A new 12,17-cyclo-labdane diterpenoid from the twigs of Dacrycarpus imbricatus

A new 12,17-cyclo-labdane diterpenoid, podoimbricatin C (1), along with 15 known compounds was isolated from the twigs of Dacrycarpus imbricatus. Their structures were elucidated by means of extensive spectroscopic analysis. Compound 1 is the second example of the unusual 12,17-cyclo-labdane diterpenoids. It showed no inhibitory effects against five human tumour lines (HL-60, SMMC-7721, A-549, MCF-7 and SW-480).