Biotransformation of digitoxigenin by cell suspension cultures of pergularia tomentosa and Ammi visnaga

ABSTRACT

Periplogenin was isolated as the major biotransformation product of digitoxigenin by both P. tomentosa and A. visnaga cell suspension cultures. In addition, 1 beta hydroxydigitoxigenin and uzarigenin were also obtained in both cultures. These products were identified by HPLC, MS, 1H- and 13C-NMR analyses. The suspension cultures of both plants, though taxonomically distinct, proved quite closely related biochemically as far as digtioxigenin metabolism is concerned. A. visnaga culture, however,was a more active biotransformation system, metabolizing 65% of digitoxigenin in one week as compared to 16% by beta. Tomentosa cultures. 5 beta -Hydroxylation, 1beta -hydroxylation and 5-epimerization were demonstrated by both suspension cultures. This represents the first report of 1beta -hydroxydigitoxigenin and uzarigenin as digitoxigenin biotransformation products using cell cultures of higher plants