New 4,5‐ seco ‐20(10→5)‐ abeo ‐Abietane Diterpenoids with Anti‐Inflammatory Activity from Isodon lophanthoides var. graciliflorus ( Benth .) H. Hara

Three new 4,5‐ seco ‐20(10→5)‐ abeo ‐abietane diterpenoids, 16‐hydroxysalvilenone ( 1 ), 15‐hydroxysalprionin ( 2 ), and 11 β ,15‐dihydroxysalprionin‐12‐one ( 3 ), and nine known abietane diterpenoids, 4 – 12 , along with one known sempervirane diterpenoid, hispidanol A ( 13 ), were isolated from the aerial parts of Isodon lophanthoides var. graciliflorus . The structures of compounds 1 – 3 were determined on the basis of spectroscopic methods including extensive analysis of NMR and mass spectroscopic data. All diterpenoids were tested for their TNF‐ α inhibitory effects on LPS‐induced RAW264.7 cells. Compound 9 (16‐acetoxyhorminone) was the most potent with an IC 50 value of 3.97±0.70 μ m .