Planta Med 1992; 58(3): 239-244
DOI: 10.1055/s-2006-961444
Paper

© Georg Thieme Verlag Stuttgart · New York

Cardenolide and Neutral Lipid Biosynthesis from Malonate in Digitalis lanata

Henri W. Groeneveld1 , Léon J. P. van Tegelen1 , Kees Versluis2
  • 1Department of Plant Ecology and Evolutionary Biology, University of Utrecht, Sorbonnelaan 16, NL-3584 CA Utrecht, The Netherlands
  • 2Department of Analytical Chemistry, University of Utrecht, Sorbonnelaan 16, NL-3584 CA Utrecht, The Netherlands
Further Information

Publication History

1991

Publication Date:
05 January 2007 (online)

Abstract

Digitalis lanata plants were grown on water culture in a controlled environment and in the young, growing leaves free sterols (0.335 µmol/g FW), triacylglycerols (0.97 µmol/g FW) and cardenolides (1.82 µmol/g FW) were the major apolar and polar lipids. The cardenolide-containing fraction from these tissues was separated into 26 cardenolides by HPLC. The 5 major components (accounting for 60 % of the occurring glycosides) lanatosides A and C, acetyldigoxin, acetyldigitoxin, and glucoevatromonoside were identified by FABMS. Incorporation experiments with [2-14 C]-acetate, [2-14 C]-malonate, [2-14 C]-mevalonate, and [U-14 C]-sucrose (absorbed by excised, young, growing leaves) showed the labelling of all the occurring cardenolides after a 3 day incorporation period (as judged by HPLC). Comparing the simultaneous synthesis of labelled sterols and triacylglycerols, malonate could be considered as the most effective precursor in cardenolide synthesis, reaching an incorporation value of 4.1 % in a 4 day incorporation period. A time-course experiment revealed a temporary accumulation of 14C in glucoevatromonoside, which may play a role as an intermediate in cardenolide production of Digitalis lanata.