2.2.1 Artemisinin
Biological Source It is obtained from the leaves and the closed, unexpanded flower heads of Artemisia annuna Linn., belonging to family Asteraceae.This particular herb has been used in the Chinese system of medicine exclusively for the treatment of malaria since more than one thousand years.
Geographical Source The plant grows abundantly in China.
Chemical Structure Though the herb was used for its wonderful proven therapeutic efficacy for more than a decade centuries, but its active principal artemisinin was isolated and identified in 1972.
It has been established experimentally that the presence of an internal peroxide linkage
strategically located in the seven membered ring is an absolute necessity for it to exert the unique antimalarial property.
Modifications in Structure On account of the poor water solubility of artemisinin an attempt was made to improve either its water solubility ir its lipid solubility. In the former instance, Sodiumartesuna te i.e., the sodium salt of its hemisuccinate ester was developed; while in the latter instance, Artemether i.e., its corresponding methyl ether analogue was produced. Evidently, sodium artesunate is employed for intraveneous injections and artemether is used as a potent long acting drug.
Uses
1. The drug and its derivatives are used as fast acting blood schizontocides in the control and management of malarial fever caused by plasmodium vivax strain.
2. These drugs are found to be active against both chloroquine resistant and chloroquine sensitive strains of Plasmodium falciparum.
3. These drugs are found to show extremely encouraging therapeutic effects specifically in the treatment of Cerebral malaria by virtue of their significant rapid clearance of the prevailing parasites when compared to either chloroquine or quinine (synthetic antimalarials)
Note: The chances of recurrence is quite substantial by the treatment of artemisinin and its derivatives; therefore, it is always necessary to adopt the course of a combination therapy employing other antimalarials.
