A new labdanic norditerpene from Pinus sylvestris.

A new labdanic norditerpene and six known labdanic diterpenes were isolated from the petroleum ether extract of the needles of Pinus sylvestris. By spectroscopic methods, the isolated compounds were determined as 15-norpinifolic acid (1), pinifolic acid (2), 4-eplimbricataloic acid (3), monomethyl pinifolate (4), 18α-acetoxylabd-8(17)-en-15-oic acid (5), 2-pentenoic acid (6) and 3β-hydroxy-8(17),E-13-labdadien-15-oic acid (7), respectively. Compound 1 showed significant anti-tumour activity.