Variation of cardenolides with growth in a Digitalis lanata Brazilian cultivar

The content of the main cardenolides in Digitalis lanata harvested in Brazil was determined by HPLC, in two different stages of growth. The analysed plants, totaling 49, presented great variation in the contents of lanatoside C and digoxin (jointly quantified), lanatoside A, lanatoside B, glucoevatromonoside, odorobioside G, glucogitoroside, glucoverodoxine, glucodigifucoside and digitalinum verum. The sum of the analysed cardenolides in the 12-month-old plants was higher than the determined concentrations in plants collected later (18 months) (P < 0.0001). Lanatoside C and digoxin were the major cardenolides in both groups, followed by glucodigifucoside. Lanatoside A content decreased in the older plants (P < 0.0001), whereas lanatoside C showed an opposite trend (P < 0.05). The estimated average dry leaf content of lanatoside C and digoxin was 1820 +/- 900 nmol g(-1) in the younger plants, and 2040 +/- 840 nmol g(-1) in the older plants. Some individual plants have shown a leaf content above 3500 nmol g(-1) of these cardenolides and will be selected for improvement of the cultivar. (C) 1997 Elsevier Science Ltd.