Cardioactive effects of Eremophila alternifolia extracts

An aqueous extract obtained from the leaves of the traditional Aboriginal medicinal plant Eremophila alternifolia R.Br. (Myoporaceae) was tested on isolated hearts of normotensive rats using the Langendorff heart preparation. A single injection of the extract into the retrograge perfusion solution induced cardioactivity, consisting of a short initial increase in force of contraction (positive inotropism), followed by a decrease in the force (negative inotropism) with simultaneous increase in heart rate (positive chronotropism) and in coronary perfusion rate. These effects were not mediated by alpha- or beta-adrenergic receptors.