title: Enantioseparation of isoxanthohumol in beer by hydroxypropyl-gamma-cyclodextrin-modified micellar electrokinetic chromatography.
abstract: Chiral resolution of isoxanthohumol (IX) in beer samples was performed by hydroxypropyl-gamma-cyclodextrin-modified micellar electrokinetic chromatography. The optimum running conditions were found to be 20 mM phosphate buffer (pH 7.0) containing 45 mM hydroxypropyl-gamma-cyclodextrin and 100 mM sodium dodecyl sulfate with an effective voltage of +20 kV at 20 degrees C using direct detection at 210, 295, and 370 nm. IX was detected in 12 beer samples and the total levels of (+)- and (-)-IX ranged from 0.15 to 1.4 mg/L. But the amount of xanthohumol (XN) was below the detection limit (0.017 mg/L). Each level of (-)-IX was almost the same as that of (+)-IX, suggesting that IX was a racemic mixture in these beer samples. The racemization of IX in beer could be attributed to the production of a racemic mixture from XN during boiling and to the fact that IX enantiomers were easily interconverted.
authors.affiliation: Toyama Institute of Health, 17-1 Nakataikoyama, Imizu, Toyama 939-0363, Japan. shuji.kodama@pref.toyama.lg.jp
authors.forename: Shuji
authors.initials: S
authors.lastname: Kodama
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sato
authors.forename: Kentaro
authors.initials: K
authors.lastname: Suzuki
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Yamashita
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kemmei
authors.forename: Atsushi
authors.initials: A
authors.lastname: Taga
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Hayakawa
mesh_terms: D001515:Beer / Q000032:analysis*; D002845:Chromatography / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D013237:Stereoisomerism; D044004:Xanthones / Q000302:isolation & purification*; D047408:gamma-Cyclodextrins
chemical_list: D008823:Micelles; D044004:Xanthones; D047408:gamma-Cyclodextrins; C479659:hydroxypropyl-gamma-cyclodextrin; C512910:isoxanthohumol