Kinetic scavenging effect of chinonin on NO and oxygen free radicals generated from ischemia reperfusion myocardium and its protective effect on the myocardium

The kinetic scavenging effect of chinonin on NO and oxygen free radicals ge nerated from ischemia reperfusion myocardium and its protective effect on t he myocardium were studied by electron spin resonance (ESR) spin trapping t echnique. It was found that after 20 minutes ischemia, the first peak of ox ygen free radical appeared at about 0.5 minutes after the beginning of repe rfusion, then the release of oxygen free radicals decreased with time. The second peak appeared at about 3 minutes. Similarly, there were two peaks of creatine kinase (CK) release, which indicated the myocardial damage, the f irst one appeared concomitantly with the first oxygen free radical peak but the second one appeared later about 1 minute after appearance of the secon d peak of oxygen free radicals. The release of NO free radicals was not sig nificant in the absence of L-arginine. However, it increased significantly in the presence of L-arginine and it also possesses a biphase profile. It c ould protect the ischemia-reperfusion damage in the presence of low concent ration of L-arginine (0.1 mM), but in high L-arginine concentration (10 mM) it generated higher concentrations of NO leading to a more serious ischemi a-reperfusion damage. Addition of chinonin could scavenge the free radicals and protect the ischemia-reperfusion injury, especially in the second phas e. The reduction stoichiometry of chinonin for Fe(III) was measured.