Question

What is the proposed mechanism of action of artemisinin in the treatment of malaria:

• A. Inhibition of dihydrofolate reductase, interfering with folate synthesis
• B. Blocking of the Plasmodium falciparum ATPase, disrupting ion homeostasis
• C. Generation of reactive oxygen species (ROS) by cleavage of the endoperoxide bridge, leading to parasite death
• D. Inhibition of the heme polymerase enzyme, causing accumulation of toxic heme

Hint:

Artemisinin works by generating reactive oxygen species (ROS) through cleavage of its endoperoxide bridge, causing oxidative damage to the malaria parasite.

Answer 1

The Correct Option is C

Step 1: Understanding artemisinin's mechanism. Artemisinin is an antimalarial drug derived from the plant Artemisia annua. Its activity is based on the cleavage of its endoperoxide bridge by iron (from heme) within the malaria parasite. This cleavage generates reactive oxygen species (ROS), which damage the parasite’s essential proteins and membranes, leading to its death. 

Step 2: Why other options are incorrect. 
- (A) Inhibition of dihydrofolate reductase: This is the mechanism of action of drugs like pyrimethamine, not artemisinin. 
- (B) Blocking of Plasmodium falciparum ATPase: This mechanism is related to other drugs like lumefantrine, not artemisinin.
- (D) Inhibition of heme polymerase enzyme: This is the mechanism of quinoline-based drugs like chloroquine, not artemisinin. 

Step 3: Conclusion. The correct mechanism of artemisinin involves ROS generation through endoperoxide cleavage, making option (C) the correct answer.