Transformations of Cardio-active Steroids by Microorganisms

Abstract

The pH of fungal fermentation beer was found to have considerable effect on the microbial transformation of cardiac aglycones. When digitoxigenin and 3-dehydrodigitoxigenin were shaken with acid fermentation beer of Rhizopus arrhizus, 7β-hydroxydigitoxigenin and 3-epi-7β-hydroxydigitoxigenin were obtained as principal dissimilation products, respectively. Upon incubation with the fermentation beer of elevated pH, these substrates were led to the common product, 3-dehydro-7β-hydroxydigitoxigenin. When digitoxigenin was bioconverted with acid and alkaline fermentation beers of Mucor parastiticus, there resulted in the formation of 7β-hydroxydigitoxigenin and of 3-dehydrodigitoxigenin and anhydroperiplogenone respectively, both accompanied with significant amount of periplogenin. With 3-dehydrodigitoxigenin as a substrate, digitoxigenin and 3-epi-digitoxigenin were shown to be present in acid fermentation beer of the same organism.

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