Fluorescent real-time quantitative measurements of intracellular peroxynitrite generation and inhibition

Peroxynitrite (ONOO^-), a strong oxidant species, is produced by the reaction of nitric oxide (NO) and superoxide (O₂^.-) radicals. It plays an important role as a biological regulator in numbers of physiological and pathological processes. In this study, we developed fluorescence-based real-time quantitative measurements to detect intracellular ONOO^-. The probe DAX-J2 PON Green showed high selectivity toward ONOO^- over other competing species, and has been successfully applied in microplate reader and flow cytometer to quantitatively measure endogenous ONOO^- production. Moreover, the results demonstrated the inhibitory effects of curcumin on intracellular ONOO^- generation.