These results may be considered as our incipient understanding about effectiveness of curcumin in ameliorating diabetes-induced oxidative stress and apoptosis in the heart tissue since a deeper investigation of the cardioprotective mechanisms of curcumin and/or metformin requires measurement of ROS, evaluation of apoptosis using TUNEL assay or flow cytometry, measurement of caspase-3 enzyme activity, investigating synergistic effects of combined treatments (curcumin + metformin), and determination of Bax and Bcl-2 at the protein level. Here, CASP3 is linked to diabetes mellitus.