Biotransformation of (20S)-20-hydroxymethylpregna-1,4-dien-3-one by four filamentous fungi

Microbial transformation of (20S)-20-hydroxymethylpregna-1,4-dien-3-one (1) by four filamentous fungi, Cunninghamella elegans, Macrophomina phaseolina, Rhizopus stolonifer, and Gibberella fujikuroi, afforded nine new, and two known metabolites 2-12. The structures of these metabolites were characterized through detailed spectroscopic analysis. These metabolites were obtained as a result of biohydroxylation of 1 at C-6 beta, -7 beta, -11 alpha, -14 alpha, -15 beta, -16 beta, and -17 alpha positions, except metabolite 2 which contain an O-acetyl group at C-22. These fungal strains demonstrated to be efficient biocatalysts for 11 alpha-hydroxylation. Compound 1, and its metabolites were evaluated for the first time for their cytotoxicity against the HeLa cancer cell lines, and some interesting results were obtained. (C) 2011 Elsevier Inc. All rights reserved.