Abstract: AimTo study the protective effect of procyanidins from the seedpod of the lotus (LSPC) on myocardial ischemia and reperfusion in rats. MethodsMyocardial injury model was made by ligating the coronary artery for 30 min followed by reperfusion for 45 min in anesthetized rat and 30 min of ischemia followed by 30 min of reperfusion in the isolated rat heart. All animals were given the medicine or normal saline before the experiment. ET, Ang I, Ang II in the serum, the MDA content, SOD activity, NO level, the recovery rate of coronary flow (CF) and heart rate (HR) after reperfusion and CK, XO from the myocardial cells were observed. ResultsLSPC was shown to inhibit the release of ET, Ang II (P﹤0.05), and the increase of MDA content (P﹤0.05). It was also found to increase the SOD activity (P﹤0.05) and NO level (P﹤0.01). LSPC was found to increase the recovery rate of the coronary flow (CF) and heart rate (HR) after reperfusion (P﹤0.05 or P﹤0.01), decrease the release of CK from the myocardial cells (P﹤0.01), depress the XO activity of myocardial tissue (P﹤0.05), as well as improve the myocyte ultrastructural pathological injury. ConclusionThe anti-ischemia effect of LSPC was related to the mechanism of scavenging the oxygen free radicals directly, cutting off the source of free radicals, reducing tissue peroxidation, stabilizing the cells membrane, depressing the production of EDCF and increasing the NO level as well.