(1) Effects on heart function:
Pueraria lobata total flavonoids and Pueraria Lobata Root Extract intravenous injection can significantly slow down the heart rate of anesthetized dogs, increase the stroke volume, decrease the total peripheral resistance, increase the aortic pressure, left ventricular end-diastolic pressure and left ventricular pressure (dp/dt ) decreased slightly, the left ventricular work decreased, and the myocardial oxygen consumption decreased. The conduction time at the atrioventricular junction was prolonged, the effective refractory period of the ventricular muscle was significantly prolonged, and the effective refractory period of the atrial muscle was slightly prolonged. Puerarin significantly prolonged the 50% and 90% repolarization process (MAPD50, MAPD90) of the monophasic action potential (MAP) in anesthetized cats, and the effective refractory period (ERP) was also significantly prolonged. Puerarin daidzein and daidzein solid dispersion (SDD) 100mg/kg orally administered, SDD can significantly lower blood pressure, slow heart rate, while daidzein has a weaker effect.
(2) Effects on myocardial metabolism:
Intravenous injection of Pueraria Lobata Root Extract 30mg/kg or Pueraria Lobata Root Extract 20mg/kg can reduce myocardial oxygen utilization rate and myocardial oxygen consumption rate in dogs, and can also reduce myocardial utilization rate of lactic acid and pyruvate. After ligation of the anterior descending coronary artery in dogs, the blood oxygen content in the coronary sinus and coronary vein decreased significantly, and the oxygen utilization rate in the normal area and the infarct area increased significantly. After intravenous injection of 30 mg/kg total flavonoids (pueraria ketone), blood oxygen content in coronary sinus and coronary vein increased significantly, and myocardial oxygen consumption in normal and infarcted areas decreased. In addition, the lactate content of arterial, coronary sinus, and coronary venous blood was reduced after ligation. Experiments have shown that intravenous injection of Gecone can reduce the elevated lactic acid content, reduce the production of lactic acid, improve myocardial oxygen metabolism, and have a beneficial effect on myocardial metabolism.
(3) Anti-myocardial ischemia effect:
Pueraria Lobata Root Extract (E21-22) has obvious protective effect on acute myocardial ischemia in rats induced by pituitrin. Pueraria total flavonoids can relieve the coronary vasospasm caused by pituitrin in acute myocardial ischemia and increase coronary blood flow. Using the canine experimental model in situ under hypothermia and external circulation, puerarin 2mg/kg was added to the perfused cold potassium cardioplegia solution, which can relieve coronary spasm, reduce myocardial energy demand, promote the recovery of left ventricular function after ischemia, and reduce lactic acid discharge , Reduce creatine phosphokinase (CPK) leakage, etc., and enhance myocardial tolerance to ischemia. Electron microscope observation also found that Pueraria Lobata Root Extract had a protective effect on ischemic myocardium, and the ultrastructure of ischemic myocardium was basically within the normal range after 140 minutes of cardiac arrest.