In vivo detection of the epimer metabolites of sweroside via ultra‐performance liquid chromatography time‐of‐flight mass spectrometry combined with DNPH derivatization

Abstract The metabolites of sweroside were first investigated in vivo with ultra‐performance liquid chromatography time‐of‐flight mass spectrometry (UPLC–TOF–MS) in combination with 2,4‐dinitrophenylhydrazine derivatization. In addition, the mass detection sensitivity of the major metabolites, epinaucledal and naucledal, via UPLC–TOF–MS was significantly enhanced, and the epimer metabolites were distinctly discovered from plasma following gavage of sweroside in rats. The plasma concentration of epinaucledal and naucledal was quantified via UPLC–TOF–MS in negative mode using erythrocentaurin as the internal standard. The maximum mean plasma concentrations of naucledal and epinaucledal were 75.36 ± 20.10 and 43.52 ± 15.60 ng/ml within 2 h, respectively, following gavage of sweroside at 20 mg/kg. Moreover, the area under the concentration–time curve of naucledal was three times that of epinaucledal. The metabolic process of conversion of sweroside to epinaucledal and naucledal was deduced, and the pharmacological effects of epinaucledal and naucledal will clarify the clinical efficacy of sweroside.