Page 131 - Pharmd general phytochemistry I-Final2024_LEUCTERS

Artemisinin

 Source: The Chinese herb known Qing Hao, Artemisia annua, Family Compositae.
 A characteristic feature in the structure of artemisinin is the presence of an endoperoxide

moiety which is essential for the antimalarial activity.

 To date, Artemisinin and its simple derivatives have been tested in China to treat more
than 1.5 million, patients suffering from malaria and particularly cerebral malaria; and
it has been shown to be valuable and effective against resistant strains of
Plasmodium.

Semisynthetic Derivatives and Analogues of Artemisinin.

 Semisynthesis enabled studying structure-activity relationships (SAR).
1- Derivatives of artemisinin:
 The preparation of semisynthetic derivatives has been stimulated by the requirement

for improved solubility because artemisinin is relatively insoluble in both water and oil
which is important to diversify routes of administration.
a- Catalytic reduction of the peroxide moiety resulted in the loss of an oxygen and total
loss of antimalarial activity. Thus, the peroxide moiety is necessary for activity.

b- Reduction of the lactone carbonyl with sodium borohydride (NaBH4) followed by
derivatization of the resulting secondary hydroxyl group led to the synthesis of
artemether and arteether which together with artemisinin can be administered as oily
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