In the presence of a reducing agent such as GSH or NADH, DCF??? is then reduced back to DCF with the formation of GS??? or NAD???, respectively, and the subsequent generation of superoxide [9].Amplex Red is a colorless and non-fluorescent derivative of resorufin (RSF) that is oxidized to the highly fluorescent RSF by H2O2/peroxidase (Scheme 1).