Isolation and characterization of cardiotonic steroid conjugates from the skin of Bufo marinus (L.) Schneider.

Abstract

The occurrence of new cardiotonic steroid conjugates in the skin of a tropical toad, B. marinus is reported. These substances were separated by chromatography on Amberlite XAD-4 resin and silica gel, high-performance liquid chromatography and gel chromatography on Sephadex LH-20. The sulfated bufogenins, marinobufagin 3-sulfate and resibufogenin 3-sulfate, were characterized by degradative and synthetic means. The structures of 2 new bufotoxins were elucidated as marinobufagin 3-pimeloylarginine ester and telocinobufagin 3-suberoylarginine ester.