2. Antimalarial Agents
• Defination-Antimalarials are chemotherapeutic agents which are
used for the prevention and treatment of malaria.
• The causal organisms responsible for malaria belong to the genus plasmodium
which is of the
• class of protozoa known as sporozoa. There are four different species which are
accepted as being responsible for human malaria. These are Plasmodium
malariae, the parasite of quartan malaria.
• Plasmodium vivax, the parasite of benign tertian malaria.
• Plasmodium falciparum, the parasite of malignant or subtertian malaria.
• Plasmodium ovale, the parasite that causes a mild type of tertian malaria
16. MOA of Chloroquine
• Uses of Chloroquin-
• Chloroquine is the drug of choice for clinical cure and suppressive prophylaxis of all types of
malaria,
• except that caused by resistant P. falciparum.
• Uncomplicated cases are treated orally, while i.v. chloroquine is rarely employed for complicated/
cerebral malaria in adults.
Heme itself or its complex with chloroquine then damages the plasmodial membranes
Polymerization of toxic haeme to nontoxic parasite pigment hemozoin is inhibited by formation of
chloroquine-heme complex
Chloroquine-It is actively concentrated by sensitive intraerythrocytic plasmodia.higher concentrationis found
in infected RBCs. By accumulating in the acidic vesicles of the parasite and because of its weakly basic nature,
it raises the vesicular pH and thereby interferes with degradation of haemoglobin by parasitic lysosomes.
17. MOA of 8-Amino quinoline(Primaquine)
Step-1
• primaquine can generate ROS via an autoxidation
of the 8-amino group. The formation of a radical
anion at the 8-amino group
Step-2
• As a result, cell -destructive oxidants, such as
hydrogen peroxide, superoxide, and hydroxyl
radical, can be formed.
Step-3
• leading to oxidative damage to critical cellular
components.
18. Mechanism of action artemisinin
inhibits protein synthesis and ultimately results in
lysis of the parasite
Iron-mediated cleavage of the bridge releases a highly reactive
free radicals species that binds to membrane proteins,
causes lipid peroxidation, damages endoplasmic reticulum.
The endoperoxide bridge in its molecule appears to
interact with haeme in the parasite.