Curcumin attenuates ovalbumin-induced airway inflammation by regulating nitric oxide

An Updated Comprehensive Review of Plants and Herbal Compounds with Antiasthmatic Effect

Background

Asthma is a common disease with rising prevalence worldwide, especially in industrialized countries. Current asthma therapy with traditional medicines lacks satisfactory success, hence the patients' search for alternative and complementary treatments for their diseases. Researchers have conducted many studies on plants with antiallergic and antiasthmatic effects in recent decades. Many of these plants are now used in clinics, and searching for their mechanism of action may result in creating new ideas for producing more effective drugs.

Purpose

The goal of this review was to provide a compilation of the findings on plants and their active agents with experimentally confirmed antiasthmatic effects. Study Design and Method. A literature search was conducted from 1986 to November 2023 in Scopus, Springer Link, EMBASE, Science Direct, PubMed, Google Scholar, and Web of Science to identify and report the accumulated knowledge on herbs and their compounds that may be effective in asthma treatment.

Results

The results revealed that 58 plants and 32 herbal extracted compounds had antiasthmatic activity. Also, 32 plants were shown to have anti-inflammatory and antioxidative effects or may act as bronchodilators and potentially have antiasthmatic effects, which must be investigated in future studies.

Conclusion

The ability of herbal medicine to improve asthma symptoms has been confirmed by clinical and preclinical studies, and such compounds may be used as a source for developing new antiasthmatic drugs. Moreover, this review suggests that many bioactive compounds have therapeutic potential against asthma.

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.

Effect of Agmatine on a mouse model of allergic airway inflammation: A comparative study

INTRODUCTION

Asthma is a chronic lung disease that injures and constricts the airways. This study evaluates the effects of agmatine on ovalbumin (OVA)-induced allergic inflammation of the airways.

METHODS

OVA sensitization by intraperitoneal injection was used to induce airway inflammation in mice on days 0 and 7; then the mice were challenged using beclomethasone (150 µg/kg, inhalation), a standard anti-asthmatic drug, from day 14 to day 16. Furthermore, agmatine (200 mg/kg) was intraperitoneally injected on day 0 and then daily for 16 days, followed by OVA challenge. The lung weight ratio, total and differential cell counts, TNF-α, interleukin-5 (IL-5) and IL-13 in bronchoalveolar lavage fluid (BALF), lung nitrite/nitrate (NO), and oxidative parameters were determined. Moreover, histopathological and immunohistochemical staining was employed.

RESULTS

Injection of agmatine (200 mg/kg) for 16 days significantly attenuated inflammation of the airways. The levels of BALF inflammatory cells, TNF-α, IL-5, IL-13, lung NO, and malondialdehyde (MDA), significantly decreased with concomitant elevation of superoxide dismutase (SOD) levels. Histological and immunohistochemical analyses of mast cells paralleled to biochemical improvements.

CONCLUSION

Finally, this study illustrated that agmatine attenuates the allergic inflammation of airways caused by OVA by mitigating cytokines release, NO expression, and oxidative stress.

Aryl Hydrocarbon Receptor in Oxidative Stress as a Double Agent and Its Biological and Therapeutic Significance

The aryl hydrocarbon receptor (AhR) has long been implicated in the induction of a battery of genes involved in the metabolism of xenobiotics and endogenous compounds. AhR is a ligand-activated transcription factor necessary for the launch of transcriptional responses important in health and disease. In past decades, evidence has accumulated that AhR is associated with the cellular response to oxidative stress, and this property of AhR must be taken into account during investigations into a mechanism of action of xenobiotics that is able to activate AhR or that is susceptible to metabolic activation by enzymes encoded by the genes that are under the control of AhR. In this review, we examine various mechanisms by which AhR takes part in the oxidative-stress response, including antioxidant and prooxidant enzymes and cytochrome P450. We also show that AhR, as a participant in the redox balance and as a modulator of redox signals, is being increasingly studied as a target for a new class of therapeutic compounds and as an explanation for the pathogenesis of some disorders.

The Aryl Hydrocarbon Receptor (AHR): A Novel Therapeutic Target for Pulmonary Diseases?

The aryl hydrocarbon receptor (AHR) is a cytoplasmic transcription factor that is well-known for regulating xenobiotic metabolism. Studies in knockout and transgenic mice indicate that the AHR plays a vital role in the development of liver and regulation of reproductive, cardiovascular, hematopoietic, and immune homeostasis. In this focused review on lung diseases associated with acute injury and alveolar development, we reviewed and summarized the current literature on the mechanistic role(s) and therapeutic potential of the AHR in acute lung injury, chronic obstructive pulmonary disease, and bronchopulmonary dysplasia (BPD). Pre-clinical studies indicate that endogenous AHR activation is necessary to protect neonatal and adult lungs against hyperoxia- and cigarette smoke-induced injury. Our goal is to provide insight into the high translational potential of the AHR in the meaningful management of infants and adults with these lung disorders that lack curative therapies.

Active ingredients from Chinese medicine plants as therapeutic strategies for asthma: Overview and challenges

Although considerable advance has been made in diagnosing and treating, asthma is still a serious public health challenge. Traditional Chinese medicine (TCM) is an effective therapy of complementary and alternative medicine. More and more scientific evidences support the use of TCM for asthma treatment, and active ingredients from Chinese medicine plants are becoming a hot issue.

PURPOSE OF REVIEW

To summarize the frontier knowledge on the function and underlying mechanisms of the active ingredients in asthma treatments and provide a fully integrated, reliable reference for exploring innovative treatments for asthma.

METHODS

The cited literature was obtained from the PubMed and CNIK databases (up to September 2020). Experimental studies on the active ingredients of Chinese medicine and their therapeutic mechanisms were identified. The key words used in the literature retrieval were "asthma" and "traditional Chinese medicine" or "Chinese herbal medicine". The literature on the active ingredients was then screened manually.

RESULTS

We summarized the effect of these active ingredients on asthma, primarily including the effect through which these ingredients can regulate the immunologic equilibrium mechanism by acting on a number of signalling pathways, such as Notch, JAK-STAT-MAPK, adiponectin-iNOS-NF-κB, PGD2-CRTH2, PI3K/AKT, Keap1-Nrf2/HO-1, T-bet/Gata-3 and Foxp3-RORγt, thereby regulating the progression of asthma.

CONCLUSION

The active ingredients from Chinese medicine have multilevel effects on asthma by regulating the immunologic equilibrium mechanism or signalling pathways, giving them great clinical value. However, the safety and functional mechanism of these ingredients still must be further determined.

Therapeutic Efficacy of Curcumin Enhanced by Microscale Discoidal Polymeric Particles in a Murine Asthma Model

Curcumin is considered a potential anti-asthmatic agent owing to its anti-inflammatory properties. The objective of the present study was to prepare curcumin-containing poly(lactic-co-glycolic acid)-based microscale discoidal polymeric particles (Cur-PLGA-DPPs) and evaluate their anti-asthmatic properties using a murine asthma model. Cur-PLGA-DPPs were prepared using a top-down fabrication method. The prepared Cur-PLGA-DPPs had a mean particle size of 2.5 ± 0.4 μm and a zeta potential value of −34.6 ± 4.8 mV. Ex vivo biodistribution results showed that the Cur-PLGA-DPPs mainly accumulated in the lungs and liver after intravenous injection. Treatment with Cur-PLGA-DPPs effectively suppressed the infiltration of inflammatory cells in bronchoalveolar lavage fluid, and reduced bronchial wall thickening and goblet-cell hyperplasia compared to those in the phosphate-buffered-saline-treated control group. No significant changes in hematology and blood biochemistry parameters were observed after treatment with Cur-PLGA-DPPs. At equal curcumin concentrations, treatment with Cur-PLGA-DPPs exhibited better therapeutic efficacy than treatment with free curcumin. Our results suggest that the microscale Cur-PLGA-DPPs can be potentially used as a lung-targeted asthma therapy.

Lung injury caused by occupational exposure to particles from the industrial combustion of cashew nut shells: a mice model

Cashew nut shells (CNS) is already used in the energy matrix of some industries. However, it is necessary to know the harmful health effects generated by exposure to pollutants of its combustion, especially in the workers exposed to industrial pollutants. In addition, it is known that the incidence of asthma grows among workers in industries, and due to its previously reported biological effects of anethole, these will also be objects of the present study. We used 64 Balb/C mice, randomly divided into eight groups. Groups were sensitized and challenged with saline or ovalbumin, then subjected to intranasal instillation of 30 µg PM_4.0 (occupational exposure) from the combustion of CNS or saline, and then were subsequently treated with oral anethole 300 mg/kg or 0.1% Tween 80. Our results serve as a starting point for the development of public policies for the prevention of diseases in workers that are exposed to the pollutants coming from industries.

Anti-inflammatory effects of linalool on ovalbumin-induced pulmonary inflammation

Linalool is a natural product present in fruits and aromatic plants with biological activities. Researchers have reported that the inhalation of linalool exerts anti-inflammatory activities. In this study, we examined the therapeutic effects of linalool on airway inflammation and mucus overproduction in mice with allergic asthma. Oral administration of linalool significantly inhibited the levels of eosinophil numbers, Th2 cytokines and immunoglobulin E (IgE) caused by ovalbumin (OVA) exposure. Linalool exerted preventive effects against the influx of inflammatory cells and mucus hypersecretion in the lung tissues. Linalool also dose-dependently decreased the levels of inducible nitric oxide synthase (iNOS) expression and protein kinase B (AKT) activation in the lung tissues. Linalool effectively downregulated the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) caused by OVA exposure. Furthermore, linalool exerted inhibitory effect on OVA-induced airway hyperresponsiveness (AHR). In the in vitro study, the increased secretion of MCP-1 was attenuated with linalool treatment in lipopolysaccharide (LPS)-stimulated H292 airway epithelial cells. In conclusion, linalool effectively exerts a protective role in OVA-induced airway inflammation and mucus hypersecretion, and its protective effects are closely related to the downregulation of inflammatory mediators and MAPKs/NF-κB signaling.

Combined delivery of curcumin and the heme oxygenase-1 gene using cholesterol-conjugated polyamidoamine for anti-inflammatory therapy in acute lung injury

BACKGROUND

Acute lung injury (ALI) is an inflammatory lung disease with a high mortality rate. In this study, combined delivery of the anti-inflammatory compound curcumin and the heme-oxygenase-1 (HO-1) gene using cholesterol-conjugated polyamidoamine was evaluated in a mouse model as a therapeutic option for ALI.

METHODS

Curcumin was loaded into cholesterol-conjugated polyamidoamine (PamChol) micelles, and curcumin-loaded PamChol (PamChol-Cur) was then complexed with plasmid DNA (pDNA) through charge interactions. The pDNA/PamChol-Cur complex was physically characterized by dynamic light scattering, gel retardation, and heparin competition assay. Gene delivery efficiency was measured by luciferase assay. The HO-1 expression plasmid (pHO-1)/PamChol-Cur complex was administrated into the ALI model via intratracheal injection. The anti-inflammatory effect of the pDNA/PamChol-Cur complex was evaluated by ELISA, immunohistochemistry, and hematoxylin and eosin staining.

RESULTS

The pDNA/PamChol-Cur complex had a size of approximately 120 nm with a positive surface charge. The in vitro plasmid DNA (pDNA) delivery efficiency of the pDNA/PamChol-Cur complex into L2 lung epithelial cells was higher than that of pDNA/PamChol. In addition, the curcumin in the pDNA/PamChol-Cur complex inhibited the nuclear translocation of NF-κB, suggesting an anti-inflammatory effect of curcumin. In the ALI animal model, the pHO-1/PamChol-Cur complex delivered the pHO-1 gene more efficiently than pHO-1/PamChol. In addition, the pHO-1/PamChol-Cur complex showed greater anti-inflammatory effects by reducing anti-inflammatory cytokine levels more than delivery of pHO-1/PamChol or PamChol-Cur only.

CONCLUSION

The pHO-1/PamChol-Cur complex had a higher pHO-1 gene-delivery efficiency and greater anti-inflammatory effects than the pHO-1/PamChol complex or PamChol-Cur. Therefore, the combined delivery of curcumin and pHO-1 using PamChol-Cur may be useful for treatment of ALI.

Intranasal curcumin regulates chronic asthma in mice by modulating NF-ĸB activation and MAPK signaling

BACKGROUND

Curcumin, a natural product found in the plant Curcuma longa, has been reported to have diverse range of molecular targets that influence numerous biochemical and molecular cascades including anti-inflammatory and antioxidant properties.

PURPOSE

The aim of the study was to investigate the therapeutic potential of intranasal curcumin on ovalbumin (OVA)-induced chronic asthma and to elucidate underlying molecular mechanisms.

STUDY DESIGN/METHOD

Mice were sensitized and exposed to 2% OVA aerosol for 2 times in a week for five consecutive weeks to study effect of intranasal curcumin on various MAPK pathway enzymes involved in chronic asthma and its effect on the activation of nuclear factor kB (NF-kB).

RESULTS

Curcumin treatment decreased the ROS level in BALF and nitrite level in blood serum of chronic asthmatic mice. Curcumin treatment had significantly decreased the phosphorylation of JNK, ERK1/2, and p38 and COX-2 expression thereby nuclear factor κB (NF-κB) activation and expression in lung tissues.

CONCLUSION

These results suggest that intranasal curcumin protects against asthma via action on mitogen-activated protein kinase (MAPK)/NF-κB signaling pathways.

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.

Flavocoxid attenuates airway inflammation in ovalbumin-induced mouse asthma model

Asthma is a common airways inflammatory disease. This study provides evidence on the efficacy of flavocoxid against ovalbumin (OVA)-induced allergic airways inflammation in a mouse model of asthma. Airway inflammation was induced by intrapеritonеal injection of 10 mg ovalbumin (OVA) on day zero and day 7 followed by OVA challenge starting from 14th day to 16th day. Beclomethasone; a standard anti-inflammatory agent was selected as a drug in asthma. Flavocoxid (20 mg/kg, i. p.) was administered on day zero till 16th day followed by OVA challenge. At the end of the study, lung weight index, bronchoalveolar lavage fluid (BALF) content of total and differential WBCs, interleukin-13(IL-13), in addition to lung tissue nitrate/nitrite (NO) and oxidative stress biomarkers were measured. Also, histological and immunohistochemical analysis were conducted. Daily i. p. injection of flavocoxid (20 mg/kg) significantly improved airway inflammation. Inflammatory cells in BALF, malondialdehyde (MDA), NO and IL-13 significantly declined with concomitant increase in superoxide dismutase (SOD) activity. Histopathological examination and immunohistochеmical staining of mast cells were correlated with observed biochemical improvements. Collectively, these results demonstrate that flavocoxid mitigates the allergic airway inflammation induced by ovalbumin through attenuation of IL-13, NO expressions and oxidative stress.

Nicorandil alleviates ovalbumin-induced airway inflammation in a mouse model of asthma

Nicorandil is an antianginal drug that has anti-inflammatory property. This study aimed to investigate the effects of nicorandil on allergic asthma induced by ovalbumin (OVA) in mice in comparison with dexamethasone. Mice were sensitized to OVA (on days 0 and 7) and challenged with OVA three times (on days 14, 15 and 16). Nicorandil was given orally for 5 days 1 h before OVA treatment in days of challenge. Progression of asthma was accompanied by significant elevation in the lung/body weight index, LDH, total protein, IL-13 and NF-κB levels besides inflammatory cell counts in BALF; Also pulmonary MDA and NO contents were significantly increased but GSH and SOD levels were decreased. Histopathological alterations in lung tissues were also observed. In contrast, nicorandil treatment significantly alleviated OVA-induced lung injury. In conclusion, our results proposed that nicorandil is equivalent to dexamethasone in ameliorating allergic asthma by restoring oxidant/antioxidant balance and reducing inflammation.

Hypoxia and Mucosal Inflammation

Sites of inflammation are defined by significant changes in metabolic activity. Recent studies have suggested that O2 metabolism and hypoxia play a prominent role in inflammation so-called "inflammatory hypoxia," which results from a combination of recruited inflammatory cells (e.g., neutrophils and monocytes), the local proliferation of multiple cell types, and the activation of multiple O2-consuming enzymes during inflammation. These shifts in energy supply and demand result in localized regions of hypoxia and have revealed the important function off the transcription factor HIF (hypoxia-inducible factor) in the regulation of key target genes that promote inflammatory resolution. Analysis of these pathways has provided multiple opportunities for understanding basic mechanisms of inflammation and has defined new targets for intervention. Here, we review recent work addressing tissue hypoxia and metabolic control of inflammation and immunity.

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.

Curcumin use in pulmonary diseases: State of the art and future perspectives

Curcumin (diferuloylmethane) is a yellow pigment present in the spice turmeric (Curcuma longa). It has been used for centuries in Ayurveda (Indian traditional medicine) for the treatment of several diseases. Over the last several decades, the therapeutic properties of curcumin have slowly been elucidated. It has been shown that curcumin has pleiotropic effects, regulating transcription factors (e.g., NF-kB), cytokines (e.g., IL6, TNF-alpha), adhesion molecules (e.g., ICAM-1), and enzymes (e.g., MMPs) that play a major role in inflammation and cancerogenesis. These effects may be relevant for several pulmonary diseases that are characterized by abnormal inflammatory responses, such as asthma or chronic obstructive pulmonary disease, acute respiratory distress syndrome, pulmonary fibrosis, and acute lung injury. Furthermore, some preliminary evidence suggests that curcumin may have a role in the treatment of lung cancer. The evidence for the use of curcumin in pulmonary disease is still sparse and has mostly been obtained using either in vitro or animal models. The most important issue with the use of curcumin in humans is its poor bioavailability, which makes it necessary to use adjuvants or curcumin nanoparticles or liposomes. The aim of this review is to summarize the available evidence on curcumin's effectiveness in pulmonary diseases, including lung cancer, and to provide our perspective on future research with curcumin so as to improve its pharmacological effects, as well as provide additional evidence of curcumin's efficacy in the treatment of pulmonary diseases.

Porous antioxidant polymer microparticles as therapeutic systems for the airway inflammatory diseases

Inhaling steroidal anti-inflammatory drugs is the most common treatment for airway inflammatory diseases such as asthma. However, frequent steroid administration causes adverse side effects. Therefore, the successful clinical translation of numerous steroidal drugs greatly needs pulmonary drug delivery systems which are formulated from biocompatible and non-immunogenic polymers. We have recently developed a new family of biodegradable polymer, vanillyl alcohol-containing copolyoxalate (PVAX) which is able to scavenge hydrogen peroxide and exert potent antioxidant and anti-inflammatory activity. In this work, we report the therapeutic potential of porous PVAX microparticles which encapsulate dexamethasone (DEX) as a therapeutic system for airway inflammatory diseases. PVAX microparticles themselves reduced oxidative stress and suppressed the expression of pro-inflammatory tumor necrosis factor-alpha and inducible nitric oxide synthase in the lung of ovalbumin-challenged asthmatic mice. However, DEX-loaded porous PVAX microparticles showed significantly enhanced therapeutic effects than PVAX microparticles, suggesting the synergistic effects of PVAX with DEX. In addition, PVAX microparticles showed no inflammatory responses to lung tissues. Given their excellent biocompatibility and intrinsic antioxidant and anti-inflammatory activity, PVAX microparticles hold tremendous potential as therapeutic systems for the treatment of airway inflammatory diseases such as asthma.

Curcumin and Health

Nowadays, there are some molecules that have shown over the years a high capacity to act against relevant pathologies such as cardiovascular disease, neurodegenerative disorders or cancer. This article provides a brief review about the origin, bioavailability and new research on curcumin and synthetized derivatives. It examines the beneficial effects on health, delving into aspects such as cancer, cardiovascular effects, metabolic syndrome, antioxidant capacity, anti-inflammatory properties, and neurological, liver and respiratory disorders. Thanks to all these activities, curcumin is positioned as an interesting nutraceutical. This is the reason why it has been subjected to several modifications in its structure and administration form that have permitted an increase in bioavailability and effectiveness against different diseases, decreasing the mortality and morbidity associated to these pathologies.

Anti-Inflammatory Effect of Rosa rugosa Flower Extract in Lipopolysaccharide-Stimulated RAW264.7 Macrophages

Rosa rugosa Thunb, a deciduous shrub of the genus Rosa, has been widely used to treat stomach aches, diarrhoea, pain, and chronic inflammatory disease in eastern Asia. In recent years, our research team has extensively studied the Rosa rugosa flower extract, and specifically undertook pharmacological experiments which have optimized the extraction process. Our methods have yielded a standard extract enriched in phenolic compounds, named PRE. Herein, we expand our efforts and evaluated the anti-inflammatory activity of PRE on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages. PRE significantly inhibited production of nitric oxide (NO), prostaglandin E₂ (PGE₂), tumor necrosis factor (TNF)-a, interleukin (IL)-6, and interleukin 1β (IL-1β), as well as expression of their synthesizing enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase2 (COX-2). Furthermore, PRE inhibited activity of mitogen-activated protein kinases (MAPK) as well as nuclear factor-kappa B (NF-κB) signaling pathway. Our findings are the first to explain the anti-inflammatory mechanism by PRE in LPS-stimulated macrophages. Given these results, we propose that PRE has therapeutic potential in the prevention of inflammatory disorders.

Intranasal curcumin ameliorates airway inflammation and obstruction by regulating MAPKinase activation (p38, Erk and JNK) and prostaglandin D2 release in murine model of asthma

Asthma, a multifactorial, chronic inflammatory disease encompasses multiple complex pathways releasing number of mediators by activated mast cells, eosinophils and T lymphocytes, leading to its severity. Presently available medications are associated with certain limitations, and hence, it is imperative to search for anti-inflammatory drug preferably targeting signaling cascades involved in inflammation thereby suppressing inflammatory mediators without any side effect. Curcumin, an anti-inflammatory molecule with potent anti-asthmatic potential has been found to suppress asthmatic features by inhibiting airway inflammation and bronchoconstriction if administered through nasal route. The present study provides new insight towards anti-asthmatic potential of intranasal curcumin at lower doses (2.5 and 5.0 mg/kg) in Balb/c mice sensitized and challenged with ovalbumin (OVA) which is effective in inhibiting airway inflammation. These investigations suggest that intranasal curcumin (2.5 and 5.0 mg/kg) regulates airway inflammation and airway obstruction mainly by modulating cytokine levels (IL-4, 5, IFN-ƴ and TNF-α) and sPLA2 activity thereby inhibiting PGD2 release and COX-2 expression. Further, the suppression of p38 MAPK, ERK 42/44 and JNK54/56 activation elucidate the mechanism behind the inhibitory role of intranasal curcumin in asthma progression. Thus, curcumin could be better alternative for the development of nasal formulations and inhalers in near future.

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.

Inhibition of airway inflammation and remodeling by sitagliptin in murine chronic asthma

In this study the role of sitagliptin, dipeptidyl peptidase inhibitor, DPP-4, and dexamethasone in ameliorating inflammation and remodeling of chronic asthma in a mouse model were investigated. Mice sensitized to ovalbumin were chronically challenged with aerosolized antigen for 3days a week continued for 8weeks. During this period animals were treated with sitagliptin or dexamethasone daily. Assessment of inflammatory cell, oxidative markers, total nitrate/nitrite (NOx), interleukin (IL)-13, transforming growth factor-beta1 (TGF-β1) in bronchoalveolar lavage (BAL) and/or lung tissue were done. Also histopathological and immuno-histochemical analysis for lung was carried out. Compared with vehicle alone, treatment with sitagliptin or dexamethasone significantly reduced accumulation of eosinophils and chronic inflammatory cells, subepithelial collagenization, and thickening of the airway epithelium. Also both drug reduced goblet cell hyperplasia, oxidative stress, TGF-β1, IL-13 and epithelial cytoplasmic immunoreactivity for nuclear factor κ-B (NFκ-B). These data indicate that sitagliptin like dexamethasone may play a beneficial role reducing airway inflammation and remodeling in chronic murine model of asthma.

Evaluation of Efficacy of Curcumin as an Add-on therapy in Patients of Bronchial Asthma

BACKGROUND

Bronchial asthma being a chronic inflammatory disease of airways has numerous treatment options none of which have disease modifying properties. Curcumin, a yellow dietary pigment has varied pharmacological activities, prominent among which is an anti-inflammatory activity which may be crucial in bronchial asthma as has been proved by various in vitro and in vivo animal studies.

AIMS

To determine the efficacy and safety of curcumin as an 'add-on' therapy in patients of bronchial asthma.

SETTINGS AND DESIGN

This study was conducted on 77 patients of mild to moderate Bronchial asthma who had a documented positive bronchodilator reversibility test with ≥15% improvement in forced expiratory volume one second (FEV1).

MATERIALS AND METHODS

Seventy seven patients were recruited for the study and randomized into either of the two groups, but 17 patients were lost to follow up. Thus Group A - Receiving standard therapy for bronchial asthma for 30d (n=30) and Group B - Receiving standard therapy for bronchial asthma + Cap Curcumin 500mg BD daily for 30d (n=30). The predefined primary endpoints were clinical assessments of dyspnoea, wheezing, cough, chest tightness and nocturnal symptoms, change in the pre-bronchodilator FEV1 during the treatment and hematological improvement. The secondary end points were assessed by the change in the post-bronchodilator FEV1, C-reactive protein (CRP) concentration and incidence of adverse events.

STATISTICAL ANALYSIS USED

The data was analysed by SPSS 17.0 software using one-way ANOVA or Paired t-test.

RESULTS AND CONCLUSION

The results showed that curcumin capsules help in improving the airway obstruction which was evident by significant improvement in the mean FEV1 values. There was also significant improvement in the hematological parameters and absence of any clinically significant adverse events indicates dependable safety profile of curcumin capsules, though there was no apparent clinical efficacy. Therefore, it is concluded that curcumin is effective and safe as an add-on therapy for the treatment of bronchial asthma.

Trypanocidal activity of free and nanoencapsulated curcumin on Trypanosoma evansi

This study aimed to evaluate in vitro and in vivo trypanocidal activity of free and nanoencapsulated curcumin against Trypanosoma evansi. In vitro efficacy of free curcumin (CURC) and curcumin-loaded in lipid-core nanocapsules (C-LNCs) was evaluated to verify their lethal effect on T. evansi. To perform the in vivo tests, T. evansi-infected animals were treated with CURC (10 and 100 mg kg(-1), intraperitoneally [i.p.]) and C-LNCs (10 mg kg(-1), i.p.) during 6 days, with the results showing that these treatments significantly attenuated the parasitaemia. Infected untreated rats showed protein peroxidation and an increase of nitrites/nitrates, whereas animals treated with curcumin showed a reduction on these variables. As a result, the activity of antioxidant enzymes (superoxide dismutase and catalase) differs between groups (P<0.05). Infected animals and treated with CURC exhibited a reduction in the levels of alanine aminotransferase and creatinine, when compared with the positive control group. The use of curcumin in vitro resulted in a better parasitaemia control, an antioxidant activity and a protective effect on liver and kidney functions of T. evansi-infected adult male Wistar rats.

Siegesbeckia glabrescens attenuates allergic airway inflammation in LPS-stimulated RAW 264.7 cells and OVA induced asthma murine model

Siegesbeckia glabrescens (SG) is a plant growing in Korea that is used as a traditional medicine for various inflammatory diseases. In this study, we investigated the protective effects of SG extract on allergic asthma in an ovalbumin (OVA)-induced asthma murine model and lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Female BALB/c mice were sensitized by intraperitoneal injection of OVA on days 0 and 14 and then challenged with OVA from days 21 to 23. SG (30mg/kg) was administered by oral gavage 1h before the OVA challenge. LPS-stimulated RAW264.7 cells were evaluated to determine their levels of nitric oxide (NO). The SG significantly reduced the number of inflammatory cells in bronchoalveolar lavage (BAL) fluid and also reduced IL-4, IL-5, IL-13, eotaxin and immunoglobulin E in OVA-sensitized/challenged mice. SG also effectively reduced airway inflammation and mucus overproduction in lung tissue in addition to decreasing the expression of iNOS and COX-2. In LPS-stimulated RAW264.7 cells, SG treatment significantly reduced the levels of NO. These findings indicate that SG effectively suppressed inflammatory responses, and its effects appear to be related to reduction in iNOS and COX-2 expression. Therefore, we suggest that SG may have potential use as a therapeutic agent for inflammatory diseases such as allergic asthma.

The role of AhR in autoimmune regulation and its potential as a therapeutic target against CD4 T cell mediated inflammatory disorder

AhR has recently emerged as a critical physiological regulator of immune responses affecting both innate and adaptive systems. Since the AhR signaling pathway represents an important link between environmental stimulators and immune-mediated inflammatory disorder, it has become the object of great interest among researchers recently. The current review discusses new insights into the mechanisms of action of a select group of inflammatory autoimmune diseases and the ligand-activated AhR signaling pathway. Representative ligands of AhR, both exogenous and endogenous, are also reviewed relative to their potential use as tools for understanding the role of AhR and as potential therapeutics for the treatment of various inflammatory autoimmune diseases, with a focus on CD4 helper T cells, which play important roles both in self-immune tolerance and in inflammatory autoimmune diseases. Evidence indicating the potential use of these ligands in regulating inflammation in various diseases is highlighted, and potential mechanisms of action causing immune system effects mediated by AhR signaling are also discussed. The current review will contribute to a better understanding of the role of AhR and its signaling pathway in CD4 helper T cell mediated inflammatory disorder. Considering the established importance of AhR in immune regulation and its potential as a therapeutic target, we also think that both further investigation into the molecular mechanisms of immune regulation that are mediated by the ligand-specific AhR signaling pathway, and integrated research and development of new therapeutic drug candidates targeting the AhR signaling pathway should be pursued urgently.

Increased aryl hydrocarbon receptor expression in patients with allergic rhinitis

BACKGROUND

A predominant Th17 population is a marker of allergic rhinitis (AR). As a ligand-activated transcription factor, the aryl hydrocarbon receptor (AhR) plays a vital role in promoting or inhibiting the development of specific Th cells. However, its role in AR remains undefined.

OBJECTIVE

To analyze the potential role of AhR in the pathogenesis of AR.

METHODS

In total, 30 AR patients and 13 healthy controls were recruited for this study and AR patients had clinical features, as demonstrated by rhinoconjunctivitis quality of life questionnaires, total symptom scores and visual analog scale scores. The expression of AhR, IL-17 and IL-22 and the presence of Th17 cells in peripheral blood mononuclear cells were measured before and after treatment with the nontoxic AhR ligand 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE).

RESULTS

Pretreatment ITE studies revealed that all AR patients had a significant increase in AhR expression compared with controls and AhR expression positively correlated with clinical parameters. After ITE intervention, a severe reduction in the differentiation of Th17 cells and the production of IL-17 and IL-22 was noted in both AR patients and normal subjects. Simultaneously, a dramatic enhancement of AhR expression was also observed in all healthy controls, but not in AR patients.

CONCLUSION

The results suggested that the AhR may be one of the mechanisms underlying the Th17 response during the pathogenesis of AR and AhR levels were closely related to clinical severity in all AR patients. Additionally, ITE may represent a new drug candidate in the treatment of AR.

Effects of maternal exposure to di(2-ethylhexyl)phthalate (DEHP) during pregnancy on susceptibility to neonatal asthma

Di(2-ethylhexyl) phthalate (DEHP) is used as a plasticizer and is widely dispersed in the environment. In this study, we investigated the effects of maternal exposure to DEHP during pregnancy on neonatal asthma susceptibility using a murine model of asthma induced by ovalbumin (OVA). Pregnant BALB/c mice received DEHP from gestation day 13 to lactation day 21. Their offspring were sensitized on postnatal days (PNDs) 9 and 15 by intraperitoneal injection of 0.5μg OVA with 200μg aluminum hydroxide. On PNDs 22, 23 and 24, live pups received an airway challenge of OVA for 30min. Offspring from pregnant mice that received DEHP showed reductions in inflammatory cell count, interleukin (IL)-4, IL-13, and eotaxin in their bronchoalveolar lavage fluid and in total immunoglobulin E and OVA-specific IgE in their plasma compared with offspring from pregnant mice that did not receive DEHP treatment. These results were consistent with histological analysis and immunoblotting. Maternal exposure to DEHP reduces airway inflammation and mucus production in offspring, with a decrease in inducible nitric oxide synthase (iNOS) in the lung tissue. This study suggests that maternal exposure to DEHP during pregnancy reduces asthmatic responses induced by OVA challenge in offspring. These effects were considered to be closely related to the suppression of Th2 immune responses and iNOS expression.

Role of the aryl hydrocarbon receptor (AhR) in lung inflammation

Millions of individuals worldwide are afflicted with acute and chronic respiratory diseases, causing temporary and permanent disabilities and even death. Oftentimes, these diseases occur as a result of altered immune responses. The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, acts as a regulator of mucosal barrier function and may influence immune responsiveness in the lungs through changes in gene expression, cell-cell adhesion, mucin production, and cytokine expression. This review updates the basic immunobiology of the AhR signaling pathway with regards to inflammatory lung diseases such as asthma, chronic obstructive pulmonary disease, and silicosis following data in rodent models and humans. Finally, we address the therapeutic potential of targeting the AhR in regulating inflammation during acute and chronic respiratory diseases.

Curcumin: an orally bioavailable blocker of TNF and other pro-inflammatory biomarkers

TNFs are major mediators of inflammation and inflammation-related diseases, hence, the United States Food and Drug Administration (FDA) has approved the use of blockers of the cytokine, TNF-α, for the treatment of osteoarthritis, inflammatory bowel disease, psoriasis and ankylosis. These drugs include the chimeric TNF antibody (infliximab), humanized TNF-α antibody (Humira) and soluble TNF receptor-II (Enbrel) and are associated with a total cumulative market value of more than $20 billion a year. As well as being expensive ($15 000-20 000 per person per year), these drugs have to be injected and have enough adverse effects to be given a black label warning by the FDA. In the current report, we describe an alternative, curcumin (diferuloylmethane), a component of turmeric (Curcuma longa) that is very inexpensive, orally bioavailable and highly safe in humans, yet can block TNF-α action and production in in vitro models, in animal models and in humans. In addition, we provide evidence for curcumin's activities against all of the diseases for which TNF blockers are currently being used. Mechanisms by which curcumin inhibits the production and the cell signalling pathways activated by this cytokine are also discussed. With health-care costs and safety being major issues today, this golden spice may help provide the solution.

LINKED ARTICLES

This article is part of a themed section on Emerging Therapeutic Aspects in Oncology. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.169.issue-8.

Curcumin inhibits the proliferation of airway smooth muscle cells in vitro and in vivo

The inhibition of the proliferation of airway smooth muscle cells (ASMCs) is crucial for the prevention and treatment of asthma. Recent studies have revealed some important functions of curcumin; however, its effects on the proliferation of ASMCs in asthma remain unknown. Therefore, in this study, we performed in vitro and in vivo experiments to investigate the effects of curcumin on the proliferation of ASMCs in asthma. The thickness of the airway wall, the airway smooth muscle layer, the number of ASMCs and the expression of extracellular signal-regulated kinase (ERK) were significantly reduced in the curcumin-treated group as compared with the model group. Curcumin inhibited the cell proliferation induced by platelet-derived growth factor (PDGF) and decreased the PDGF-induced phosphorylation of ERK1/2 in the rat ASMCs. Moreover, the disruption of caveolae using methyl-β-cyclodextrin (MβCD) attenuated the anti-proliferative effects of curcumin in the ASMCs, which suggests that caveolin is involved in this process. Curcumin upregulated the mRNA and protein expression of caveolin-1. The data presented in this study demonstrate that the proliferation of ASMCs is inhibited by curcumin in vitro and in vivo; curcumin exerts these effects by upregulating the expression of caveolin-1 and blocking the activation of the ERK pathway.

Antioxidant polymeric nanoparticles as novel therapeutics for airway inflammatory diseases

Successful pulmonary drug delivery requires polymeric drug delivery systems which have excellent biocompatibility and fast degradation rates, when frequent administration is necessary. Here, we report a new family of fully biodegradable hydroxybenzyl alcohol (HBA)-incorporated polyoxalate (HPOX) as a novel therapeutics of airway inflammatory diseases. HPOX was designed to incorporate antioxidant and anti-inflammatory HBA and peroxalate ester linkages capable of reacting with hydrogen peroxide (H2O2) in its backbone. HPOX nanoparticles exhibited highly potent antioxidant and anti-inflammatory effects by scavenging H2O2, reducing the generation of intracellular oxidative stress and suppressing the expression of pro-inflammatory mediators such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and interleukin (IL)-1β in stimulated macrophages. The potential of HPOX nanoparticles as an anti-asthmatic agent was evaluated using a murine model of asthma. Intratracheal administration of HPOX nanoparticles remarkably reduced the recruitment of inflammatory cells and expression of pro-inflammatory mediators such as IL-4 and iNOS. Based on their excellent antioxidant, anti-inflammatory and anti-asthmatic activities, we believe that HPOX nanoparticles have great potential as therapeutics and drug carriers for the treatment of airway inflammatory diseases such as asthma.

EBM84 attenuates airway inflammation and mucus hypersecretion in an ovalbumin-induced murine model of asthma

EBM84 is a traditional herbal medicine and a combination of extracts obtained from Pinellia ternata and Zingiber officinale. It is traditionally used to treat vomiting, nausea, sputum and gastrointestinal disorders, and functions is an effective expectorant. In this study, we evaluated the protective effects of EBM84 on asthmatic responses, particularly mucus hypersecretion in an ovalbumin (OVA)-induced murine model of asthma. We also analyzed EBM84 composition using high performance liquid chromatography. Animals were sensitized on days 0 and 14 via intraperitoneal injection using 20 µg OVA. On days 21, 22 and 23 after initial sensitization, the mice received an airway challenge with OVA (1% w/v in PBS) for 1 h using an ultrasonic nebulizer (NE-U12). EBM84 was administered by gavage to the mice at doses of 16.9, 33.8 and 67.5 mg/kg once daily from days 18 to 23. EBM84 administration significantly lowered elevated levels of interleukin (IL)-4, IL-13, eotaxin and immunoglobulin (Ig)E in the bronchoalveolar lavage fluid or plasma. Airway inflammation and mucus hypersecretion were attenuated following EBM84 administration. EBM84 also inhibited the overexpression of mucin 5AC (MUC5AC) induced by OVA challenge in lung tissue. This result was consistent with the immunohistochemistry results. Our results indicate that EBM84 effectively inhibited airway inflammation and mucus hypersecretion via the downregulation of T helper 2 (Th2) cytokines, which reduced MUC5AC expression. Therefore, EBM84 has potential as a useful medicine for the treatment of allergic asthma.

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.

Dianthus superbus fructus suppresses airway inflammation by downregulating of inducible nitric oxide synthase in an ovalbumin-induced murine model of asthma

Background

Dianthus superbus has long been used as a herbal medicine in Asia and as an anti-inflammatory agent. In this study, we evaluated the anti-inflammatory effects of Dianthus superbus fructus ethanolic extract (DSE) on Th2-type cytokines, eosinophil infiltration, and other factors in an ovalbumin (OVA)-induced murine asthma model. To study the possible mechanism of the anti-inflammatory effect of DSE, we also evaluated the expression of inducible nitric oxide synthase (iNOS) in the respiratory tract.

Methods

Mice were sensitized on days 0 and 14 by intraperitoneal injection of OVA. On days 21, 22 and 23 after initial sensitization, mice received an airway challenge with OVA for 1 h using an ultrasonic nebulizer. DSE was applied 1 h prior to OVA challenge. Mice were administered DSE orally at doses of 100 mg/kg or 200 mg/kg once daily from day 18 to 23. Bronchoalveolar lavage fluid (BALF) was collected 48 h after the final OVA challenge. Levels of interleukin (IL)-4, IL-13 and eotaxin in BALF were measured using enzyme-linked immunosorbent assays (ELISAs). Lung tissue sections were stained with hematoxylin and eosin for assessment of cell infiltration and mucus production with periodic acid shift staining, in conjunction with ELISA and western blot analyses for iNOS expression.

Results

DSE significantly reduced the levels of IL-4, IL-13, eotaxin, and immunoglobulin (Ig) E, number of inflammatory cells in BALF, and inflammatory cell infiltration and mucus production in the respiratory tract. DSE also attenuated the overexpression of iNOS protein induced by OVA challenge.

Conclusion

Our results suggest that DSE effectively protects against allergic airway inflammation by downregulating of iNOS expression and that DSE has potential as a therapeutic agent for allergic asthma.

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.

Anti-inflammatory effects of curcumin in a murine model of chronic asthma

BACKGROUND

Curcumin, a dietary pigment responsible for the yellow colour of curry, has been used for the treatment of inflammatory diseases and exhibits a variety of pharmacological effects.

METHODS

Forty-two BALB/c mice were divided into six groups: I, II, III, IV, V, and control group. All groups except the controls were sensitised and challenged with ovalbumin. Group I received nebulised saline in challenge period. Mice in groups II, III, IV, and V were administered curcumin at a dose of 10 mg/kg, curcumin 20 mg/kg, dexamethasone 1 mg/kg, and dimethyl sulfoxide 1 mg/kg, respectively, intraperitoneally once a day for the final 5 days of the challenge period. Animals were sacrificed 24 h after the last drug administration and the airway samples were evaluated histologically by light microscopy.

RESULTS

All histological parameters in Group III improved similar to Group IV when compared to Group I. In Group II, only thickness of epithelium was significantly lower compared with regard to Group I. All variables except epithelium thicknesses were found to be significantly better in Group III compared to Group II.

CONCLUSIONS

In our study, we demonstrated that curcumin administration alleviates the pathological changes of chronic asthma. Curcumin might be a promising therapy for asthma in the future.

Sitagliptin exerts anti-inflammatory and anti-allergic effects in ovalbumin-induced murine model of allergic airway disease

Sitagliptin, a new oral glucose lowering medication, is used for treatment of type 2 diabetes mellitus. The anti-inflammatory property of sitagliptin is reported, yet no studies have been done on asthma. In the present study, the effect of sitagliptin on allergic asthma was investigated using ovalbumin (OVA)-induced asthma model in mice. Swiss male albino mice sensitized and challenged to ovalbumin were treated with sitagliptin (8 mg/kg administered orally twice a day). Drug treatment was done on each day from days 16 to 23, 1 h before the challenge on the days of challenge. Sitagliptin treatment markedly decreased inflammatory cell accumulation in bronchoalveolar lavage (BAL) fluid and in the lungs, as revealed by histopathological examination. Furthermore, the levels of interleukin (IL)-13 in BAL fluid, total and OVA specific immunoglobulins (Ig)-E in serum, were significantly reduced as compared to the OVA group. In addition, sitagliptin significantly increased superoxidase dismutase (SOD) and reduced glutathione (GSH) activities with significant decrease in malondialdehyde (MDA) content in the lung. Importantly, sitagliptin decreased mRNA expression of the inflammatory cytokines tumor necrosis factor-α (TNF-α) and transforming growth factor-β(1) (TGF-β(1)) in lung tissues as compared to the OVA group. Moreover, nitric oxide content as well as the mRNA expression of inducible nitric oxide synthase (iNOS) was remarkably decreased by sitagliptin treatment. Sitagliptin attenuates the allergic airway inflammation suggesting that sitagliptin may have applications in the treatment of bronchial asthma.

FICZ, a tryptophan photoproduct, suppresses pulmonary eosinophilia and Th2-type cytokine production in a mouse model of ovalbumin-induced allergic asthma

Most studies about functions of aryl hydrocarbon receptor (AhR) in the pathogenesis of asthma have been carried out with non-physiological industrial by-products such as 2,3,7,8-tetrachlorodibenzo-p-dioxin and benzo(a)pyrene. In the present study, effects of 6-formylindolo[3,2-b]carbazole (FICZ), a tryptophan photoproduct postulated as a candidate physiological ligand of AhR, on the pathogenesis of asthma were examined and then underlying mechanisms of its immumodulatory effects were investigated. FICZ significantly reduced pulmonary eosinophilia and Th2 cytokine expression in the lungs. Flow cytometric analysis of mediastinal lymph nodes showed that IL-4 producing cells decreased in FICZ-treated mice compared with PBS control. Next, effects of FICZ on in vitro Th2 differentiation and expression of the Th2 transcription factor GATA-3 were examined. CD4+ T cells were isolated from the spleen and incubated under the Th2 differentiation conditions. FICZ inhibited both Th2 differentiation and the expression of GATA-3. Finally, activation of STAT6, which is necessary for Th2 differentiation, was inhibited by FICZ.

Effects of curcumin on lung histopathology and fungal burden in a mouse model of chronic asthma and oropharyngeal candidiasis

BACKGROUND AND AIMS

Oropharyngeal candidiasis (OPC) is one of the most common local side effects of current therapy in chronic asthma. New therapeutic options with fewer side effects and reverse chronic changes are needed. Curcumin, as a promising antiinflammatory and antifungal agent, could be a candidate of alternative therapy in asthma. This study aimed to determine the efficacy of orally administrated curcumin on lung histopathology, serum nitric oxide levels and fungal burden in a murine model of asthma and OPC.

METHODS

Thirty five BALB/c mice were divided into five groups: I, II, III, IV (placebo) and V (control). All groups except the control were sensitized and challenged with ovalbumin. OPC model was established after the model of chronic asthma. Lung histology, serum nitric oxide levels and fungal burden were evaluated after 5 days of treatment with curcumin, dexamethasone, curcumin-dexamethasone combination and placebo. Evaluation of lung histology included subepithelial smooth muscle and epithelial thickness and number of goblet and mast cells by using light microscopy.

RESULTS

All histological parameters improved in curcumin group similar to dexamethasone group. Curcumin and dexamethasone-curcumin combination were also as effective as dexamethasone on decreasing nitric oxide levels. Oral fungal burden was significantly lower in curcumin-treated group than dexamethasone.

CONCLUSIONS

In our study we demonstrated that curcumin administration alleviates the pathological changes in asthma and decreases the fungal burden. Curcumin may have a potential effect on treating chronic asthma and decreasing the frequency of the OPC.

Curcumin attenuates allergic airway inflammation and hyper-responsiveness in mice through NF-κB inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Curcumin, a polyphenol compound from Curcuma longa L. has been used for centuries as an anti-inflammatory remedy including asthma. Curcumin has been reported to exert an anti-inflammatory effect, in part, through inhibition of the NF-κB pathway.

AIM OF THE STUDY

The purposes of this study were to determine whether curcumin inhibits NF-κB-dependent transcription in vitro, and test whether treatment with curcumin reduces allergen-induced airway inflammation and hyper-responsiveness in a mouse model of asthma through inhibition of NF-κB pathway.

MATERIALS AND METHODS

The effect of curcumin on NF-κB transcriptional activity was investigated using a cell-based luciferase reporter assay in A549 cells and by measuring inhibitory κBα (IκBα), p65, and p50 levels after exposure of Raw264.7 cells to lipopolysaccharide (LPS). BALB/c mice were sensitized to ovalbumin (OVA) by intraperitoneal injection, and challenged with repeated exposure to aerosolized OVA. The effects of daily administered curcumin (200mg/kg body weight, i.p.) on airway hyper-responsiveness (AHR), inflammatory cell number, and IgE levels in bronchoalveolar lavage (BAL) fluid were analyzed. NF-κB activation in lung tissue was also assessed by Western blot analyses.

RESULTS

Curcumin inhibited NF-κB-dependent transcription in reporter assays in A549 cells with an IC(50) of 21.50±1.25μM. Curcumin stabilized IκBα and inhibited nuclear translocation of p65 and p50 in LPS-activated Raw264.7 cells, and curcumin-treated mice showed reduced nuclear translocation of p65 in lung tissue. Treatment with curcumin significantly attenuated AHR and reduced the numbers of total leukocytes and eosinophils in BAL fluid. Infiltration of inflammatory cells and mucus occlusions in lung tissue were significantly ameliorated by treatment with curcumin, which also markedly decreased the level of IgE in BAL fluid.

CONCLUSION

Curcumin attenuates the development of allergic airway inflammation and hyper-responsiveness, possibly through inhibition of NF-κB activation in the asthmatic lung tissue. Our results indicate that curcumin may attenuate development of asthma by inhibition of NF-κB activation.