Echinophyllins A and B, novel nitrogen-containing clerodane diterpenoids from Echinodorus macrophyllus

Two novel nitrogen-containing clerodane diterpenoids, echinophyllins A (1) and B (2), were isolated from the leaves of the Brazilian medicinal plant Echinodorus macrophyllus (‘Chapéu-de-couro’), and their structures and relative stereochemistry were elucidated by spectroscopic data. Echinophyllins A (1) and B (2) possess a unique α,β-unsaturated γ-lactam ring consisting of a clerodane diterpene and a tyramine unit or N-feruloyl putrescine unit, respectively.