Microbial Transformations of Artemisinin and Artemisinin Derivatives: an Example of the Microbial Generation of Molecular Diversity

The biotransformations of artemisinin and artemisinin derivatives leading to metabolites that may serve as prospective candidates for antimalarial evaluation or as starting materials for hemisynthesis of antimalarial derivatives are reviewed, focusing on the preparation of regio- and stereoselectively hydroxylated derivatives still possessing the 1,2,4- trioxane structure that can be used as scaffolds for the production of novel antimalarials with increased water solubility, lower toxicity and decreased potential for resistance. A special emphasis has been also placed on the recent manufacturing of artemisinin and derivatives via microbiological methods, involving cloning and overexpression of biosynthetic enzymes and allowing to design an alternative route for artemisinin production.