Metabolic map of the antiviral drug podophyllotoxin provides insights into hepatotoxicity
Creators: name: Sun, Dongxue
name: Gao, Xiaoxia
name: Wang, Qiao
name: Krausz, Kristopher W.
name: Fang, Zhongze
name: Zhang, Youbo
name: Xie, Cen
name: Gonzalez, Frank J.
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biochemistry
subject: Space Science
subject: Microbiology
subject: FOS: Biological sciences
subject: Genetics
subject: Physiology
subject: Pharmacology
subject: Biotechnology
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Science Policy
subject: Biological Sciences not elsewhere classified
subject: Cancer
subject: Inorganic Chemistry
subject: FOS: Chemical sciences
subject: Computational Biology

description: Podophyllotoxin (POD) is a natural compound with antiviral and anticancer activities. The purpose of the present study was to determine the metabolic map of POD <i>in vitro</i> and <i>in vivo</i>.Mouse and human liver microsomes were employed to identify POD metabolites <i>in vitro</i> and recombinant drug-metabolizing enzymes were used to identify the mono-oxygenase enzymes involved in POD metabolism. All <i>in vitro</i> incubation mixtures and bile samples from mice treated with POD were analysed with ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry.A total of 38metabolites, including six phase-I metabolites and 32 phase-II metabolites, of POD were identified from bile and faeces samples after oral administration, and their structures were elucidated through interpreting MS/MS fragmentation patterns.Nine metabolites, including two phase-I metabolites, five glucuronide conjugates, and two GSH conjugates were detected in both human and mouse liver microsome incubation systems and the generation of all metabolites were NADPH-dependent. The main phase-I enzymes involved in metabolism of POD <i>in vitro</i> include CYP2C9, CYP2C19, CYP3A4, and CYP3A5.POD administration to mice caused hepatic and intestinal toxicity, and the cellular damage was exacerbated when 1-aminobenzotriazole, a broad-spectrum inhibitor of CYPs, was administered with POD, indicating that POD, but not its metabolites, induced hepatic and intestinal toxicities.This study elucidated the metabolic map and provides important reference basis for the safety evaluation and rational for the clinical application of POD. Podophyllotoxin (POD) is a natural compound with antiviral and anticancer activities. The purpose of the present study was to determine the metabolic map of POD <i>in vitro</i> and <i>in vivo</i>. Mouse and human liver microsomes were employed to identify POD metabolites <i>in vitro</i> and recombinant drug-metabolizing enzymes were used to identify the mono-oxygenase enzymes involved in POD metabolism. All <i>in vitro</i> incubation mixtures and bile samples from mice treated with POD were analysed with ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry. A total of 38metabolites, including six phase-I metabolites and 32 phase-II metabolites, of POD were identified from bile and faeces samples after oral administration, and their structures were elucidated through interpreting MS/MS fragmentation patterns. Nine metabolites, including two phase-I metabolites, five glucuronide conjugates, and two GSH conjugates were detected in both human and mouse liver microsome incubation systems and the generation of all metabolites were NADPH-dependent. The main phase-I enzymes involved in metabolism of POD <i>in vitro</i> include CYP2C9, CYP2C19, CYP3A4, and CYP3A5. POD administration to mice caused hepatic and intestinal toxicity, and the cellular damage was exacerbated when 1-aminobenzotriazole, a broad-spectrum inhibitor of CYPs, was administered with POD, indicating that POD, but not its metabolites, induced hepatic and intestinal toxicities. This study elucidated the metabolic map and provides important reference basis for the safety evaluation and rational for the clinical application of POD.