Abstract
In this work, biotransformations of pregnenolone 1 by Ulocladium chartarum MRC 72584, Cladosporium sphaerospermum MRC 70266 and Cladosporium cladosporioides MRC 70282 have been reported. U. chartarum MRC 72584 only hydroxylated 1 at C-7β and hydroxylated 1 at either C-7β or C-14α, accompanied with a concurrent epoxidation from the β-face. The same fungus hydroxylated a small amount of 1 at both C-7 and C-14α, accompanied with a subsequent oxidation at C-7. 3β,14α-Dihydroxy-5β,6β-epoxypregnan-20-one 4 and 3β,7β-dihydroxy-5β,6β-epoxypregnan-20-one 5 obtained from the incubation of 1 with this fungus were determined as new metabolites. C. sphaerospermum MRC 70266 converted most of 1 into a 3-keto-4-ene steroid and independently hydroxylated it at C-6α, C-6β and C-7β. This fungus also hydroxylated 1 at C-7 and C-11α and then oxidized it at C-7. C. cladosporioides MRC 70282 converted almost half of 1 into a 3-keto-4-ene steroid. The same fungus reduced some of this 3-keto-4-ene steroid by a 5α-reductase activity while it hydroxylated the rest at C-6α and C-6β.
Acknowledgments
We are grateful to Yavuz Derin and Fatih Sonmez for running the 1H and 13C NMR spectra.
Disclosure statement
The authors report no declaration of interest. The authors alone are responsible for the content and writing of the paper.