Plasmodium hemozoin formation pathway

The Plasmodium hemozoin formation pathway is a critical metabolic process employed by malaria parasites to detoxify the byproduct of hemoglobin digestion. During the intraerythrocytic stage, Plasmodium species ingest host hemoglobin, releasing free heme (ferriprotoporphyrin IX), which is toxic to the parasite as it induces oxidative stress and membrane lysis (Sullivan, 2002). To survive, the parasite sequesters this free heme into an insoluble, non-toxic crystalline form called hemozoin, also known as malaria pigment (Egan, 2008). This biocrystallization process occurs within the parasite's acidic food vacuole and is facilitated by proteins such as the Heme Detoxification Protein (HDP) (Coronado et al., 2014). This pathway serves as the primary target for several major classes of antimalarial drugs, including quinolines like chloroquine and quinine. These drugs bind to heme or the growing crystal surface, preventing further crystallization and leading to the accumulation of lethal levels of free heme (Wellems & Plowe, 2001). Consequently, the inhibition of hemozoin formation remains a cornerstone of antimalarial therapy, although its efficacy is increasingly challenged by the emergence of drug-resistant parasite strains.

Other names

Heme detoxification pathwayHemozoin biocrystallizationMalaria pigment formationHeme sequestration

Inhibition of the conversion of toxic free heme (ferriprotoporphyrin IX) into non-toxic hemozoin crystals, leading to the accumulation of free heme which causes oxidative damage and parasite lysis (Sullivan, 2002; Egan, 2008).