Category:TP3O

Bufanolides (C24)

The backbone of toad skin secretions and the sea onion or squill (Scilla maritima) with a δ-lactone ring at C-17. As for cardenolides, 14β, 17β, and 20R-configurations are assumed (the rings C/D are cis). They naturally occur as glycosides or conjugates of suberylarginine.

Gorgostane (C30)

Gorgostanes occur in marine organisms. Its backbone is ergostane with an additional metyl group at C-23 and ana methylene bridge between C-22 and C-23.