Transformations of Cardio-active Steroids by Microorganisms

Part IV Bioconversion of 3-Epidigitoxigenin and 17α-Digitoxigenin

Abstract

The microbial activity to dehydrogenate 3-hydroxyl groups of cardenolides was found not to be affected greatly by the change in spatial arrangement of the hydroxyl group at C-3 or of the unsaturated lactone ring at C-17. Whereas 3-epidigitoxigenin resisted the microbial hydroxylation, 17α-periplogenin was isolated and identified on incubation of 17α-digitoxigenin with Absidia orchidis, thereby showing that the change in orientation of lactone ring at C-17 does not have a decisive effect on microbial hydroxylating activity.