Origin of Cardenolides in Rhizomes and Roots of Convallaria majalis L. Biogenesis in situ or Transport from Leaves?

Abstract

Abstract After administration of sodium[1 - 14C]acetate to rhizome or root cuttings of Convallaria majalis L. two of the main cardiac glycosides were isolated and examined for incorporated radioactivity. With a detection limit of 0.0003% of incorporated label it can be assumed, that the subterranean organs of C. majalis are not capable of cardenolide biogenesis de novo. Interconversions on the cardenolide level do not take place, too. as was proved by application of (U - 14C]convallatoxol and examination of convallatoxin, the main metabolite in leaves. Therefore the cardenolide content of the subterranean parts of C. majalis (0.2%) must have its origin in the leaves, from where the cardiac glycosides are translocated to rhizomes and roots, which only fulfil a storage function in this respect.