Abstract

EVALUATION OF CARDIOPROTECTIVE ACTIVITY OF MYRICETIN AND KAEMPFEROL IN ISCHAEMIA–REPERFUSIONINDUCED MYOCARDIAL INFARCTION IN BOTH NORMAL AND STREPTOZOTOCIN-INDUCED TYPE I DIABETIC RATS

Pottendla Srikanth* and Dr. P. Padmabhushanam

Abstract

Revascularization therapy is the mainstay of treatment in the management of myocardial infarction in normal and diabetic patients. We attempted to evaluate the cardioprotective actions of myricetin and kaempferol in ischaemia–reperfusion-induced myocardial infarction in both normal and diabetic rats. Myocardial infarct size was measured using the staining agent 2,3,5- triphenyl tetrazolium chloride. Serum and tissue malondialdehyde levels, superoxide dismutase and catalase in heart tissue were estimated spectrophotometrically. A lead II electrocardiogram was monitored at various intervals throughout the experiment. Results demonstrated the larger infarct size, enhanced lipid peroxidation, partial depletion of antioxidant enzymes and drastic drop in heart rate in diabetic hearts subjected to in-vivo ischaemia–reperfusion in comparison to normal rats subjected to ischaemia–reperfusion. Furthermore, myricetin and kaempferol significantly limit the infarct size in both normal and diabetic animals in a similar fashion. However, kaempferol offered complete cardioprotection at a dose of 10 mg/kg in terms of limiting infarct size. Both flavonoids could partially but significantly attenuate the lipid peroxidation. In addition, treatment has shown moderate improvement in heart rate in both normal and diabetic rats. Our data suggest the possible cardioprotective effects of myricetin and kaempferol in ischaemia–reperfusion injury in both normal and diabetic rats, and that protection might be in part due to the attenuation of oxidative stress and moderate increment in antioxidant reserves.

Keywords: cardioprotection; flavonoids; free radicals; reperfusion injury; myricetin; kaempferol.