The effect of Ligustrum delavayanum on isolated perfused rat heart

Extract of ligustrum leaves (Ligustrum delavayanum Hariot [Oleaceae]) is well known in traditional Chinese medicine. One of the active components, oleuropein, displays vasodilating and hypotensive effects.

To analyze the effect of 0.008% lyophilized extract of ligustrum dissolved in 0.5% ethanol on heart function.

Experiments were done on isolated rat hearts perfused by the Langendorff method in control conditions and during ischemic-reperfusion injury.

Application of ligustrum induced positive inotropic and vasodilating effects in spontaneously beating hearts. Pretreatment of the hearts with ligustrum reduced left ventricular diastolic pressure measured during reperfusion and improved left ventricular contraction compared with hearts without any pretreatment. Ligustrum significantly suppressed the incidence and duration of cardiac reperfusion arrhythmias, expressed as G-score, from 7.40+/-0.58 in nontreated rats to 1.97+/-0.50.

Application of ligustrum or ethanol alone induced changes in coordination between atria and ventricles during ischemia-reperfusion injury. The 'g-score', a new parameter summing the incidence and duration of atrioventricular blocks, atrioventricular dissociation and cardiac arrest, is introduced. The g-scores with ligustrum pretreatment were higher during ischemia than during reperfusion. Ethanol significantly depressed myocardial contractility and coronary flow, and nonsignificantly decreased heart rate of isolated rat hearts. Electrical changes observed during coronary reperfusion in the presence of ethanol were accompanied by deterioration of contractile function.

Ligustrum had a significant protective effect on rat myocardium against ischemic-reperfusion injury. Ethanol partially attenuated the protective effect of ligustrum.