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.