ABSTRACT
Sesquiterpenes are a structurally highly diverse class of terpenoids with 15 carbon atoms skeleton and derived biosynthetically from farnesyl pyrophosphate. There are more than 70 different ring systems that have been identified [8]. Many of them show quite broad and significant biological activities. Artemisinin is a member of the amorphane sub-class of cadinane sesquiterpenes with artemisinic acid as its major bioprecursor (Fig. 11.1). It is a sesquiterpene lactone with an endoperoxide oxygen bridge across the seven-member ring. As the most promising compound with outstanding anti-malarial activity at low toxicity, it was found from the aerial parts of the plant Artemisia annua L., which were used for many centuries in traditional Chinese medicine for the treatment of high fever and malaria. Artemisinin is effective against chloroquine resistant strains of Plasmodium falciparum and P. vivax, as well as against cerebral malaria. An ether-substituted derivative, artemether (Fig. 11.1), is soluble in sesame or peanut oil, and can be administered by intramuscular injection. Artemisinin-based combination therapies (ACT) are recommended by the World Health Organization (WHO) to treat especially multi-drug-resistant forms of malaria as currently used medications have become increasingly ineffective [9].
