Two New Labdane-type Diterpenes from the Wood of Cunninghamia konishii

Phytochemical investigation of the methanol extract of the wood of Cunninghamia konishii resulted in the isolation of two new acidic labdane-type diterpenoids, 12( S)-hydroxy-15,16-epoxylabda-8(17),13-dien-19-oic acid (1) and 12( S)-hydroxy-15,16-epoxylabda-8(17),13-dien-18-oic acid (2), along with one known labdane-type diterpene, 7,13 E-labdadien-15-ol (3). Their structures were determined by analysis of spectroscopic data and comparison with the data of known analogues.