Inhibition of Na⁺, K⁺-ATPase by the Glycosides fromCoronilla varia

Abstract

A precise and simple method for the quantitative estimation of Na,K-ATPase activity is based on the uptake of 1°Rb into human erythrocytes in vitro (6). We used this method in 5 experiments to compare the inhibitory effects of Coronilla glycosides with those of ouabain and digitoxin. The results were evaluated by non-linear regression analysis and expressed as LC51 SE (Fig.2). RE OH 1 t HYE P -O-fl-D-g1ucolyraeosyi-I3-D -ytOpyraflOSyt 2 DRY) P /7 -D-xytopyranosy) Fig. 1 Structures of hyrcanoside (1) and deglucohyrcanoside (2). 467Coronilla z'aria L. (Fabaceae) (Crownvetch) is a perennial plant widely spread in Europe and cultivated in the U.S.A. From the seeds, the glycosides hyrcanoside (1; HY) and deglucohyrcanoside (2; DHY) ( Fig. 1) were isolated by Russian (1) (from a not exactly defined taxon) and American workers (2. 3) (from the cv. Penngift). Only the antineoplastic effect of these substances has been studied so far (2, 3). We have, therefore, isolated these substances from the seeds of the taxon growing in Bohemia (4) in order to study their biological activities in more detail.Since the glycosides under investigation are steroids with a lactone ring in the molecule, their possible cardiotonic properties were examined. The inhibition of Na, K-ATPase is the basis for the cardiotonic activity of cardiac glycosides (5). We have, therefore, studied the Nat. KtATPase inhibitory activity of Coronilla glycosides. \0 0 z 0 Iz [JrY 3,80 0,50 tI.J 3,07 0,27Both Coronilla glycosides showed remarkable Na, K-ATPase inhibitory activity increasing in the range iO to 1O"'mol, 1_I. Their activities lie between those of ouabain and dixitoxin, DEW being slightly more active than FlY.Other substances isolated from Crownvetch and studied (daphnoretin, scopoletin, umbelliferone, and epicatechin) neither showed an effect on ATPase activity nor did they interfere with the inhibitory effect of the glycosides (data not shown). Fig. 2 Inhibition of Na', K'-ATPase by digitoxin (.DT), hyrcanoside (0 HY)), deglucohyrcanoside (SDNY), and ouabain (x OU). H3 0 CH I 80 20 1C50± SE ( _8 nul . 1) * Dl 9,15 1,27 o HY 4,680,76 . 0,01 0,1 CONCENTRATION io6 mol . 1 2 Downloaded by: University of Arizona Library. Copyrighted material.

Medicinal plants with cardiovascular effects (part 2): plant based review

“…Evaluation of the cardiotonic effect using the methods of heart (in situ) and the isolated heart (Langendorff) proved that deglucohyrcanoside was more effective than hyrcanoside and that its effect was equal to that of digoxin as well as ouabain. The efficacy of deglucohyrcanoside at least equal to that of digoxin, while the toxicity of the former was several times lower, which indicated that the glycoside a potential candidate for therapeutic use [102][103][104][105][106].…”