2,2′-Pyridoin derivatives protect HL-60 cells against oxidative stress

Focusing on 2,2′-pyridoin (1, 1,2-di(2-pyridyl)-1,2-ethenediol) and its synthetic derivatives as the lead compound of the potent antioxidative enediol, their protective effect against oxidative stress was evaluated on the HL-60 cell system. 2,2′-Pyridoins showed no remarkable cytotoxic effect on HL-60 cells. The derivatives 1, 2, 3, 5, and 6 inhibited H2O2-induced cell death and intracellular oxidative stress more significantly than ascorbic acid. Since 2,2′-pyridoins are oxidized to the diketones, 2,2′-pyridils, in a protic solvent, the antioxidant activity of 2,2′-pyridils was also investigated. 2,2′-Pyridils showed antioxidant activity in the cell; however, the activity was lower than that of 2,2′-pyridoins. These results suggested that 2,2′-pyrdoin derivatives can be good cytoprotective agents against oxidative stress.