Biotransformation of Cardiac Glycosides by Immobilized Cells of Digitalis lanata¹

Abstract

Biotransformation of digitoxin and of ß-methyldigitoxin by Digitalis lanata cells entrapped in alginate gel was investigated. In shake cultures of both freely suspended and of entrapped cells, respectively, the biotransformation products of each substrate are quite the same. Most of the added digitoxin is glucosylated to purpureaglycoside A, whereas digoxin and deacetyllanatoside C are found only in minute amounts. ß-Methyldigitoxin is hydroxylated to ß-methyldigoxin with only small amounts of the side product purpureaglycoside A. The hydroxylating activity of the entrapped cells is about one half of that of freely suspended cells under the same cultural conditions. Advantageously, the immobilized biocatalyst can be used for more than 60 days.

Key Word Index

Digitalis lanata - Scrophulariaceae - Plant Cell Cultures - Immobilized Cells - Biotransformation - 12ß-Hydroxylation - Cardiac Glycosides.