Biotransformation of an antimalarial drug, artemether by plant and fungal cell cultures

Biotransformation of 1 with Fusarium lini, Macrophomina phaseolina, and plant cell suspension culture of Azadirachta indica yielded five biotransformed products with the lacking of peroxy-linkage, 9α-acetoxy, 10β-methoxyartemethin-I (2), 9α-hydroxyartemethin-II (3), 10β-hydroxyartemethin-I (4) and 3α-hydroxy,12β-methoxyartemethin-III (5) and 3α-12β-dihydroxyartemethin-III (6). Metabolites 2 and 5 were obtained through metabolism with A. indica culture. Metabolites 3 and 4 were found to be new compounds. Their structures were deduced by spectroscopic techniques while single-crystal X-ray diffraction technique was used for the unambiguous characterization of compounds 2, 3 and 6. All biotransformed products were evaluated by in vitro antimalarial assay.