Diverse Types of Diterpenoids with an Aromatized C Ring from the Twigs of Podocarpus imbricatus .

An ethanol extract of the powdered twigs of Podocarpus imbricatus afforded 14 new diterpenoids ( 1 - 14 ), which all share an aromatized C ring. These isolates belong to five diterpenoid types that include abietanes ( 1 - 3 ), semperviranes ( 4 - 9 ), totaranes ( 10 - 12 ), a C-17 norabietane ( 13 ), and an icetexane ( 14 ). Their structures were assigned mainly by analysis of the spectroscopic data, and the absolute configuration of 1 was determined by X-ray crystallography. A biosynthetic pathway for five of the biogenetically related types of diterpenoids was proposed. Compound 7 showed moderate inhibitory activity against Zika virus with an IC ₅₀ value of 2.5 μM.