Phytic acid suppresses ischemia-induced hydroxyl radical generation in rat myocardium

The present study examined whether ischemia-reperfusion-induced hydroxyl radical (center dot OH) generation was attenuated by myo-inositol hexaphosphoric acid (phytic acid). A flexibly mounted microdialysis technique was used to detect the generation of center dot OH in in vivo rat hearts. To measure the level of center dot OH, sodium salicylate in Ringer's solution (0.5 mM or 0.5 nmol/mu l/min) was infused directly through a microdialysis probe to detect the generation of center dot OH as reflected by the nonenzymatic formation of 2,3-dihydroxybenzoic acid (2,3-DHBA). To confirm the generation of center dot OH by Fenton-type reaction, iron(II) was infused through a microdialysis probe. A positive linear correlation between iron(II) and the formation of 2,3-DHBA (R-2=0.983) was observed. However, the level of 2,3-DHBA in norepinephrine (100 mu M) plus phytic acid (100 mu M) treated group were significantly lower than those observed in norepinephrine-only-treated group (n=6, *p < 0.05). To examine the effect of phytic acid on ischemia-reperfusion-induced center dot OH generation, the heart was subjected to myocardial ischemia for 15 min by occlusion of the left anterior descending coronary artery (LAD). When the heart was reperfused, the normal elevation of 2,3-DHBA in the heart dialysate was not observed in animals pretreated with phytic acid. These results suggest that phytic acid is associated with antioxidant effect due to the suppression of iron-induced center dot OH generation. (C) 2016 Published by Elsevier B.V.