Determination of xanthohumol in hops (Humulus lupulus L.) by nonaqueous CE

Xanthohumol (XN) is a prenylated chalcone with antimutagenic and anticancer activity from hops. A nonaqueous reverse polarity capillary electrophoretic method for the determination of XN in hop extract was developed and validated. The optimal parameters were a 64.5 cm long fused-silica capillary with 50 microm id at 25 degrees C; 30 kV negative voltage (anode at detector side of the capillary); nonaqueous buffer with 75 mM NaOH and 50 mM boric acid in methanol; hydrodynamical injection with 10 mbar for 40 s; and detection at 440 nm. XN, isoxanthohumol (IX), colupulone, adlupulone, and n-lupulone were well resolved on the electropherogram. The LOD for XN was 0.05 mg/L and RSD for peak area was below 3%. The amount of XN in different samples of hop pellets varied from 0.14 to 0.42%.