Effects of organic and inorganic Ca(2+)-antagonists on acetylcholine-induced contraction in molluscan (Mytilus edulis) smooth muscle

The Effect of Ocimum basilicum L. and Its Main Ingredients on Respiratory Disorders: An Experimental, Preclinical, and Clinical Review

Ocimum basilicum L. (O. basilicum) and its constituents show anti-inflammatory, immunomodulatory, and antioxidant effects. The plant has been mainly utilized in traditional medicine for the treatment of respiratory disorders. In the present article, effects of O. basilicum and its main constituents on respiratory disorders, assessed by experimental and clinical studies, were reviewed. Relevant studies were searched in PubMed, Science Direct, Medline, and Embase databases using relevant keywords including “Ocimum basilicum,” “basilicums,” “linalool,” “respiratory disease,” “asthma,” “obstructive pulmonary disease,” “bronchodilatory,” “bronchitis,” “lung cancer,” and “pulmonary fibrosis,” and other related keywords.The reviewed articles showed both relieving and preventing effects of the plant and its ingredients on obstructive pulmonary diseases such as chronic obstructive pulmonary disease (COPD), asthma, and other respiratory disorders such as bronchitis, aspergillosis tuberculosis, and lung cancer. The results of the reviewed articles suggest the therapeutic potential of O. basilicum and its constituent, linalool, on respiratory disorders.

Experimental and clinical studies on the effects of Portulaca oleracea L. and its constituents on respiratory, allergic, and immunologic disorders, a review

Various pharmacological effects for Portulaca oleracea were shown in previous studies. Therefore, the effects of P. oleracea and its derivatives on respiratory, allergic, and immunologic diseases according to update experimental and clinical studies are provided in this review article. PubMed/Medline, Scopus, and Google Scholar were searched using appropriate keywords until the end of December 2020. The effects of P. oleracea and its constituents such as quercetin and kaempferol on an animal model of asthma were shown. Portulaca oleracea and its constituents also showed therapeutic effects on chronic obstructive pulmonary disease and chronic bronchitis in both experimental and clinical studies. The possible bronchodilatory effect of P. oleracea and its ingredients was also reported. Portulaca oleracea and its constituents showed the preventive effect on lung cancer and a clinical study showed the effect of P. oleracea on patients with lung adenocarcinoma. In addition, a various constituents of P. oleracea including, quercetin and kaempferol showed therapeutic effects on lung infections. This review indicates the therapeutic effect of P. oleracea and its constituents on various lung and allergic disorders but more clinical studies are required to establish the clinical efficacy of this plant and its constituents on lung and allergic disorders.

Relaxant Effect of Urginea maritima on Tracheal Smooth Muscle Mediated by the Effect on Beta-2 Adrenergic, Muscarinic Receptors and Calcium and Potassium Channels

Urginea maritima (U. maritima) showed anti-inflammatory, antioxidant, antibacterial, diuretic, vasodilatation, and wound-healing effects on fungal infections, cardiac disorders, digestive disorders, rheumatoid disease, and respiratory disorders such as bronchitis, bronchial nosocomial infections, and severe cough. To examine the bronchodilatory effect of U. maritima, the relaxant effect of its extract on rat tracheal smooth muscle (TSM) and its possible mechanism was examined in this study. Male Wistar rats' TSM were divided into eight groups (n = 8 in each group). Four of these groups were TSM tissues, contracted with KCl (60 mM) incubated with atropine, glibenclamide, and indomethacin and nonincubated TSM, while the other four groups were TSM tissues contracted with methacholine (10 μM) for 5 min, incubated with propranolol, chlorpheniramine, and diltiazem and nonincubated TSM. Cumulative concentrations of U. maritima extract (12.5, 25, 50, 100, 20, and 400 μg/ml) were then added to organ bath every 5 min. Theophylline (0.2, 0.4, 0.6, and 0.8 mM) as positive control and saline (1 ml) as negative control were also examined in nonincubated tissues. A concentration-dependent relaxant effect of U. maritima on nonincubated TSM contracted with KCl (60 mM) or methacholine (10 μM) (p < 0.01 and p < 0.001) was observed. The relaxant effects of U. maritima extract in the incubated tissues with glibenclamide, propranolol, diltiazem, atropine, and chlorpheniramine were significantly lower than those in the nonincubated tissues (p < 0.05 to p < 0.001). EC₅₀ values of U. maritima extract in the incubated TSM with glibenclamide, propranolol, diltiazem, and atropine were significantly higher than those in the nonincubated tissues (p < 0.05 for diltiazem-incubated tissues and p < 0.001 for other cases). U. maritima extract displayed considerable relaxant effect on TSM comparable to the effect of theophylline. Beta-2 adrenoceptor stimulation and muscarinic receptor inhibition as well as potassium opening and calcium channels blocking effects are the possible mechanisms for the relaxant effects of the plant.

Differentiation of Tarchonanthus camphoratus L. and Tarchonanthus parvicapitulatus P.P.J. Herman (Asteraceae) using electron microscopy, and comparison of their biological activities

ETHNOPHARMACOLOGICAL RELEVANCE

Tarchonanthus camphoratus L. complex has numerous medicinal uses amongst the sub-Saharan African populace, including treatment for bronchospasm. This study focused on providing scientific rationale for the traditional use of the extracts of T. camphoratus and T. parvicapitulatus. T. camphoratus L. complex has been published under diverse names by various taxonomists. Tarchonanthus parvicapitulatus was one of the newly described taxa, leaving Tarchonanthus camphoratus L. sens. strict. as a homogenous taxon. However, some of the morphological characters used tend to overlap, making it difficult to identify the different taxa.

AIMS

The aim of this study was to evaluate the bronchodilatory, antioxidant and toxicological properties of the leaves of T. camphoratus L. and T. parvicapitulatus. This study also aimed to use scanning electron microscopy (SEM) to assess the differences between T. camphoratus L. and T. parvicapitulatus.

MATERIALS AND METHODS

Thin layer chromatography (TLC) with vanillin as visualizing agent was used to qualitatively compare the phytoconstituents of the plant acetone extracts. The free radical scavenging antioxidant qualitative assay was done by spraying TLC plates with DPPH free radical. The bronchodilatory effects of the aqueous extracts were assessed using pre-contracted guinea pig trachea. The effects of the extracts of T. camphoratus L. and T. parvicapitulatus on superoxide and ATP production was also investigated on isolated human neutrophils. A micromorphology study was done using scanning electron microscopy to study the leaves.

RESULTS

Different compounds were visualized on the TLC plates with more than 40 compounds of intermediate polarity. The TLC plates sprayed with DPPH revealed the presence of 20 and 23 antioxidant compounds for T. camphoratus and T. parvicapitulatus respectively. Upon pre-contraction of the tracheal smooth muscles, the aqueous extracts of T. parvicapitulatus significantly relaxed the trachea while the relaxation observed for T. camphoratus was not significant. All the tested concentrations had a dose dependent inhibitory effect on superoxide production. The crude extract of T. parvicapitulatus at the highest concentration (10 mg/ml) significantly decreased ATP production while a non-significant increase in ATP production was observed for T. camphoratus at the highest concentration (10 mg/ml) when compared with the control. The micromorphology study was useful in revealing the presence of trichomes on the upper leaf surface of the studied taxa.

CONCLUSIONS

The results obtained from this study showed that the studied plant extracts had bronchodilatory effects on contracted guinea pig trachea and could also inhibit the production of free radicals including superoxide anions. To the best of our knowledge, this is the first report on the bronchodilatory activity of T. camphoratus and T. parvicapitulatus. The micromorphological studies were useful in distinguishing between the two species, confirming that T. camphoratus L. and T. parvicapitulatus are different taxa. This study provides evidence to support the traditional use of T. camphoratus and T. parvicapitulatus in managing bronchospasm.

Calcium and potassium channels are involved in curcumin relaxant effect on tracheal smooth muscles

Context: Curcumin, the active component of Curcuma longa L. (Zingiberaceae), exhibits a wide variety of biological activities including vasodilation and anti-inflammation.Objective: The relaxant effect of curcumin in tracheal smooth muscle (TSM) was not examined so far, thus, this study was designed to assess the relaxant effect of curcumin on rat TSM and examine the underlying mechanism(s) responsible for this effect.Materials and methods: TSM was contracted by KCl (60 mM) or methacholine (10 μM), and cumulative concentrations of curcumin (12.5, 25, 50, and 100 mg/mL) or theophylline (0.2, 0.4, 0.6, and 0.8 mM, as positive control) were added to organ bath. The relaxant effect of curcumin was examined in non-incubated or incubated tissues with atropine (1 μM), chlorpheniramine (1 μM), indomethacin (1 μM), and papaverine (100 μM).Results: In non-incubated TSM, curcumin showed significant relaxant effects on KCl-induced contraction in a concentration-dependent manner (p < 0.001 for all concentrations). The relaxant effects of curcumin 12.5, 25, and 50 mg/mL were significantly lower in atropine-incubated tissue compared to non-incubated TSM (p < 0.05 to p < 0.001). A significant difference was observed in EC₅₀ between atropine-incubated (48.10 ± 2.55) and non-incubated (41.65 ± 1.81) tissues (p < 0.05). Theophylline showed a significant relaxant effect on both KCl and methacholine-induced contraction in a concentration-dependent manner (p < 0.001 for all cases).Conclusions: The results indicated a relatively potent relaxant effect of curcumin on TSM, which was less marked than the effect of theophylline. Calcium channel blocking and/or potassium channel opening properties of curcumin may be responsible for TSM relaxation.

The Possible Therapeutic Effects of Some Medicinal Plants for Chronic Cough in Children

The use of plants or their isolated bioactive components for the prevention and treatment of various disorders has been developed. Here, we aim to identify effective medicinal plants for relief of cough and respiratory symptoms in children. The data of this review article were obtained from published articles in scientific databases, including PubMed, Google Scholar, and Scopus, until December 2019. The keywords, including "Zataria multiflora Boiss." OR "Portulaca oleracea L." OR "Ferula assa-foetida L." OR "Nigella sativa L." AND "respiratory symptoms" OR "airway inflammation" OR "smooth muscle relaxant effects," were searched individually or combined. The mentioned medicinal plants decreased total white blood cell (WBC), neutrophils, and eosinophils counts of blood and lung lavage in animal model-induced respiratory disorders. These plants also have protective effects on serum immunoglobulin, antibody titer, eosinophil count, and proinflammatory cytokines. Evidence from the studies indicated that the abovementioned medicinal plants have smooth muscle relaxant properties (bronchodilator effects) via stimulation of β-adrenoceptor or inhibition of muscarinic receptors (in vitro) and also improved the pulmonary function test in clinical settings. These medicinal plants are safe and easy to use. Based on the anti-inflammatory, anti-antispasmodic, and immunomodulatory effects, the clinical benefit may be assumed, therefore considering a place for these medicinal plants in relieve of chronic cough and symptoms of children's allergy, asthma, and common cold.

The contribution of beta-2 adrenergic, muscarinic and histamine (H1) receptors, calcium and potassium channels and cyclooxygenase pathway in the relaxant effect of Allium cepa L. on the tracheal smooth muscle

ETHNOPHARMACOLOGICAL RELEVANCE

There are report regarding therapeutic effects for Allium cepa L. (A. cepa) in Iranian traditional medicine and the plant has showed anti-inflammatory, anti-allergic, anti-hyperglycemic, antioxidant, anti-cancer, anti-hypertension, anti-hypercholesterolemia and anti-asthmatic activities in previous studies.

AIM OF THE STUDY

In this study, the contribution of β2 adrenergic, muscarinic and histamine (H1) receptors, calcium and potassium channels, and cyclooxygenase pathway in the relaxant effect of A. cepa extract on tracheal smooth muscle (TSM) was assessed.

MATERIALS AND METHODS

TSM was contracted by KCl (60 mM) or methacholine (10 μM) for 5 min and cumulative concentrations of A. cepa extract (2, 4, 8, 16, 32 and 64 mg/ml) were added to organ bath every 5 min. Theophylline (0.2, 0.4, 0.6 and 0.8 mM) as positive control, and saline (1 ml) as negative control were also examined in non-incubated tissues. The relaxant effect of A. cepa extract was examined on non-incubated and incubated TSM with propranolol, chlorpheniramine, diltiazem, atropine, glibenclamide and indomethacin.

RESULTS

A. cepa showed concentration-dependent relaxant effects on non-incubated TSM contracted by KCl (60 mM) or methacholine (10 μM), (P < 0.01 to p < 0.001). There was no significant difference in the relaxant effects of A. cepa between non-incubated and incubated tissues with glibenclamide, atropine, chlorpheniramine and indomethacin. The plant extract showed significant lower relaxant effects in incubated TSM with propranolol and diltiazem compared to non-incubated tissues. EC50 values of A. cepa extract in incubated TSM with propranolol and diltiazem were significantly lower than non-incubated tissues (p < 0.001 and p < 0.05, respectively). The relaxant effects of different concentrations of the extract of A. cepa were not significantly different with those of theophylline. The concentrations of A. cepa extract and theophylline were significant correlated with their relaxant effects (p < 0.05 to p < 0.001). In incubated TSM with propranolol and diltiazem, concentration ratio minus one (CR-1) values was positive (2.65 ± 0.63 and 1.28 ± 0.43 respectively).

CONCLUSION

The A. cepa extract showed relatively potent relaxant effect on TSM which was comparable to the effect of theophylline. The results showed that β2-adrenergic stimulatory and/or calcium channel blockade are the possible mechanisms for the relaxant effects of the plant.

Anti-Asthmatic Effects of Portulaca Oleracea and its Constituents, a Review

OBJECTIVES

The medicinal plants are believed to enhance the natural resistance of the body to infections. Some of the main constituents of the plant and derived materials such as, proteins, lectins and polysaccharides have anti-inflammatory effects. Portulaca oleracea (P. oleracea) were used traditionally for dietary, food additive, spice and various medicinal purposes. This review article is focus on the anti-asthmatic effects of P. oleracea and its constituents.

METHODS

Various databases, such as the PubMed, Scopus, and Google Scholar, were searched the keywords including "Portulaca oleracea", "Quercetin", "Anti-inflammatory", "Antioxidant", "Cytokines", "Smooth muscle ", and " Relaxant effects " until the end of Jul 2018.

RESULTS

P. oleracea extracts and its constituents increased IFN-γ, IL-2, IFNγ/IL-4 and IL- 10/IL-4 ratio, but decreased secretion of TNF-α, IL-4 and chemokines in both in vitro and in vivo studies. P. oleracea extracts and quercetin also significantly decreased production of NO, stimulated β-adrenoceptor and/or blocking muscarinic receptors in tracheal smooth muscles. Conclusion: P. oleracea extracts and quercetin showed relatively potent anti-asthmatic effects due to decreased production of NO, inflammatory cytokines and chemokines, reduced oxidant while enhanced antioxidant markers, and also showed potent relaxant effects on tracheal smooth muscles via stimulatory on β-adrenoceptor or/and blocking muscarinic receptors.

Relaxant effect of Curcuma longa on rat tracheal smooth muscle and its possible mechanisms

CONTEXT

Turmeric is a spice obtained from the root of Curcuma longa L. (Zingiberaceae) with anti-aging, anticancer, anti-Alzheimer's disease, antioxidant and other medicinal properties.

OBJECTIVE

The relaxant effect of C. longa on rat tracheal smooth muscle and its possible mechanisms were investigated in this study.

MATERIALS AND METHODS

The relaxant effects of four cumulative concentrations of hydro-ethanol extract of C. longa (6.25, 12.5, 25, 50 mg/mL) were studied on tracheal smooth muscle precontracted by methacholine or KCl in non-incubated or incubated with different substances including propranolol, diltiazem, L-NAME, glibenclamide, atropine, chlorpheniramine, indomethacin and papaverine. The duration of the study was 84 days.

RESULTS

In non-incubated tracheal smooth muscle, the extract of C. longa showed significant concentration-dependent relaxant effects (p < 0.001 for all concentrations on both KCl and methacholine-induced contraction). There was no significant difference in the relaxant effects between C. longa and theophylline in both methacholine and KCl-induced contraction conditions. In tissues incubated with propranolol, diltiazem, L-NAME and glibenclamide on methacholine-induced contraction and in tissues incubated with atropine, chlorpheniramine, indomethacin and papaverine on KCl-induced contraction, the extract also showed significant concentration-dependent relaxant effects (p < 0.001). EC₅₀ values of C. longa between non-incubated (16.22 ± 0.62) and incubated tissues (atropine: 13.03 ± 0.55, chlorpheniramine: 12.94 ± 0.68, indomethacin: 14.80 ± 0.57 and papaverine: 16.16 ± 1.42) were not significantly different.

CONCLUSIONS

Tracheal smooth muscle relaxant effects of C. longa, were comparable to those of theophylline, which could be due to the presence of methylxanthines or its possible interaction with non-adrenergic non-cholinergic nervous system.

A review of the relaxant effect of various medicinal plants on tracheal smooth muscle, their possible mechanism(s) and potency

ETHNOPHARMACOLOGICAL RELEVANCE

The therapeutic effects of the medicinal plants described in the current review on obstructive pulmonary diseases have found mention in ancient Iranian medical texts and in traditional folk medicine. These effects are attributed to their bronchodilatory activity, which relaxes the smooth muscles of the airway. Therefore, in the present review, the relaxant effects of various extracts, fractions and constituents of medicinal plants on tracheal smooth muscle are reviewed in light of their therapeutic effects on obstructive pulmonary diseases.

MATERIALS AND METHODS

The online literature was searched using Medline, PubMed, ScienceDirect, Scopus, Google Scholar, Web of Science and SID (for articles written in Persian). Moreover, local books on ethnopharmacology from 1918 to 2014 were searched with keywords such as tracheal smooth muscle, airway smooth muscle, relaxant effect, bronchodilatory effect and related mechanisms to identify studies on the relaxant effects of medicinal plants on tracheal smooth muscle and the possible mechanism(s) of these effects.

RESULTS

All studied plants showed significant relaxant effects on tracheal smooth muscle, which were similar or superior to the effect of theophylline at the used concentrations. According to the results, most of these plants also showed an inhibitory effect on muscarinic and histamine (H1) receptors, whereas some plants showed more pronounced stimulatory effects on the beta-adrenergic receptor. Some of the studied plants also showed inhibitory effects on calcium and potassium channels.

CONCLUSION

The present article reviewed the relaxant effects of several medicinal plants on tracheal smooth muscle, which were comparable or superior to the effect of theophylline at the studied concentration. The possible mechanisms of the relaxant effects of the studied medicinal plants and a comparison of these effects were also reviewed. This review presents the fractions and constituents of plants with potent relaxant effects on tracheal smooth muscle, which can be used to treat obstructive pulmonary disease.

Contribution of water and lipid soluble substances in the relaxant effects of Tymus vulgaris extract on guinea pig tracheal smooth muscle in vitro

OBJECTIVE

To examine the relaxant effects of hydro-ethanolic, macerated aqueous (MA) and lipidfree macerated aqueous (LFMA) extract of Tymus vulgaris on tracheal chains of guinea pigs.

METHODS

The relaxant effects of five cumulative concentrations of each extract (0.4, 0.8, 1.2, 1.6 and 2.0 g/100 mL) were compared with saline as negative control and five cumulative concentrations of theophylline (0.1, 0.2, 0.4, 0.6 and 0.8 mmol/L) on precontracted tracheal smooth muscle of guinea pig with 60 mmol/L KCl (group 1) and 10 µmol/L methacholine (group 2, n=6 for each group).

RESULTS

In group 1 all concentrations of theophylline, three higher concentrations of hydro-ethanolic, two concentrations of LFMA and last concentration of MA extracts showed significant relaxant effects compared with that of saline (P<0.05 or P<0.01). Two lower concentrations of LFMA and all concentrations of MA except higher one caused contraction compared with saline (P<0.05 or 0.01). In group 2 experiments, all concentrations of theophylline, hydro-ethanolic, MA and LFMA extracts showed significant relaxant effects compared to that of saline (P<0.05 or P<0.01). In both groups, the relaxant effect of all concentrations of hydro-ethanolic extract were significantly higher than most concentrations of others (P<0.05 or P<0.01). The relaxant effect of different concentrations of three extracts were significantly greater in group 2 compared with group 1 experiments (all P<0.01). There were significantly positive correlations between the relaxant effects and concentrations for theophylline and all extracts in both groups (P<0.05 or P<0.01).

CONCLUSION

Hydro-ethanolic extract has a potent weaker relaxant effect for other extracts from Tymus vulgaris on tracheal chains of guinea pigs.

Relaxant effect of Crocus sativus (saffron) on guinea-pig tracheal chains and its possible mechanisms

As indicated in ancient Iranian medical books, Crocus sativus has therapeutic effects on respiratory diseases. The relaxant effect of this plant has been observed also on smooth muscles in previous studies. Therefore, in this study the relaxant effects of aqueous-ethanolic extracts of C. sativus and one of its main constituents, safranal, were examined on guinea-pig tracheal chains. The relaxant effects of four cumulative concentrations of aqueous-ethanolic extract (0.15, 0.3, 0.45, and 0.60 g %) and safranal (0.15, 0.30, 0.45, and 0.60 mL 0.2 mg mL(-1) solution) in comparison with saline, as negative control, and four cumulative concentrations of theophylline (0.15, 0.30, 0.45, and 0.60 mM), as positive control, were examined using guinea-pig precontracted tracheal chains. The tracheal chains had been precontracted by three different methods. Group 1 had been precontracted using 10 microM methacholine. The other two groups had been precontracted using 60 mM KCl at two different conditions: non-incubated tissues (group 2) and tissues incubated with 1 microM propranolol, 1 microM chlorpheniramine and 1 microM atropine (group 3) (for each group, n = 6). In group 1 all concentrations of theophylline, extract and safranal showed significant relaxant effects compared with saline (P < 0.05 to P < 0.001). In group 2 theophylline, extract and safranal showed concentration-dependent relaxant effects also compared with saline (P < 0.05 to P < 0.001 for different concentrations except two low concentrations of safranal). However, in group 3 the extracts of C. sativus showed a weak relaxant effect (P < 0.05 only for the highest concentration). The effects of the last concentration of safranal (0.60 mL 0.2 mg mL(-1) solution) in group 1, and all its concentrations in group 2 were significantly lower than those of theophylline (P < 0.05 to P < 0.001). In addition, the effects of safranal 0.45 and 0.60 mL 0.2 mg mL(-1) solution in groups 1 and 2 were significantly lower than that of C. sativus extract. There were significant correlations between the relaxant effects and concentrations for extract, safranal and theophylline in all experimental groups (P < 0.001 for all cases). These results showed a potent relaxant effect of C. sativus on tracheal chains of guinea-pigs that was comparable to or even higher than that of theophylline at the concentrations used. The results indicated that safranal was, at least in part, responsible for the relaxant effect of C. sativus.

Relaxant effects of Rosa damascena on guinea pig tracheal chains and its possible mechanism(s)

Several therapeutic effects including hypnotic, antispasmodic, treatment of abdominal and chest pain and strengthening the heart have been described for the flowers of Rosa damascena. Therefore in the present study, the relaxant effects of ethanolic extract and essential oils of Rosa damascena on tracheal chains of guinea pigs were examined. The relaxant effects of four cumulative concentrations of ethanolic extract (0.25, 0.5, 0.75, and 1.0g%) and essential oils (0.25, 0.5, 0.75, and 1.0vol.%) in comparison with saline as negative control and four cumulative concentrations of theophylline (0.25, 0.5, 0.75, and 1.0mM) were examined by their relaxant effects on precontracted tracheal chains of guinea pig by 60mM KCl (group 1, n=5) and 10microM methacholine in two different conditions including: non-incubated tissues (group 2, n=8) and incubated tissues with 1microM propranolol and 1microM chlorpheniramine (group 3, n=5). In group 1 experiments two final concentrations of essential oil and theophylline and only final concentration of ethanolic extract showed relaxant effects compared to that of saline (p<0.01-0.001). In group 2 three higher concentrations of ethanolic extract and theophylline and all concentrations of essential oil showed concentration dependent relaxant effects compared to that of saline (p<0.05-0.001). In addition, the effect of 0.25 and 0.5g% of essential oils in group 2 was significantly higher than those of theophylline and ethanolic extract (p<0.01 for all cases). However, in group 3 experiments the extract and essential oil of Rosa damascena did not show any significant relaxant effect. There were significant correlations between the relaxant effects and concentrations for ethanolic extract and essential oil and theophylline in groups 1 and 2. These results showed a potent relaxant effect of Rosa damascena on tracheal chains of guinea pigs that was comparable to that of theophylline at concentrations used.

Relaxant effect ofThymus vulgaris on guinea-pig tracheal chains and its possible mechanism(s)

Thymus vulgaris for the treatment of respiratory diseases is indicated widely, and relaxant effects on smooth muscle have been shown previously. In the present study, the relaxant effects of macerated and aqueous extracts of Thymus vulgaris on tracheal chains of guinea-pigs were examined using cumulative concentrations of macerated and aqueous extracts in comparison with saline (as the negative control) and theophylline (as the positive control). The relaxant effects of four cumulative concentrations of macerated and aqueous extracts (0.25, 0.5, 0.75 and 1.0 g %) in comparison with saline (as the negative control) and four cumulative concentrations of theophylline (0.25, 0.5, 0.75 and 1.0 mm; as the positive control) were examined for their relaxant effects on precontracted tracheal chains of guinea-pig by 60 mm KCl and 10 microm methacholine in two different conditions: non-incubated tissues and incubated tissues with 1 microm propranolol and 1 microm chlorphenamine. There were significant correlations between the relaxant effects and the concentrations for both extracts and theophylline in all experimental groups (p < 0.01 to p < 0.001). These results demonstrated a potent relaxant effect of Thymus vulgaris on guinea-pig tracheal chains that was comparable to theophylline at the concentrations used.

Bronchodilatory effect of Portulaca oleracea in airways of asthmatic patients

Therapeutic effects of Portulaca oleracea for respiratory diseases are indicated in ancient Iranian medical books. The relaxant effect of this plant have also been observed on smooth muscle tissue in previous studies. Therefore, in the present study, the bronchodilatory effect of the boiled extract of Portulaca oleracea in the airway of asthmatic patients was examined. The relaxant effect of the orally administered 0.25 ml/kg of 5% boiled extract in comparison with 3 mg/kg oral theophylline and 200 microg inhaled salbutamol was studied by measuring forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), maximal mid-expiratory flow (MEF(25-75)), and specific airway conductance (sGaw). The FEV1, PEF, MEF(25-75), and sGaw were measured before, administration and repeated 15, 30, 60, 90, and 120 min after administration of the oral extract and theopylline. For inhaled salbutamol measurements were performed 5, 15, 30, and 60 min post-inhalation. Results showed that the boiled extract of Portulaca oleracea caused significant increases in all measured pulmonary function tests (PFTs), (P < 0.05 to P < 0.01). There was no significant difference between the maximum increase in measured PFTs due to the boiled extract and theophylline. However, maximum increase in PEF and MEF(25-75) due to the boiled extract were significantly lower than those of salbutamol (P < 0.05 for both cases). The onset of brochodilatory effect of extract was similar to that of theophylline beginning 60 min, but the effect of extract decline after 120 min after administration. In conclusion, the results of the present study showed that Portulaca oleracea has a relatively potent but transient bronchodilatory effect on asthmatic airways.

Possible mechanism(s) for relaxant effect of aqueous and macerated extracts from Nigella sativa on tracheal chains of guinea pig

BACKGROUND

In previous studies, the relaxant, anticholinergic (functional antagonism) and antihistaminic effects of Nigella sativa have been demonstrated on guinea pig tracheal chains. To elucidate the other mechanisms responsible for the relaxant effect of this plant, its inhibitory effect on the calcium channel was examined in this study.

RESULTS

The inhibitory effects of both concentrations of diltiazem in all three groups of experiments were significantly greater than those of saline (p < 0.01 to P < 0.001). The inhibitory of two larger concentrations of aqueous extracts in group 1 and 2 were significantly greater than those of saline (p < 0.01 to P < 0.001). The effect of two larger concentrations of macerated extract in group 1 and all concentrations of this extract in group 2 were also significantly greater than those of saline (p < 0.01 to P < 0.001). However, the extract of Nigella sativa did not show any inhibitory effect in group 3. There was a significant correlation between inhibitory effect and increasing concentrations for both extracts and diltiazem in groups 1 and 2 (p < 0.05 to p < 0.005).

CONCLUSION

Although the extracts of Nigella sativa showed inhibitory effects on pre-contracted tracheal chains in the presence of both ordinary and calcium free Krebs solution, the absence of inhibitory effects of the extracts on KCl induced contraction of tracheal chains suggest that the calcium channel blocking effect of this plant dose not contribute to the relaxant effect of this plant on the tracheal chains of guinea pigs.

Relaxant effects of different fractions of essential oil fromCarum copticum on guinea pig tracheal chains

In previous studies, the relaxant and anticholinergic (functional antagonism), histamine(H1) inhibitory, and xanthine-like activity effect of Carum copticum have been demonstrated on guinea pig tracheal chains. To investigate the effective component(s) of this plant, responsible for the observed bronchodilatory effect, fractionation of the essential oil from Carum copticum was carried out and the relaxant effects of different fractions were examined in this study. The bronchodilatory effect of different fractions of essential oil from Carum copticum and theophylline in comparison with ethanol was examined by their relaxant effects on precontracted tracheal chains of guinea pig by 60 mM KCl (group 1) and 10 microM methacholine in two different conditions including: non-incubated tissues (group 2) and incubated tissues with 1 microM propranolol and 1 microM chlorpheniramine (group 3). In addition the relaxant effect of carvacrol was also examined on precontracted tracheal chains of guinea pig by 10 microM methacholine (group 4), (for each group, n = 5). In group 1 experiments, only theophylline and fraction 2 showed significant relaxant effect compared to that of ethanol. Fraction 2 and 3 of essential oil from carum copticum showed potent and volume (concentration) dependent relaxant effects comparable to that of theophylline in groups 2 and 3 experiments. The relaxant effects of different volumes of these two fractions were significantly higher than that of ethanol (p < 0.05 to p < 0.002 ). The volumes of fraction 1 showed relatively small relaxant effects in groups 2 and 3 experiments which were not significantly different from that of ethanol. However, the relaxant effect of different volumes of fractions 2 and 3 obtained in group 2 experiments were not significantly different from those of group 3 experiments. The volumes of fraction 4 did not show any relaxant effects. In addition volumes of carvacrol also showed comparable relaxant effect with those of fraction 2 and theophylline which was significantly greater than that of ethanol. These results indicate that the relaxant effect of essential oil from carum copticum is mainly due to its fraction 2 which is presumably carvacrol and to lesser extent due to fraction 3, and their relaxant effects are not due to anticholinergic or beta-adrenegic stimulatory effects.

Inhibitory effect of Carum copticum on histamine (H1) receptors of isolated guinea-pig tracheal chains

In a previous study, the relaxant and anti-cholinergic (functional antagonism) effects of Carum copticum were demonstrated on guinea-pig tracheal chains. To elucidate the other mechanisms responsible for this relaxant effect, the inhibitory effect of this plant on histamine H1 receptors was examined in this study. The anti-histaminic effects of extracts, essential oil, 5 nM chlorpheniramine, and saline were tested by performing the cumulative log concentration-response curves of histamine induced contraction of isolated guinea-pig tracheal chains incubated with three different conditions: 1.4 microM indomethacin (group 1, n = 9); indomethacin, 1 microM propranolol, and 10 nM atropine (group 2, n = 8); and indomethacin and propranolol (group 3, n = 7). The results showed clear rightward shifts in histamine response curves obtained in the presence of extracts, essential oil, and chlorpheniramine in all three sets of experiments compared with the curves obtained in the presence of saline. The effective concentrations of histamine causing 50% of maximum response (EC50) obtained in the presence of extracts, essential oil, and chlorpheniramine in all three sets of experiments were significantly higher than those of saline (P < 0.05- < 0.001) except EC50 of macerated extract in group 1. However, maximum response to histamine obtained in the presence of extracts and essential oil were lower (P = 0.005- < 0.001) except maximum response of essential oil in group 2. In addition, the maximum responses obtained in the presence of extracts in group 2 experiments compared to the other two sets of experiments were improved. Comparison of the slope of histamine-response curves showed parallel shifts of the curves obtained in the presence of all extracts and essential oil in group 2 experiments. The results of this study indicated a competitive antagonism effect of C. copticum at histamine H1 receptors. A beta-adrenergic stimulatory effect of essential oil and an anti-cholinergic property of the plant were also suggested.