Inhibitory Role of Dalbergia saxatilis on β-adrenergic Actions of Salbutamol in Isolated Rat Uterine Strips

Objective: To evaluate the biological activity of aqueous ischolar_main extract of Dalbergia saxatilis on isolated uterine muscle strips of the rat. Materials and methods: The plant material was subjected to cold extraction, initially in petroleum ether (60°-80°C) and subsequently in water. The dried aqueous extract was redissolved in water and tested on isolated uterine muscle strips of the rat mounted in a thermostatically controlled organ bath (37°C) containing physiological solution. Results : The extract (0.58-2.32 mg/ml) had no effect on spontaneous or carbachol (1.97 μmol) induced myometrial contractions but potentiated contractions initiated by phenylephrine (3.5 μmol). Salbutamol (0.15 μmol) abolished both spontaneous contractions and uterine motility stimulated by carbachol (1.97 μmol). These inhibitory effects of salbutamol on contractility were reversed by the extract (1.16 mg/ml). Conclusion : The aqueous ischolar_main extract of D. saxatilis contains biologically active principle that acted as a competitive inhibitor of the β₂ - selective adrenoreceptor agonist and enhanced α-adrenoreceptor function.