Identification of metabolites of liquiritin in rats by UHPLC-Q-TOF-MS/MS: metabolic profiling and pathway comparison<i>in vitro</i>and<i>in vivo</i>

Abstract

Liquiritin (LQ), the main bioactive constituent of licorice, is a common flavoring and sweetening agent in food products and has a wide range of pharmacological properties, including antidepressant-like, neuroprotective, anti-cancer and anti-inflammatory properties. This study investigated the metabolic pathways of LQ <i>in vitro</i> (rat liver microsomes) and <i>in vivo</i> (rat model) using ultra high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). Moreover, supplementary tools such as key product ions (KPIs) were employed to search for and identify compounds. As a result, 56 <i>in vivo</i> metabolites and 15 <i>in vitro</i> metabolites were structurally characterized. Oxidation, reduction, hydrolysis, methylation, acetylation, and sulfate and glucuronide conjugation were determined to be the major metabolic pathways of LQ, and there were differences in LQ metabolism <i>in vitro</i> and <i>in vivo</i>. In addition, the <i>in vitro</i> and <i>in vivo</i> metabolic pathways were compared in this study.