RESUMO
Objective:To study the serum pharmacochemistry of Aurantii Fructus （AF）， and to investigate the pharmacological material basis of AF extract in rats. Method:Rapid identification and speculation of the prototype constituents and their metabolites in vivo were carried out according to the relative retention time， accurate relative molecular mass， cleavage fragments of MS/MS and neutral loss of metabolites with ultrahigh performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry （UPLC-Q-TOF/MS） technique by comparing the differences between different samples such as AF extracts， blank plasma， and administered plasma under the same chromatographic and mass spectrometric conditions. Result:After oral administration of the AF extract， 74 transitional constituents absorbed into the blood were detected in serum， in which 49 compounds were prototype constituents and the other 25 were metabolites. The prototype constituents could be divided into dihydroflavones， polymethoxyflavonoids， limonins， coumarins and alkaloids. The identified metabolites included glucuronic acid conjugates， sulfuric acid conjugates， hydroxylated products of flavonoid glycosides and polymethoxyflavonoids， as well as the simultaneous glucuronidation and sulfation products. Conclusion:The constituents absorbed into the blood and their metabolites may be the pharmacodynamic components of AF. Among them， alkaloids， polymethoxyflavonoids and coumarins are mainly introduced into the blood in the prototype form， while naringin and neohesperidin （the index components） exert effect mainly through hydrolysis into aglycones. This work will help to further elucidate the material basis of AF.