42261-16-5Relevant academic research and scientific papers
Assay of labile estrogen o-quinones, potent carcinogenic molecular species, by high performance liquid chromatography-electrospray ionization tandem mass spectrometry with phenazine derivatization
Yamashita, Kouwa,Masuda, Akina,Hoshino, Yuka,Komatsu, Sachiko,Numazawa, Mitsuteru
experimental part, p. 141 - 148 (2011/02/22)
A sensitive and selective assay method for labile estrogen o-quinones, estrone (E1)-2,3-quinone (Q), E1-3,4-Q, estradiol (E2)-2,3-Q and E2-3,4-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 5ng/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 89.6-113.0% and 3.1-12.6% (5, 125 and 2000ng/ml in MeCN-blank matrix). Applications of this method enabled to determine the catalytic activities on hydroxylation and subsequent oxidation of E1 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.
Preparation of Unstable Quinones in Aqueous Solution via Pulse Radiolytic One-electron Oxidation of Dihydroxybenzenes
Land, Edward J.
, p. 803 - 810 (2007/10/02)
The stoichiometry of the reactions of semiquinones resulting from the one-electron oxidation of various dihydroxybenzenes is examined.It is verified that the semiquinones of hydroquinone and catechol disproportionate completely to give p-benzoquinone and o-benzoquinone, respectively.With resorcinol, however, the corresponding semioxidised radical reaction is different, giving unstable dimers which subsequently rearrange to tetrahydroxybiphenyls.The usefulness of catechol one-electron oxidation followed by o-semiquinone disproportionation as a means of preparing biologically important unstable o-quinones is exemplified by three new examples: (1) The o-quinone of oestradiol which may have melanocytotoxic properties; (2) the o-quinone of salsolinol whose oxidative metabolites may be responsible for neuronal damage in alcoholism and (3) o-quinone of tetrahydropapaveroline whose oxidative metabolism may play a role in both alcohol addiction and Parkinson's disease.
