Preparation and Practical Applications of 2′,7′-Dichlorodihydrofluorescein in Redox Assays

Oxidative stress, a state in which intra- or extracellular oxidant production outweighs the antioxidative capacity, lies at the basis of many diseases. DCFH2-DA (2′,7′-dichlorodihydrofluorescein diacetate) is the most widely used fluorogenic probe for the detection of general oxidative stress. However, the use of DCFH2-DA, as many other fluorogenic redox probes, is mainly confined to the detection of intracellular oxidative stress in vitro. To expand the applicability of the probe, an alkaline hydrolysis and solvent extraction procedure was developed to generate high-purity DCFH2 (2′,7′-dichlorodihydrofluorescein) from DCFH2-DA using basic laboratory equipment. Next, the utility of DCFH2 was exemplified in a variety of cell-free and in vitro redox assay systems, including oxidant production by transition metals, photodynamic therapy, activated macrophages, and platelets, as well as the antioxidative capacity of different antioxidants. In cells, the concomitant use of DCFH2-DA and DCFH2 enabled the measure...