Cardiotonic activity of aqueous extract of heartwood of Pterocarpus marsupium.

The present study was undertaken to evaluate cardiotonic activity of aqueous extract of heartwood of P. marsupium. This plant species contains 5,7,2-4 tetrahydroxy isoflavone 6-6 glucoside which are potent antioxidant and are believed to prevent cardiovascular diseases. Cardiotonic effect of aqueous extract of heartwood of P. marsupium was studied by using isolated frog heart perfusion technique (IFHP). Calcium free Ringer solution was used as vehicle for administration of aqueous extract of P. marsupium as a test extract and digoxin as a standard. A significant increase in height of force of contraction (positive inotropic effect) and decrease in heart rate (negative chronotropic effect) at a very low concentration (0.25 mg/ml) was observed with test extract as compared to the same dose of a standard digoxin. The present results indicated that a significant increase in height of force of contraction with decrease in heart rate was observed as the dose of test extract increased. The test extract produced cardiac arrest at 4 mg/ml, a higher concentration, as compared to standard, digoxin (0.5 mg/ml). Compared to digoxin, a drug with narrow therapeutic window, P. marsupium showed wide therapeutic window.