Quinine

Quinine is a cinchona alkaloid extracted from the bark of the Cinchona tree. Within red blood cells, Plasmodium degrades hemoglobin to obtain amino acids, and this process generates highly toxic free heme. Under normal conditions, the parasite polymerizes heme into the non-toxic pigment hemozoin. Quinine inhibits the conversion of free heme into hemozoin, causing heme to accumulate within the parasite and leading to its death.