Bioconversion of Cardiac Aglycones by Gibberella saubinettii (MONT.) SACC

Abstract

Bioconversions of several cardiac aglycones by a strain of Gibberella saubinettii (MONT.) SACC. were repoted. Digitoxigenin was converted to digoxigenin in a good yield. Digitoxigenone was transformed into 3-dehydrodigoxigenin, 3-epidigitoxigenin, and 3-epidigoxigenin. Diginatigenin was obtained in approximately 6% yield from gitoxigenin. Oleandrigenin gave 16-monoacetyldiginatigenin (ca. 15% yield) and diginatigenin (ca. 2%yield), but the formation of gitoxigenin from oleandrigenin by incubation was found to be quite small. Enzymatic hydrolysis of 16β-acetoxyl group of the cardenolide was discussed.