Antioxidant and antiasthmatic effects of saucerneol D in a mouse model of airway inflammation

Sesquilignans: Current research and potential prospective

Lignans are widely distributed in nature, primarily found in the xylem and resins of plants, with the constituent units C6-C3, and their dimers are the most common in plants. In recent years, the trimeric sesquilignans have also received increasing attention from scholars. More than 200 derivatives have been isolated and identified from nearly 50 families, most of which are different types (monoepoxy lignans, bisepoxy lignans, benzofuran lignans) connected with simple phenylpropanoids through ether bonds, C-C bonds, and oxygen-containing rings to constitute sesquilignans. Some of them also possess pharmacological properties, including antioxidants, hepatoprotectives, antitumors, anti-inflammatory properties, and other properties. In addition, the chemical structure of sesquilignans is closely related to the pharmacological activity, and chemical modification of methoxylation enhances the pharmacological activity. In contrast, phenolic hydroxyl and hydroxyl glycosides reduce the pharmacological activity. Therefore, the present review aims to summarize the chemical diversity, bioactivities, and constitutive relationships to provide a theoretical basis for the more profound development and utilization of sesquilignans.

Structure-Based Pharmacophore Screening Coupled with QSAR Analysis Identified Potent Natural-Product-Derived IRAK-4 Inhibitors

Interleukin-1 Receptor-Associated Kinase 4 (IRAK-4) has crucial functions in inflammation, innate immunity, and malignancy. Structure-based pharmacophore modeling integrated with validated QSAR analysis was implemented to discover structurally novel IRAK-4 inhibitors from natural products database. The QSAR model combined molecular descriptors with structure-based pharmacophore capable of explaining bioactivity variation of structurally diverse IRAK-4 inhibitors. Manually built pharmacophore model, validated with receiver operating characteristic curve, and selected using the statistically optimum QSAR equation, was applied as a 3D-search query to mine AnalytiCon Discovery database of natural products. Experimental in vitro testing of highest-ranked hits identified uvaretin, saucerneol, and salvianolic acid B as active IRAK-4 inhibitors with IC₅₀ values in low micromolar range.

Saururus chinensis-controlled allergic pulmonary disease through NF-κB/COX-2 and PGE2 pathways

Saururus chinensis is a perennial herb found in the northeastern regions of Asia, including Korea, China, and Japan, and is used in traditional medicine. Studies have identified the four major constituents in Saururus chinensis water extract (LHF618^®) as miquelianin (11.75 ± 0.092 mg/g), rutin (1.20 ± 0.008 mg/g), quercitrin (2.38 ± 0.389 mg/g), and quercetin (0.068 ± 0.017 mg/g). Saururus chinensis can improve the symptoms of ovalbumin- or fine dust-induced allergic pulmonary disease by suppressing the effects of WBCs and neutrophils in BALF and IgE in the serum. Saururus chinensis dose-dependently recovered morphological changes such as mucous hyper secretion (from 2.7 ± 0.46 to 0.6 ± 0.65), pulmonary epithelial cell hyperplasia (from 2.4 ± 0.55 to 0.7 ± 0.67), and inflammatory cell infiltration (from 2.3 ± 0.45 to 0.6 ± 0.43), and effectively controlled cDNA levels and protein levels of IL-13. It inhibited NF-κB translocation and COX-2 protein synthesis and suppressed the expression of PGE₂. Our results show that Saururus chinensis controlled allergic pulmonary disease via the anti-inflammatory pathways, NF-κB/COX-2 and PGE₂. Saururus chinensis may be a promising drug candidate against fine dust-induced allergic pulmonary disease.

Modulatory role of gabapentin against ovalbumin-induced asthma, bronchial and airway inflammation in mice

Allergic asthma is a type of chronic immune-mediated inflammatory lung disorders with constantly increased worldwide prevalence. Gabapentin is an L-type calcium channel blocker used essentially as antiepileptic and recently has been indicated for management of post-operative and neuropathic pains as an anti-inflammatory. The current study was conducted to evaluate the anti-inflammatory and anti-allergic properties of gabapentin in a mouse-model of Ovalbumin-induced allergic asthma. Mice received OVA (10 mg) adsorbed on Al(OH)₃ on days 0 and 7 and were challenged by exposure to nebulized OVA solution (1%) form days 14-16. Asthma induction was associated with significant biochemical, oxidative and inflammatory imbalance. Daily oral gabapentin (50 mg/kg), significantly reduced lung inflammatory cells counts', serum LDH and catalase activities and lung/body weight index. Moreover, gabapentin significantly increased lung GSH concentration and enhanced SOD activity. Lung contents of TNFα, IL-4 and IL-13 significantly declined as well. IL-13; is the major contributor to airway hyper-responsiveness; the charetrestic hallmark of asthma and IL-4; a major chemoattractant cytokine. Lung histopathology significantly improved parallel to the biochemical improvements. In conclusion; Gabapentin's modulatory effect on IL-4, IL-13 and TNFα activities accounts for the observed anti-inflammatory and anti-allergic properties.

The Anti-Inflammatory Effects of Fermented Herbal Roots of Asparagus cochinchinensis in an Ovalbumin-Induced Asthma Model

Introduction: Roots of Asparagus cochinchinensis, which have pharmacologically active ingredients, have received great attention because they show good therapeutic effects for various inflammatory diseases without specific toxicity. This study investigated the anti-asthmatic effects of a butanol extract of Asparagus cochinchinensis roots that had been fermented with Weissella cibaria (BAW) and its possible underlying cholinergic regulation. Methods: Alterations of the anti-asthmatic markers and the molecular response factors were measured in an ovalbumin (OVA)-induced asthma model after treatment with BAW. Results: Treatment with BAW decreased the intracellular reactive oxygen species (ROS) production in lipopolysaccharides (LPS) activated RAW264.7 cells. The results of the animal experiments revealed lower infiltration of inflammatory cells and bronchial thickness, and a significant reduction in the number of macrophages and eosinophils, concentration of OVA-specific IgE, and expression of Th2 cytokines in the OVA + BAW treated group. In addition, a significant recovery of goblet cell hyperplasia, MMP-9 expression, and the VEGF signaling pathway was observed upon airway remodeling in the OVA + BAW treated group. Furthermore, these responses of BAW were linked to recovery of acetylcholine esterase (AChE) activity and muscarinic acetylcholine receptor (mAChR) M3 downstream signaling pathway in epithelial cells, smooth muscle cells, and afferent sensory nerves of OVA + BAW-treated mice. Conclusion: Overall, these findings are the first to provide evidence that the therapeutic effects of BAW can prevent airway inflammation and remodeling through the recovery of cholinergic regulation in structural cells and inflammatory cells of the chronic asthma model.

Dose dependence and durability of the therapeutic effects of Asparagus cochinchinensis fermented extract in an ovalbumin-challenged asthma model

The butanol extract of Asparagus cochinchinensis roots fermented with Weissella cibaria (BAfW) significantly suppressed the inflammatory response induced by lipopolysaccharide (LPS) treatment in RAW264.7 cells. To investigate the dose dependence and durability of BAfW on the anti-asthma effects, alterations in key parameters were measured in ovalbumin (OVA)-challenged Balb/c mice treated with the different doses of BAfW at three different time points. The number of immune cells, OVA-specific IgE level, thickness of respiratory epithelium and mucus score decreased significantly in a dose-dependent manner in response to treatment with 125 to 500 mg/kg BAfW (P<0.05), although the highest level was detected in the 500 mg/kg treated group. Moreover, the decrease in these parameters was maintained from 24 to 48 h in the 500 mg/kg of BAfW treated group. At 72 h, the effects of BAfW on the number of immune cells, OVA-specific IgE level and thickness of respiratory epithelium partially disappeared. Overall, this study provides the first evidence that the anti-asthma effect of BAfW may reach the maximum level in OVA-challenged Balb/c mice treated with 500 mg/kg and that these effects can last for 48 h.

Novel glutathione-containing dry-yeast extracts inhibit eosinophilia and mucus overproduction in a murine model of asthma

BACKGROUND/OBSECTIVE

Airway inflammation by eosinophils, neutrophils and alveolar macrophages is a characteristic feature of asthma that leads to pathological subepithelial thickening and remodeling. Our previous study showed that oxidative stress in airways resulted in eosinophilia and epithelial apoptosis. The current study investigated whether glutathione-containing dry yeast extract (dry-YE) ameliorated eosinophilia, goblet cell hyperplasia and mucus overproduction.

MATERIALS/METHOD

This study employed 2 µg/mL lipopolysaccharide (LPS)- or 20 ng/mL eotaxin-1-exposed human bronchial epithelial cells and ovalbumin (OVA)-challenged mice. Dry-YE employed in this study contained a significant amount of glutathione (140 mg in 100 g dry yeast).

RESULTS

Human bronchial epithelial cell eotaxin-1 and mucin 5AC (MUC5AC) were markedly induced by the endotoxin LPS, which was dose-dependently attenuated by nontoxic dry-YE at 10-50 µg/mL. Moreover, dry-YE inhibited the MUC5AC induction enhanced by eotaxin-1, indicating that eotaxin-1-mediated eosinophilia may prompt the MUC5AC induction. Oral supplementation with 10-100 mg/kg dry-YE inhibited inflammatory cell accumulation in airway subepithelial regions with a reduction of lung tissue level of intracellular adhesion molecule-1. In addition, ≥ 50 mg/kg dry-YE diminished the lung tissue levels of eotaxin-1, eosinophil major basic protein and MUC5AC in OVA-exposed mice. Alcian blue/periodic acid schiff staining revealed that the dry-YE supplementation inhibited goblet cell hyperplasia and mucus overproduction in the trachea and bronchiolar airways of OVA-challenged mice.

CONCLUSIONS

Oxidative stress may be involved in the induction of eotaxin-1 and MUC5AC by endotoxin episode and OVA challenge. Dry-YE effectively ameliorated oxidative stress-responsive epithelial eosinophilia and mucus-secreting goblet cell hyperplasia in cellular and murine models of asthma.

Saponin-enriched extract of Asparagus cochinchinensis alleviates airway inflammation and remodeling in ovalbumin-induced asthma model

Asthma is a chronic inflammatory disease characterized by T-lymphocyte and eosinophil infiltration, mucus overproduction and airway hyper-responsiveness. The present study examined the therapeutic effects and action mechanism of a saponin-enriched extract of Asparagus cochinchinensis (SEAC) on airway inflammation and remodeling in an ovalbumin (OVA)-induced asthma model. To accomplish this, alterations of the nitric oxide (NO) level, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression levels, as well as variations in immune cell numbers, immunoglobulin E (IgE) concentration, histopathological structure and inflammatory cytokine levels were measured in lipopolysaccharide (LPS)-activated RAW264.7 cells or an OVA-induced mouse model of asthma treated with SEAC. The concentration of NO and mRNA levels of COX-2 and iNOS were significantly decreased in the SEAC + LPS-treated RAW264.7 cells compared with the vehicle + LPS-treated RAW264.7 cells. Additionally, in the OVA-induced asthma model, the number of immune cells in the bronchoalveolar lavage fluid, the concentration of OVA-specific IgE, the infiltration of inflammatory cells, the bronchial thickness and the levels of the inflammatory mediators interleukin-4 (IL-4), IL-13 and COX-2 were significantly lower in the OVA + SEAC-treated group compared with the OVA + vehicle-treated group. In addition, a significant reduction in goblet cell hyperplasia, peribronchiolar collagen layer thickness and VEGF expression for airway remodeling was detected in the OVA + SEAC-treated group compared with the OVA + vehicle-treated group. These findings indicate that SEAC is a suppressor of airway inflammation and remodeling, and may therefore be useful as an anti-inflammatory drug for the treatment of asthma.

Herbal Medicines for Asthmatic Inflammation: From Basic Researches to Clinical Applications

Asthma is one of the most common chronic inflammatory disorders, associated with reversible airflow obstruction, airway hyperresponsiveness, and airway remodeling. This disease has a significant impact on individuals, their families, and society. Standardized therapeutics such as inhaled corticosteroid in combination with long acting β2 agonist have been applied for asthma control; however, complementary and alternative medicines, especially herbal medicines, are still widely used all over the world. A growing body of literature suggests that various herbals or related products might be effective in inhibiting asthmatic inflammation. In this review, we summarize recent advances about the mechanistic studies of herbal medicines on allergic airway inflammation in animal models and their potential application into clinic for asthma control.

Anti-inflammatory effects of Saururus chinensis aerial parts in murine macrophages via induction of heme oxygenase-1

Saururus chinensis (Lour.) Baill. is a perennial plant distributed throughout Northeast Asia and its roots have been widely used as a traditional medicine for hepatitis, asthma, pneumonia, and gonorrhea. This study was designed to investigate the anti-inflammatory activity of an extract of S. chinensis of the aerial parts (rather than the root), and the signaling pathway responsible for this effect in lipopolysaccharide-stimulated murine macrophages. The subfraction 4 (SCF4) from the n-hexane layer of the ethanol extract of the aerial parts of S. chinensis exhibited the highest nitrite-inhibitory activity. SCF4 significantly inhibited the production of nitrite and the expression of pro-inflammatory mediators via heme oxygenase-1 upregulation. SCF4 caused significant phosphorylation of p38 MAPK and Akt, which subsequently induced the nuclear translocation of p-p65 nuclear factor-κB and Nrf2. SCF4 also suppressed the phosphorylation of signal transducers and activators of transcription 1 (p-STAT1). The heme oxygenase-1 inhibitor zinc protoporphyrin attenuated the inhibitory effect of SCF4 on lipopolysaccharide-stimulated nitrite production and expression of inflammatory mediators, tumor necrosis factor alpha, and p-STAT1. We identified sauchinone as the active compound in S. chinensis extract and SCF4. Sauchinone was shown to significantly inhibit nitrite production and inflammatory mediators expression via heme oxygenase-1 upregulation. These results suggest that S. chinensis extract, SCF4, and its active compound, sauchinone, could be used as an anti-inflammatory agent.

Saucerneol D inhibits dendritic cell activation by inducing heme oxygenase-1, but not by directly inhibiting toll-like receptor 4 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Saururus chinensis is a medicinal plant used to treat jaundice, pneumonia, edema, fever, and several inflammatory diseases. Saucerneol D (SD), a lignan constituent of this plant, has antioxidant, anti-asthmatic, and anti-inflammatory activities. SD has been previously reported to inhibit the pro-inflammatory responses of RAW264.7 cells and primary mast cells. In this study, we investigated the effect of SD on the functions of dendritic cells (DCs).

MATERIALS AND METHODS

SD was isolated from methanol extract of the roots of S. chinensis. Bone marrow-derived DCs were used as target cells. The effects of SD on the following DC functions were examined: surface molecule expression, cytokine expression, migration, allogenic T cell activation, heme oxygenase-1 expression, and Toll-like receptor 4 signaling.

RESULTS

In lipopolysaccharide (LPS)-treated DCs, SD inhibited the expression of cell surface molecules (MHC I/II, CD40, CD80, and CD86), the production of inflammatory mediators (nitric oxide, IL-12, IL-1β, and TNF-α), and allogenic T cell activation capacity. SD also inhibited DC migration toward MIP-3β by down-regulating CCR7 expression. SD attenuated LPS-induced activation of NF-κB and MAPK signaling in DCs, but did not directly inhibit kinase activities of IRAK1, IRAK4, TAK1, or IKKβ in enzymatic assays. SD did not inhibit LPS binding to myeloid differentiation protein-2, co-receptor of TLR4. SD increased the production of reactive oxygen species, Nrf-2, and heme oxygenase (HO)-1, which degrades the heme to immunosuppressive carbon monoxide and biliverdin, which may underlie the anti-inflammatory effects in SD-treated DCs.

CONCLUSIONS

Taken together, these data suggest that SD suppresses LPS-induced activation of DCs through the induction of HO-1, but not by directly affecting Toll-like receptor 4 signaling.

Some medicinal plants with antiasthmatic potential: a current status

Asthma is a common disease that is rising in prevalence worldwide with the highest prevalence in industrialized countries. Asthma affects about 300 million people worldwide and it has been estimated that a further 100 million will be affected by 2025. Since the ancient times, plants have been exemplary sources of medicine. Current asthma therapy lack satisfactory success due to adverse effect, hence patients are seeking complementary and alternative medicine to treat their asthma. Ayurveda and other Indian literature mention the use of plants in various human ailments. India has about 45,000 plant species and among them several thousand are claimed to possess medicinal properties. Researches conducted in the last few decades on the plants mentioned in ancient literature or used traditionally for asthma have shown antiasthmatic, antihistaminic and antiallergic activity. This review reveals that some plants and their extract have antiasthmatic, antihistaminic, anticholinergic and antiallergic activity.

Attenuation of inflammatory-mediated neurotoxicity by Saururus chinensis extract in LPS-induced BV-2 microglia cells via regulation of NF-κB signaling and anti-oxidant properties

Background

A Saururus chinensis Baill (SC) has been used by Native Americans, early colonists and practitioners of Korean traditional medicine for treating several diseases including cancer, rheumatoid arthritis and edema. The objective of this study was to evaluate the effects of SC extract in lipopolysaccharide (LPS)-stimulated neuroinflammatory responses in BV-2 microglial cells.

Methods

The effects of SC on the LPS–induced neuroinflammatory responses in BV-2 microglial cells were assessed by Western blotting, RT-PCR and immunofluorescence labeling techniques. DPPH and alkyl radical scavenging assay was performed to evaluate the anti-oxidant effects. Comparisons between groups were analyzed using one-way analysis of variance followed by Dunnett’s multiple comparisons test using GraphPad Prism V5.01 software.

Results

Pre-treatment with SC extract (1, 5 and 10 μg/mL) significantly (p < 0.001 at 10 μg/mL) and concentration dependently inhibited LPS-induced production of nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2) and suppressed the inflammatory cytokine levels such as tumor necrosis factor-alpha and interleukin (IL)-6 in BV-2 microglial cells (p < 0.001 at 10 μg/mL). Further, SC suppressed the nuclear factor-kappa B (NF-κB) activation by blocking the degradation of IκB-α. SC also exhibited profound anti-oxidant effects by scavenging 1, 1-diphenyl-2-picrylhydrazyl (DPPH) (IC50: 0.055 mg/mL) and alkyl radicals (IC50: 0.349 mg/mL). High performance liquid chromatography finger printing analysis of SC revealed quercetin (QCT) as one of the major constituents compared with reference standard. QCT also inhibited the excessive release of NO, and inhibited the increased expressional levels of IL-6, iNOS and COX-2 in LPS-stimulated BV-2 cells.

Conclusions

Our results indicated that SC inhibited the LPS-stimulated neuroinflammatory responses in BV-2 microglia via regulation of NF-κB signaling. The antioxidant active constituents of SC might be partly involved in delivering such effects. Based on the traditional claims and our present results SC can be potentially used in treating inflammatory-mediated neurodegenerative diseases.

Administration of mycobacterial Ag85A and IL-17A fusion protein attenuates airway inflammation in a murine model of asthma

Interleukin (IL)-17A contributes to the development of asthma, especially in severe asthma which has characteristic neutrophil infiltration in airways. However, IL-17A-blocking antibody could escalate T helper (Th) 2 cytokines, such as IL-13, IL-4 in murine models. We aimed at determining the effect of mycobacterial Ag85A and IL-17A fusion protein—Ag85A-IL-17A on airway inflammation in a murine model of asthma. IL-17A recombinant protein fused mycobacterial immunodominant antigen Ag85A was constructed, expressed and purified. The fusion protein was then administrated into BALB/c mice and its anti-inflammatory effects in the infiltration of inflammatory cells, Th2/Th17 cytokines in BALF, histopathological changes of lung tissues as well as chemokines in lung tissues were evaluated in the murine model of asthma. We found that administration of mycobacterial Ag85A and IL-17A fusion protein induced IL-17A specific immunoglobulin (Ig)G in sera and significantly decreased IL-17A and IL-6 levels in bronchoalveolar lavage fluid (BALF). Ag85A-IL-17A vaccinated mice also showed marked reduction in the infiltration of inflammatory cells in peribronchiolar region and significant decrease in total cells, eosinophil cells and neutrophil cells in BALF. The increased levels of IL-13 and IL-4 in BALF of ovalbumin-sensitized mice were significantly reduced by the administration of Ag85A-IL-17A. Furthermore, CD3+CD4+IL-13+ splenocytes stimulated with OVA and CXCL1 mRNA, CCL2 mRNA and GATA-3 mRNA expressed in lung tissues were decreased markedly in Ag85A-IL-17A vaccinated group. Our results demonstrate remarkable antiallergic effects of Ag85A-IL-17A in a murine model of asthma and it may have protective effects on allergic asthma.

The effects of Valeriana officinalis L. hydro-alcoholic extract on depression like behavior in ovalbumin sensitized rats

BACKGROUND

Neuroimmune factors have been considered as contributors to the pathogenesis of depression. Beside other therapeutic effects, Valeriana officinalis L., have been suggested to have anti-inflammatory effects. In the present study, the effects of V. officinalis L. hydro alcoholic extract was investigated on depression like behavior in ovalbumin sensitized rats.

MATERIALS AND METHODS

A total of 50 Wistar rats were divided into five groups: Group 1 (control group) received saline instead of Valeriana officinalis L. extract. The animals in group 2 (sensitized) were treated by saline instead of the extract and were sensitized using the ovalbumin. Groups 3-5 (Sent - Ext 50), (Sent - Ext 100) and (Sent - Ext 200) were treated by 50, 100 and 200 mg/kg of V. officinalis L. hydro-alcoholic extract respectively, during the sensitization protocol. Forced swimming test was performed for all groups and immobility time was recorded. Finally, the animals were placed in the open-field apparatus and the crossing number on peripheral and central areas was observed.

RESULTS

The immobility time in the sensitized group was higher than that in the control group (P < 0.01). The animals in Sent-Ext 100 and Sent-Ext 200 groups had lower immobility times in comparison with sensitized group (P < 0.05 and P < 0.01). In the open field test, the crossed number in peripheral by the sensitized group was higher than that of the control one (P < 0.01) while, the animals of Sent-Ext 50, Sent-Ext 100 and Sent-Ext 200 groups had lower crossing number in peripheral compared with the sensitized group (P < 0.05 and P < 0.01 respectively). Furthermore, in the sensitized group, the central crossing number was lower than that of the control group (P < 0.001). In the animals treated by 200 mg/kg of the extract, the central crossing number was higher than that of the sensitized group (P < 0. 05).

CONCLUSIONS

The results of the present study showed that the hydro-alcoholic extract of V. officinalis prevents depression like behavior in ovalbumin sensitized rats. These results support the traditional belief on the about beneficial effects of V. officinalis in the nervous system. Moreover, further investigations are required in order to better understand this protective effect.

A water extract of Samchulkunbi-tang attenuates airway inflammation by inhibiting inos and MMP-9 activities in an ovalbumin-induced murine asthma model

Background

In this study, we investigated the effect of Samchulkunbi-tang water extract (SCTE) in an established mouse model of ovalbumin (OVA)-induced allergic asthma. The effects of SCTE on the production of Th1 and Th2 cytokines, eotaxin, and total and OVA-specific immunoglobulin E, inducible nitric oxide synthase expression, and matrix metalloproteinase-9 activity were measured.

Methods

Mice were sensitized on days 0 and 14 with an intraperitoneal injection of 20 μg ovalbumin (OVA) emulsified in 2 mg aluminum hydroxide in 200 μL PBS buffer. On days 21, 22, and 23, mice received an airway exposure to OVA (1%, w/v, in PBS) for 1 h. SCTE was administered orally to mice at doses of 200 and 400 mg/kg per day from days 18 to 23.

Results

SCTE reduced the number of inflammatory cells, cytokines, and chemokines in bronchoalveolar lavage fluids and iNOS expression and MMP-9 activity in mouse lung tissue. Histological studies using hematoxylin & eosin and periodic acid-schiff staining showed that SCTE substantially inhibited OVA-induced inflammatory cell infiltration in lung tissue and goblet cell hyperplasia in the airway. SCTE also reduced IL-4 and IL-13 expression in concanavalin-A-stimulated splenocytes. These results were similar to those obtained with montelukast as a positive control.

Conclusions

Collectively, these results suggest that SCTE may be an effective oral treatment for allergic airway inflammation by virtue of its anti-inflammatory activity.

Saucerneol D inhibits eicosanoid generation and degranulation through suppression of Syk kinase in mast cells

Previously we reported that saucerneol D (SD), a naturally occurring sesquilignan isolated from Saururus chinensis (S. chinensis) suppressed lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells. The aim of this study was to elucidate whether SD modulates the generation of other inflammatory mediators in activated mast cells. We investigated the effects of SD on cyclooxygenase-2 (COX-2)-dependent prostaglandin D(2) (PGD(2)) and 5-lipoxygenase (5-LO)-dependent leukotriene C(4) (LTC(4)) generations as well as degranulation in cytokine-stimulated mouse bone marrow-derived mast cells (BMMCs). Biochemical analyses of the cytokine-mediated signaling pathways showed that SD suppressed the phosphorylation of Syk kinase and multiple downstream signaling processes including phospholipase Cγ1 (PLCγ1)-mediated intracellular Ca(2+) influx and activation of mitogen-activated protein kinases (MAPKs; including extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH(2)-terminal kinase (JNK) and p38) and the nuclear factor-κB (NF-κB) pathway. Taken together, the present study suggests that SD suppresses eicosanoid generation and degranulation through Syk-dependent pathway in BMMCs.

Tiarellic acid attenuates airway hyperresponsiveness and inflammation in a murine model of allergic asthma

Asthma is a persistent inflammatory disease characterized by airway obstruction and hyperresponsiveness in association with airway inflammation. In the current research, we studied the anti-inflammatory and anti-asthmatic effects of tiarellic acid (TA) isolated from Tiarella polyphylla, based on asthmatic parameters, such as immunoglobulin E (IgE) level, cytokine release, eosinophilia, airway hyperresponsiveness (AHR), reactive oxygen species (ROS) and mucus hypersecretion, in an ovalbumin (OVA)-sensitized/challenged mouse model. TA significantly inhibited increases in IgE, levels of ROS and T helper cytokines, such as interleukin (IL)-4, IL-5, TNF-α, and IL-13, in bronchoalveolar lavage fluid (BALF), and effectively suppressed airway hyperresponsiveness, eosinophilia, and mucus hypersecretion in the asthmatic mouse model. In addition, we found that administration of TA attenuated ovalbumin-induced increases in NF-κB activity in lungs. The efficacy of TA was comparable to that of montelukast, a currently available anti-asthmatic drug. Our results support the utility of TA as a herbal medicine for asthma treatment and may have application in the development of anti-inflammatory and anti-asthmatic drugs.