Abstract: Objective To observe the protective effect of Allium macrostemon extract on acute myocardial ischemia injury in rats，and to explore its mechanism. Methods An acute myocardial ischemia injury model was established with ligation of the left coronary artery in rats，after intervention of Allium macrostemon extract and nitroglycerin，the changes of ST segment of ECG Ⅱ lead before and after mod? eling in rats were monitored；the levels of serum glutathione transferase（GSH-Px），cholinesterase（TChE），nomesterified fatty acids（NEFA）and malondialdehyde（MDA）were measured；pathological changes of myocardial ischemia injury were observed under microscope. Results Compared with the sham operation group，the ST segment of ECG in the model group was obviously upshifted，the serum GSH-Px activity was significantly decreased（ P <0. 01），the activity of TChE，the content of NEFA and MDA increased significantly（ P <0. 01），and the pathological study showed that the myocardial injury was more serious；compared with the model group，the ST segment of ECG was lower in the medicine groups（ P <0. 01），the serum GSH-Px activity was significantly increased in the medicine groups （ P <0. 01），the activity of TChE and the content of NEFA and MDA were significantly decreased in the medicine groups（ P <0. 05 ，P <0. 01），the degree of myocardial damage reduced in pathologicalfindings in the medicine groups. Conclusion Allium macrostemon extract has a protective effect on acute myocardial ischemia injury in rats.

Key words: Allium macrostemon extract, acute myocardial ischemia, GSH-Px, TChE, NEFA, MDA