Abstract
BACKGROUND: Nyctanthes arbortristis has been used in traditional medicine for the treatment of asthma and cough. AIM: In this study, bronchodilatory effect of ethanolic extract of the N. arbortristis was investigated under in vitro conditions. The concentration-response curve of the tracheal smooth muscle (TSM) to histamine was recorded in presence or absence of ethanolic extract and N(ω)-nitro-l-arginine methyl ester (L-NAME). Dose-response effect of ethanolic extract on pre-constricted tissues was investigated. The ethanolic extract inhibited the histamine-induced maximum contractile responses of TSM (P < 0.001). Ethanolic extract also cause dose-dependent relaxation of TSM. These effects were reversed by L-NAME. Phytochemical analysis showed the presence of typical plant constituents. These results suggest the possible use of extract of the leaves of N. arbortristis as a bronchodilator in therapeutic treatment of asthma.