Structure-activity relationship of the cardenolide, with special reference to the substituents and configurations at C-14 and C-15

A Short Review on Cardiotonic Steroids and Their Aminoguanidine Analogues

“…Furthermore, the effect of OH groups varies depending on whether the cardenolide or the pregnane framework are considered, which in turn could depend on the characteristics of the side chain at position C17, bulky and rigid or small and flexible. The OH group at position C14β is not an essential feature for inotropic activity, although when it is replaced by a Hydrogen atom potency decreases considerably [49]. Particularly, an OH group at position C16β reduces potency in a large extent, but if such an OH is esterified, potency increases.…”

Bufadienolides of plant and animal origin

“…Shigei et al 186 studied the influence of substituents at C-14 and C-15 on the structure-activity relationships of cardenolides, e.g. digitoxigenin 2.…”

Chemistry and Structure-Activity Relationships of Cardioactive Steroids

“…Only the inhibition of beef brain and dog heart Na +, K + -ATPase was tested by SIEBENEICK and HOFFMANN (1978), hence nothing is known about the positive inotropic action of these substances.…”