SOD1 and myocardial ischemia: Danhong injection can increase superoxide dismutase (SOD) activity, alleviate calcium ion overload and reactive oxygen species production (Duan et al., 2015), scavenge lipid peroxidation caused by free radicals, and reduce damage to cardiomyocytes by free radicals (Wang et al., 2010), and also inhibit the overflow of CK and LDH from damaged cardiomyocytes to reduce damage to cardiomyocytes during myocardial ischemia and exert a protective effect on cardiomyocytes (Guo et al., 2008).