Abstract: Twelve isoprenylated phenolic compounds including four flavonoids (1-4) and eight coumarins (5-12) were isolated from Poncirus trifoliata.They were identified as 3′′,4′′-dihydroxy-atalantoflavone (1),alatanoflavone (2),7,8-(2′′,2′′-dimethylpyrano)-5,3′,4′-trihydroxy-3-methoxylflavone (3),citflavanone (4),seselin (5),xanthyletin (6),isoangenomalin (7),nordentatin (8),clausarin (9),3-(1,1-dimethylallyl)-8-hydroxy-7-methoxycoumarin (10),anisocoumarin B (11),auraptene (12),on the basis of NMR and MS spectroscopic data,as well as by comparison of data with those reported in the literature.Compounds 2 and 4 exhibited moderated NO production inhibitions with IC₅₀ values of 17.3 and 22.8 μM,respectively.

Key words: Poncirus trifoliata, flavonoids, coumarins, structural elucidation, NO production inhibition