Diterpenoids from Pinus massoniana resin and their cytotoxicity against A431 and A549 cells

Diterpenoids 1-5 and fourteen known diterpenoids 6-19 were isolated from the petroleum ether extract of Pinus massoniana resin. In vitro cytotoxicity bioassays established three of the less polar diterpenoids have strong cytotoxicity against A431 and A549 cancer cells.