Four new irisflavones A-D (1-4) and irilin D (5) have been isolated from th
e underground parts of Iris bungei along with known isoflavones, irilins A-
B (6-7) and tlatancuayin (8). The structures of the new compounds were dete
rmined using NMR and mass spectroscopic methods and were found to be 2',5,7
-trihydroxy-3,6-dimethoxyflavone (1), 2',5-dihydroxy-3,6,7-trimethoxyflavon
e (2), 2',5,6'-trihydroxy-3,6,7-trimethoxyflavone (3), 3,3',5-trihydroxy-2'
,7-dimethoxyflavone (4), and 3',4',5,7-tetrahydroxy-6-methoxyisoflavone (5)
. The structures of irisflavones 1, 3, and 4 were confirmed by single-cryst
al X-ray diffraction studies.