Biotransformation of digitoxigenin by Fusarium ciliatum

• Autor(a) principal: Pádua,Rodrigo M.
• Data de Publicação: 2005
• Outros Autores: Oliveira,Alaíde B., Souza Filho,José D., Vieira,Géssy J., Takahashi,Jacqueline A., Braga,Fernão C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532005000400019
• topic: digitoxigenin; Fusarium ciliatum; digoxigenin; digoxigenone; digitoxigenone

The biotransformation of digitoxigenin (1) by Fusarium ciliatum was investigated. The cardenolide 1 was obtained by the acid hydrolysis of digitoxin and the reaction also afforded two side products, identified as delta14-15-digitoxigenin (2) and delta8-14-digitoxigenin (3) by spectroscopic analysis. The biotransformation reaction was carried out in a 5 days process and three products were isolated and had their structures elucidated as digoxigenin (4), digoxigenone (5) and digitoxigenone (6). The investigation of the biotransformation kinetics disclosed 6 as the first derivative to be formed, followed by the more polar hydroxylated products 4 and 5, suggesting the involvement of different enzymes in 12beta hydroxylation and C-3 oxydation of digitoxigenin (1). The production of 5 and 6 under the employed conditions has never been reported. The biotransformation reaction was also undertaken with digitoxin, but F. ciliatum has been unable to promote its hydroxylation.