Identification of Phase II Metabolites of Thiol-conjugated 6-Shogaol in Mouse Urine Using High-Performance Liquid Chromatography Tandem Mass Spectrometry

摘要

Ginger is frequently consumed as a spice and has numerous medicinal properties. Extensive research has characterized the anti-inflammatory, antioxidant, and antitumor activities of ginger. Previously, we reported the mercapturic acid pathway as a major metabolic route of [6]-shogaol in mice and the thiol conjugates of [6]-shogaol existed in the glucuronidated and sulfated forms in mouse urine. However, their structures are still unknown. In the present study, we further investigated the phase II metabolism of thiol-conjugated [6]-shogaol in mouse urine, in which we identified sixteen phase II metabolites of thiol-conjugated [6]-shogaol: 5-cysteinyl-[6]-shogaol glucuronide (>9), 5-N-acetylcysteinyl-[6]-shogaol glucuronide (>10), 5-cysteinylglycinyl-[6]-shogaol glucuronide (>11), 5-methylthio-[6]-shogaol glucuronide (>12), 5-cysteinyl-M6 glucuronide (>13 and >14), 5-cysteinyl-M6 sulfate (>15 and >16), 5-N-acetylcysteinyl-M6 glucuronide (>17 and >18), 5-cysteinylglycinyl-M6 glucuronide (>19 and >20), 5-cysteinylglycinyl-M6 sulfate (>21 and >22), and 5-methylthio-M6 glucuronide (>23 and >24) using liquid chromatography/electrospray ionization tandem mass spectrometry. The structures of these metabolites were confirmed by analyzing their MSⁿ (n =1! 4) spectra as well as comparing with the tandem mass spectra of authentic standards. To our knowledge, this is the first report involving identification of phase II urinary metabolites of [6]-shogaol in mice.