Identification of hydroxylate metabolites of daidzein and its sulfate conjugates in rat urine by LC-ESI/MSⁿ

AimTo identify the hydroxylate metabolites and its sulfate conjugates of daidzein in rat urine. MethodsUrine samples from 0-24 h were collected after single ig dose of 500 mg·kg^-1 daidzein to each of six rats. The urine samples were purified by SPE column (SPE C₁₈) and analyzed with liquid chromatographic-tandem electrospray ionization ion trap mass spectrometry (LC-ESI/MSⁿ) for potential metabolites. ResultsSeveral new hydroxylate metabolites and its sulfate conjugates were found and identified in rat urine. ConclusionLC-ESI/MSⁿ is proved to be a simple, rapid, sensitive and specific technique for identification of the hydroxylate metabolites and its sulfate conjugates of daidzein in rat urine.