Diterpenoids from Rosmarinus officinalis L. and their nitric oxide inhibitory activity

One icetexane diterpenoid, demethylsalvicanol ( 1 ) and four abietane diterpenoids, sageone ( 2 ), 20‐deoxocarnosol ( 3 ), 11,12,20‐trihydroxy‐abieta‐8,11,13‐triene ( 4 ), and 7α α ‐ethoxyrosmanol ( 5 ) were isolated from the n ‐hexane layer of the leaves and twigs of Rosmarinus officinalis L. Chemical structures of compounds were identified by ESI‐MS, 1D‐, 2D‐NMR spectra and by comparison of the spectral data in the literature. Compounds 1 ‐ 5 were evaluated anti‐inflammatory activity by inhibitory NO production, LPS stimulated on RAW 264.7 cells. At a concentration of 100 μM, compound 4 exhibited inhibitory percentage of 34.7±1.8 %, meanwhile compounds 1‐3 and 5 showed cytotoxic effect. After dilution to concentration of 20 μM, except compound 1 and 2 , compounds 3‐5 did not show cytotoxic effect. Their NO inhibitory productions were ranging from 20.5±2.4 % to 26.7±1.9 %. Compounds 1 , 3 and 4 have been reported for the first time from the Rosmarinus genus.