MYOCARDIAL PROTECTIVE EFFECT OF AN ANTHRAQUINONE-CONTAINING EXTRACT OF POLYGONUM-MULTIFLORUM EX-VIVO

An ethyl acetate er:tract of Polygonum multiflorum Thunb. (PME) was fr actionated into an anthraquinone-containing (PME-I) and a non-anthraqu inone-containing (PME-II) fraction. The effects of PME and its related extracts pretreatment on myocardial ischemia-reperfusion (IR) injury in isolated perfused rat hearts were examined. Pretreatment with PME e xtract or its anthraquinone-containing fraction produced a dose-depend ent protection against myocardial IR injury, as evidenced by a signifi cant decrease in the extent of LDH leakage as well as an improvement i n contractile force recovery. The myocardial protection was found to b e associated with an enhancement in myocardial glutathione antioxidant status, as indicated by significant reductic,ns in both the extent of IR-induced reduced glutathione (GSH) depletion and inhibition of Se-g lutathione peroxidase (GPX) and glutathione reductase (GRD) activities . Both alpha-tocopherol acetate (VE) and emodin (EMD) pretreatments pr otected against IR-induced myocardial injury as assessed by the decrea se in the extent of LDH leakage. But the contractile force recovery of the ischemic-reperfused hearts prepared from VE or EMD pretreated ani mals was not improved. The more complete myocardial protection afforde d by the anthraquinone-containing fraction of PME extract may be relat ed to its ability to sustain the glutathione antioxidant status under the condition of IR-induced oxidative stress.