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Artemether,
isolated from Chinese-Vietnamese plant Artemisia
annua L., locally called "qing hao", is used to
treat fever and malaria. It is a white
crystalline powder with a bitter taste;
practically insoluble in water, soluble in
chloroform, acetone, and alcohols. Its chemical
designation is
(+)-(3-alpha,5a-beta,6-beta,8a-beta,
9-alpha,12-beta,12aR)- decahydro- 10-methoxy-
3,6,9-trimethyl- 3,12-epoxy- 12H-pyrano
(4,3-j)-1,2-benzodioxepin. Malaria is one of
leading re-emerging infectious disease due to
murative malarial parasite developed resistance
to chloroquine. Sulfadoxine-pyrimethamine is an
alternative can be used in the treatment of the
disease resistant to chloroquine, but resistance
to sulfadoxine- pyrimethamine has been reported
also in some areas. Artemisinin is an
alternative used in areas where the disease has
become highly resistant to
sulfadoxine-pyrimethamine. Dihydroartemisinin,
its methyl ether (artemether), its ethyl ether (arteether)
and its hemisuccinate ester (artesunate) are
known as more effective than its parent material
- artemisinin. But their activity decreases
after one or two hours. For simultaneous
administration to counter the drawback,
combination therapy of artemisinin along with
lumefantrine, mefloquine, amodiaquine,
sulfadoxine, and pyrimethamine is useful. The
term of artemotil refers to the pure beta-epimer
of arteether. Artemisinin is a peroxide-bridged
sesquiterpene lactone compound which has no N
atom, unlike quinine class anti-malarial drugs.
The characteristic peroxide lactone structure is
indispensable for anti-malarial activity. This
structure is also under the research for the
treatment of cancer. |