The molecule is a cardiotonic steroid secreted by the toad Bufo rubescens and other related species such as Bufo marinus. An endogenous Na/K-ATPase inhibitor, it is a vasoconstrictor with effects similar to digitalis. It has a role as an EC 3.6.3.9 (Na(+)/K(+)-transporting ATPase) inhibitor and an epitope. It is a steroid hormone and an epoxy steroid. It derives from a (5beta)-bufadienolide.
5-[(1R,2S,4R,6R,7R,10S,11R,14S,16S)-14,16-dihydroxy-7,11-dimethyl-3-oxapentacyclo[8.8.0.02,4.02,7.011,16]octadecan-6-yl]pyran-2-one