Biotransformation of β -Artemether by Aspergillus niger and Aspergillus flavus , and Antifungal Activity of Their Metabolites

β-Artemether ( 1 ) on fermentation with Aspergillus niger and Aspergillus flavus by liquid-phase medium yielded β-artemetherfurano acetate ( 2 ) and 3α-hydroxydeoxy-β-artemether ( 3 ), whereas with Aspergillus niger by solid-phase medium yielded β-artemetherfurano acetate ( 2 ) and deoxydihydroartemisinin (mixture of α and β isomers) ( 4 and 5 ). Their structures were elucidated by modern spectroscopic methods and reported data. β-Artemether ( 1 ) and both of its biotransformed products 2 and 3 were screened for their antifungal activity using the agar-well method.