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Updated: Feb 18, 2026

In vitro Measurements of Tracheal Constriction Using Mice
Published on: June 25, 2012
Relaxant effect of Curcuma longa on rat tracheal smooth muscle and its possible mechanisms
Bahman Emami1,2, Farzaneh Shakeri1,2, Vahideh Ghorani1,2
1a Neurogenic Inflammation Research Centre , Mashhad University of Medical Sciences , Mashhad , Iran.
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.
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