with model group, CPPD significantly reduced airway hyperreactivity and airway eosinophilic inflammation, improved pathologic lesion of the lungs, reduced levels of IL-4, IL-5, IL-13 in BALF and OVA-specific IgE in serum, inhibited the activities of EPO in lung, and up-regulated levels of IL-10 and IFN-γ in BALF as well as the percentage of CD4⁺CD25⁺Foxp3⁺ regulatory T cells in spleen.

Conclusion

CPPD can significantly suppress OVA-induced airway inflammation, airway hyperreactivity and Th2 predominant response in mice, showing great therapeutic potential for the treatment of allergic asthma.     

Aqueous extracts from Menyanthes trifoliate and Achillea millefolium affect maturation of human dendritic cells and their activation of allogeneic CD4+ T cells in vitro

Ethnopharmacological relevance: Menyanthes trifoliate and Achillea millefolium have been used in traditional medicine to ameliorate chronic inflammatory conditions. The aim of this study was to identify the effects of ethanol and aqueous extracts of Menyanthes trifoliate and Achillea millefolium on maturation of dendritic cells (DCs) and their ability to activate allogeneic CD4⁺ T cells.

Materials and methods

Human monocyte-derived DCs were matured in the absence or presence of lyophilised aqoueous or ethanol extracts from Menyanthes trifoliate or Achillea millefolium and their expression of surface molecules analysed with flow cytometry and cytokine secretion measured by ELISA. DCs matured in the presence of aqueous extracts from Menyanthes trifoliate and Achillea millefolium were co-cultured with allogeneic CD4⁺ T cells and the expression of surface molecules by T cells and their cytokine secretion and cell proliferation determined.

Results

Maturation of DCs in the presence of aqueous extracts from Menyanthes trifoliate or Achillea millefolium did not affect expression of the surface molecules examined but reduced the ratio of secreted IL-12p40/IL-10, compared with that by DCs matured in the absence of extracts. Allogeneic CD4⁺ T cells co-cultured with DCs matured in the presence of aqueous extract from Menyanthes trifoliate secreted less IFN-γ, IL-10 and IL-17 than CD4⁺ T cells co-cultured with DCs matured without an extract. Maturation of DCs in the presence of aqueous extract from Achillea millefolium decreased IL-17 secretion but did not affect IFN-γ and IL-10 secretion by allogeneic CD4⁺ T cells.

Conclusions

Aqueous extract from Menyanthes trifoliate induces a suppressive phenotype of DCs that has reduced capacity to induce Th1 and Th17 stimulation of allogeneic CD4⁺ T cells, whereas aqueous extract from Achillea millefolium reduces the capacity of DCs to induce a Th17 response.     

Immunomodulatory activity of Asparagus racemosus on systemic Th1/Th2 immunity: Implications for immunoadjuvant potential

Ethnopharmacological relevance

Roots of Asparagus racemosus Willd (Shatavari in vernacular) are widely used in Ayurveda as Rasayana for immunostimulation, galactogogue as also in treatment of conditions like ulcers and cancer. Various studies have indicated immunomodulatory properties of Shatavari root extracts and formulations.

Aim of the study

To study the effect of standardized Asparagus racemosus root aqueous extract (ARE) on systemic Th1/Th2 immunity of SRBC sensitized animals.

Materials and methods

We used HPTLC to quantify steroidal saponins (Shatavarin IV, Immunoside^®) and flow cytometry to study effects of ARE on Th1/Th2 immunity. SRBC specific antibody titres and DTH responses were also monitored as markers of Th2 and Th1 responses, respectively. We also studied lymphocyte proliferation. Cyclosporin, cyclophosphamide and levamisole were used as controls.

Results

Treatment with ARE (100 mg/(kg b.w. p.o.)) resulted in significant increase of CD3⁺ and CD4/CD8⁺ percentages suggesting its effect on T cell activation. ARE treated animals showed significant up-regulation of Th1 (IL-2, IFN-g) and Th2 (IL-4) cytokines suggesting its mixed Th1/Th2 adjuvant activity. Consistent to this, ARE also showed higher antibody titres and DTH responses. ARE, in combination with LPS, Con A or SRBC, produced a significant proliferation suggesting effect on activated lymphocytes.

Conclusion

The study suggests mixed Th1/Th2 activity of ARE supports its immunoadjuvant potential.     

Selective Th1 upregulation by ethyl acetate fraction of Labisia pumila

Aim of the study

Labisia pumila has rejuvenating properties that help women to regain the strength and vigour after giving birth (Burkill, 1935) leading us to speculate that Labisia pumila might also modulate the immune matrix as it is one of the important aspect of healthy state of the living body.

Materials and methods

Studies were carried out for the evaluation of pro-inflammatory cytokines in murine neutrophils followed by expression of T cell-surface markers and corresponding intracellular expression of cytokines related to T helper1 (Th1) and T helper 2 (Th2) activity.

Results

The ethyl acetate fraction (A001/3b) obtained from ethanolic extract of leaves of Labisia pumila at graded doses (in vitro) showed increased expression of TNF-α, IL-6 and IL-12. IL-12 is a strong inducer of Th1 response in activated CD4+ T cells and accordingly T cell studies were carried out (in vivo). These specific studies showed A001/3b to cause marked stimulation of CD4+ T helper cells and related cytokine expression like IL-2 and IFN-gamma (a potent Th1 inducer), thereby, having a predominant Th1 upregulation pathway. This was further validated by suppression of IL-4 and IL-10 expression which are the Th2 pathway cytokines.

Conclusion

This study showed ethyl acetate fraction (A001/3b) of Labisia pumila to have Th1 upregulating activity and suggests its possible usefulness as a therapeutic agent in immune compromised patients.     

Inhibitory effects of Duchesnea chrysantha extract on ovalbumin-induced lung inflammation in a mouse model of asthma

Ethnopharmacological relevance

Duchesnea chrysantha (D. chrysantha) is a herb with anti-oxidative, anti-inflammatory and immune-enhancing properties.

Aim of the study

Asthma is an inflammatory disease of the lungs, and the hallmarks of the disease are increased inflammatory cell infiltration into the airways and poor respiratory function. Although there is the possibility that D. chrysantha may have an inhibitory effect on lung inflammation, the effects of D. chrysantha on asthma have not been fully investigated. In the present study, we investigated the anti-inflammatory activity of D. chrysantha extract (Dc extract) on lung inflammation in a murine model of ovalbumin-induced asthma.

Materials and methods

Dc extract was obtained from dried and powdered whole plants of D. chrysantha using 80% ethanol. BALB/c mice induced by ovalbumin sensitization and nebulization were used as a mouse model of asthma. RT-PCR and ELISA were performed to measure mRNA and protein expression of cytokines. We examined the effects of Dc extract on leukocyte infiltration and mucus secretion using periodic acid-Schiff staining as well as hematoxylin and eosin staining.

Results

Dc extract significantly inhibited leukocytosis and eosinophilia in the bronchoalveolar lavage (BAL) fluid (p < 0.01). Dc extract significantly reduced the elevated infiltration of inflammatory cells (p < 0.05) and inhibited the increased mucus secretion, despite the absence of significant value. Although Dc extract weakly inhibited the mRNA expression of IL-4, IL-5, IL-13, and eotaxin, it strongly inhibited the protein expression of IL-5 (p < 0.05) and eotaxin (p < 0.01) in BAL fluid. Ovalbumin-specific IgE levels in the serum and BAL fluid were blocked by Dc extract (p < 0.05).

Conclusions

These results suggest the possibility that Dc extract can exert suppressive effects on asthma and may provide evidence that Dc extract is a useful agent for the treatment of allergic airway disease.     

Production of Th1- and Th2-dependent cytokines induced by the Chinese medicine herb, Rhodiola algida, on human peripheral blood monocytes

Ethnopharmacological relevance

Rhodiola algida, an herb ingredient used in Chinese medicine, has been clinically proven to be effective in enhancing human immune responses.

Aim of study

This study attempted to identify the potential immunomodulatory effect of Rhodiola algida extract in human immune system in vitro, and to examine its underlying molecular effects.

Materials and methods

Firstly, the bioactive marker compound salidroside was used for standardization of Rhodiola algida extract by reversed-phase HPLC. Secondly, the regulation of human immune responses was investigated in human peripheral blood monocytes. A series of cytokines known to play important roles in the human immune responses were examined.

Results

The current study provided quantitative assay for the marker compound, salidroside, in the Rhodiola algida extract for ensuring the quality consistency of Rhodiola algida used in the following experiments. Biological assay indicated that Rhodiola algida stimulates human peripheral blood lymphocytes and its underlying immunomodulatory effects probably through its regulation of IL-2 in Th1 cells and IL-4, IL-6, IL-10 in Th2 cells.

Conclusion

The findings may enable us to further explain the pharmacological properties in Chinese medicine and make Rhodiola algida a very promising immunomodulating agent.     

Ethanol extracts of Saururus chinensis suppress ovalbumin-sensitization airway inflammation

Aim of the study

The aerial part of Saururus chinensis has been used in folk medicine to treat several inflammatory diseases in China and Korea. Previously, our group reported that anti-asthmatic activity of an ethanol extract of Saururus chinensis (ESC) might occur, in part, via the inhibition of prostaglandin D₂ (PGD₂) and leukotriene C₄ (LTC₄) production, and degranulation reaction in vitro, as well as through the down-regulation of interleukin (IL)-4 and eotaxin mRNA expression in an in vivo ovalbumin-sensitization animal model. However, the effects of Saururus chinensis on eicosanoid generation, as well as Th2 cytokines and eotaxin production in an in vivo asthma model, have not been fully investigated. Moreover, it has not been determined whether ESC can ameliorate airway inflammation in vivo. In the present study, we investigated the therapeutic activity of Saururus chinensis on ovalbumin (OVA)-sensitized airway inflammation and its major phytochemical compositions.

Materials and methods

Asthma was induced in BALB/c mice by ovalbumin-sensitization and inhalation. ESC (10-100 mg/kg) or dexamethasone (5 mg/kg), a positive control, was administered 7 times orally every 12 h from one day before the first challenge to 1 h before the second challenge. The recruitment of inflammatory cells and hyperplasia of goblet cells were evaluated by H&E and PAS staining. Levels of Th2 cytokines, eotaxin, PGD₂ and LTC₄ were measured to evaluate the anti-inflammatory activity of ESC in OVA-sensitized mice. Contents of major components were analyzed by HPLC using a reversed-phase C18 column.

Results

ESC (10 mg/kg) suppressed allergic airway inflammation by inhibition of the production of IL-4 (P < 0.001), IL-5 (P < 0.05), IL-13 (P < 0.001), eotaxin (P < 0.001), PGE₂ (P < 0.001), LTC₄ (P < 0.001) in lung extract and IgE level (P < 0.001) in the serum. In addition, ESC (50 mg/kg) reduced the infiltration of inflammatory cells and hyperplasia of goblet cells in the lung tissues. The anti-inflammatory effect of ESC was comparable to that of the positive control drug, dexamethasone. Its major phytochemical composition includes manassantin A, B and sauchinone.

Conclusions

These results suggest that ESC decreased inflammation and mucus secretion in the OVA-induced bronchial asthma model, and its anti-asthmatic activity may occur in part via the inhibition of Th2 cytokines and eotaxin protein expression, as well as through prostaglandin E₂ (PGE₂) and leukotriene C₄ (LTC₄) generation. This effects may be attributed particularly to the presence of manassantin A, B and sauchinone major component evidenced by a HPLC analysis.     

Inonotus obliquus extracts suppress antigen-specific IgE production through the modulation of Th1/Th2 cytokines in ovalbumin-sensitized mice

Ethnopharmacological relevance

Chaga mushroom (Inonotus obliquus, IO) has been used as a folk remedy for cancer, digestive system diseases, and other illnesses in Russia and Eastern Europe.

Aim of the study

In the present study, we investigated the immunomodulating effects of IO through in vivo and ex vivo studies.

Materials and methods

Serum immunoglobulins (IgE, IgG₁, and IgG_2a) and cytokines (interleukin (IL)-4, interferon (IFN)-γ, and IL-2) were measured in concanavalin A (ConA)-stimulated splenocytes and CD4⁺ T cells. The nitric oxide (NO) secretion of lipopolysaccharide (LPS)-stimulated peritoneal macrophages was also measured after oral administration of 50, 100, or 200 mg kg⁻¹ d⁻¹ IO hot water extract (IOE) to ovalbumin (OVA)-sensitized BALB/c mice.

Results

We found that the OVA-induced increase in serum IgE and IgG_2a was significantly suppressed when IOE was orally administered after the second immunization with OVA. ConA stimulation in spleen cells isolated from OVA-sensitized mice treated with 100 mg kg⁻¹ IOE resulted in a 25.2% decrease in IL-4 production and a 102.4% increase in IFN-γ, compared to the controls. Moreover, IL-4, IFN-γ, and IL-2 were significantly reduced after ConA stimulation in isolated CD4⁺T cells. We also determined that IOE inhibits the secretion of NO from LPS-stimulated peritoneal macrophages ex vivo.

Conclusions

We suggest that IO modulates immune responses through secretion of Th1/Th2 cytokines in immune cells and regulates antigen-specific antibody production.     

Preventive effects of skullcap (Scutellaria baicalensis) extract in a mouse model of food allergy

Ethnopharmacological relevance

Food allergy, which accompanies acute symptoms such as pruritus, vomiting, diarrhea, and lethal anaphylactic shock is an increasing clinical problem. Skullcap (Scutellaria baicalensis Georgi) has been widely used as a traditional herbal medicine to treat inflammation, cancer, and allergy, but its effects in treating food allergy are not yet known.

Materials and methods

To examine the effect of skullcap on food allergy, female BALB/c mice were sensitized with 20 μg OVA and 2 mg alum by intraperitoneal injection on day 0. From day 17, mice were orally challenged with OVA (50 mg) in saline every 3 days, for a total of six times. To investigate the preventive effect, skullcap (25 mg/kg) was orally administered every day from day 17 to 34.

Results

Food allergy symptoms were evaluated by the criteria for diarrhea, anaphylactic response, and rectal temperature. Severe symptoms of food allergy were observed in the sham group (diarrhea, 3 points; anaphylactic response, 2.6 points; rectal temperature, −8.36 °C. In contrast, the skullcap treatment group had a significantly suppressed OVA-induced anaphylactic response (1.3 points) and rectal temperature (−4.76 °C). Moreover, both OVA-specific IgE, Th17 cytokine (IL-17), and Th2-related cytokines (IL-4, IL-5, IL-10, and IL-13), which increased with food allergy, were significantly inhibited by skullcap treatment.

Conclusion

We demonstrate that the administration of skullcap attenuates OVA-induced food allergy symptoms through regulating systemic immune responses of Th cells. These results indicate that skullcap may be a potential candidate as a preventive agent for food allergy.     

Anti-inflammatory and anti-allergic effects of Agrimonia pilosa Ledeb extract on murine cell lines and OVA-induced airway inflammation

Ethnopharmacological evidence

Agrimonia pilosa Ledeb (Rosaceae, AP) has long been used as a traditional medicine in Korea and other Asian countries to treat various diseases.

Aim of the study

In the present study, the anti-inflammatory and anti-allergic effects of AP extract in in vitro cell lines and in vivo mouse model of inflammation and the molecular mechanisms involved were reported.

Materials and methods

Using Raw 264.7 murine macrophages the effects of methanol extract of AP in lipopolysaccharide (LPS)-induced production of inflammatory mediators were measured. Further IgE-DNP-induced interleukin (IL)-4 production and degranulation in RBL-2H3 rat basophilic cell lines was also estimated. To investigate the anti-asthmatic effect of AP in vivo, airway inflammation in ovalbumin (OVA)-induced mouse model was used.

Results

AP attenuated the production of inflammatory mediators such as NO, PGE₂ and pro-inflammatory cytokines in LPS-induced Raw 264.7 cells. Further, AP inhibited IL-4 production and degranulation in IgE-DNP-induced RBL-2H3 cells. Furthermore, AP attenuated the infiltration of immune cells into lung, cytokines production in broncho-alveolar lavage fluid (BALF) and airway-hyperresponsiveness (AHR) on OVA-induced mouse model of inflammation.

Conclusion

Our results showed that AP attenuated the activation of macrophages, basophils, and inhibited the OVA-induced airway inflammation. The molecular mechanisms leading to AP's potent anti-inflammatory and anti-allergic effects might be through regulation of TRIF-dependent and Syk-PLCγ/AKT signaling pathways, suggesting that AP may provide a valuable therapeutic strategy in treating various inflammatory diseases including asthma.     

Protective effects of Ulmus davidiana var. japonica against OVA-induced murine asthma model via upregulation of heme oxygenase-1

Aim of the study

Traditionally, the stem and root bark of Ulmus davidiana var. japonica (Ulmaceae) are Korean herbal medicines used for anti-inflammatory and anticancer therapy. In this study, we investigated the protective effects of Ulmus davidiana var. japonica ethanolic extract (UD) in a murine asthma model. Furthermore, we determined whether heme oxygenase (HO)-1 is required for the protective activity of UD.

Materials and methods

Airways of ovalbumin (OVA)-sensitized mice exposed to OVA challenge developed eosinophilia, mucus hypersecretion and increased cytokine levels. UD was applied 1 h prior to OVA challenge. Mice were administered UD orally at doses of 100 and 200 mg/kg once daily on days 18–23. Bronchoalveolar lavage fluid (BALF) was collected 48 h after the final OVA challenge. Levels of interleukin (IL)-4 and IL-5 in BALF were measured using enzyme-linked immunosorbent assays (ELISAs). Lung tissue sections 4 μm in thickness were stained with Mayer's hematoxylin and eosin for assessment of cell infiltration and mucus production with PAS (periodic acid shift reagent) staining, in conjunction with ELISA, immunohistochemistry and Western blot analyses for HO-1 protein expression.

Results and conclusion

Orally administered UD significantly inhibited the number of OVA-induced inflammatory cells and IgE production, along with reduced T-helper (Th)2 cytokine levels, such as IL-4 and IL-5, in BALF and lung tissue. In addition, UD induced a marked decrease in OVA-induced reactive oxygen species (ROS), inflammatory cell infiltration and mucus production in lung tissue. These effects were correlated with HO-1 mRNA and protein induction. Our results indicate that UD protects against OVA-induced airway inflammation, at least in part, via HO-1 upregulation.     

Propolis effect on Th1/Th2 cytokines production by acutely stressed mice

Aim of the study

Propolis has gained special attention due to its biological properties, however, little is known about its immunomodulatory effects in stress conditions. The purpose of this study was to investigate propolis effect on Th1/Th2 cytokines production by spleen cells of acutely stressed mice. Serum corticosterone concentration was determined as a stress indicator.

Materials and methods

Male BALB/c mice were submitted to restraint stress and treated with propolis (200 mg/kg) for 3 days. Supernatants of splenocytes cultures were assessed for Th1/Th2 cytokines determination.

Results

Regarding Th1 cytokines production, no alterations were seen in IL-2 production; however, IFN-γ production was inhibited in stressed mice, even when treated with propolis. As to Th2 cytokines, IL-4 was inhibited in stressed mice, but normal levels were seen when these animals were treated with propolis. No significant differences were found in IL-10 production between the experimental groups. Stressed groups (treated or not with propolis) showed higher corticosterone concentrations in comparison to control group.

Conclusions

Data suggest that propolis treatment was not able to counteract the stress-induced immunosuppressive effect on IFN-γ production; however, propolis showed an immunorestorative role, increasing IL-4 production in stressed mice, favoring humoral immune response during stress. Since the exact mechanisms of this natural product on immune system are still unclear, further studies are still required for a better comprehension of propolis use as a therapeutic alternative against the stress-induced negative effects that could lead to the development of various diseases.     

Effects of Korean red ginseng extract on the prevention of atopic dermatitis and its mechanism on early lesions in a murine model

Ethnopharmacological relevance

Korean red ginseng (KRG) has been shown to possess various biological activities including anti-inflammatory properties.

Aim of the study

We aimed to investigate the effects and mechanism of KRG on the prevention of atopic dermatitis (AD) using a mouse model.

Materials and methods

The effect of KRG in trinitrochlorobenzene (TNCB)-treated NC/Nga mice was assessed by measuring ear thickness, transepidermal water loss (TEWL), total serum IgE, histologic changes of lesional skin, mRNA and protein expression of thymic stromal lymphopoietin (TSLP) and tumor necrosis factor (TNF)-α, immunohistochemistry for tissue interleukin (IL)-4, IL-17, and interferon (IFN)-γ.

Results

KRG significantly reduced ear thickness. Oral administration of KRG significantly prevented the increase in TEWL induced by TNCB. The serum IgE level was significantly lower in the KRG group. Histologically, lymphocyte infiltration was markedly decreased by KRG. CD1a positive (CD1a+) cells were diminished by KRG. Immunohistochemically, KRG significantly suppressed the protein expression of TSLP and TNF-α. The mRNA expression of TSLP in the lesions was significantly reduced by KRG. These results demonstrate that oral administration of KRG may inhibit the development of AD-like skin lesions in NC/Nga mice by modifying TSLP, DCs, and at least in part, the Th2 response.

Conclusion

KRG may be a potential therapeutic modality for the prevention of AD.     

Effects of taraxasterol on ovalbumin-induced allergic asthma in mice

Ethnopharmacological relevance

Taraxasterol was isolated from the Chinese medicinal herb Taraxacum officinale which has been frequently used as a remedy for inflammatory diseases. In the present study, we determined the in vivo protective effect of taraxasterol on allergic asthma induced by ovalbumin (OVA) in mice.

Materials and methods

Mice were sensitized and challenged with OVA, and were orally treated daily with taraxasterol at 2.5, 5 and 10 mg/kg from day 23 to 27 after sensitization. The number of inflammatory cells in bronchoalveolar lavage fluid (BALF) was determined. Th2 cytokine interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-13 (IL-13) production in BALF and OVA-specific immunoglobulin E (IgE) production in sera were measured using ELISA. Histological changes in lung tissues were examined using hematoxylin and eosin (H&E) and periodic acid-Schiff staining (PAS). Airway hyperresponsiveness (AHR) to inhaled methacholine was assessed.

Results

Taraxasterol dramatically decreased the total inflammatory cell and main inflammatory cell counts, reduced the production of Th2 cytokine IL-4, IL-5, IL-13 in BALF and OVA-specific IgE in sera, and suppressed AHR in a dose-dependent manner. Histological studies demonstrated that taraxasterol substantially suppressed OVA-induced inflammatory cells infiltration into lung tissues and goblet cell hyperplasia in airways.

Conclusions

This finding suggests that taraxasterol protects against OVA-induced allergic asthma in mice.