title: Determination of glabridin in human plasma by solid-phase extraction and LC-MS/MS.
abstract: Glabridin is a major flavonoid included specifically in licorice (Glycyrrhiza glabra L.), and has various physiological activities including antioxidant and anti-inflammatory effects. We have developed and validated an analytical method for determination of glabridin in human plasma by solid-phase extraction (SPE) and LC-MS/MS. Glabridin was extracted from plasma by SPE using a C8 cartridge and analyzed by LC-MS/MS using mefenamic acid as an internal standard (IS). The analyte were separated by a C18 column on LC, and monitored with a fragment ion of m/z 201 formed from a molecular ion of m/z 323 for glabridin and that of m/z 196 from m/z 240 for IS during negative ion mode with tandem MS detection. The lower limit of quantitation (LLOQ) of glabridin was 0.1 ng/mL in plasma, corresponding to 1.25 pg injected on-column. The calibration curves exhibited excellent linearity (r>0.997) between 0.1 and 50 ng/mL. Precision and accuracy were <17 and <+/-7% at LLOQ, and <11 and <+/-5% at other concentrations. Glabridin was recovered >90%, and was stable when kept at 10 degrees C for 72 h, at -20 degrees C until 12 weeks, and after three freeze-thaw cycles. This is the first report on determination of glabridin in body fluids by the selective, sensitive, and reproducible method.
authors.affiliation: Research and Development Group, Functional Food Ingredients Division, Kaneka Corporation, 1-8 Miyamae-machi, Takasago-cho, Takasago, Hyogo 676-8688, Japan. Fumiki.Aoki@kn.kaneka.co.jp
authors.forename: Fumiki
authors.initials: F
authors.lastname: Aoki
authors.forename: Kaku
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Tanaka
authors.forename: Kazue
authors.initials: K
authors.lastname: Matsuzaki
authors.forename: Naoki
authors.initials: N
authors.lastname: Arai
authors.forename: Tatsumasa
authors.initials: T
authors.lastname: Mae
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D007529:Isoflavones; D013058:Mass Spectrometry; D010636:Phenols / Q000032:analysis* / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D007529:Isoflavones; D010636:Phenols; C107601:glabridin