Protective effect of crataegus extract on the cardiac mechanical dysfunction in isolated perfused working rat heart.

The effect of the water-soluble fraction of Crataegus (Crataegus extract) on the cardiac mechanical and metabolic function was studied in the isolated, perfused working rat heart during ischemia and reperfusion. Ischemia (15 min) was produced by removing afterload pressure, and reperfusion (20 min) was produced by returning it to the original pressure. In the control (no drug) heart, ischemia decreased mechanical function to the lowest level, which did not recover even after the end of reperfusion. Crataegus extract (0.01 or 0.05%) was applied to the heart from 5 min before ischemia through the first 10 min after reperfusion. With the high concentration of Crataegus extract (0.05%) the mechanical function recovered during reperfusion incompletely without increasing coronary flow, but the low concentration of Crataegus extract (0.01%) did not. In the heart treated with the high concentration of Crataegus extract, the reperfusion-induced recovery of the energy metabolism was accelerated, and the level of lactate during ischemia was lower than that in the control heart, although the myocardial levels of free fatty acids during ischemia and reperfusion were not greatly affected. These results demonstrate that Crataegus extract (0.05%) has a cardioprotective effect on the ischemic-reperfused heart, and that the cardioprotective effect is not accompanied by an increase in coronary flow.