**Potentiation of reactive species: Nitric oxide in view**

Nitric oxide (•NO), which is also considered a ROS, is produced by macrophages against *Plasmodium*. The free radical nitric oxide reacts with the primary radical, O2 •−, to give peroxynitrite, a more lethal reactive species, which can also damage biomolecules such as proteins and DNA. It remains to be seen if •NO, produced by human phagocytes, diffuses into the parasitic cytosol. However, •NO production has also been reported in the parasite by an isoform of nitric oxide synthase (NOS), which is calcium-independent and whose inhibition affects the growth of *P. falciparum*. The •NO production is higher in the trophozoite than in the ring stage. Although •NO may not be very deleterious, its reaction with H2O2 to form peroxynitrite will potentiate their radicality
