Microbial Transformation Studies on Arteannuin B

Abstract

The microbial transformation of the sesquiterpene lactone arteannuin B {3} using Aspergillus flavipes produced dihydroarteannuin B {4} as the main transformation product. Preparative-scale fermentation of 3 with Beauveria bassiana, on the other hand, has resulted in the production of two metabolites, 3.beta.-hydroxyarteannuin B {5} and 13-hydroxy-11-epi-dihydroarteannuin B {6}. The structure of these metabolites, all of which are new compounds, was established using chemical and spectroscopic techniques. The isomeric dihydrocompound, 11-epi-dihydroarteannuin B {7} and an isomer of artrannuin B {8} were also prepared chemically. All compounds were subjected to 2D-nmr experiments and full 1H- and 13C-nmr assignments were made.