GSR and myocardial infarction: Syringic acid, an antioxidant, is said to increase GSH content and the activities of SOD, catalase, glutathione peroxidase (GPx), glutathione-S-transferase (GST), and glutathione reductase (GR) in the isoproterenol-induced myocardial infarction rat model, as well as show cardioprotective effects by scavenging reactive oxygen species [39].