Bio-Transformation of (G-³H)-Digitoxin and (G-³H)-Digoxin by Digitalis purpurea

Abstract

The biotransformation of (G-³H) digitoxin and (G-³H) digoxin has been studied in a strain of Digitalis purpurea in which cardenolides of the B series were predominant. A direct method of introducing the tritiated glycosides into the plant is described and the conversions monitored at intervals during the subsequent 6 weeks. Conversion of labelled digitoxin to purpurea glycosides A and B, gitoxin and gitaloxin occurred. Of particular interest was the conversion of digitoxin to the digitalose - containing glycosides, strospeside and verodoxin. Digoxin, an exogenous glycoside to D. purpurea, was glycosylated to desacetyl lanatoside C; there was some conversion to B and E series glycosides but only minimal formation of A series cardenolides.

Key Word Index

Digitalis purpurea - Scrophulariaceae - Cardenolides - (G-³H) Digitoxin - (G-³H) Digoxin - Biotransformation