[Mechanism of Canscora lucidissima xanthones against arrhythmia induced by myocardial ischemia-reperfusion in rats].

OBJECTIVE: To study the protective effect of 1,8-dihydroxy-3,5- dimethoxyxanthone (Xan-I) 1-hydroxy-5-dimethoxyxanthone(Xam-II) and 1-hydroxy-3,7,8-trimethoxyanthone (Xan-III) on arrhythmia induced by myocardial ischemia-reperfusion injury and their mechanism. METHOD: A rat model was used. The experimental result shows that. RESULT: An intravenous injection of Xan-I, Xan-II and Xan-III 1 mg/kg given 3 min before left coronary artery ligation reduces significantly the incidence of ventricular arrhythmia and its duration, diminishes the release of glutamic oxaloacetic transaminase and lactate dehydrogenase, elevates the activity of superoxide dismutase and reduces the amount of malondialdehyde. The potency of the above effect among 3 Xans is Xan-I > Xan-III > Xan-II. CONCLUSION: It follows that the protective effect of Xans on myocardial ischemia reperfusion induced by arrhythmia might be associated with the reduction of myocardial lipid peroxidation and the enhancement of SOD activity, and the amount and site of-OH(hydroxy) and -OCH3 (methoxy) on the benzenoid structure may be related to the affinity of Xan.