Digitalis-like compounds of toad bile: Sulfation and reduction of bufadienolides decrease potency of Na+,K+-ATPase inhibition
Journal
Heterocycles
Journal Volume
39
Journal Issue
2
Pages
669-686
Date Issued
1994
Author(s)
Derguini F.
Bruening R.C.
Nakanishi K.
Wallick E.T.
Akizawa T.
Rosenbaum C.S.
Butler Jr. V.P.
Abstract
The most abundant digitalis-like compound in the bile of the toad, Bufo marinus, was identified as 12β-hydroxytetrahydroresibufogenin-3-sulfate. Other digitalis-like compounds in toad bile had the properties of bufadienolide-3-sulfates, the most abundant of which was found to be marinobufagin-3-sulfate, a compound previously described only as a trace component in toad skin. Both compounds were less effective than unconjugated marinobufagin in the inhibition of Na+,K+-ATPase enzymatic activity and of Na+,K+-ATPase ouabain binding. This study suggests that sulfation of the A ring and reduction of the lactone ring may be responsible for bufadienolide inactivation in vivo. © 1994.
Type
journal article