Abstract

Biotransformation of the diterpene jatrophone (1) by Aspergillus niger ATCC 16404 afforded the new diterpene 9β -hydroxyisabellione (2). The compounds were characterized by spectroscopic analysis. The cytotoxicity of the compounds as IC50 values on AGS and lung fibroblasts was 2.4 and 2.8 μM for compound 1 and 53.1 and 260 μM for 2, respectively. Microbial transformation of 1 into compound 2 strongly reduced the cytotoxicity and enhanced the selectivity against AGS cells. © 2007 Verlag der Zeitschrift für Naturforschung.