Inhibition of nitric oxide production in RAW 264.7 macrophages by diterpenoids from Phellinus pini.

8,14-labdadien-13-ol (1) and dehydroabietic acid (2) were isolated from the fruit body of Phellinus pini. Elucidation of their structures was based on spectroscopic methods including IR, MS, and NMR (1D and 2D). Two compounds were screened for their ability to inhibit NO production in LPS-activated RAW 264.7 cells. Compounds 1 and 2 at 30 μM and 50 μM, respectively, inhibited NO production in activated macrophages.