Assay of labile estrogen o-quinones, potent carcinogenic molecular species, by high performance liquid chromatography–electrospray ionization tandem mass spectrometry with phenazine derivatization
作者:Kouwa Yamashita、Akina Masuda、Yuka Hoshino、Sachiko Komatsu、Mitsuteru Numazawa
DOI:10.1016/j.jsbmb.2010.02.016
日期:2010.4
A sensitive and selective assay method for labile estrogen o-quinones, estrone (E-1)-2,3-quinone (Q), E-1-3,4-Q, estrachol (E-2)-2,3-Q and E-2-3,4-Q based on the use of phenazine (Phz) derivatization with o-phenylenediamine and high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) was described The Phz derivatives of four estrogen o-quinones were purified by solid phase extraction and analyzed by HPLC-ESI-MS/MS The protonated molecule was observed as a base peak for all Phz derivatives in their ESI-mass spectra (positive mode) In multiple reaction monitoring, the transition from [M+H](+) to m/z 231 was chosen for quantification Calibration curves for the o-quinones were obtained using standard catechol estrogens after sodium metaperiodate treatment and Phz derivatization Using this method, these four estrogen o-quinones were analyzed with the limit of quantification of 5 ng/ml in acetonitrile (MeCN)-blank matrix (1 4, v/v), respectively, on a basis of the weight of catechol estrogens Assay accuracy and precision for four estrogen o-quinones were 896-113 0% and 3 1-12.6% (5, 125 and 2000 ng/ml in MeCN-blank matrix) Applications of this method enabled to determine the catalytic activities on hydroxylation and subsequent oxidation of E-1 and E2 of Mushroom tyrosinase and rat liver microsomal fraction It was confirmed by this method that tyrosinase exhibited 2- and 4-hydroxylation and further oxidation activities for catechols in the ring-A of estrogens. Whereas rat liver microsomal fraction possessed only 2- and 4-hydroxylation activities, and further oxidation activity for catechol estrogens was low (C) 2010 Elsevier Ltd All rights reserved.