Dual-phase response model for bronchial asthma

The chemical profile and pharmacodynamic properties of extracellular Wollea saccata biopolymer

Microalgae organisms are of interest for many biotechnology applications due to the production of a wide range of biologically active compounds. Incubation of Wollea saccata in a large scale afforded a mucilaginous, high molecular weight biopolymer composed of carbohydrate, protein and phenolic compounds. Sugar moiety was rich in hexoses (60%) and 6-deoxyhexoses (31%), while only 9% of pentoses was identified. Methylation analysis revealed about 40 types of methylated sugar derivatives, suggesting a very complex structure of Wollea biopolymer. Pharmacological studies revealed new pharmacodynamic properties of cyanobacteria biopolymer, i.e. antitussive and bronchodilatory. Biopolymer was able to suppress the cough reflex induced by chemical tussigen, but its effect was lower than that of codeine, the strongest antitussive agent. The bronchodilatory effect was similar or higher than the effect of salbutamol, a bronchodilatory drug used in a clinical practice. In pharmacological studies, there were no signs of toxicity or side effects in the animals following administration of Wollea biopolymer.

Structural Elements and Cough Suppressing Activity of Polysaccharides from Zingiber officinale Rhizome

Zingiber officinale is used for the management of fever, bronchial asthma and cough for thousands of years. While the link to a particular indication has been established in human, the active principle of the formulation remains unknown. Herein, we have investigated a water extracted polysaccharides (WEP) containing fraction from its rhizome. Utilizing a traditional aqueous extraction protocol and using chemical, chromatographic and spectroscopic methods a fraction containing a branched glucan and polygalaturonan in a ratio of 59:1 was characterized. This glucan, which has a molecular mass of 36 kDa, is made up of terminal-, (1,4)- and (1,4,6)-linked α-Glcp residues. Oral administration of WEP in doses of 25 and 50 mg/kg body weight significantly inhibited the number of citric acid-induced cough efforts in guinea pigs. It does not alter the specific airway smooth muscle reactivity significantly. Thus, traditional aqueous extraction method provides molecular entities, which induces antitussive activity without addiction.

In vivo antitussive activity of a pectic arabinogalactan isolated from Solanum virginianum L. in Guinea pigs

ETHNOPHARMACOLOGICAL RELEVANCE

Solanum virginianum L. is used for the management of fever, bronchial asthma and cough for thousands of years. While the link to a particular indication has been established in human, the active principle of the formulation remains unknown. Herein, we have investigated a polysaccharide isolated from its leaves.

MATERIALS AND METHODS

Utilizing traditional aqueous extraction protocol and using chemical, chromatographic, spectroscopic and biological methods we have analysed an antitussive pectic arabinogalactan isolated from its leaves.

RESULTS

The water extracted polymer (WEP) is a highly branched arabinogalactan containing, inter alia, (1,3)-, (1,6)- and (1,3,6)-linked β-Galp residues, terminal-, (1,5)- and (1,3,5)-linked units of α-Araf together with (1,2)- and (1,2,4)-linked Rhap. In vivo investigation on the citric-acid induced cough efforts in guinea pigs shows that the antitussive activity of the orally administered pectic arabinogalactan is greater than codeine phosphate. Remarkably, this macromolecule neither altered specific airway smooth muscle reactivity significantly nor it induced considerable change on levels of NO in expiratory flow in guinea pigs.

CONCLUSIONS

Thus, traditional aqueous extraction method provides a molecular entity, which induces antitussive activity without addiction: this could represent an attractive approach in phytotherapeutic management.

Antitussive Activity of the Water-Extracted Carbohydrate Polymer from Terminalia chebula on Citric Acid-Induced Cough

Terminalia chebula, a medicinal plant, is widely used in the management of various diseases. As the water extract of its dried ripe fruit is a frequently used preparation, we decided to look for bioactive polysaccharide in this extract. We demonstrate that the obtained polysaccharide fraction, CP, contained a highly branched arabinogalactan protein having a (1 → 3)-, (1 → 6)- and (1 → 3, 6)-linked β-D-Galp together with (1 → 5)- and (1 → 3)-linked α-L-Araf and nonreducing end units of α-L-Araf. This polymer possesses strong antitussive property. Our results showed that the number of citric acid-induced cough efforts decreased significantly after the oral application of polysaccharide fraction in a dose of 50 mg kg⁻¹ body weight. Its antitussive efficacy was higher than cough suppressive effect of standard drug codeine. Therefore, traditional aqueous extraction method provides a major polysaccharide, which induces a pharmacological effect: this could represent an attractive approach in phytotherapeutic managements.

CRAC ion channels and airway defense reflexes in experimental allergic inflammation

Calcium release-activated calcium channels (CRAC) play unambiguous role in secretory functions of mast cells, T cells, and eosinophils. Less knowledge exists about the role of CRAC, widely distributed in airway smooth muscle (ASM) cells, in airway contractility. The presented study seeks to determine the possible participation of CRAC in ASM-based inflammatory airway disorders in guinea pigs. The acute and long-term administration (14 days) of the CRAC antagonist 3-fluoropyridine-4-carboxylic acid was used to examine the ASM contractility and associated reflexes in the guinea pig model of allergic airway inflammation by the following methods: (i) evaluation of specific airway resistance in vivo; (ii) evaluation of the contractile response of isolated ASM strips in vitro; and (iii) citric acid-induced cough reflex; (iv) measurement of exhaled NO levels (E(NO)). Allergic airway inflammation was induced by repetitive exposure of guinea pigs to ovalbumin (10(-6) M). The CRAC antagonist administered in a single dose to guinea pigs with confirmed allergic inflammation significantly reduced the cough response and the airway resistance, which corresponded with the findings in vitro. Long-term application of the CRAC antagonist had more strongly expressed effects. The results confirm the role of CRAC in the pathophysiology of experimental animal asthma and have a potential meaning for anti-asthma therapy.

Anti-asthmatic effects of phenylpropanoid glycosides from Clerodendron trichotomum leaves and Rumex gmelini herbes in conscious guinea-pigs challenged with aerosolized ovalbumin

Clerodendron trichotomum leaves and Rumex aquatica herbs are used as a folk medicine for the treatment of inflammatory diseases, but their active ingredients are not known until now. We isolated caffeic acid and phenylpropanoid glycosides, 1-O-caffeoyl glycoside and acteoside [β-(3',4'-dihydroxyphenyl) ethyl-O-α-l-rhamnopyranosyl(1→3)-β-d-(4-O-caffeoyl)-glucopyranoside] from their ethylacetate fractions, respectively, and evaluated their anti-asthmatic effects on the aerosolized ovalbumin (OA) challenge in the OA-sensitized guinea-pigs measuring the specific airway resistance (sRaw) during the immediate-phase response (IAR) and late-phase response (LAR), and also measured recruitment of leukocytes and chemical mediators on the bronchoalveolar lavage fluids (BALF) in LAR, as well as histopathological survey. Acteoside and 1-O-caffeoyl glycoside (25mg/kg) significantly (P<0.05) inhibited sRaw by 32.14 and 26.79% in IAR, and by 55.88% and 52.94% in LAR, respectively, whereas caffeic acid (25mg/kg) inhibited sRaw by 30.36% in IAR and 44.12% in LAR, compared to control, but with less effective than dexamethasone, disodium cromoglycate, and salbutamol, respectively. In addition, phenylpropanoid glycosides (25mg/kg) significantly inhibited the recruitments of leukocytes, particularly neutrophils and eosinophils into lung, Furthermore, 1-O-caffeoyl glycoside, acteoside and caffeic acid significantly (P<0.05) inhibited protein content at a dose of 25mg/kg, and histamine content and PLA(2) activity at a dose of 50mg/kg, in BALF. Acteoside had more active than caffeic acid and 1-O-caffeoyl glycoside. However, their anti-asthmatic effects were less than the reference drugs. These results indicated that caffeic acid and its glycosides (25mg/kg) have anti-asthmatic effect as the same manner with dexamethasone and disodium cromoglycate.

Inhibitory effects of diterpene acids from root of Aralia cordata on IgE-mediated asthma in guinea pigs

This study evaluated the anti-asthmatic activities of four diterpene acids isolated from Aralia cordata root that are proposed to be the active ingredients in its traditional use as a treatment for inflammation, overheating, pain and spasm in Korea. The diterpene acids were identified as kaurenoic acid, 7-oxo-sandaracopimaric acid, 17-hydroxy-ent-kaur-15-en-19-oic acid, and hederagenin, by comparing their phytochemical and spectroscopic data with previous reports. The effects of diterpene acids on asthma were evaluated by determining the specific airway resistance (sRaw) during the immediate asthmatic response (IAR) and the late-phase asthmatic response (LAR) in guinea pigs with IgE-mediated asthma. Recruitment of leukocytes and the presence of chemical mediators in bronchoalveolar lavage fluid (BALF) were determined, and histopathological surveys performed. The four diterpene acids dosed at 25 approximately 100 mg/kg had dose-dependently anti-asthmatic effects: 7-oxo-sandaracopimaric acid > 17-hydroxy-ent-kaur-15-en-19-oic acid > kaurenoic acid > hederagenin. 7-oxo-sandaracopimaric acid (25 mg/kg) significantly (p < 0.05) inhibited sRaw by 59.5% in IAR and LAR, and also dose-dependently inhibited recruitment of eosinophils and neutrophils into lung and release of chemical mediators, histamine, and the activity of phospholipase A(2) and eosinophil peroxidase in BALF. 7-Oxo-sandaracopimaric acid had the highest activity among the diterpene acids. But its effect was lower than cromolyn sodium, salbutamol, or dexamethasone in both the IAR and the LAR. These results suggested that C(7)-oxo radical of 7-oxo-sandaracopimaric acid was more active than the C(7)-hydroxy and hydrogen of the other compounds, and showed diterpene acids have anti-asthmatic effects, supporting the traditional application of this herb in treating IgE-mediated asthma.

Anti-asthmatic activity of phenolic compounds from the roots of Gastrodia elata Bl

We previously reported that 4-hydroxy-3-methoxybenzaldehyde has the most potent anti-inflammatory and analgesic activity of eight phenolic compounds obtained from the dried roots of Gastrodiaelata (GE) Blume (Orchidaceae); its activity may be related to inhibition of cyclooxygenase activities and oxidation. In the present study, the effects of nine phenolic compounds from GE on immediate-phase (IAR) and late-phase (LAR) asthmatic responses after aerosolized-ovalbumin (OA) challenge were evaluated by determining the specific airway resistance (sRaw) using a double-chambered plethysmograph in conscious guinea pigs with IgE-mediated asthma. Furthermore, recruitment of leukocytes, histamine release, and eosinophil peroxidase (EPO) and phospholipase A(2) (PLA(2)) activities were determined in bronchoalveolar lavage fluids (BALF) 24h after the antigen challenge. 4-Hydroxy-3-methoxybenzyl alcohol (12.5mg/kg) significantly (p<0.05) inhibited sRaw in IAR and in LAR by 51.97+/-4.96% and 39.93+/-3.46%, respectively, compared to that of the controls. Further, hydroxy-3-methoxybenzyl alcohol significantly (p<0.05) inhibited recruitment of leukocytes in accordance with amelioration of eosinophilia and neutrophilia, histamine (30.66+/-5.20%), EPO activity (21.58+/-2.02%), and specific PLA(2) activity (16.60+/-2.52%) in BALF compared with the control. In addition, bis-(4-hydroxyphenyl) methane, 4-hydroxy-3-methoxybenzoic acid, and 4-hydroxy-3-methoxybenzaldehyde (12.5mg/kg) significantly (p<0.05) inhibited sRaw, while bis-(4-hydroxyphenyl) methane, benzyl alcohol, and 4-hydroxybenzaldehyde at 12.5mg/kg significantly (p<0.05) inhibited leukocytes, histamine, EPO and PLA(2) activities in BALF compared with the controls. The phenolic glycoside, parishin had less activity compared to aglycones, 4-hydroxybenzyl compounds. These results suggest that the C(4) hydroxy and C(3) methoxy radicals in benzyl alcohols and aldehydes play important roles in mediating the anti-asthmatic activities of these compounds.

Possible mechanisms of dose-dependent cough suppressive effect of Althaea officinalis rhamnogalacturonan in guinea pigs test system

The rhamnogalacturonan, isolated from the roots of medicinal plant Althaea officinalis L., showed various biological effects on the citric acid-induced cough reflex and reactivity of airways smooth muscle in vitro and in vivo conditions. It possessed dose-dependent cough suppression effect comparable with opioid agonist codeine. However, reactivity of the airways smooth muscle, measured in vitro as well as in vivo conditions was not significantly affected by rhamnogalacturonan and thus bronchodilatory activity did not participate in the cough suppression effect of polysaccharide tested. Moreover, the cough suppression effect of the polymer was not significantly modified by pretreatment of K(+)(ATP) ion channels with selective antagonist and therefore activation of this type of ion channels is not involved in the mechanism of rhamnogalacturonan cough suppressive ability. On the contrary, pretreatment of animals with selective 5-HT(2) receptors antagonist significantly decreased rhamnogalacturonan antitussive efficacy. From this point of view it seems that the cough suppression effect of the polymer is associated with the serotonergic 5-HT(2) receptor's function.

Continued inhalation of lidocaine suppresses antigen-induced airway hyperreactivity and airway inflammation in ovalbumin-sensitized guinea pigs

It is unclear whether inhaled lidocaine is effective against airway hyperreactivity and inflammation in asthma. The aim of this study was to investigate the effects of inhaled lidocaine on airway hyperreactivity and inflammation. Airway reactivity to inhaled histamine, cellular composition of bronchoalveolar lavage (BAL) fluid, plasma substance P (SP), and isolated lung tissue were evaluated in ovalbumin (OVA)-sensitized guinea pigs 7 days after OVA challenge. The effects of inhaled lidocaine on this model were also evaluated. Treatment with lidocaine was administered in two fashions: as single inhalation or inhalation bid for 7 consecutive days, for comparison with a saline-inhaled control group. Airway hyperreactivity to histamine, increase in number of total cells and increased proportion of eosinophils in BAL fluid, and marked eosinophil infiltration in airway walls were noted even 7 days after OVA challenge in the control group. Plasma SP level was also significantly increased. Although treatment with single lidocaine inhalation did not affect airway hyperreactivity, continued inhalation (bid for 7 days) attenuated airway hyperreactivity. Continued, but not single, inhalation of lidocaine also suppressed infiltration of eosinophils in BAL fluid and in airway walls. In addition, plasma SP levels were significantly reduced by continued but not by single inhalation. It appears possible that lidocaine when inhaled suppresses eosinophilic inflammation of the airway and SP-induced neurogenic inflammation, leading to alleviation of airway hyperreactivity.

Effects of inhaled eotaxin on airway function and inflammatory cell influx in sensitised and non-sensitised guinea pigs

Eotaxin is a chemokine that has high potency and selectivity as a chemoattractant agent for eosinophils, signalling exclusively through the CCR3 receptor. Eotaxin is upregulated in the lungs within 3 h of antigen challenge, levels peak at 6 h in lung tissue and bronchoalveolar (BAL) fluid, and fall within 12 h of exposure. This study aimed to look at the effect(s) of eotaxin inhalation on airway function in guinea pigs, to determine if the expected inflammatory cell (eosinophil) infiltration could induce airway hyperreactivity (AHR) and a bronchoconstrictor response equivalent to the late asthmatic response (LAR) seen after antigen challenge. Animals were sensitised with 100 microg/ml OA with a dose on days 1 and 5. Airway responses to inhaled eotaxin (10 or 20 microg/ml) were determined by whole body plethysmography as the change in specific airway conductance (sGaw). Inhaled histamine (1mM) was used to investigate AHR, and cell influx was determined by BAL. Senitised animals exposed to 10 microg/ml eotaxin did not reveal a bronchoconstrictor response or AHR and cellular infiltration to the lungs was not evident 24 h after exposure. Both sensitised and non-sensitised animals exposed to 20 microg/ml eotaxin however revealed a significant bronchoconstrictor response 6h post-challenge, with reductions in sGaw of -27.0+/-6.6% and -32.3+/-6.8%, respectively. Both groups also displayed a bronchoconstrictor response to inhaled histamine 24h after exposure, indicating AHR, and a significant increase in both total and differential cell counts. Sensitised animals, however, revealed a significant increase in cell influx compared to non-sensitised animals. Nebulised eotaxin can reveal a LAR, AHR to inhaled histamine, and cellular infiltration to the lungs, possibly via the mobilisation of eosinophils from the bone marrow, and their subsequent recruitment to the airways.

Modulation of experimentally-induced cough by stimulation of nasal mucosa in cats and guinea pigs

Stimulation of afferent nerves in upper airways may contribute to the pathogenesis of chronic cough in chronic disorders of nose and/or sinuses. We tested the hypothesis that stimulation of the nasal afferent nerves enhances experimentally-induced cough. Intranasal administration of capsaicin (50 microM, 25 microl) did not evoke cough in anaesthetized cats, but enhanced cough induced by mechanical stimulation of the tracheobronchial mucosa (number of coughs, median [IQR]) (6.5 [5.5-8.5] versus 10 [7-14]; P = 0.028, n = 13). In contrast, intranasal histamine (16 mM, 25 microl) had no effect. Intranasal capsaicin (50 microM, 15 microl) did not evoke cough, but enhanced cough evoked by mechanical stimulation of the tracheobronchial mucosa (1 [1-3] versus 3 [2-4]; P = 0.0037, n = 15) in anaesthetized guinea pigs and cough induced by inhalation of citric acid (0.3M, 2 min) in awake guinea pigs (3 [2-5] versus 5 [3-7], P ? 0.0026, n = 23). We conclude that stimulation of nasal afferent nerves with capsaicin enhances experimentally-induced cough. Our results suggest that afferent inputs from the nose interact with the cough reflex pathways in a manner that enhances cough.

Role of muscarinic acetylcholine receptors in a guinea pig model of asthma

We examined the density of muscarinic acetylcholine receptor (mACh-R) subtypes (M1R, M2R and M3R) in guinea pig lung. The density of M3R in the lung tissue of ovalbumin (OA)-sensitized guinea pigs was higher than that in the control group. However, no difference was observed in the affinity of M3R between the sensitized and the control lungs. No difference was observed in the density and affinity of M1R and M2R in sensitized and control lungs. Pilocarpine, which is an M2R stimulant, increased the density of M3R in the lung tissue and the rate of the increase in sensitized guinea pigs was less than that in the control group. In contrast, methoctranine, which is an M2R antagonist, decreased the density of M3R and the rate ofthis decrease was the same in the sensitized and control groups. These results suggest that, in OA-sensitized guinea pigs, a dysfunction of M2R leads to the abnormal density of M3R.