Comprehensive metabolic profile of phenolic acids and flavonoids in Glechomae Herba using ultra-high-performance liquid chromatography coupled to quadrupole-time-of-flight tandem mass spectrometry with diagnostic ion filtering strategy

Glechomae Herba (GH), a traditional Chinese medicine, is commonly used for the treatment of urolithiasis and cholelithiasis based on its diuretic and cholagogic actions. However, relatively few studies have been conducted to describe this medicine's metabolites. Therefore, an ultra-high-performance liquid chromatography coupled to quadrupole time of flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) analysis with diagnostic product ions and neutral loss filtering strategy was established for the metabolic profiling profile of GH. First, an analytical method was established to detect the compounds in GH extracts and complex rat biosamples, including urine, bile, plasma and feces, after oral administration of GH extracts based on the holistic fingerprint approach utilizing UHPLC-QTOF-MS/MS. Second, the exogenously sourced ions were filtered out by the MarkerView software incorporated in Microsoft Office. Third, the diagnostic product ions and neutral loss filtering strategy were developed for the rapid identification of the metabolites. Finally, a total of 91 constituents, including 13 prototype compounds and 78 metabolites, were unambiguously or reasonably identified in rat biosamples. The metabolites were mainly eliminated by urine (82 metabolites) and bile (19 metabolites), and notably few metabolites were eliminated through feces (4 metabolites). Glucuronidation, methylation and sulfation were the primary metabolic pathways of phenolic acids and flavonoids. The primarily urine and bile elimination of metabolites may be related to the anti-urolithiasis and anti-cholelithiasis effects of GH. This work demonstrated the feasibility of an integrated strategy for the rapid identification of the metabolites after oral administration of GH extracts provided essential data for exploring the bioactive ingredients of GH in the treatment of urolithiasis and cholelithiasis. (C) 2018 Elsevier B.V. All rights reserved.