Wafaa Ahmed Hewedy*
Background: Boswellia serrata (family Burseraceae) has been traditionally used for the treatment of a wide variety of diseases as arthritis, inflammatory bowel diseases, and airway diseases. However, the direct bronchodilator efficacy of Boswellia serrata hasn’t been explored yet.
Objective: We aimed at the present study to evaluate the direct effect of Boswellia serrata extract (BSE) on isolated rat tracheal preparations precontracted with either acetylcholine (ACh) or potassium chloride (KCl).
Method: Tracheal rings were prepared from male Wistar rats (200-250 g). BSE (1-200 μg/ml) was added to tracheal strips precontracted with either ACh or KCl and the response was observed. We also investigated the consequences of epithelial denudation, indomethacin, and N-Nitro-L-arginine on the relaxant effect of BSE as compared to that of the β-adrenoceptor agonist isoprenaline, or the bitter taste receptor (TAS2R) agonist denatonium benzoate. Finally, the possible additive effects of BSE to isoprenaline or denatonium-induced relaxation were evaluated.
Results: By using a set of serial dosing and washout experiments with tracheal rings, results showed that exposure to BSE resulted into a significant and concentration-dependent inhibitory effect on airway smooth muscle contractions precontracted with either ACh or KCl. Epithelial denudation, indomethacin, or N-Nitro-L-arginine had no significant effect on the obtained relaxation. Furthermore, BSE potentiated the relaxant effect of isoprenaline on rat trachea.
Conclusion: BSE exerts a direct concentration-dependent relaxant effect on precontracted tracheal strips. These results could contribute towards validation of the traditional use of BSE in the treatment of airway diseases.
Airway diseases, asthma, boswellia serrata, bronchodilation, denatonium, tracheal contraction.
Department of Clinical Pharmacology, Faculty of Medicine, Alexandria University, Alexandria