**Question:** Malarial pigment is formed by -

A. Hemozoin
B. Sapropterin
C. Chloroquine
D. Quinine

**Core Concept:** Malarial pigment is a product of Plasmodium falciparum, a parasite that causes severe malaria. Malaria is a vector-borne disease transmitted by infected Anopheles mosquitoes.

**Why the Correct Answer is Right:** Malarial pigment, known as hemozoin, is formed when the parasite breaks down heme, a byproduct of hemoglobin degradation in infected red blood cells. Hemozoin is a biocrystalline complex that prevents the toxic effects of heme on the host's cells and tissues.

**Why Each Wrong Option is Incorrect:**

A. Hemozoin is the correct answer, as it is the malarial pigment formed by Plasmodium parasites. Hemozoin is not formed from sapropterin (B), which is a co-enzyme involved in tetrahydrobiopterin synthesis.

B. Quinine (D) is an antimalarial drug, not a malarial pigment. Quinine works by inhibiting the parasite's ability to synthesize its own hemozoin, leading to the death of the parasite.

C. Chloroquine (A) is another antimalarial drug, not a malarial pigment. Chloroquine interferes with parasite growth and survival, but it does not result in the formation of hemozoin.

**Clinical Pearl:** Understanding the formation of malarial pigment helps in understanding the pathogenesis of malaria and the mechanisms of action of antimalarial drugs like quinine and chloroquine. These drugs aim to disrupt parasite survival by interfering with hemozoin synthesis, which is crucial for parasite survival. In contrast, sapropterin and chloroquine are drugs used to treat malaria, not the malarial pigment itself.