Spasmolytic, bronchodilator and vasorelaxant activity of methanolic extract of Tephrosia purpurea.

The methanolic extract of the whole plant of Tephrosia pupurea, Linn. was subjected to find out its possible therapeutic utility to validate its folkloric use in native systems of medicine. The extract on application to spontaneous contractions in isolated rabbit jejunum preparations exerted a concentration dependent (0.003-3.0 mg/mL) relaxant effect. The extract also caused concentration dependent relaxation of K+(80 mM)-induced spastic contractions. These findings were further supported by the observations that the extract caused a concentration dependent right ward shift of the Ca2+ response curves in manner similar to that of verapamil. The extract exhibited a relaxant effect on carbachol and high K+ (80 mM)-induced contractions of isolated rabbit tracheal preparations in a manner similar to verapamil. The observed non-specific bronchodilator response is possibly mediated through Ca2+ channel blockade. Moreover, the extract also exhibited a dose dependent relaxant effect on phenylephrine (1 microM) and K+(80 mM)-induced contractions in a manner similar to verapamil. On the basis of the above-mentioned findings, it can be concluded that the use of Tephrosia purpurea, in gastrointestinal spasm, asthma and hypertension is likely to be mediated through calcium channel blockage.