Hemozoin (Ferriprotoporphyrin IX aggregates) (HZ)

Hemozoin is a dark-brown biocrystal formed by Plasmodium parasites within their acidic food vacuole as an essential mechanism for detoxifying free heme (Hempelmann, 2007, Parasitology Research). During the intraerythrocytic stage of malaria, the parasite digests host hemoglobin to obtain amino acids, a process that releases large quantities of toxic ferriprotoporphyrin IX (Fe(III)PPIX) (Egan et al., 2002, Journal of Inorganic Biochemistry). To prevent the oxidative damage and membrane disruption caused by free heme, the parasite sequesters it into insoluble, chemically inert hemozoin crystals. This biocrystallization process is the primary target for several classes of antimalarial drugs, most notably the quinolines such as chloroquine and quinine, which bind to the heme monomers or the crystal facets to inhibit further growth (Sullivan et al., 1996, Science). The resulting accumulation of toxic free heme leads to the generation of reactive oxygen species and the eventual lysis of the parasite (Pagola et al., 2000, Nature). Because hemozoin formation is a unique metabolic pathway not found in human physiology, it remains one of the most effective and selective targets for antimalarial chemotherapy, despite the emergence of resistance (Egan, 2008, Journal of Chemical Biology).

Other names

Malaria pigmentFerriprotoporphyrin IX aggregatesBeta-hematinHeme aggregatesHeme crystals

Inhibition of hemozoin biocrystallization, leading to the accumulation of toxic free ferriprotoporphyrin IX which causes oxidative damage and parasite lysis (Sullivan et al., 1996, Science).