Heme (Protoporphyrin IX iron(II)) (FePPIX)

Free heme, specifically protoporphyrin IX iron(II) (FePPIX), is a potent pro-oxidant molecule that serves as a critical therapeutic target in the treatment of malaria (PubChem CID 444098). During the intraerythrocytic stage of infection, Plasmodium parasites catabolize host hemoglobin to obtain essential amino acids, a process that releases large amounts of toxic free heme (NIH/NCBI PMC3111641). To survive, the parasite must rapidly detoxify this heme by converting it into an inert crystalline polymer known as hemozoin or malaria pigment (Nature Communications 10.1038/ncomms14401). Antimalarial drugs such as chloroquine and other quinolines function by binding to free heme or the surface of hemozoin crystals, effectively blocking further crystallization (Science 10.1126/science.252.5004.436). This inhibition results in the accumulation of free heme and heme-drug complexes, which disrupt parasite membranes and induce lethal oxidative stress (Trends in Parasitology 10.1016/j.pt.2011.03.003). In humans, elevated levels of free heme during hemolytic crises act as a damage-associated molecular pattern (DAMP), triggering inflammatory pathways and contributing to vascular dysfunction (Frontiers in Immunology 10.3389/fimmu.2020.00758).

Other names

Ferriprotoporphyrin IXIron-protoporphyrin IXHeme bFree hemeFe(II)-protoporphyrin IX

Inhibition of heme biocrystallization into hemozoin, formation of toxic heme-drug complexes, and induction of oxidative stress within the parasite food vacuole.