The tripeptide glutathione (GSH) has been widely studied as an antioxidant for its role in the enzymatic decomposition of H2O2 by glutathione peroxidase (GPx) and its radical scavenging ability; it also plays a critical role in cellular detoxification [42]. GSH is the most abundant non-protein thiol in cells, with concentrations of 1–11 mM in cytosol, 3–15 mM in nuclei, and 5–11 mM in mitochondria [1,43]. Respiratory and enzymatic processes as well as drug interactions continually generate ROS and RNS, causing oxidation of intracellular components, including GSH, and increasing oxidative stress in cells [44–48]. Unsurprisingly, cells depleted of glutathione also have increased oxidative stress levels, an underlying cause of many diseases [49,50].