Mevalonic Acid as A Precursor in the Biogenesis of Digitoxigenin

Abstract

Abstract (±)-Mevalonic acid-2-14C has been injected into a growing plant of Digitalis lanata L. to test if this acid serves as a precursor in the biosynthesis of cardenolides. After nine days a portion of the leaves was extracted and the constituents submitted to paper chromatography followed by autoradiography. The carbon 14 was detected in the lipid fraction and in the cardiac glycoside spots, but mostly in an area containing an as yet unidentified compound. Of the two glycosides forming the major glycoside area, one was predominant and, as after Mannich hydrolysis and chromatography, glucose, digitoxose and digitoxigenin were identified, this corresponds to lanatoside A. The aglycone fraction contained the radioactivity.