Investigation into the Mechanism of Action of Abutilon indicum in the Treatment of Bronchial Asthma

There is a high prevalence of usage of complementary and alternative medicines for the treatment of bronchial asthma which is considered as a chronic inflammatory disorder of the airways. Abutilon indicum G. Don. (Fam: Malvaceae) is abundantly found as a weed throughout the tropical parts of India. It is reported to have anti-inflammatory action and is used internally for inflammation of the bladder. Our previous clinical studies done on Indian asthmatic patients have proved the effectiveness of Abutilon indicum (A. indicum) in bronchial asthma. The objective of our present investigation was to determine the mechanism of action of A. indicum in the treatment of bronchial asthma by carrying out various experimental studies. In the present study, methanolic extract of aerial parts of A. indicum did not show bronchodilating activity against histamine and acetylcholine induced bronchospasm in guinea pigs. A. indicum also did not show any inhibitory effect on agonist induced contractions of guinea pig ileum and tracheal chain preparations. However it was found to have significant mast cell stabilizing effect (p<0.05, Student’s t test) against compound 48/80 and egg albumin induced rat peritoneal mast cell degranulation. Also A. indicum showed significant anti-inflammatory activity (p<0.05, Student’s t test) when estimated using carageenan induced rat paw edema model. The results of the present study indicate that possible mechanism of action of A. indicum in the treatment of bronchial asthma is its mast cell stabilizing and anti-inflammatory activity.