“ Phenanthraquinone reacted readily with dithiol … as dithiothreitol (DTT), 2,3-dimercapto-1-propanol (BAL), and 2,3-dimercapto-1-propanesulfonic acid (DMPS), resulting in modification of the thiol groups, whereas minimal … of this quinone with monothiol compounds such as GSH, 2-mercaptoethanol, and N-acetyl-L-cysteine were seen.”