Title

Bronchodilator, cardiotonic and spasmolytic activities of the stem barks of Terminalia arjuna.

Document Type

Article

Department

Biological and Biomedical Sciences

Abstract

Terminalia arjuna, Roxb barks has a folkloric repute to possess spasmolytic, bronchodilator and cardiotonic, properties. The present study was undertaken to evaluate possible effects of methanolic extract of barks of Terminalia arjuna (Ta.Cr) in gastrointestinal, respiratory and cardiovascular systems via in vitro experiments to rationalize its use in traditional system of medicine. The phytochemical analysis of crude methanolic extract of Terminalia arjuna barksrevealed the presence of tannins and saponins as methanol soluble extractable constituents. The spontaneous contractions in isolated rabbit jejunum were relaxed at tissue bath concentrations of 0.01-5.0 mg/ml, however, addition of propranolol to the tissue bath reduced the extent of relaxation and same level of effect was achieved at increased concentrations, i.e., 0.1-10.0 mg/ml. The Ta.Cr showed a weak relaxant effect on high K+(80 mM) low K+ (25 mM) and carbachol (1 μM)-induced contractions. Similarly, it also caused partial relaxation of high K+ (80 mM) and low K+ (25 mM)-induced contractions in isolated rabbit tracheal preparations. However, it relaxed completely the carbachol (1 μM)-induced contractions, but addition of propranolol (1 μM) to the tissue bath minimized the relaxant effect. Moreover, the Ta.Cr caused partial relaxation of the phenylephrine (1 μM)-induced contractions in isolated rabbit aorta preparations. Furthermore, the Ta.Cr showed a positive inotropic and positive chronotropic effects at lower tissue bath concentrations in isolated rabbit paired atria preparations but these effects were found to be antagonized by the presence of propranolol in the tissue bath. Further addition of Ta.Cr to the tissue bath caused a decrease in the magnitude of observed inotropic and chronotropic effects in isolated rabbit paired atria; which was found to be abolished on addition of atropine. Thus; in conclusion, the crude methanolic extract of barks of Terminalia arjuna, Roxb exhibited spasmolytic, bronchodilator and cardiotonic properties which are likely to be mediated through presence of dominant _-adrenergic agonistic activity along with presence of some weak muscarininc agonistic activity.

Publication

Canadian Journal of Applied Sciences