Which statement accurately describes a mechanism of action of Chloroquine?

• A. Inhibit ergosterol synthesis
• B. Build up of heme leads to intracellular toxicity
• C. Inhibit Reverse Transcriptase
• D. Inhibit Phospholipase A2

Answer: (B)

Chloroquine works by disrupting the malaria parasite’s ability to detoxify heme inside its food vacuole. As the parasite digests hemoglobin, toxic free heme would accumulate, but chloroquine inhibits the polymerization of heme into the non-toxic hemozoin, causing a buildup of toxic heme that kills the parasite. That’s why the statement about a buildup of heme leading to intracellular toxicity best describes its mechanism. The other options describe mechanisms seen in other drugs (fungal ergosterol synthesis inhibitors, reverse transcriptase inhibitors, or phospholipase A2 inhibitors) and don’t apply to how chloroquine acts.